View allAll Photos Tagged stability
ENGLISH:
Slope tractor for driving on inclines of 45%. To ensure stability, twin wheels are attached at the rear. The tractor has a dual-circuit compressed air brake system, which acts separately on the rear and front wheels.
The 4 cylinder diesel engine has an output of 100 HP. The dead weight of the four-wheel drive tractor is 6.5 tons.
For better ventilation, the cabin roof can be opened diagonally upwards at the front.
Manufacturer: Kombinat Progress Agricultural Machinery – VEB Traktorenwerk Schönebeck, GDR.
In my 1:87 diorama the tractor is equipped with a sowing machine.
ESPAÑOL:
Tractor de pendientes para circular en pendientes de hasta el 45%. Para garantizar la estabilidad, se colocan ruedas gemelas en la parte trasera. El tractor dispone de un sistema de frenos de aire comprimido de doble circuito que actúa por separado sobre las ruedas traseras y delanteras.
El motor diésel de 4 cilindros tiene una potencia de 100 CV. El peso propio del tractor con tracción en las cuatro ruedas es de 6,5 toneladas.
Para una mejor ventilación, el techo de la cabina se puede abrir hacia arriba en la parte delantera.
Fabricante: Kombinat Progress Agriculture Machinery – VEB Traktorenwerk Schönebeck, RDA.
En mi diorama a escala 1:87, el tractor está equipado con una sembradora.
DEUTSCH:
Hangtraktor zum Befahren von Steigungen bis 45 %. Um die Stabilität zu gewährleisten, sind am Heck Zwillingsräder angebracht. Der Traktor verfügt über eine Zweikreis-Druckluftbremsanlage, die getrennt auf die Hinter- und Vorderräder wirkt.
Der 4-Zylinder-Dieselmotor hat eine Leistung von 100 PS. Das Eigengewicht des Allradschleppers beträgt 6,5 Tonnen.
Zur besseren Belüftung lässt sich das Kabinendach vorne schräg nach oben öffnen.
Hersteller: Kombinat Fortschritt Landmaschinen – VEB Traktorenwerk Schönebeck, DDR.
In meinem Diorama im Maßstab 1:87 ist der Traktor mit einer Sämaschine ausgestattet.
PHILIPPINE SEA (Aug. 12, 2020) An MH-60S Seahawk helicopter from Helicopter Sea Combat Squadron (HSC) 25 delivers cargo to the forward-deployed amphibious assault ship USS America (LHA 6) during a replenishment at sea. America, flagship of the America Expeditionary Strike Group, is operating in the U.S. 7th Fleet area of operations to enhance interoperability with allies and partners and serve as a ready response force to defend peace and stability in the Indo-Pacific region. (U.S. Navy photo by Mass Communication Specialist Seaman Matthew Cavenaile)
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From deep in the Achieves!
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Lodge Park was built as a grandstand in the Sherborne Estate near the villages of Sherborne, Aldsworth and Northleach in Gloucestershire, England). The site is owned by the National Trust and the former grandstand is designated by English Heritage as a Grade I listed building. It is England's only surviving 17th-century deer course and grandstand. In the 19th century Lodge Park was modified into a house, then a row of cottages, and then into a house again. It was bequeathed to the National Trust in 1982, and restored to its original form as a grandstand. Lodge Park is open to the public at advertised times, and the footpaths in the Sherborne Estate are available to the public at all times. In the early 1630s John 'Crump' Dutton created a deer course on his Sherborne Estate; this consisted of a park for containing the deer, a mile-long walled enclosure for the chase, and, overlooking the finish, a grandstand. His grandfather, Thomas Dutton, was descended from the Dutton family of Dutton, Cheshire, and had bought the manor of Sherborne in 1551. As originally constructed, the grandstand consisted of two storeys with a flat roof and a basement. At the entrance was a portico with a balcony, and the basement contained the kitchens. At the back of the building was a range containing the staircases linking the floors. The ground floor was the entrance hall for welcoming guests, and the first floor consisted of the Great Room where the guests were entertained. The deer coursing could be observed from the flat roof or from the balcony over the portico. During the 1720s the building was remodelled and refurnished by Sir John Dutton, 2nd Baronet. New stone floors were added, a new plasterwork ceiling was added to the Great Room, and new furniture was designed. Dutton employed Charles Bridgeman to redesign the landscaping. Jeffrey Haworth is of the opinion that the new interiors and some of the furniture was designed by William Kent. There were then few changes until the early 19th century when the building was modified to make it into a house. The staircase range and the chimney piece from the Great Room were removed; the latter was incorporated in the rebuilding of Sherborne House to the design of Lewis Wyatt. The removal of the staircase range adversely affected the stability of the house. A pitched roof was installed in place of the original flat roof, lowering the ceiling of the former Great Room. In the middle of the 19th century the interior of the building was gutted and it was converted into a row of cottages; this further impaired the stability of the building. Between 1898 and 1902 the building was converted into a dower house for Emily, the wife of the 4th Baron Sherborne. The rear wing was rebuilt in a different form. The first floor was made into a bedroom with an en suite bathroom. The dining room was on the ground floor, with a lounge and a staircase in the newly built rear wing; the staircase led to a drawing room on the first floor. However Lady Sherborne died in 1905 before her husband, and it is unlikely that she ever occupied the house. Further alterations were made in 1938, when the house was tenanted, and again in the 1950s, when Charles, the 7th Baron, and his wife moved into the house. Charles died in 1982 and bequeathed the house and the estate to the National Trust. When the National Trust acquired the property the house was in a poor condition; the external walls were moving and the chimney stacks were collapsing. The interior consisted of "a jumble of small-scale modern rooms and corridors". Howard Colvin had discovered a 1634 description of the building. Further information was found in the Sherborne Archive in the Gloucester Record Office. Essential repairs were carried out, and archaeological investigations revealed more evidence about the building's original form and its subsequent alterations. It was decided to restore the building to a condition close to its original form. As Clive Aslet states, the building "is bursting with architecture". A description written in 1634 suggests that the design was inspired by Inigo Jones' Banqueting House in Whitehall, London. At one time it was thought that it had been designed by Jones, but this is incorrect. The citation in Images of England states that it was probably designed by John Webb and built by Valentine Strong of Taynton. The building is constructed in ashlar stone, with rusticated quoins and a moulded plinth. Its main part has a rectangular plan in two storeys, with a flat lead roof and an extension to the rear. The east face forms the entrance front. It is symmetrical in five bays with a protruding three-bay single-storey portico. The portico has three round arches on columns and is surmounted by a balustrade. The central doorway has a round arch and on each side are two mullioned and transomed windows. On the first floor is a central doorway with a mullioned window above and arched niches in each side. The other bays contain mullioned and transomed windows. There are string courses between the storeys and over the upper storey. Over the lateral two windows on the ground floor are curved tympani, and over each bay in the upper storey is a broken tympanum. Each of these tympani contains a sculpted human head. A balustrade runs around the top of the roof, and at its rear are six joined chimneys. The entrance hall contains two original arches. One of these includes a fireplace, the other leads to the staircase. The National Trust has inserted a panelled wall on the left. The staircase has been rebuilt by the National Trust in a stairwell measuring 18 feet (5 m) by 18 feet (5 m), and its oak balusters have been copied from those at Cornbury Park in Oxfordshire. The Great Room on the first floor has been restored in an attempt to link with its original design, including its classical ordering with a dado, pilasters and entablature. The walls would have been hung with tapestry, but this has been replaced with family portraits that originally hung in Sherborne House. The floor has been reconstructed, using chestnut boards measuring 49 feet (15 m) from the Welsh border. The chimneypiece has been reconstructed by masons from the Hereford Cathedral workshop.
PACIFIC OCEAN (Jan. 7, 2020) Gunner’s Mate 2nd Class Austin Perry instructs Logistics Specialist 3rd Class Annette Hertz as she fires a .50-caliber machine gun during crew-served weapons training aboard the Ticonderoga-class guided-missile cruiser USS Chancellorsville (CG 62). Chancellorsville is forward-deployed to the U.S. 7th Fleet area of operations in support of security and stability in the Indo-Pacific region. (U.S. Navy photo by Mass Communication Specialist 1st Class Jeremy Graham)
WATERS OFF THE KOREAN PENINSULA (Oct. 11, 2018) The Ticonderoga class cruiser USS Chancellorsville (CG 62) steams alongside the forward-deployed aircraft carrier USS Ronald Reagan (CVN 76) before a pass-in-review as part of the Republic of Korea (ROK) International Fleet Review (IFR) 2018. IFR 2018 is hosted by the Republic of Korea Navy to help enhance mutual trust and confidence with navies from around the world. Ronald Reagan is forward-deployed to the U.S. 7th Fleet area of operations in support of security and stability in the Indo-Pacific region. (U.S. Navy photo by Mass Communication Specialist 2nd Class Brandon Martin)
Skara Brae is a stone-built Neolithic Settlement located on the Bay of Skaill on the West Coast of Mainland the largest island in the Orkney archipelago of Scotland. It's older than Stone Henge and the Great Pyramids of Egypt - occupied from roughly 3,100BC to about 2,500BC and is Europe's most complete Neolithic Village.
Around 2,500BC after the climate changed becoming much colder and wetter it is believed the settlement was rapidly abandoned as they seem to have been taken by surprise having fled leaving their prized possessions - such as necklaces etc.
8 clustered houses remain and used 'Earth Sheltering' - being sunk into the ground providing not only stability but also acting as insulation against Orkney's harsh climate. each mesures roughly 40 sq metres (430 sq feet) with a large square room containing a hearth used for heating and cooking.
House No. 8 (pictured here) is 'Unique' having no storage boxes or dresser and is divided into small cubicles and is a stand alone structure above ground with walls over 2 metres (6.5 feet) thick and has a porch protecting its entrance. Fragments of stone, bone and antler were excavated suggesting the house may have been used to make tools such as bone needles or flint axes. The presence of hot damaged volcanic rocks and what appears to be a flue support this interpretation.
The site was first discovered in 1850, when a severe storm stripped the earth away that had previously concealed it. Thereafter, amateur excavation was started. 4 houses were fully excavated but worked ceased in 1868.
In 1924, another storm swept away part of one house and it was then decided to properly secure and investigate the site. The settlement originally was much farther from the sea than today and many unknown structures have been lost to sea erosion. It is now fully protected by a seal wall.
A fascinating place well worth visiting!
PHILIPPINE SEA (July 21, 2020) From left, HMAS Arunta (FFH 151), HMAS Hobart (DDG 39), USS Mustin (DDG 89), HMAS Canberra (L02), USS Ronald Reagan (CVN 76), HMAS Sirius (O 266), USS Antietam (CG 54), JS Teruzuki (DD 116) and HMAS Stuart (FFH 153) steam in formation during a trilateral exercise. Trilateral exercises between the JMSDF, ADF and U.S. Navy support shared goals of peace and stability while enhancing regional security and the right of all nations to trade, communicate, and choose their destiny in a free and open Indo-Pacific region. (U.S. Navy photo by Mass Communication Specialist 2nd Class Codie L. Soule)
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Abandoned Abused Street Dogs.
Nikon D300 DX Camera.
Nikkor 70-300 VR Lens.
Back Story ........
This is just a follow up showing a blind Mr Brown following my scent while leaning into the wall for guidance and stability.
I'm up on the 3rd floor [roof] shooting down at Mr B on the 2nd floor.
We finally met up in front of the Buddha along with Mama.
Inserted photo tells the whole story........
Thank You.
Jon&Crew.
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www.gofundme.com/saving-thai-temple-
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Elakala Falls #1 on Shays Run, Blackwater Falls State Park, Tucker County, West Virginia.
Returning home after spending some time with my mother in Ohio last week, we spent Sunday and Monday nights at Blackwater Lodge in Blackwater Falls State Park near Davis, West Virginia. This waterfall is a short distance from the lodge, and it's not too difficult to get down to stream level, but I confess the tripod was used as a walking stick to provide improved stability, especially where there was mud or moss.
One motivation for returning to this area at this time was the opportunity to see Flickr friend Randall Sanger, who is resident photographer this month at Canaan Valley National Wildlife Refuge, and to meet his wife, Melissa. Ruth Ann -- a native West Virginian -- and I both like the area very much, and we thoroughly enjoyed visiting with Randy and Melissa. For those familiar with Randy's photography, it may seem somewhat odd that I was not shooting with Randy when this photo was taken. However, I did benefit from his suggestion of shooting this fall, the best time of day to go, and the degree of underexposure likely to work best. I underexpose most shots about 1/3 of a stop, flowers generally at least 2/3 of a stop, and certain scenes such as this a stop or so. Randy suggested more underexposure, and this was shot at -1.67. He also suggested using a neutral density filter along with a polarizer, and I fully intended to follow this advice; Saturday evening I cleaned the filters and attached them to the 17-40 lens. But as I told Randy afterwards, in old-man fashion, I then put the lens back in its bag and left it, going to shot the falls with the 24-105 lens attached to the camera; a polarizer was in place, but no ND filter. Going back to the room for the other lens and filters would have been simple enough, but before I realized what lens I was using, I was getting results I liked.
EAST CHINA SEA (Sept. 17, 2022) Aviation Boatswain’s Mate (Handling) 3rd Class Joseph Barrios, from Miami, assigned to forward-deployed amphibious assault carrier USS America (LHA 6), signals an MV-22B Osprey tiltrotor aircraft from the “Flying Tigers” of Marine Medium Tiltrotor Squadron (VMM) 262, to stand by on America’s flight deck during flight operations in the East China Sea. America, lead ship of America Amphibious Ready Group, is operating in U.S. 7th Fleet to enhance interoperability with allies and partners and serve as a ready-response force to defend peace and stability in the Indo-Pacific region. (U.S. Navy photo by Mass Communication Specialist 3rd Class Amy Mullins)
TIMOR SEA (May 13, 2022) Landing Craft Mechanized (LCM) 8, assigned to 36 Water Transport Troop, 10 Force Support Battalion, Australian Army, conducts amphibious operations with U.S. Navy forward-deployed amphibious dock landing ship USS Ashland (LSD 48) in support of Operation Croc Response. Ashland, part of the America Expeditionary Strike Group is operating in U.S. 7th Fleet to enhance interoperability with allies and partners, serving as a ready-response force to defend peace and stability in the Indo-Pacific region. (U.S. Navy photo by Ensign Juliana LaFrance)
PACIFIC OCEAN (Jan. 17, 2019 The aircraft carrier USS John C. Stennis (CVN 74) receives supplies from USNS Cesar Chavez (T-AKE 14) during a replenishment-at-sea in. The John C. Stennis Carrier Strike Group is deployed to the U.S. 7th Fleet area of operations in support of security and stability in the Indo-Pacific region. (U.S. Navy photo by Mass Communication Specialist 1st Class Bryan Niegel)
Nature's magnificent structure, the tree combines two elements to achieve strength and balance. Trees, have a single, superbly engineered material, wood and are ingeniously designed to combine strength and flexibility. They can respond to their environment and change their design accordingly. This allows them to support their canopy of leaves using a bare minimum of structural material.
We are no different, our limbs hold us, or we find a way if they fail, our bodies and minds change through time, supporting our thoughts, ideas and dreams. We too have a persistent need to grow and endevour to remain stable, throughout of lives. Keep rooted, use creativity for your own pleasure and grow.
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PHILIPPINE SEA (Sept. 17, 2020) Sailors assigned to the forward-deployed amphibious assault ship USS America (LHA 6) conduct flight operations with the 31st Marine Expeditionary Unit (MEU), Marine Medium Tiltrotor Squadron (VMM) 262 (Reinforced). America, lead ship of the America Expeditionary Strike Group, is operating in the U.S. 7th Fleet area of responsibility to enhance interoperability with allies and partners and serve as a ready response force to maintain security and stability in the Indo-Pacific region. (U.S. Navy photo by Mass Communication Specialist Seaman Matthew Cavenaile)
I captured this shot with my Pixel 6 phone but without a tripod. It was about 7 AM and I was walking to my office at the time, which is the building on the right. I think the moon would have been sharper if I had more stability. . . I will probably try this shot again with a tripod and my DSLR and also expose for the moon then adjust the overall light in Adobe Lightroom.
PHILIPPINE SEA (Aug. 12, 2020) The forward-deployed amphibious assault ship USS America (LHA 6) conducts a replenishment at sea with the dry cargo and ammunition ship USNS Cesar Chavez (T-AKE 14). America, flagship of the America Expeditionary Strike Group, is operating in the U.S. 7th Fleet area of operations to enhance interoperability with allies and partners and serve as a ready response force to defend peace and stability in the Indo-Pacific region. (U.S. Navy photo by Mass Communication Specialist Seaman Matthew Cavenaile)
SOUTH CHINA SEA (Sept. 6, 2020) As seen from the amphibious dock landing ship USS Germantown (LSD 42), the amphibious transport dock ship USS New Orleans (LPD 18) sails in the South China Sea during a visit, board, search and seizure exercise aboard Germantown. Germantown, part of the America Amphibious Ready Group assigned to Amphibious Squadron 11, along with the 31st Marine Expeditionary Unit, is operating in the U.S. 7th Fleet area of responsibility to enhance interoperability with allies and partners, and serve as a ready response force to defend peace and stability in the Indo-Pacific region. (U.S. Navy photo by Mass Communication Specialist 2nd Class Taylor DiMartino)
See more photos of this, and the Wikipedia article.
Details, quoting from Smithsonian National Air and Space Museum | Lockheed P-38J-10-LO Lightning
In the P-38 Lockheed engineer Clarence "Kelly" Johnson and his team of designers created one of the most successful twin-engine fighters ever flown by any nation. From 1942 to 1945, U. S. Army Air Forces pilots flew P-38s over Europe, the Mediterranean, and the Pacific, and from the frozen Aleutian Islands to the sun-baked deserts of North Africa. Lightning pilots in the Pacific theater downed more Japanese aircraft than pilots flying any other Allied warplane.
Maj. Richard I. Bong, America's leading fighter ace, flew this P-38J-10-LO on April 16, 1945, at Wright Field, Ohio, to evaluate an experimental method of interconnecting the movement of the throttle and propeller control levers. However, his right engine exploded in flight before he could conduct the experiment.
Transferred from the United States Air Force.
Manufacturer:
Date:
1943
Country of Origin:
United States of America
Dimensions:
Overall: 390 x 1170cm, 6345kg, 1580cm (12ft 9 9/16in. x 38ft 4 5/8in., 13988.2lb., 51ft 10 1/16in.)
Materials:
All-metal
Physical Description:
Twin-tail boom and twin-engine fighter; tricycle landing gear.
Long Description:
From 1942 to 1945, the thunder of P-38 Lightnings was heard around the world. U. S. Army pilots flew the P-38 over Europe, the Mediterranean, and the Pacific; from the frozen Aleutian Islands to the sun-baked deserts of North Africa. Measured by success in combat, Lockheed engineer Clarence "Kelly" Johnson and a team of designers created the most successful twin-engine fighter ever flown by any nation. In the Pacific Theater, Lightning pilots downed more Japanese aircraft than pilots flying any other Army Air Forces warplane.
Johnson and his team conceived this twin-engine, single-pilot fighter airplane in 1936 and the Army Air Corps authorized the firm to build it in June 1937. Lockheed finished constructing the prototype XP-38 and delivered it to the Air Corps on New Year's Day, 1939. Air Corps test pilot and P-38 project officer, Lt. Benjamin S. Kelsey, first flew the aircraft on January 27. Losing this prototype in a crash at Mitchel Field, New York, with Kelsey at the controls, did not deter the Air Corps from ordering 13 YP-38s for service testing on April 27. Kelsey survived the crash and remained an important part of the Lightning program. Before the airplane could be declared ready for combat, Lockheed had to block the effects of high-speed aerodynamic compressibility and tail buffeting, and solve other problems discovered during the service tests.
The most vexing difficulty was the loss of control in a dive caused by aerodynamic compressibility. During late spring 1941, Air Corps Major Signa A. Gilke encountered serious trouble while diving his Lightning at high-speed from an altitude of 9,120 m (30,000 ft). When he reached an indicated airspeed of about 515 kph (320 mph), the airplane's tail began to shake violently and the nose dropped until the dive was almost vertical. Signa recovered and landed safely and the tail buffet problem was soon resolved after Lockheed installed new fillets to improve airflow where the cockpit gondola joined the wing center section. Seventeen months passed before engineers began to determine what caused the Lightning's nose to drop. They tested a scale model P-38 in the Ames Laboratory wind tunnel operated by the NACA (National Advisory Committee for Aeronautics) and found that shock waves formed when airflow over the wing leading edges reached transonic speeds. The nose drop and loss of control was never fully remedied but Lockheed installed dive recovery flaps under each wing in 1944. These devices slowed the P-38 enough to allow the pilot to maintain control when diving at high-speed.
Just as the development of the North American P-51 Mustang, Republic P-47 Thunderbolt, and the Vought F4U Corsair (see NASM collection for these aircraft) pushed the limits of aircraft performance into unexplored territory, so too did P-38 development. The type of aircraft envisioned by the Lockheed design team and Air Corps strategists in 1937 did not appear until June 1944. This protracted shakedown period mirrors the tribulations suffered by Vought in sorting out the many technical problems that kept F4U Corsairs off U. S. Navy carrier decks until the end of 1944.
Lockheed's efforts to trouble-shoot various problems with the design also delayed high-rate, mass production. When Japan attacked Pearl Harbor, the company had delivered only 69 Lightnings to the Army. Production steadily increased and at its peak in 1944, 22 sub-contractors built various Lightning components and shipped them to Burbank, California, for final assembly. Consolidated-Vultee (Convair) subcontracted to build the wing center section and the firm later became prime manufacturer for 2,000 P-38Ls but that company's Nashville plant completed only 113 examples of this Lightning model before war's end. Lockheed and Convair finished 10,038 P-38 aircraft including 500 photo-reconnaissance models. They built more L models, 3,923, than any other version.
To ease control and improve stability, particularly at low speeds, Lockheed equipped all Lightnings, except a batch ordered by Britain, with propellers that counter-rotated. The propeller to the pilot's left turned counter-clockwise and the propeller to his right turned clockwise, so that one propeller countered the torque and airflow effects generated by the other. The airplane also performed well at high speeds and the definitive P-38L model could make better than 676 kph (420 mph) between 7,600 and 9,120 m (25,000 and 30,000 ft). The design was versatile enough to carry various combinations of bombs, air-to-ground rockets, and external fuel tanks. The multi-engine configuration reduced the Lightning loss-rate to anti-aircraft gunfire during ground attack missions. Single-engine airplanes equipped with power plants cooled by pressurized liquid, such as the North American P-51 Mustang (see NASM collection), were particularly vulnerable. Even a small nick in one coolant line could cause the engine to seize in a matter of minutes.
The first P-38s to reach the Pacific combat theater arrived on April 4, 1942, when a version of the Lightning that carried reconnaissance cameras (designated the F-4), joined the 8th Photographic Squadron based in Australia. This unit launched the first P-38 combat missions over New Guinea and New Britain during April. By May 29, the first 25 P-38s had arrived in Anchorage, Alaska. On August 9, pilots of the 343rd Fighter Group, Eleventh Air Force, flying the P-38E, shot down a pair of Japanese flying boats.
Back in the United States, Army Air Forces leaders tried to control a rumor that Lightnings killed their own pilots. On August 10, 1942, Col. Arthur I. Ennis, Chief of U. S. Army Air Forces Public Relations in Washington, told a fellow officer "… Here's what the 4th Fighter [training] Command is up against… common rumor out there that the whole West Coast was filled with headless bodies of men who jumped out of P-38s and had their heads cut off by the propellers." Novice Lightning pilots unfamiliar with the correct bailout procedures actually had more to fear from the twin-boom tail, if an emergency dictated taking to the parachute but properly executed, Lightning bailouts were as safe as parachuting from any other high-performance fighter of the day. Misinformation and wild speculation about many new aircraft was rampant during the early War period.
Along with U. S. Navy Grumman F4F Wildcats (see NASM collection) and Curtiss P-40 Warhawks (see NASM collection), Lightnings were the first American fighter airplanes capable of consistently defeating Japanese fighter aircraft. On November 18, men of the 339th Fighter Squadron became the first Lightning pilots to attack Japanese fighters. Flying from Henderson Field on Guadalcanal, they claimed three during a mission to escort Boeing B-17 Flying Fortress bombers (see NASM collection).
On April 18, 1943, fourteen P-38 pilots from the 70th and the 339th Fighter Squadrons, 347th Fighter Group, accomplished one of the most important Lightning missions of the war. American ULTRA cryptanalysts had decoded Japanese messages that revealed the timetable for a visit to the front by the commander of the Imperial Japanese Navy, Admiral Isoroku Yamamoto. This charismatic leader had crafted the plan to attack Pearl Harbor and Allied strategists believed his loss would severely cripple Japanese morale. The P-38 pilots flew 700 km (435 miles) at heights from 3-15 m (10-50 feet) above the ocean to avoid detection. Over the coast of Bougainville, they intercepted a formation of two Mitsubishi G4M BETTY bombers (see NASM collection) carrying the Admiral and his staff, and six Mitsubishi A6M Zero fighters (see NASM collection) providing escort. The Lightning pilots downed both bombers but lost Lt. Ray Hine to a Zero.
In Europe, the first Americans to down a Luftwaffe aircraft were Lt. Elza E. Shahan flying a 27th Fighter Squadron P-38E, and Lt. J. K. Shaffer flying a Curtiss P-40 (see NASM collection) in the 33rd Fighter Squadron. The two flyers shared the destruction of a Focke-Wulf Fw 200C-3 Condor maritime strike aircraft over Iceland on August 14, 1942. Later that month, the 1st fighter group accepted Lightnings and began combat operations from bases in England but this unit soon moved to fight in North Africa. More than a year passed before the P-38 reappeared over Western Europe. While the Lightning was absent, U. S. Army Air Forces strategists had relearned a painful lesson: unescorted bombers cannot operate successfully in the face of determined opposition from enemy fighters. When P-38s returned to England, the primary mission had become long-range bomber escort at ranges of about 805 kms (500 miles) and at altitudes above 6,080 m (20,000 ft).
On October 15, 1943, P-38H pilots in the 55th Fighter Group flew their first combat mission over Europe at a time when the need for long-range escorts was acute. Just the day before, German fighter pilots had destroyed 60 of 291 Eighth Air Force B-17 Flying Fortresses (see NASM collection) during a mission to bomb five ball-bearing plants at Schweinfurt, Germany. No air force could sustain a loss-rate of nearly 20 percent for more than a few missions but these targets lay well beyond the range of available escort fighters (Republic P-47 Thunderbolt, see NASM collection). American war planners hoped the long-range capabilities of the P-38 Lightning could halt this deadly trend, but the very high and very cold environment peculiar to the European air war caused severe power plant and cockpit heating difficulties for the Lightning pilots. The long-range escort problem was not completely solved until the North American P-51 Mustang (see NASM collection) began to arrive in large numbers early in 1944.
Poor cockpit heating in the H and J model Lightnings made flying and fighting at altitudes that frequently approached 12,320 m (40,000 ft) nearly impossible. This was a fundamental design flaw that Kelly Johnson and his team never anticipated when they designed the airplane six years earlier. In his seminal work on the Allison V-1710 engine, Daniel Whitney analyzed in detail other factors that made the P-38 a disappointing airplane in combat over Western Europe.
• Many new and inexperienced pilots arrived in England during December 1943, along with the new J model P-38 Lightning.
• J model rated at 1,600 horsepower vs. 1,425 for earlier H model Lightnings. This power setting required better maintenance between flights. It appears this work was not done in many cases.
• During stateside training, Lightning pilots were taught to fly at high rpm settings and low engine manifold pressure during cruise flight. This was very hard on the engines, and not in keeping with technical directives issued by Allison and Lockheed.
• The quality of fuel in England may have been poor, TEL (tetraethyl lead) fuel additive appeared to condense inside engine induction manifolds, causing detonation (destructive explosion of fuel mixture rather than controlled burning).
• Improved turbo supercharger intercoolers appeared on the J model P-38. These devices greatly reduced manifold temperatures but this encouraged TEL condensation in manifolds during cruise flight and increased spark plug fouling.
Using water injection to minimize detonation might have reduced these engine problems. Both the Republic P-47 Thunderbolt and the North American P-51 Mustang (see NASM collection) were fitted with water injection systems but not the P-38. Lightning pilots continued to fly, despite these handicaps.
During November 1942, two all-Lightning fighter groups, the 1st and the 14th, began operating in North Africa. In the Mediterranean Theater, P-38 pilots flew more sorties than Allied pilots flying any other type of fighter. They claimed 608 enemy a/c destroyed in the air, 123 probably destroyed and 343 damaged, against the loss of 131 Lightnings.
In the war against Japan, the P-38 truly excelled. Combat rarely occurred above 6,080 m (20,000 ft) and the engine and cockpit comfort problems common in Europe never plagued pilots in the Pacific Theater. The Lightning's excellent range was used to full advantage above the vast expanses of water. In early 1945, Lightning pilots of the 12th Fighter Squadron, 18th Fighter Group, flew a mission that lasted 10 ½ hours and covered more than 3,220 km (2,000 miles). In August, P-38 pilots established the world's long-distance record for a World War II combat fighter when they flew from the Philippines to the Netherlands East Indies, a distance of 3,703 km (2,300 miles). During early 1944, Lightning pilots in the 475th Fighter Group began the 'race of aces.' By March, Lieutenant Colonel Thomas J. Lynch had scored 21 victories before he fell to antiaircraft gunfire while strafing enemy ships. Major Thomas B. McGuire downed 38 Japanese aircraft before he was killed when his P-38 crashed at low altitude in early January 1945. Major Richard I. Bong became America's highest scoring fighter ace (40 victories) but died in the crash of a Lockheed P-80 (see NASM collection) on August 6, 1945.
Museum records show that Lockheed assigned the construction number 422-2273 to the National Air and Space Museum's P-38. The Army Air Forces accepted this Lightning as a P-38J-l0-LO on November 6, 1943, and the service identified the airplane with the serial number 42-67762. Recent investigations conducted by a team of specialists at the Paul E. Garber Facility, and Herb Brownstein, a volunteer in the Aeronautics Division at the National Air and Space Museum, have revealed many hitherto unknown aspects to the history of this aircraft.
Brownstein examined NASM files and documents at the National Archives. He discovered that a few days after the Army Air Forces (AAF) accepted this airplane, the Engineering Division at Wright Field in Dayton, Ohio, granted Lockheed permission to convert this P-38 into a two-seat trainer. The firm added a seat behind the pilot to accommodate an instructor who would train civilian pilots in instrument flying techniques. Once trained, these test pilots evaluated new Lightnings fresh off the assembly line.
In a teletype sent by the Engineering Division on March 2, 1944, Brownstein also discovered that this P-38 was released to Colonel Benjamin S. Kelsey from March 3 to April 10, 1944, to conduct special tests. This action was confirmed the following day in a cable from the War Department. This same pilot, then a Lieutenant, flew the XP-38 across the United States in 1939 and survived the crash that destroyed this Lightning at Mitchel Field, New York. In early 1944, Kelsey was assigned to the Eighth Air Force in England and he apparently traveled to the Lockheed factory at Burbank to pick up the P-38. Further information about these tests and Kelsey's involvement remain an intriguing question.
One of Brownstein's most important discoveries was a small file rich with information about the NASM Lightning. This file contained a cryptic reference to a "Major Bong" who flew the NASM P-38 on April 16, 1945, at Wright Field. Bong had planned to fly for an hour to evaluate an experimental method of interconnecting the movement of the throttle and propeller control levers. His flight ended after twenty-minutes when "the right engine blew up before I had a chance [to conduct the test]." The curator at the Richard I. Bong Heritage Center confirmed that America's highest scoring ace made this flight in the NASM P-38 Lightning.
Working in Building 10 at the Paul E. Garber Facility, Rob Mawhinney, Dave Wilson, Wil Lee, Bob Weihrauch, Jim Purton, and Heather Hutton spent several months during the spring and summer of 2001 carefully disassembling, inspecting, and cleaning the NASM Lightning. They found every hardware modification consistent with a model J-25 airplane, not the model J-10 painted in the data block beneath the artifact's left nose. This fact dovetails perfectly with knowledge uncovered by Brownstein. On April 10, the Engineering Division again cabled Lockheed asking the company to prepare 42-67762 for transfer to Wright Field "in standard configuration." The standard P-38 configuration at that time was the P-38J-25. The work took several weeks and the fighter does not appear on Wright Field records until May 15, 1944. On June 9, the Flight Test Section at Wright Field released the fighter for flight trials aimed at collecting pilot comments on how the airplane handled.
Wright Field's Aeromedical Laboratory was the next organization involved with this P-38. That unit installed a kit on July 26 that probably measured the force required to move the control wheel left and right to actuate the power-boosted ailerons installed in all Lightnings beginning with version J-25. From August 12-16, the Power Plant Laboratory carried out tests to measure the hydraulic pump temperatures on this Lightning. Then beginning September 16 and lasting about ten days, the Bombing Branch, Armament Laboratory, tested type R-3 fragmentation bomb racks. The work appears to have ended early in December. On June 20, 1945, the AAF Aircraft Distribution Office asked that the Air Technical Service Command transfer the Lightning from Wright Field to Altus Air Force Base, Oklahoma, a temporary holding area for Air Force museum aircraft. The P-38 arrived at the Oklahoma City Air Depot on June 27, 1945, and mechanics prepared the fighter for flyable storage.
Airplane Flight Reports for this Lightning also describe the following activities and movements:
6-21-45 Wright Field, Ohio, 5.15 hours of flying.
6-22-45Wright Field, Ohio, .35 minutes of flying by Lt. Col. Wendel [?] J. Kelley and P. Shannon.
6-25-45Altus, Oklahoma, .55 hours flown, pilot P. Shannon.
6-27-45Altus, Oklahoma, #2 engine changed, 1.05 hours flown by Air Corps F/O Ralph F. Coady.
10-5-45 OCATSC-GCAAF (Garden City Army Air Field, Garden City, Kansas), guns removed and ballast added.
10-8-45Adams Field, Little Rock, Arkansas.
10-9-45Nashville, Tennessee,
5-28-46Freeman Field, Indiana, maintenance check by Air Corps Capt. H. M. Chadhowere [sp]?
7-24-46Freeman Field, Indiana, 1 hour local flight by 1st Lt. Charles C. Heckel.
7-31-46 Freeman Field, Indiana, 4120th AAF Base Unit, ferry flight to Orchard Place [Illinois] by 1st Lt. Charles C. Heckel.
On August 5, 1946, the AAF moved the aircraft to another storage site at the former Consolidated B-24 bomber assembly plant at Park Ridge, Illinois. A short time later, the AAF transferred custody of the Lightning and more than sixty other World War II-era airplanes to the Smithsonian National Air Museum. During the early 1950s, the Air Force moved these airplanes from Park Ridge to the Smithsonian storage site at Suitland, Maryland.
• • •
Quoting from Wikipedia | Lockheed P-38 Lightning:
The Lockheed P-38 Lightning was a World War II American fighter aircraft built by Lockheed. Developed to a United States Army Air Corps requirement, the P-38 had distinctive twin booms and a single, central nacelle containing the cockpit and armament. Named "fork-tailed devil" by the Luftwaffe and "two planes, one pilot" by the Japanese, the P-38 was used in a number of roles, including dive bombing, level bombing, ground-attack, photo reconnaissance missions, and extensively as a long-range escort fighter when equipped with drop tanks under its wings.
The P-38 was used most successfully in the Pacific Theater of Operations and the China-Burma-India Theater of Operations as the mount of America's top aces, Richard Bong (40 victories) and Thomas McGuire (38 victories). In the South West Pacific theater, the P-38 was the primary long-range fighter of United States Army Air Forces until the appearance of large numbers of P-51D Mustangs toward the end of the war. The P-38 was unusually quiet for a fighter, the exhaust muffled by the turbo-superchargers. It was extremely forgiving, and could be mishandled in many ways, but the rate of roll was too slow for it to excel as a dogfighter. The P-38 was the only American fighter aircraft in production throughout American involvement in the war, from Pearl Harbor to Victory over Japan Day.
Variants: Lightning in maturity: P-38J
The P-38J was introduced in August 1943. The turbo-supercharger intercooler system on previous variants had been housed in the leading edges of the wings and had proven vulnerable to combat damage and could burst if the wrong series of controls were mistakenly activated. In the P-38J model, the streamlined engine nacelles of previous Lightnings were changed to fit the intercooler radiator between the oil coolers, forming a "chin" that visually distinguished the J model from its predecessors. While the P-38J used the same V-1710-89/91 engines as the H model, the new core-type intercooler more efficiently lowered intake manifold temperatures and permitted a substantial increase in rated power. The leading edge of the outer wing was fitted with 55 gal (208 l) fuel tanks, filling the space formerly occupied by intercooler tunnels, but these were omitted on early P-38J blocks due to limited availability.
The final 210 J models, designated P-38J-25-LO, alleviated the compressibility problem through the addition of a set of electrically-actuated dive recovery flaps just outboard of the engines on the bottom centerline of the wings. With these improvements, a USAAF pilot reported a dive speed of almost 600 mph (970 km/h), although the indicated air speed was later corrected for compressibility error, and the actual dive speed was lower. Lockheed manufactured over 200 retrofit modification kits to be installed on P-38J-10-LO and J-20-LO already in Europe, but the USAAF C-54 carrying them was shot down by an RAF pilot who mistook the Douglas transport for a German Focke-Wulf Condor. Unfortunately the loss of the kits came during Lockheed test pilot Tony LeVier's four-month morale-boosting tour of P-38 bases. Flying a new Lightning named "Snafuperman" modified to full P-38J-25-LO specs at Lockheed's modification center near Belfast, LeVier captured the pilots' full attention by routinely performing maneuvers during March 1944 that common Eighth Air Force wisdom held to be suicidal. It proved too little too late because the decision had already been made to re-equip with Mustangs.
The P-38J-25-LO production block also introduced hydraulically-boosted ailerons, one of the first times such a system was fitted to a fighter. This significantly improved the Lightning's rate of roll and reduced control forces for the pilot. This production block and the following P-38L model are considered the definitive Lightnings, and Lockheed ramped up production, working with subcontractors across the country to produce hundreds of Lightnings each month.
Noted P-38 pilots
Richard Bong and Thomas McGuire
The American ace of aces and his closest competitor both flew Lightnings as they tallied 40 and 38 victories respectively. Majors Richard I. "Dick" Bong and Thomas J. "Tommy" McGuire of the USAAF competed for the top position. Both men were awarded the Medal of Honor.
McGuire was killed in air combat in January 1945 over the Philippines, after racking up 38 confirmed kills, making him the second-ranking American ace. Bong was rotated back to the United States as America's ace of aces, after making 40 kills, becoming a test pilot. He was killed on 6 August 1945, the day the atomic bomb was dropped on Japan, when his P-80 Shooting Star jet fighter flamed out on takeoff.
Charles Lindbergh
The famed aviator Charles Lindbergh toured the South Pacific as a civilian contractor for United Aircraft Corporation, comparing and evaluating performance of single- and twin-engined fighters for Vought. He worked to improve range and load limits of the F4U Corsair, flying both routine and combat strafing missions in Corsairs alongside Marine pilots. In Hollandia, he attached himself to the 475th FG flying P-38s so that he could investigate the twin-engine fighter. Though new to the machine, he was instrumental in extending the range of the P-38 through improved throttle settings, or engine-leaning techniques, notably by reducing engine speed to 1,600 rpm, setting the carburetors for auto-lean and flying at 185 mph (298 km/h) indicated airspeed which reduced fuel consumption to 70 gal/h, about 2.6 mpg. This combination of settings had been considered dangerous; it was thought it would upset the fuel mixture and cause an explosion. Everywhere Lindbergh went in the South Pacific, he was accorded the normal preferential treatment of a visiting colonel, though he had resigned his Air Corps Reserve colonel's commission three years before. While with the 475th, he held training classes and took part in a number of Army Air Corps combat missions. On 28 July 1944, Lindbergh shot down a Mitsubishi Ki-51 "Sonia" flown expertly by the veteran commander of 73rd Independent Flying Chutai, Imperial Japanese Army Captain Saburo Shimada. In an extended, twisting dogfight in which many of the participants ran out of ammunition, Shimada turned his aircraft directly toward Lindbergh who was just approaching the combat area. Lindbergh fired in a defensive reaction brought on by Shimada's apparent head-on ramming attack. Hit by cannon and machine gun fire, the "Sonia's" propeller visibly slowed, but Shimada held his course. Lindbergh pulled up at the last moment to avoid collision as the damaged "Sonia" went into a steep dive, hit the ocean and sank. Lindbergh's wingman, ace Joseph E. "Fishkiller" Miller, Jr., had also scored hits on the "Sonia" after it had begun its fatal dive, but Miller was certain the kill credit was Lindbergh's. The unofficial kill was not entered in the 475th's war record. On 12 August 1944 Lindbergh left Hollandia to return to the United States.
Charles MacDonald
The seventh-ranking American ace, Charles H. MacDonald, flew a Lightning against the Japanese, scoring 27 kills in his famous aircraft, the Putt Putt Maru.
Robin Olds
Main article: Robin Olds
Robin Olds was the last P-38 ace in the Eighth Air Force and the last in the ETO. Flying a P-38J, he downed five German fighters on two separate missions over France and Germany. He subsequently transitioned to P-51s to make seven more kills. After World War II, he flew F-4 Phantom IIs in Vietnam, ending his career as brigadier general with 16 kills.
Clay Tice
A P-38 piloted by Clay Tice was the first American aircraft to land in Japan after VJ-Day, when he and his wingman set down on Nitagahara because his wingman was low on fuel.
Antoine de Saint-Exupéry
Noted aviation pioneer and writer Antoine de Saint-Exupéry vanished in a F-5B-1-LO, 42-68223, c/n 2734, of Groupe de Chasse II/33, out of Borgo-Porreta, Bastia, Corsica, a reconnaissance variant of the P-38, while on a flight over the Mediterranean, from Corsica to mainland France, on 31 July 1944. His health, both physical and mental (he was said to be intermittently subject to depression), had been deteriorating and there had been talk of taking him off flight status. There have been suggestions (although no proof to date) that this was a suicide rather than an aircraft failure or combat loss. In 2000, a French scuba diver found the wreckage of a Lightning in the Mediterranean off the coast of Marseille, and it was confirmed in April 2004 as Saint-Exupéry's F-5B. No evidence of air combat was found. In March 2008, a former Luftwaffe pilot, Horst Rippert from Jagdgruppe 200, claimed to have shot down Saint-Exupéry.
Adrian Warburton
The RAF's legendary photo-recon "ace", Wing Commander Adrian Warburton DSO DFC, was the pilot of a Lockheed P-38 borrowed from the USAAF that took off on 12 April 1944 to photograph targets in Germany. W/C Warburton failed to arrive at the rendezvous point and was never seen again. In 2003, his remains were recovered in Germany from his wrecked USAAF P-38 Lightning.
• • • • •
Quoting Smithsonian National Air and Space Museum | Boeing B-29 Superfortress "Enola Gay":
Boeing's B-29 Superfortress was the most sophisticated propeller-driven bomber of World War II and the first bomber to house its crew in pressurized compartments. Although designed to fight in the European theater, the B-29 found its niche on the other side of the globe. In the Pacific, B-29s delivered a variety of aerial weapons: conventional bombs, incendiary bombs, mines, and two nuclear weapons.
On August 6, 1945, this Martin-built B-29-45-MO dropped the first atomic weapon used in combat on Hiroshima, Japan. Three days later, Bockscar (on display at the U.S. Air Force Museum near Dayton, Ohio) dropped a second atomic bomb on Nagasaki, Japan. Enola Gay flew as the advance weather reconnaissance aircraft that day. A third B-29, The Great Artiste, flew as an observation aircraft on both missions.
Transferred from the United States Air Force.
Manufacturer:
Date:
1945
Country of Origin:
United States of America
Dimensions:
Overall: 900 x 3020cm, 32580kg, 4300cm (29ft 6 5/16in. x 99ft 1in., 71825.9lb., 141ft 15/16in.)
Materials:
Polished overall aluminum finish
Physical Description:
Four-engine heavy bomber with semi-monoqoque fuselage and high-aspect ratio wings. Polished aluminum finish overall, standard late-World War II Army Air Forces insignia on wings and aft fuselage and serial number on vertical fin; 509th Composite Group markings painted in black; "Enola Gay" in black, block letters on lower left nose.
Purple combines the stability of blue and the energy of red. Why is it so difficult to catch this color ?
from the SRGC Scottish Rock Garden Club seed exchange
#nothipstamatic
Testing stability of my hands or the camera phone's abilities in low & uneven light...
photo rights reserved by B℮n
Khao Hin Thoen Stone Park is located in Prachuap Khiri Khan province in the narrowest part of Thailand, which is only 15 kilometers wide, close to the border with Myanmar Burma. Khao Hin Theun Stone Park is a hilly area where many large granite stones are stacked naturally. The fact that these large rocks appear to remain balanced despite their size and weight reminds us of the delicate balance and stability in nature. It is a reminder of the forces of nature and the unique geological processes that create such formations. These formations are often the result of centuries of geological processes, including erosion, sedimentation, landslides and other forces. It's amazing how nature can create these complex structures over time. From the top of the hill you can enjoy breathtaking panoramic views of the Gulf of Thailand and the surrounding coastline. Just a few kilometers away, at the Singkhon checkpoint, is the border with Myanmar; a route with rich historical significance as it once served as a military trail during the late Ayutthaya period. At the summit there is also a secluded temple built between three large massive granite boulders. Essentially an open cave, this temple is a hidden gem maintained by a lone monk. This venerable monk, now 78 years old, has been living here in solitude for more than 40 years. The temple and living area are built into the large boulders. Surrounded by lush green forests, this open temple cave also offers an opportunity to enjoy the natural beauty and tranquility. Hiking trails are available for those who want to enjoy the natural environment. The peaceful surroundings and natural beauty make it a popular place for meditation and contemplation.
Hidden deep within the lush landscape of Khao Hin Thoen Stone Park is an open cave that serves as the home of the wise Buddhist monk Pasek Pakuno, a 78-year-old man. He has lived in this remote hideaway for 40 years. His story has become a legend among the locals. Venerable Pasek Pakuno left his worldly possessions at a young age and dedicated his life to spiritual enlightenment. For four decades he has found peace and his calling in this remote environment. His daily routine is simple. He awakens with the rising sun and greets the new day with meditation and prayer. The sound of birds singing and the rustling of the trees serve as his companions during his meditative hours. He lives on donations from passers-by, which he gratefully accepts, but he has no material wealth. The monk sleeps on a simple mat on the cool floor. He welcomes them all with kindness and a smile. He loves the quiet moments when the sunset fills the cave with a soft light, and he looks to the stars in the night sky as witnesses to his spiritual journey. His life story inspires many to think about their own choices in life. He reminds them that happiness is not always found in material possessions, but in the simplicity of the heart and soul. His cave remains a sacred place, an oasis of peace and reflection for those who find their way to this remote place. I was deeply impressed by Monk Pasek because of his dedication to spirituality. I was deeply impressed by Monk Pasek because of his dedication to spirituality. When we arrived at the cave, we didn't even see the monk sitting there as he was sitting as still as a Buddha.
Khao Hin Thoen Stone Park ligt in de provincie Prachuap Khiri Khan in in het smalste stukje van Thailand, dat slechts 15 kilometer breed is, dichtbij de grens met Myanmar (Birma). Khao Hin Theun Stone Park is een heuvelachtig gebied waar veel grote granieten stenen op natuurlijke wijze zijn gestapeld. Diep verscholen in het weelderige landschap van Khao Hin Thoen Stone Park bevindt zich een open grot die dient als de thuisbasis van de wijze boeddhistische monnik Pasek Pakuno, een man van 78 jaar oud. Hij woont al 40 jaar lang in deze afgelegen schuilplaats. Zijn verhaal is een legende geworden onder de lokale bevolking. De eerwaarde Pasek Pakuno heeft op jonge leeftijd zijn wereldse bezittingen achtergelaten en zijn leven gewijd aan spirituele verlichting. Al vier decennia lang heeft hij vrede en zijn roeping gevonden in deze afgelegen omgeving. Zijn dagelijkse routine is eenvoudig. Hij ontwaakt met de opkomende zon en begroet de nieuwe dag met meditatie en gebed. Het geluid van zingende vogels en het ruisen van de bomen dienen als zijn metgezellen tijdens zijn meditatieve uren. Hij leeft van de donaties van voorbijgangers, die hij dankbaar accepteert, maar hij bezit geen materiële rijkdom. De monnik slaapt op een eenvoudige mat op de koele vloer. Hij verwelkomt hen allen met vriendelijkheid en een glimlach. Hij houdt van de rustige momenten wanneer de zonsondergang de grot met een zacht licht vult, en hij beschouwt de sterren aan de nachtelijke hemel als getuigen van zijn spirituele reis. Zijn levensverhaal inspireert velen om na te denken over hun eigen keuzes in het leven. Hij herinnert hen eraan dat geluk niet altijd te vinden is in materiële bezittingen, maar in de eenvoud van het hart en de ziel. Zijn grot blijft een heilige plaats, een oase van vrede en reflectie voor degenen die de weg naar deze afgelegen plek vinden. Ik was diep onder de indruk van monnik Pasek vanwege zijn toewijding aan spiritualiteit. Toen we bij de grot aankwamen, zagen we de monnik niet eens zitten, aangezien hij zo stil zat als een Boeddha.
EAST CHINA SEA (Aug. 4, 2020) Boatswain’s Mate Seaman Valentina Imokhai, from New York, operates the ship’s helm during a full power engine run aboard the amphibious dock landing ship USS Germantown (LSD 42). Germantown, part of America Expeditionary Strike Group, is operating in the 7th Fleet area of operations to enhance interoperability with allies and partners, and serves as a ready response force to defend peace and stability in the Indo-Pacific region. (U.S. Navy photo by Mass Communication Specialist 2nd Class Taylor DiMartino)
tasmania.com/things-to-do/hiking-walking/south-coast-track/
SOUTH COAST TRACK
Summon up a map of Tasmania and take a good look. You'll find Hobart in the southeast with plenty of roads leading north to Launceston and Devonport. Then take your eye down to the southwest of the island to see a large swath of green. Look closer. There are no roads, no towns and only one tiny port on the southwest tip of the island. You're marvelling at Southwest National Park and all of its wild glory. You'll find the South Coast Track along its southern edge.
Spanning 85 kilometres from Melaleuca to Cockle Creek, this walk takes 6 to 8 days to complete. It meanders through some of the wildest lands on planet Earth, and, because of this wildness, it is recommended that you gain experience on some of Tasmania's other difficult walks before challenging yourself on the South Coast Track. The Overland Track in Cradle Mountain-Lake St Clair National Park serves as a good warmup.
While there is a rugged road to Cockle Creek, there are no roads to Melaleuca. The small encampment on the southwest side of Southwest National Park has a small airstrip and Port Davey for the landing of boats. You can only fly, boat or walk your way out of Melaleuca. Boats and planes can be arranged in the west coast town of Strahan.
The South Coast Track by Season
It is advisable to take the track during the summer months. It is warmer between September and March but you are at risk of high winds, cold temperatures and a deluge of rain at any time of year. And while it is possible to complete the track alone or during winter, it is highly inadvisable to complete the track alone in winter. After all, you're a long ways from help if you need it. Always hike in groups of 6 or less.
Here is a wonderful quote from the back of David Attenborough's new (2020) book:
"A Life on Our Planet; my witness statement and a vision for the future":
"We share Earth with the living world - the most
remarkable life-support system imaginable,
constructed over billions of years. The planet's
stability has wavered just as its biodiversity has
declined - the two things are bound together.
To restore stability to our planet, therefore, we must restore its biodiversity, the very thing we have removed. It is the only way out of this crisis that we ourselves have created. We must rewild the world."
William Wallace, in full Sir William Wallace, (born c. 1270, probably near Paisley, Renfrew, Scotland—died August 23, 1305, London, England), one of Scotland’s greatest national heroes and the chief inspiration for Scottish resistance to the English king Edward I. He served as guardian of the kingdom of Scotland during the first years of the long and ultimately successful struggle to free his country from English rule.
Early Life, Initial Campaigns Against The English, And The Battle Of Stirling Bridge
Wallace was the second son of Sir Malcolm Wallace of Elderslie in Renfrewshire. The elder Wallace was a minor landowner and a vassal of James, 5th steward of Scotland. In 1296 King Edward I of England deposed and imprisoned the Scottish king John de Balliol and declared himself ruler of Scotland. Sporadic resistance had already occurred when, in May 1297, Wallace and a band of some 30 men burned Lanark and killed its English sheriff. Joined by Sir William Douglas (“the Hardy”), Wallace next marched on Scone, drove out the English justiciar, and attacked the English garrisons between the Rivers Forth and Tay. The Scottish steward, Robert the Bruce (later King Robert I), and others now gathered an army, but it was forced to surrender at Irvine by Sir Henry de Percy and Sir Robert de Clifford (July 1297). Wallace, however, remained in action “with a large company in the Forest of Selkirk,” according to a contemporary report made to Edward. Wallace laid siege to Dundee but abandoned it to oppose, with Andrew de Moray, an English army that was advancing toward Stirling under John de Warenne, earl of Surrey.
Surrey failed to bring Wallace to terms outside Stirling, and, on the morning of September 11, 1297, the English began to file across the narrow bridge over the Forth. Wallace and Moray, in a position northwest of the Abbey Craig, held back their troops until about half the English had crossed. They then attacked with such sudden fury that almost all who had crossed were killed or driven into the river and drowned. Surrey, with the rest of his army, retreated hastily, having first destroyed the bridge, but the Scots crossed by a ford and pursued them. With only a small following, Surrey escaped to Berwick and York. For the moment Scotland was almost free of occupation. A letter long survived in which Moray and Wallace, writing from Haddington on October 11, urged the Hanseatic towns of Hamburg and Lübeck to resume trade with Scotland, now “recovered by war from the power of the English.” Moray, who had been wounded at Stirling Bridge, died soon afterward. Wallace now ravaged Northumberland and Cumberland, burning Alnwick and besieging Carlisle. To the monks of Hexham, however, he granted special protection.
Guardian Of Scotland And The Battle Of Falkirk
Upon returning to Scotland early in December 1297, Wallace was knighted (it is not known by whom) and was elected or assumed the title of guardian of the kingdom. In the name of King John de Balliol, then a prisoner in London, Wallace set himself to reorganize the army and regulate the affairs of the country. He seems to have acted wisely and vigorously and to have been supported by Bishop Robert Wishart of Glasgow, the steward’s brother Sir John Stewart, Sir John Graham of Dundaff, Sir John Comyn (“the Red”), Robert the Bruce, and others. Some nobles, many of whom had English estates and hostages in Edward’s hands, were only lukewarm to Wallace’s leadership, and his position depended entirely upon his success on the battlefield.
Early in 1298 Surrey returned and relieved the English-held castles of Roxburgh and Berwick but by Edward’s orders advanced no farther. Edward himself crossed the Tweed on July 3 and moved toward Stirling with a strong force of heavy cavalry, a body of archers, and Irish and Welsh auxiliaries. Wallace retreated slowly, wasting the country behind him so Edward’s force could not resupply itself on the march. Edward, with his army half-starved and mutinous, was on the point of retreat when, early on July 21 near Kirkliston, he learned that Wallace was awaiting him near Falkirk.
Edward advanced and on the following day found Wallace on a carefully chosen sloping ground, his front protected by a small river. The English cavalry, having with some difficulty crossed the river and the adjacent marshy ground, launched repeated charges on the four schiltrons (circular battle formations) of Wallace’s spearmen. They drove off the field the small body of Scottish horse under Comyn but made no impression on the schiltrons and suffered considerable losses. The archers, however, now advanced, and their deadly volleys soon broke up the spearmen’s ranks, and further cavalry charges turned them to flight. Thousands of the Scots were slain in the pursuit, and among the dead were Sir John Stewart and Sir John de Graham. Wallace retired northward with the survivors, burning Stirling and Perth as he went. Edward, unable to maintain his forces in Scotland, returned south, reaching Carlisle on September 8. His military reputation ruined, Wallace resigned the guardianship in December 1298 and was succeeded by Bruce and Comyn.
Capture And Execution
There is some evidence that Wallace went to France in 1299 and thereafter returned to Scotland to act as a solitary guerrilla leader, but from the autumn of 1299 nothing is known of his activities for more than four years. The rebellion he had led nevertheless continued until 1304, at which point most Scottish nobles submitted to Edward. How much this continued resistance was due to Wallace’s influence is uncertain, but Wallace was the one leader to whom Edward would never offer any terms of capitulation and whom he most persistently tried to capture. On August 5, 1305, Wallace was arrested near Glasgow by Sir John Menteith, and, according to two early chroniclers, by treachery. He was carried to Dumbarton Castle and then to London, having possibly been brought before King Edward along the way.
Legacy And Influence
Wallace was unmarried and is not known to have fathered any children. There is no portrait of him and no contemporary description of his appearance. Many of the stories surrounding Wallace have been traced to a late 15th-century romance ascribed to Harry the Minstrel, or “Blind Harry.” The most popular tales are not supported by documentary evidence, but they show Wallace’s firm hold on the imagination of his people. A huge monument (1861–69) to Wallace stands atop the rock of Abbey Craig near Stirling. Mel Gibson portrayed Wallace in Braveheart (1995), an Academy Award-winning film that was loosely based on Wallace’s life.
Georgetown, Queensland:
Georgetown, a rural centre 270km southwest of Innisfail, Queensland, is on the road to Croydon. Originally known as Etheridge, it is the administrative centre of Etheridge Shire.
Georgetown began in 1869 as an alluvial gold mining centre, based on the Etheridge River. Mining came about mainly from Queensland Government geologist Richard Daintree's exploratory work. When the gold field was approved as a township it was named Georgetown in honour of the local gold commissioner, Howard Saint George. The alluvial gold attracted a rush of prospectors, estimated at up to 3000 at its peak. This number was short-lived, however, as footloose prospectors were soon drawn to more rewarding sites such as the Palmer River and Hodgkinson fields.
In 1870 a telegraph repeating station for an overland line to the Gulf was built at Georgetown, and a post office and a court opened in 1872. Buildings were primitive, including the school (1874), the Catholic chapel (1876), and the numerous hotels. The school closed in 1877 for want of pupils during one of the miners' periodic desertions to other fields (a government primary school opened again in 1878, today's State school tracing its origins to this date). The telegraph station, colonial-administrative functions and reliable river flows ensured a degree of economic stability and buffered Georgetown against the vagaries of fluctuating mining fortunes. The district's fertile red basalt soils encouraged beef pastoralism, and the town developed as a commercial service centre.
By 1880 the original wood and canvas buildings were wearing out. White-ant proof iron and hardwood structures replaced them (the Bank of New South Wales' new building built in 1890 lasted until 1988). In 1882 Georgetown had ten hotels, ten billiards rooms, and an enlarged courthouse to deal with participants in drunken brawls, assaults, indecent language, and livestock theft. The rich mineral lodes paid well enough to offset the costs caused by lack of water and distance, and continued to provide enough return to keep miners employed. By the early 1900s, however, mining was reported as being depressed, with cyanide processing of tailings giving the best results. There were still several hotels, and a hospital had been opened. Copper mining began at Einasleigh and a railway line was opened in 1908 to carry the ore to the Chillagoe smelters. The line, however, was not extended to Georgetown.
Georgetown was made the administrative centre of Etheridge Shire, which, together with the hospital and recreation facilities, has offset its never having a railway line. Georgetown is at the heart of some of Queensland's best gemfields, and the shire has embraced outback tourism. Outside of the town are several heritage-listed gold mines. A house in South Street built with antbed bricks circa 1890 (possibly the sole surviving example) is also heritage-listed. In Georgetown itself are a motel, hotel, and three camping/caravan parks, together with Anglican and Catholic churches, a general store, the State primary school, racecourse, swimming pool and a tourist information centre, which in 2003 acquired a notable minerals collection.
In 2004, the Ewamian people surrendered native title over the far northern Queensland townships of Einasleigh, Forsayth, Mount Surprise, and Georgetown. In return, they received access to their traditional country through three reserves along with land and housing in Georgetown.
Source: Britannica, Queensland Places (www.queenslandplaces.com.au/georgetown), & Queensland Heritage Register.
YOKOSUKA, Japan (March 2, 2018) The Los Angeles-class attack submarine USS Topeka (SSN 754) sits along the pier at Fleet Activities Yokosuka after arriving for a port visit. U.S. Navy port visits represent an important opportunity to promote stability and security in the Indo-Pacific region, demonstrate commitment to regional partners and foster relationships. (U.S. Navy photo by Mass Communication Specialist 2nd Class Jeremy Graham/Released)
A good friend has this wee beauty parked in his garage awaiting some restoration work , I have hoped to capture it many times in the past however on this occasion the light was right and he had her parked in his drive , this photo is one of a few I took .
Vehicle details
Vehicle make: VOLKSWAGEN
Date of first registration: January 1973
Year of manufacture: 1972
Cylinder capacity (cc): 1584 cc
CO₂Emissions: Not available
Fuel type: PETROL
Export marker: No
Vehicle status: SORN in place
Vehicle colour: ORANGE
Wheelplan: 2-AXLE-RIGID BODY
The Volkswagen Beetle—officially the Volkswagen Type 1, informally in German the Käfer (literally "beetle"), in parts of the English-speaking world the Bug, and known by many other nicknames in other languages—is a two-door, rear-engine economy car, intended for five passengers, that was manufactured and marketed by German automaker Volkswagen (VW) from 1938 until 2003.
History of the Volkswagen T1 Beetle
Introduction
The VW Beetle has become an iconic vehicle worldwide, and has built a huge loyal following. It is known by numerous names, for example, in Germany it’s a Kafer, in the USA a Bug or salon, England a Beetle etc. As the floor pan and running gear can be used without the body being attached, they became a firm favourite of the kit car builders. They were turned into Porsche 356 replicas, beach buggies, and Nova kit cars to mention just a few. When production stopped in 2003 in Mexico over 21 million air-cooled Volkswagen Beetles had been produced. During eight decades of manufacturing came a whole variety of models, ranging from 25Hp through to the 1303S or Super Beetle with its Independent Rear Suspension (also known as IRS). Salons, sunroof models, cabrios and even specialist versions as police cars, German post office delivery vehicles and in Mexico City, the green and white Beetle taxi, with its missing passengers seat, was a common sight until recently.
Personalisation and the custom scene
Fashions change and over the years the VW Beetle or Bug has seen styles come and go. The 1950’s saw shiny and standard Beetles as the common style. But by the 1960’s the trend to ‘soup them up’ and build street legal drag racers was taking hold in the USA, especially on the West Coast. This was the time of legends such as Gene Berg and cars such as the Empi Inch Pincher. In the UK, smaller tuning companies such as Speedwell developed carb tuning kits and alloy wheels. By the mid 1970’s the Bug was being used for time trials and autocross racing.
This was also the start of a ‘dark’ time for the Beetle customising scene, as the fat whale tailed body kits were fitted, so if you saw it on a dark foggy night, it could look a little like a Porsche 911! However as the whale tail was strapped on, in California they developed what has come to be known as ‘Calook’ or Californian Look. Lowered, smoothed out, de-chromed, alloys, neat interiors and performance engines were the main features of the Calook scene. Luckily by the mid 1980s in the UK, the body kits were out of fashion and the Calook scene took hold, initially from Essex. Since then there have been a variety of fashions, with the VW drag racing scene now in its fourth decade. We’ve seen ‘Old School’ lowered, lots of chrome and accessories, neat and tidy. ‘Rat look’ is almost the polar opposite, with flat mat paint, original and lived in interiors but shares the passion for vintage accessories! Calook in various rebirths has been a steady influence. However, today there seems to be strong move back to ‘stock’.
Please Note: When trying to identify a Beetle, bear in mind that on all models (except 1302/1303) most body panels are interchangeable, so if a Beetle has sloping headlights, don’t assume that it is a 1957>1967 model. Many late Beetles have early wings, lights, bonnet, engine lid and front and rear valances, making them, at first glance identical to a 1964 to 1967 model, but generally if it has an external fuel filler cap it is likely to be built between 1968 and 2003.
Production history and technical changes
Here are the main changes that took place to the Volkswagen Beetle during its eight decades of production.
1936 > 1952 ‘Splitscreen Beetle’ The Beetle story started in the early 1930’s, but production started officially in 1936. The Second World War all but stopped production until the British army rebuilt the factory and production commenced of the ‘Splitscreen’ Beetles (named after the shape of the small ‘split’ rear window). These were very basic cars with engines from 985cc (24bhp) to 1131cc (25bhp) but are rare and very desirable.
1953 > 1956 ‘Oval Beetle’ Very similar to the Splitscreen, but with the split removed from the rear window making it an oval. Small developments aimed at improving driver comfort and making the Beetle appeal to foreign markets, including a new 1192cc (30bhp) engine.
1957 > 67 Little difference in appearance from the Oval Beetle, the biggest being the rear window, which was enlarged in August 1957 to the large rectangular shape that would remain for the remainder of production. The windscreen and side glass were also enlarged in August 1964. These Beetles still retained the sloping headlights, long bonnet, link and king pin torsion bar front suspension and swing axle torsion bar suspension at the rear and 5 bolt wheels as previous models, but in Aug 1966 the link pins were replaced with ball joints and the wheels used four bolts instead of five. Engine options were now 1192cc (34bhp), 1285cc (40bhp) and in Aug 1966 the 1493cc engine with (44bhp).
1968 > 2003 August 1967 saw the first major styling change with upright headlights, a shorter bonnet and engine lid, plus an exterior mounted fuel filler cap. These models retained the torsion bar front suspension and swing axle rear suspension, which remained until the end of Brazilian production in 2003. The only exceptions were the semi-automatic Beetle which came with I.R.S rear suspension and the 1302 and 1303 models which used front coil springs... (see below). Engine options for these were 1192cc (34bhp), 1285cc (44bhp), 1493cc engine with (44bhp) and 1584cc (50bhp).
1971 > 72 ‘The 1302 Beetle’ In an effort to make the Beetle more practical and improve sales, VW offered a restyled version alongside the regular Beetle which was badged the 1302 (1285cc) and the 1302S (1584cc). This had a more bulbous front bodywork but retained the flat windscreen and the torsion bar front suspension was replaced with MacPherson struts with coil springs, similar to the VW Golf. The rear suspension was also the much improved I.R.S torsion bar system similar to the Porsche 911 of the same era. These changes improved the handling, ride comfort and stability, plus the front luggage area increased from 5 cu ft to over 9 cu ft, however, the styling proved unpopular and it was replaced after 2 years by the 1303 model.
1973 > 80 ‘The 1303 Beetle’ This was a revision of the 1302 Beetle and was available as the 1303A (1192cc) 1303 (1283cc) and the 1303S (1584cc). The only major change was that the flat windscreen was replaced with a more modern curved windscreen, which improved aerodynamics and interior space. This was also sold alongside the regular, torsion bar; flat windscreen Beetle, with the last 1303 was built in 1980.
The classic styling of the torsion bar Beetles helped them outlive the improved design of the 1302/1302 ‘Super Beetles’ and production was ended in 2003 to free up factory space for the front engined, water-cooled ‘New Beetle.’
German Beetle production chassis numbers
The chassis number is very useful when ordering parts for your Beetle as it gives the date of manufacture, model type. These can be found in two places. Firstly, in the front luggage compartment, by the bonnet lock and secondly, under the rear seat on the central tunnel.
The sculpture is called the Churning of the Milk Ocean or the Scene of the Churning of the Milk Ocean. It is believed to be the place that holds the nectar of immortality, thus it portrays immortality and stability. Likewise Suvarnabhumi Airport represents the golden land/resources/prosperity/stability and eternality.
The sculpture has the statue of four-hand Narayana (Vishnu) placed on top of the Mount Madura. 9 gods are on one side and 9 demons on the opposite are pulling the king of Nagas from both sides. The turtle (Koorm Avatar) is the tortoise-incarnation of Vishnu which is the third incarnation form out of the ten forms according to the Scene of the Churning of the Milk Ocean. Koorm Avatar uses the shell to be a pivot for the churning stick. BKK airport Bangkok Thailand
The Sea Vixen entered service with the Fleet Air Arm in 1959 replacing the Sea Venom. Sea Vixens, flying from HMS Centaur in 1964, took part in the successful operation to restore stability in the East African state of Tanganyika. In 1961 and 1964, Sea Vixens saw service in the Persian Gulf and later in the 1960s they played a crucial role during the days of the Beira Patrol preventing oil reaching landlocked Rhodesia. In 1967 Sea Vixens also helped cover the withdrawal from Aden.
XP 924 first flew on 23 September 1963 and was delivered to 899 Squadron at RNAS Yeovilton on 18 December 1963. The aircraft suffered a number of incidents during its time in squadron service. Tyre bursts, canopy shattering, some engine problems and, while serving at sea in HMS Eagle, an inadvertent release of a practice bomb near the island of Gan in the Indian Ocean! Retirement from active service sent her to Royal Naval Aircraft Yard at Belfast in August 1971. The Royal Aircraft Establishments (RAE) at Farnborough and Llanbedr were in possession from 4 June 1973 until August 1977. Flight Refuelling took over on 11 October 1977 at Tarrant Rushton and converted her to a Drone (D3) with a Red and Yellow paint scheme to improve visual acuity. In February 1996 she was taken on by de Havilland Aviation and was re-registered as G-CVIX. In May 2003 she was painted in “Red Bull” colours as a sponsorship arrangement and was subsequently purchased on 18 April 2006 by Drilling Systems Ltd (Mr Julian Jones) and operated from Bournemouth. March 2007 saw a return to Naval colours as XP 924 with the 899 Squadron mailed fist logo. The aircraft was gifted to Naval Aviation Ltd in September 2014 and now operates from the Royal Naval Air Station Yeovilton.
Unfortunately on her return from Duxford the pilot was unable to get the wheels down and he had to do a controlled belly landing at Yeovilton, a marvellous piece of airmanship. Fortunately the pilot sustained no injury and the aeroplane is undergoing assessment. As of late 2021 it looks like she will not fly again and will be on display at the RNAS Museum Yeovilton. Below is a link to a video of the wheels up landing.
Link to video
www.youtube.com/watch?v=x64-Bea7xXc
MY THANKS TO ALL WHO VISIT AND COMMENT IT IS APPRECIATED
SEXT IS ASSOCIATED with the stillness and peace of noon, but it also evokes crisis and danger. Crisis is always a purification if we understand it correctly. The very word “crisis” comes from a root that means sifting out. Crisis is a separation, a sifting out of that which is viable and can go on from that which is dead and has to be left behind.
-Music of Silence: A Sacred Journey Through the Hours of the Day
Brother David Steindl-Rast, Sharon Lebell, and Kathleen Norris
PHILIPPINE SEA (Jan. 26, 2022) Aviation Boatswain’s Mate (Handling) 3rd Class Donald Elliot, from Kansas City, Missouri, assigned to forward-deployed amphibious assault ship USS America (LHA 6), directs a CH-53E Super Stallion, assigned to the 31st Marine Expeditionary Unit (MEU), to land on the ship’s flight deck. America, the lead ship of America Amphibious Ready Group (ARG), along with the 31st MEU, is operating in U.S. 7th Fleet to enhance interoperability with allies and partners and serve as a ready response force to defend peace and stability in the Indo-Pacific region. (U.S. Navy photo by Mass Communication Specialist 3rd Class Theodore C. Lee)
Auto rickshaws are a common means of public transportation in many countries in the world. Also known as a three-wheeler, Samosa, tempo, tuk-tuk, trishaw, autorick, bajaj, rick, tricycle, mototaxi, baby taxi or lapa in popular parlance, an auto rickshaw is a usually three-wheeled cabin cycle for private use and as a vehicle for hire. It is a motorized version of the traditional pulled rickshaw or cycle rickshaw. Auto rickshaws are an essential form of urban transport in many developing countries, and a form of novelty transport in many developed countries. However, in some parts of Europe they remain an essential mode of transportation, notably Italy's.
OVERVIEW
ORIGN
Auto rickshaws of Southeast Asia started from the knockdown production of the Daihatsu Midget which had been introduced in 1957.
Japan had been exporting three-wheelers to Thailand since 1934. Moreover, The Ministry of Posts and Telecommunications of Japan donated about 20,000 used three-wheelers to Southeast Asia. In Japan, three-wheelers went out of use in the latter half of the 1960s.
DESIGN
An auto rickshaw is generally characterized by a sheet-metal body or open frame resting on three wheels, a canvas roof with drop-down sides, a small cabin in the front of the vehicle for the driver (sometimes called an auto-wallah), and seating space for up to three passengers in the rear. Newer models are generally fitted with a compressed natural gas (CNG) fuel scooter version of a 200 cc four-stroke engine, with handlebar controls instead of a steering wheel.
REGIONAL VARIATIONS
AFRICA
EASTERN AFRICA
There are tuk-tuks in several Kenyan towns. Using them is somewhat cheaper than ordinary taxis. However, tuk-tuks cannot operate in mountainous towns, which are common in Kenya. Fierce competition with Boda-bodas (bicycle taxis) and Matatus (minibuses) hinders popularity of Tuk-tuks, especially within the interior of Kenya. While they may not be widely found in Kenya, they are numerous in the coastal regions, which are less mountainous. For example, in the town of Malindi they offer an economical and convenient mode of transportation.
Tuk-tuks are also common in Ethiopia and are becoming common in Tanzania, particularly in the outer areas of Dar es Salaam. In Tanzania and Ethiopia they are known as "Bajaj" or "Bajajis", after the Bajaj Auto company which manufactures many of them. Since 2009, tuk-tuks have become common in Maputo, Mozambique.
EGYPT
In Egypt, auto rickshaws are called toktok (Egyptian Arabic: توك توك pronounced [ˈtoktok], plural: تكاتك takātek [tæˈkæːtek]); they are widely used as taxis in poorer neighborhoods of the capital, and have become a popular symbol for lower class Egyptians, although they are banned from the streets of wealthier neighborhoods. Deposed president Mohamed Morsi (June 2012-July 2013) in his opening speech addressed the Tuk-Tuk (toktok) drivers as a symbol of the lower class population, but his political rivals and mass media considered it as a mean of emotional deception for the masses by rendering what could be a promise to legalize their status.
MADAGASCAR
In Madagascar, man-pulled rickshaws are a common form of transportation in a number of cities, especially Antsirabe. They are known as "posy" from pousse-pousse, meaning push-push. Cycle rickshaws never took off, yet Posy are threatened by the auto-rickshaws, introduced in numbers since 2009. Provincial capitals like Toamasina, Mahajanga, Toliara, Antsiranana are taking to them rapidly. They are known as "bajaji" and now licenced to operate as taxis. They are not yet allowed an operating licence in the congested, and more pollution prone national capital, Antananarivo.
NIGERIA
There are keke-marwa's in several Nigerian towns and cities. Although not as popular as the ubiquitous "Okada" in Nigeria, keke-marwa's are embraced as an alternative means of transport by the middle and lower class citizens. Keke-marwa is named after Lagos former military Governor, Buba Marwa in the late 1990s.
SOUTH AFRICA
Tuk-tuks, introduced in Durban in the late 1980s enjoyed growing popularity in recent years, particularly in Gauteng.
SUDAN
Rickshaws are a major means of transport in all parts of Sudan, it's locally known as Raksha.
ASIA
BANGLADESH
Auto rickshaws (locally called "baby taxis" and more recently "CNGs" due to their fuel source) are one of the most popular modes of transport in Bangladesh mainly due to their size and speed. They are best suited to narrow, crowded streets, and are thus the principal means of covering longer distances within urban areas.
Earlier, auto rickshaws were colored black with a yellow canvas topping and ran on gasoline without any meter system. However, due to the vast supplies of natural gas in Bangladesh, the government has since encouraged the development of four-stroke compressed natural gas (CNG)-powered engines rather than the older two-stroke engine petrol-running models. Two-stroke engines had been identified as one of the leading sources of air pollution in Dhaka. Thus, since January 2003, traditional auto rickshaws were banned from the capital; only the new CNG-powered models were permitted to operate within the city limits. The newly manufactured CNG auto rickshaws are more fuel-efficient and have a lower center of gravity, making them safer than older models. All CNGs are painted green to signify that the vehicles are eco-friendly and that each one has a meter built in as standard.
Another version of the auto rickshaw can be seen in rural areas of Bangladesh, where they are called "helicopters". "Helicopters" are auto rickshaws modified to have a large body with which it can carry more than six or seven passengers.
At the end of the 1980s, a local company Atlas designed and built a new version of the auto rickshaw, called mishuk, a name derived from a children's mascot of a local deer. Unlike baby taxis, mishuks have spoke wheels and a green body, and have no meter system. Mishuks have more space than baby taxis or CNGs, which makes it more popular with women. They are commonly found in Dhaka and elsewhere in the country due to its four-stroke engine, which is not listed as a significant source of air pollution.
CAMBODIA
In Cambodia, the term tuk-tuk (Khmer: ទុកទុក) is used to refer to a motorcycle with a cabin attached to the rear. Cambodian cities have a much lower volume of automobile traffic than Thai cities, and tuk-tuks are still the most common form of urban transport. At the temple complex of Angkor, for example, tuk-tuks provide a convenient form of transport around the complex for tourists. One can hire a tuk-tuk and driver by the day.[citation needed]
Siem Reap tuk-tuks are generally of the style of motorcycle and trailer. This version does not have rear brakes.
Phnom Penh tuk-tuks are one piece. The one piece tuk-tuk is the front end of a motorcycle consisting of steering, tank and engine/gearbox with a covered tray mounted at the back. The power is transferred by chain to an axle mounted to the modified rear fork which drives the two rear wheels. Suspended upon the rear fork is an open cabin with an in-line seat on each side. This arrangement can carry 6 people at ease, with their luggage in the leg space. It is not unusual to see these vehicles greatly overloaded, especially in outer suburbs and around markets.
Sihanoukville tuk-tuks are generally a motorcycle and articulated trailer without rear brakes on the trailer. A minority of tuk-tuks are three wheeled. The rear wheel of the motorcycle is removed and the front of the bike is melded with a trailer. Power is supplied to the trailer wheels by a driveshaft and differential. Rear wheel brakes add significantly to the safety of this design, especially when going downhill.
Currently, Tuk Tuk in Cambodia is being developed to be more convenient and safer. It is also becoming a popular form of transportation for Phnom Penh residents.
Gaza
Together with the recent boom of recreational facilities in Gaza for the local residents, donkey carts have all but been displaced by tuk-tuks in 2010. Due to the ban by Israel on the import of most motorised vehicles, the tuk-tuks have had to be smuggled in parts through the tunnel network connecting Gaza with Egypt.
CHINA
Various types of auto rickshaw are used around China, where they are called 三轮 (Sān lún - three wheeler) or 嘟嘟车 (Dū dū chē - beep beep car).
In Hainan, the southernmost province, electric models are used in the capital Haikou. These may be heavy, purpose-built vehicles, or simple bicycles attached to a light chassis, with a small electric motor housed underneath.
In rural areas, a sturdy, petrol-powered, plastic-bodied type is common, similar to the Philippine motorized tricycle.
INDIA
OVERVIEW
Most cities offer auto rickshaw service, although hand-pulled rickshaws do exist in some areas, such as Kolkata.
Auto rickshaws are used in cities and towns for short distances; they are less suited to long distances because they are slow and the carriages are open to air pollution. Auto rickshaws (often called "autos") provide cheap and efficient transportation. Modern auto rickshaws run on compressed natural gas (CNG) and are environmentally friendly compared to full-sized cars.
It is also not uncommon in many parts of India (including major cities like Delhi) to see primary school children crammed into an auto-rickshaw, transporting them between home and school.
To augment speedy movement of traffic, Auto rickshaws are not allowed in the southern part of Mumbai.
DESIGN & MANUFACTURE
There are two types of autorickshaws in India. In older versions the engines were situated below the driver's seat, while in newer versions engines are located in the rear. They normally run on petrol, CNG and diesel. The seating capacity of a normal rickshaw is four, including the driver's seat. Six-seater rickshaws exist in different parts of the country, but the model was officially banned in the city of Pune 10 January 2003 by the Regional Transport Authority (RTA).
CNG autos are distinguishable from the earlier petrol-powered autos by a green and yellow livery, as opposed to the earlier black and yellow appearance. Certain local governments are advocating for four-stroke engines instead of the current two-stroke versions.
Auto rickshaw manufacturers in India include Bajaj Auto, Kumar Motors, Kerala Automobiles Limited, Force Motors (previously Bajaj Tempo), Mahindra & Mahindra, Piaggio Ape and TVS Motors.
LEGISLATION
Generally rickshaw fares are controlled by the government.
INDONESIA
In Indonesia, auto rickshaws are popular in Jakarta, Medan, Java, and Sulawesi. In Jakarta, the auto rickshaws are similar to the ones in India but are colored blue and orange. Outside of Jakarta the bentor-style auto rickshaw is more ubiquitous, with the passenger cabin mounted as a sidecar to a motorcycle. Where these sidecar style auto rickshaws do occur in Jakarta they are not referred to as bentor, but rather as bajaj (bajai). They were also popular in East Java until the end of the 20th century and were known as a bemo.
LAOS
Lao tuk-tuks come as tuk-tuks or jumbo tuk-tuks. Jumbos have a larger 3- or 4-cylinder four-stroke engine, and many are powered by Daihatsu engines. Jumbos' larger engine and cabin size allow for greater loads, up to 12 persons, and higher top speeds. Jumbos are (with few exceptions) only found in Vientiane and Luang Prabang.
NEPAL
Auto rickshaws were the popular mode of transport in Nepal during the 1980s and 1990s, till Nepal Government decided to ban the movement of 600 such vehicles in the early 2000. Earliest model of auto rickshaw running in Kathmandu were manufactured by Bajaj Auto. Nepal has been a popular destination for Rickshaw Run. The 2009 Fall Run took place in Goa, India and concluded in Pokhara, Nepal.
PAKISTAN
Auto rickshaws are a popular mode of transport in Pakistani towns and is mainly used for traveling short distances within cities. One of the major brands of auto rickshaws is Vespa (an Italian Company). Lahore is hub of CNG Auto rikshaws manufacturers in Pakistan.The government of Pakistan is taking measures to convert all the gasoline run auto-rickshaws to more effective CNG rickshaw by 2015 in all the major cities of Pakistan by issuing easy loans through commercial banks. Environment Canada is implementing pilot projects in Lahore, Karachi and Quetta with engine technology developed in Mississauga, Ontario, Canada that uses CNG instead of gasoline in the two-stroke engines, in an effort to combat environmental pollution and noise levels.
In many cities in Pakistan, there are also motorcycle rickshaws, usually called chand gari (moon car) or Chingchi (after the Chinese company Jinan Qingqi Motorcycle Co. Ltd who first introduced these to the market).
Rickshaws are forbidden in the capital, Islamabad.
Auto rickshaws have had a history of displaying political statements. In February 2013, that legacy was modified to promote peace. According to Syed Ali Abbas Zaidi, head of the Pakistan Youth Alliance, "We need to take back this romanticized art form and use it for peace sloganeering and conflict resolution."
Manufacturers There are many companies involving in Rickshaw manufacturing in Pakistan, some of them are, AECO Export Company, STAHLCO Motors, Global Sources, Parhiyar Automobiles, Global Ledsys Technologies, Siwa Industries, Prime Punjab Automobiles, Murshid Farm Industries, Sazgar Automobiles, NTN Enterprises, Imperial Engineering Company
PHILLIPINES
Auto rickshaws are an especially popular form of public transportation in the Philippines, where they are referred to as "tricycles" (Filipino: traysikel; Cebuano: traysikol). In the Philippines, the design and configuration of tricycles varies widely from place to place, but tends towards rough standardization within each municipality. The usual design is a passenger or cargo sidecar fitted to a motorcycle, usually on the right of the motorcycle. It is rare to find one with a left sidecar. Tricycles can carry five passengers or more in the sidecar, one or two pillion passengers behind the motorcycle driver, and even a few on the roof of the sidecar. Tricycles are one of the main contributors to air pollution in the Philippines, since majority of them employ two-stroke motorcycles. However, some local governments are working towards phasing out two-stroke-powered tricycles for ones with cleaner four-stroke motorcycles.
SRI LANKA
Auto rickshaws, commonly known as three-wheelers and more recently tuk-tuk, can be found on all roads in Sri Lanka from the curvy roads through the hill country to the congested roads of Colombo transporting locals, foreigners, or freight about. Sri Lankan three-wheelers are of the style of the light Phnom Penh type. Most of the three-wheelers in Sri Lanka are a slightly modified Indian Bajaj model, imported from India though there are few manufactured locally and increasingly imports from other countries in the region and other brands of three-wheelers such as Piaggio. In 2007 January the Sri Lankan government imposed a ban on all 2-stroke three-wheelers, due to environmental concerns and therefore the ones imported to the island now are the ones with four-stroke engines. Most three-wheelers are available as hiring vehicles, with few being used to haul goods and as private company or advertising vehicles. Bajaj enjoys a virtual monopoly in the island, with its agent being David Pieries Motor Co Ltd. A few three-wheelers in Sri Lanka have distance meters, and in the capital city it is becoming more and more common, however the vast majority of charges are negotiated between the passenger and driver.
THAILAND
The auto rickshaw, called tuk-tuk (Thai: ตุ๊กตุ๊ก, pronounced "took-took") or sam-lor (Thai: สามล้อ) meaning three-wheeler in Thailand, is a widely used form of urban transport in Bangkok and other Thai cities. It is particularly popular where traffic congestion is a major problem, such as in Bangkok and Nakhon Ratchasima. The name is onomatopoeic, mimicking the sound of a small (often two-cycle) engine. An equivalent English term would be "putt-putt."
Bangkok and other cities in Thailand have many tuk-tuks which are a more open variation on the Indian auto-rickshaw. There are no meters, and trip costs are negotiated in advance. Bangkok fares have risen to nearly equal normal taxis due to uninformed foreigners willing to pay the asking price, but leaves passengers more exposed to environmental pollution than taxis. The solid roof is so low that the tuk-tuk is a difficult touring vehicle. Today few locals take one unless they are burdened with packages or travelling in a big group for short distances.
The Thai tuk-tuk is starting to change from the old smoke-spewing vehicle of yesteryear. Many Thai tuk-tuk manufacturers now produce low emission vehicles, and even old ones are having new engines fitted along with LPG conversions. In an early morning of Bangkok, these same passenger vehicles can be seen busily transporting fresh produce around the city. Newer tuk-tuks also have wet weather sides to keep passengers and drivers dry.
The Thai auto-rikshaw manufacturers are, Monika Motors Ltd., TukTuk (Thailand) Co., Ltd., TukTuk Forwerder Co., Ltd. Bangkok and MMW Tuk-Tuks Co.,Ltd. in Hua Hin. Smaller manufacturers are the Chinnaraje Co., Ltd. in Chiang Mai and the Expertise Co., Ltd. in Chonburi which manufactures its models in Komaki, Japan, also.
VIETNAM
Known locally as xe lam, the vernacular pronunciation of the Lambro from the Lambretta line by Innocenti of Italy, these vehicles were very popular in the 1960s and 1970s, especially the urban centers of South Vietnam. Over time the authorities have moved to limit their use.
Xe lam with 1-wheel forward and 2-aft were designed to carry passengers whereas other variants with 2-forward and 1-aft, used mostly to transport goods are known as Xe ba gác máy. The motorized version of cycle rickshaw is the Xích lô máy is of the same design.
EUROPE
FRANCE
A number of Tuk-tuks ( 250 in 2013 according to the Paris Prefecture)are used as an alternative tourist transport system in Paris, some off them being pedal operated with the help of an electric engine. They are not yet fully licenced to operate and await customers on the streets. 'Velos taxis' were common during the Occupation years in Paris due to fuel restrictions.
ITALY
Auto rickshaws have been commonly used in Italy since the late 1940s, providing a low-cost means of transportation in the post-World-War-II years when the country was short of economic resources. The Piaggio Ape, designed by Vespa creator Corradino D'Ascanio and first manufactured in 1948 by the Italian company Piaggio, though primarily designed for carrying freight has also been widely used as an auto rickshaw. It is still extremely popular throughout the country, being particularly useful in the narrow streets found in the center of many little towns in central and southern Italy. Though it no longer has a key role in transportation, Piaggio Ape is still used as a minitaxi in some areas such as the islands of Ischia and Stromboli (on Stromboli no cars are allowed). It has recently been re-launched as a trendy-ecological means of transportation, or, relying on the role the Ape played in the history of Italian design, as a promotional tool. Since 2006 the Ape has been produced under licence in India.
NETHERLANDS
Since 2007, tuk-tuks have been active in the Netherlands, starting with Amsterdam. They now operate in Amersfoort, Amsterdam, The Hague, Zandvoort, Bergen op Zoom, the popular beach resort Renesse and Rotterdam. The tuk-tuks in the Netherlands are imported from India and Thailand. They are fitted with CNG engines and have passed the EURO-4 rules.
UNITED KINGDOM
The first Tuk Tuks to enter service in the United Kingdom were supplied and built by MMW Imports in 1999, under the brand name MMW Tuk Tuks. The very first Private Hire licence was issued to an MMW Tuk Tuk for tours of Bath in the year 2000, MMW also gained full Hackney license in Weston-super-Mare. MMW also now export Tuk Tuks from Thailand to the Netherlands, Germany, Spain, New Zealand and Australia. All the MMW range are built in their own factory in Thailand and are custom made for each customer's needs; hence no two tuk tuks are the same, and they come fully customized as per required spec.
Tukshop of Southampton started the commercial importing of Tuk Tuks into the UK in 2003, which resulted in many people being inspired to set up taxi-type operations in a number of cities including Blackpool, Brighton and Leeds. Tukshop failed to gain a taxi operator license for London after a number of media appearances in 2004. The company, founded by mrsteve, are specialists in experiential marketing using the iconic three-wheelers for street marketing campaigns. Clients of Tukshop include many household names, such as T Mobile, Harrods, Universal Pictures, O2, BBC, Freeview, Price Waterhouse Coopers, Tiger Beer & Grolsch lager. Tukshop have imported and put over one hundred tuk tuks on the roads of the UK and Europe between starting the business and Oct 2010. The company currently stocks models from Piaggio & Bajaj, including the commercial versions such as the TM Van.
A Bajaj tuk tuk is currently operated by Bangwallop of Salcombe, South Devon. Taking just two passengers at a time, the tuk tuk has an operator's licence issued by VOSA and trips can be booked in advance.[citation needed]
Auto rickshaws were introduced to the city of Brighton and Hove on 10 July 2006 by entrepreneur Dominic Ponniah's company Tuctuc Ltd, who had the idea after seeing the vehicles used in India and Sri Lanka. They were CNG-powered, using a four-speed (plus reverse) 175 cc engine. Under the terms of their license, the Bajas ran on a fixed single route, and stopped only at designated stops. They are of the same design as traditional auto rickshaws in other countries.
An investigation was launched into Tuctuc Ltd's operation of the service after complaints were raised, primarily by the city's taxi drivers, that routes, stopping points and timetables were not being adhered to. In November 2006, the company was fined £16,500 – the maximum penalty possible – by the South East Traffic Commissioner. After amendments were made to the timetable to reduce delays and improve reliability, the Commissioner allowed the company to keep its operating license. However, the company announced in January 2008 that it was ceasing operations, citing "archaic legislation" as the reason.
In the Scottish capital, Edinburgh, there is a new street food restaurant called Tuk Tuk Indian Street Food, that has its own branded Tuk Tuks, which are used for marketing around the town and picking up customers on special occasions.
CENTRAL AMERICA
EL SALVADOR
The mototaxi or moto is the El Salvadoran version of the auto rickshaw. These are most commonly made from the front end and engine of a motorcycle attached to a two-wheeled passenger area in back. Commercially produced models, such as the Indian Bajaj brand, are also employed.
GUATEMALA
In Guatemala the commercial vehicles are referred to as tuk-tuks. Tuk-tuks operate, both as taxis and private vehicles, in Guatemala City, Guatemala, around the island town of Flores, Peten, in the mountain city of Antigua Guatemala, and in many small towns in the mountains. In 2005 the tuk-tuks prevalent in the Lago de Atitlán towns of Panajachel and Santiago Atitlán all appeared to be from India (Bajaj Auto).
HONDURAS
Three-wheeled all-in-one tuk-tuks are used in the place of traditional taxis in most rural towns and villages.
NICARAGUA
As of 2011 there were an estimated 5,000 mototaxis, popularly known as "caponeras".
CARIBBEAN
Three-wheeled Coco taxis in Havana, Cuba
CUBA
Three-wheeled Coco taxis, named for their resemblance to a coconut, are used in Havana, Cuba.
SOUTH AMERICA
ECUADOR
The mototaxi is the Ecuatorian version of the auto rickshaw. These are most commonly made from the front end and engine of a motorcycle attached to a two-wheeled passenger area in back.
PERU
It is a common sight in the rural areas, towns and cities of Peru to see auto rickshaws, locally known as "mototaxis," "motokars", "taxi cholo", or "cholotaxi" lining up to pick up passengers as their fares are generally lower than car taxis. They are also in the capital, Lima, but they are usually restricted to the peripheral districts. The "jungle" cities and towns in eastern Peru are famous for their prevalence of auto rickshaws. This vehicle, usually running on regular unleaded gasoline, is the main non-private transport vehicle, and is known as "motocarro", "mototaxi" or "tuk-tuk" (for foreigners).
Many of the jungle areas of eastern Peru can be extremely noisy as a result of poorly maintained auto rickshaws and other 2 or 3-wheel vehicles, especially in high traffic or hilly areas. Auto-rickshaw brands such as the Indian-made Bajaj, which use GLP [a form of liquified petroleum gas which some car taxis also use] are much quieter.
NORTH AMERICA
UNITED STATES
Tuk Tuks were introduced to the United States through Tuk Tuk North America of Swainsboro, Georgia. As early as 2006, Mr. Roy Jordan, the owner of Tuk Tuk North America, began working with both the U.S. federal government and manufacturers in Thailand to configure a tuk tuk that was cost effective but adaptable to meet or exceed U.S. Department of Transportation regulations. He was able to contract a manufacturer who could make imported tuk tuks that could meet all necessary federal regulations in the U.S. Original products were imported from Thailand and were gas propelled. Due to the changing regulations of the Environmental Protection Agency, the introduction of imported gas-propelled tuk tuks was short-lived. Due to such changes, in 2009 Tuk Tuk North America decided to go dormant in its importing of gas propelled tuk tuks into the U.S.
However, with the growing emphasis on sustainable “green” energy and the recognition of the continuing rising oil prices, in 2011 the project's short dormancy was rejuvenated being redirected towards introduction of a complete line of all-electric tuk tuks. The line included eight models of "street legal" tuk tuks including passenger, utility, and delivery vehicles. These were offered under the manufacturer’s new name, Electro Technologies LLC, and marketed and sold exclusively through Tuk Tuk Transport LLC of Lenoir City, Tennessee, under the leadership of C. Phillip Tallant.
Prior to 2013, the greatest obstacle to commercial transportation usage of the electric tuk tuks created by Electro Technologies was addressed in mid 2013 by providing a means by which ET Tuk Tuks could be in service 24/7. With this advancement grew the opportunity for formation of Tuk Tuk of America, a company by which partnering affiliates across the U.S. could begin their own local niche urban mobility transportation company with guaranteed protected territories.
FUEL EFFICIENCY & POLLUTION
In July 1998, the Supreme Court of India ordered the Delhi government to implement CNG or LPG (Autogas) fuel for all autos and for the entire bus fleet in and around the city.[citation needed] Delhi's air quality has improved with the switch to CNG. Initially, auto rickshaw drivers in Delhi had to wait in long queues for CNG refueling, but the situation has improved with the increase of CNG stations. Certain local governments are pushing for four-stroke engines instead of the current two-stroke versions. Typical mileage for an Indian-made auto rickshaw is around 35 kilometers per liter of petrol (about 2.9 L per 100 km, or 82 miles per gallon [United States (wet measure), 100 miles per gallon Imperial (United Kingdom, Canada)]. Pakistan has passed a similar law prohibiting auto rickshaws in certain areas. CNG auto rickshaws have started to appear in huge numbers in many Pakistani cities.
In January 2007 the Sri Lankan government also banned two-stroke trishaws to reduce air pollution. In the Philippines there are projects to convert carburated two-stroke engines to direct-injected via Envirofit technology. Research has shown LPG or CNG gas direct-injection to be retrofit-able to existing engines in similar fashion to the Envirofit system. In Vigan City majority of tricycles-for-hire as of 2008 are powered by motorcycles with four-stroke engines, as tricycles with two-stroke motorcycles are prevented from receiving operating permits. Direct injection is standard equipment on new machines in India.
In March 2009 an international consortium coordinated by the International Centre for Hydrogen Energy Technologies initiated a two-year public-private partnership of local and international stakeholders aiming at operating a fleet of 15 hydrogen-fueled three-wheeled vehicles in New Delhi's Pragati Maidan complex. As of January 2011, the project was upon completion.
In the meantime, in October, 2011, the Department of Transportation for the U.S. approved the complete 2012 series of American made, all-electric tuk tuks by Electro Technologies. Chassis were still being shipped in from Thailand, but now with the inclusion of all electrical components as manufactured only in the U.S. with assembly completed in Chattanooga, Tennessee. The American made electric tuk tuks were unique in that they were charged through common 110v outlets providing a range of 60 to 100(+) miles per charge (depending upon model and conditions) with a recharge time between 4 to 6 hours. The Electro Technologies Tuk Tuks topped out at 40 miles per hour which perfectly addresses the needs of their design; niche urban mobile transportation.
The greatest obstacle to daily usage in niche urban mobile commercial transportation was addressed in 2013 by Electro Technologies when they introduced their quick-release battery pack allowing for restoration of 100% power availability in just a few short minutes. This commercial upgrade allowed niche urban transportation businesses to operate 24/7 with no interruption to business.
TRAFFIC ISSUES
Auto rickshaws have a top-speed of around 50 km/h (about 31 mph) and a cruising speed of around 35 km/h (22 mph), much slower than the automobiles they share the road with. Traffic authorities in big cities try to implement mechanisms to reduce the resulting traffic slowing, but none have proven effective.
The MMW Tuk Tuk has a top speed of around 70 mph and with the introduction of the new turbo will have much improved acceleration, to allow for increased speed these Tuk Tuks have anti-roll bars and are fitted with disc brakes.
The triangular form of the vehicle makes maneuvering easy, with the single front wheel negotiating the available gap, and the rear two wheels forcing a larger space. Care must be taken even at low speeds, however, because of the stability problems of three-wheeler vehicles with a single front wheel. Such a "delta"-configuration three-wheeler can easily roll if the driver turns while braking.
In the Philippines, 2-stroke motor tricycle such as Yamaha RS-100T can give a top speed of 55 km/h (one passenger in the sidecar), or 30–40 km/h (full passengers in the sidecar).
More powerful four-stroke motor tricycles such as Honda TMX & Yamaha STX & Bajaj CT-100 can give a top speed up to 70–85 km/h (special trip/one passenger) or 40–50 km/h (full passengers).
RACING
Due to their relatively low top-speed, auto rickshaws have never lent themselves to conventional road or street racing. However, their modest speed, simple construction and impressive fuel economy has endeared them to the international amateur adventuring community, most notably with the Rickshaw Run and also the Indian Autorickshaw Challenge, and even off-road racing with the Apecar competitions in Italy. A Tuk Tuk built by Art In Motion, LLC competed in the 2008 Fireball Run II – Back to the Track
PORTRAYAL IN MEDIA
Auto rickshaws are often portrayed in Indian films (Auto Shankar, Basha, Aye Auto, Oram Po, Hero Hiralal) as well as some Hollywood and foreign productions such as the James Bond film Octopussy, the Canada-India film Amal and the Indonesian movie Pembalasan Rambu. Auto rickshaws are also prominent in the fuel-poor London of 2027 A.D. depicted in Children of Men. A memorable tuk-tuk chase features in the Thai film Ong-Bak: Muay Thai Warrior, climaxing with many of them driving off the edge of an unfinished elevated expressway. The video games Just Cause 2, Stuntman, Far Cry 4 and Battlefield: Bad Company 2: Vietnam feature Tuk-Tuks as drivable vehicles. James Bond (Pierce Brosnan) rides in a tuk-tuk in a Visa Card commercial.
WIKIPEDIA
Different forms of fluctuations of the terrestrial gravity field are observed by gravity experiments. For example, atmospheric pressure fluctuations generate a gravity-noise foreground in measurements with super-conducting gravimeters. Gravity changes caused by high-magnitude earthquakes have been detected with the satellite gravity experiment GRACE, and we expect high-frequency terrestrial gravity fluctuations produced by ambient seismic fields to limit the sensitivity of ground-based gravitational-wave (GW) detectors. Accordingly, terrestrial gravity fluctuations are considered noise and signal depending on the experiment. Here, we will focus on ground-based gravimetry. This field is rapidly progressing through the development of GW detectors. The technology is pushed to its current limits in the advanced generation of the LIGO and Virgo detectors, targeting gravity strain sensitivities better than 10−23 Hz−1/2 above a few tens of a Hz. Alternative designs for GW detectors evolving from traditional gravity gradiometers such as torsion bars, atom interferometers, and superconducting gradiometers are currently being developed to extend the detection band to frequencies below 1 Hz. The goal of this article is to provide the analytical framework to describe terrestrial gravity perturbations in these experiments. Models of terrestrial gravity perturbations related to seismic fields, atmospheric disturbances, and vibrating, rotating or moving objects, are derived and analyzed. The models are then used to evaluate passive and active gravity noise mitigation strategies in GW detectors, or alternatively, to describe their potential use in geophysics. The article reviews the current state of the field, and also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations, active gravity noise cancellation, and time-domain models of gravity perturbations from atmospheric and seismic point sources. Our understanding of terrestrial gravity fluctuations will have great impact on the future development of GW detectors and high-precision gravimetry in general, and many open questions need to be answered still as emphasized in this article.
Keywords: Terrestrial gravity, Newtonian noise, Wiener filter, Mitigation
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Introduction
In the coming years, we will see a transition in the field of high-precision gravimetry from observations of slow lasting changes of the gravity field to the experimental study of fast gravity fluctuations. The latter will be realized by the advanced generation of the US-based LIGO [1] and Europe-based Virgo [7] gravitational-wave (GW) detectors. Their goal is to directly observe for the first time GWs that are produced by astrophysical sources such as inspiraling and merging neutron-star or black-hole binaries. Feasibility of the laser-interferometric detector concept has been demonstrated successfully with the first generation of detectors, which, in addition to the initial LIGO and Virgo detectors, also includes the GEO600 [119] and TAMA300 [161] detectors, and several prototypes around the world. The impact of these projects onto the field is two-fold. First of all, the direct detection of GWs will be a milestone in science opening a new window to our universe, and marking the beginning of a new era in observational astronomy. Second, several groups around the world have already started to adapt the technology to novel interferometer concepts [60, 155], with potential applications not only in GW science, but also geophysics. The basic measurement scheme is always the same: the relative displacement of test masses is monitored by using ultra-stable lasers. Progress in this field is strongly dependent on how well the motion of the test masses can be shielded from the environment. Test masses are placed in vacuum and are either freely falling (e.g., atom clouds [137]), or suspended and seismically isolated (e.g., high-quality glass or crystal mirrors as used in all of the detectors listed above). The best seismic isolations realized so far are effective above a few Hz, which limits the frequency range of detectable gravity fluctuations. Nonetheless, low-frequency concepts are continuously improving, and it is conceivable that future detectors will be sufficiently sensitive to detect GWs well below a Hz [88].
Terrestrial gravity perturbations were identified as a potential noise source already in the first concept laid out for a laser-interferometric GW detector [171]. Today, this form of noise is known as “terrestrial gravitational noise”, “Newtonian noise”, or “gravity-gradient noise”. It has never been observed in GW detectors, but it is predicted to limit the sensitivity of the advanced GW detectors at low frequencies. The most important source of gravity noise comes from fluctuating seismic fields [151]. Gravity perturbations from atmospheric disturbances such as pressure and temperature fluctuations can become significant at lower frequencies [51]. Anthropogenic sources of gravity perturbations are easier to avoid, but could also be relevant at lower frequencies [163]. Today, we only have one example of a direct observation of gravity fluctuations, i.e., from pressure fluctuations of the atmosphere in high-precision gravimeters [128]. Therefore, almost our entire understanding of gravity fluctuations is based on models. Nonetheless, potential sensitivity limits of future large-scale GW detectors need to be identified and characterized well in advance, and so there is a need to continuously improve our understanding of terrestrial gravity noise. Based on our current understanding, the preferred option is to construct future GW detectors underground to avoid the most dominant Newtonian-noise contributions. This choice was made for the next-generation Japanese GW detector KAGRA, which is currently being constructed underground at the Kamioka site [17], and also as part of a design study for the Einstein Telescope in Europe [140, 139]. While the benefit from underground construction with respect to gravity noise is expected to be substantial in GW detectors sensitive above a few Hz [27], it can be argued that it is less effective at lower frequencies [88].
Alternative mitigation strategies includes coherent noise cancellation [42]. The idea is to monitor the sources of gravity perturbations using auxiliary sensors such as microphones and seismometers, and to use their data to generate a coherent prediction of gravity noise. This technique is successfully applied in gravimeters to reduce the foreground of atmospheric gravity noise using collocated pressure sensors [128]. It is also noteworthy that the models of the atmospheric gravity noise are consistent with observations. This should give us some confidence at least that coherent Newtonian-noise cancellation can also be achieved in GW detectors. It is evident though that a model-based prediction of the performance of coherent noise cancellation schemes is prone to systematic errors as long as the properties of the sources are not fully understood. Ongoing experiments at the Sanford Underground Research Facility with the goal to characterize seismic fields in three dimensions are expected to deliver first data from an underground seismometer array in 2015 (see [89] for results from an initial stage of the experiment). While most people would argue that constructing GW detectors underground is always advantageous, it is still necessary to estimate how much is gained and whether the science case strongly profits from it. This is a complicated problem that needs to be answered as part of a site selection process.
More recently, high-precision gravity strainmeters have been considered as monitors of geophysical signals [83]. Analytical models have been calculated, which allow us to predict gravity transients from seismic sources such as earthquakes. It was suggested to implement gravity strainmeters in existing earthquake-early warning systems to increase warning times. It is also conceivable that an alternative method to estimate source parameters using gravity signals will improve our understanding of seismic sources. Potential applications must still be investigated in greater detail, but the study already demonstrates that the idea to use GW technology to realize new geophysical sensors seems feasible. As explained in [49], gravitational forces start to dominate the dynamics of seismic phenomena below about 1 mHz (which coincides approximately with a similar transition in atmospheric dynamics where gravity waves start to dominate over other forms of oscillations [164]). Seismic isolation would be ineffective below 1 mHz since the gravitational acceleration of a test mass produced by seismic displacement becomes comparable to the seismic acceleration itself. Therefore, we claim that 10 mHz is about the lowest frequency at which ground-based gravity strainmeters will ever be able to detect GWs, and consequently, modelling terrestrial gravity perturbations in these detectors can focus on frequencies above 10 mHz.
This article is divided into six main sections. Section 2 serves as an introduction to gravity measurements focussing on the response mechanisms and basic properties of gravity sensors. Section 3 describes models of gravity perturbations from ambient seismic fields. The results can be used to estimate noise spectra at the surface and underground. A subsection is devoted to the problem of noise estimation in low-frequency GW detectors, which differs from high-frequency estimates mostly in that gravity perturbations are strongly correlated between different test masses. In the low-frequency regime, the gravity noise is best described as gravity-gradient noise. Section 4 is devoted to time domain models of transient gravity perturbations from seismic point sources. The formalism is applied to point forces and shear dislocations. The latter allows us to estimate gravity perturbations from earthquakes. Atmospheric models of gravity perturbations are presented in Section 5. This includes gravity perturbations from atmospheric temperature fields, infrasound fields, shock waves, and acoustic noise from turbulence. The solution for shock waves is calculated in time domain using the methods of Section 4. A theoretical framework to calculate gravity perturbations from objects is given in Section 6. Since many different types of objects can be potential sources of gravity perturbations, the discussion focusses on the development of a general method instead of summarizing all of the calculations that have been done in the past. Finally, Section 7 discusses possible passive and active noise mitigation strategies. Due to the complexity of the problem, most of the section is devoted to active noise cancellation providing the required analysis tools and showing limitations of this technique. Site selection is the main topic under passive mitigation, and is discussed in the context of reducing environmental noise and criteria relevant to active noise cancellation. Each of these sections ends with a summary and a discussion of open problems. While this article is meant to be a review of the current state of the field, it also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations (Sections 3.3.2 and 3.3.3), active gravity noise cancellation (Section 7.1.3), and timedomain models of gravity perturbations from atmospheric and seismic point sources (Sections 4.1, 4.5, and 5.3).
Even though evident to experts, it is worth emphasizing that all calculations carried out in this article have a common starting point, namely Newton’s universal law of gravitation. It states that the attractive gravitational force equation M1 between two point masses m1, m2 is given by
equation M21
where G = 6.672 × 10−11 N m2/kg2 is the gravitational constant. Eq. (1) gives rise to many complex phenomena on Earth such as inner-core oscillations [156], atmospheric gravity waves [157], ocean waves [94, 177], and co-seismic gravity changes [122]. Due to its importance, we will honor the eponym by referring to gravity noise as Newtonian noise in the following. It is thereby clarified that the gravity noise models considered in this article are non-relativistic, and propagation effects of gravity changes are neglected. While there could be interesting scenarios where this approximation is not fully justified (e.g., whenever a gravity perturbation can be sensed by several sensors and differences in arrival times can be resolved), it certainly holds in any of the problems discussed in this article. We now invite the reader to enjoy the rest of the article, and hope that it proves to be useful.
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Gravity Measurements
In this section, we describe the relevant mechanisms by which a gravity sensor can couple to gravity perturbations, and give an overview of the most widely used measurement schemes: the (relative) gravimeter [53, 181], the gravity gradiometer [125], and the gravity strainmeter. The last category includes the large-scale GW detectors Virgo [6], LIGO [91], GEO600 [119], KAGRA [17], and a new generation of torsion-bar antennas currently under development [13]. Also atom interferometers can potentially be used as gravity strainmeters in the future [62]. Strictly speaking, none of the sensors only responds to a single field quantity (such as changes in gravity acceleration or gravity strain), but there is always a dominant response mechanism in each case, which justifies to give the sensor a specific name. A clear distinction between gravity gradiometers and gravity strainmeters has never been made to our knowledge. Therefore the sections on these two measurement principles will introduce a definition, and it is by no means the only possible one. Later on in this article, we almost exclusively discuss gravity models relevant to gravity strainmeters since the focus lies on gravity fluctuations above 10 mHz. Today, the sensitivity near 10 mHz of gravimeters towards gravity fluctuations is still competitive to or exceeds the sensitivity of gravity strainmeters, but this is likely going to change in the future so that we can expect strainmeters to become the technology of choice for gravity observations above 10 mHz [88]. The following sections provide further details on this statement. Space-borne gravity experiments such as GRACE [167] will not be included in this overview. The measurement principle of GRACE is similar to that of gravity strainmeters, but only very slow changes of Earth gravity field can be observed, and for this reason it is beyond the scope of this article.
The different response mechanisms to terrestrial gravity perturbations are summarized in Section 2.1. While we will identify the tidal forces acting on the test masses as dominant coupling mechanism, other couplings may well be relevant depending on the experiment. The Shapiro time delay will be discussed as the only relativistic effect. Higher-order relativistic effects are neglected. All other coupling mechanisms can be calculated using Newtonian theory including tidal forces, coupling in static non-uniform gravity fields, and coupling through ground displacement induced by gravity fluctuations. In Sections 2.2 to 2.4, the different measurement schemes are explained including a brief summary of the sensitivity limitations (choosing one of a few possible experimental realizations in each case). As mentioned before, we will mostly develop gravity models relevant to gravity strainmeters in the remainder of the article. Therefore, the detailed discussion of alternative gravimetry concepts mostly serves to highlight important differences between these concepts, and to develop a deeper understanding of the instruments and their role in gravity measurements.
Gravity response mechanisms
Gravity acceleration and tidal forces We will start with the simplest mechanism of all, the acceleration of a test mass in the gravity field. Instruments that measure the acceleration are called gravimeters. A test mass inside a gravimeter can be freely falling such as atom clouds [181] or, as suggested as possible future development, even macroscopic objects [72]. Typically though, test masses are supported mechanically or magnetically constraining motion in some of its degrees of freedom. A test mass suspended from strings responds to changes in the horizontal gravity acceleration. A test mass attached at the end of a cantilever with horizontal equilibrium position responds to changes in vertical gravity acceleration. The support fulfills two purposes. First, it counteracts the static gravitational force in a way that the test mass can respond to changes in the gravity field along a chosen degree of freedom. Second, it isolates the test mass from vibrations. Response to signals and isolation performance depend on frequency. If the support is modelled as a linear, harmonic oscillator, then the test mass response to gravity changes extends over all frequencies, but the response is strongly suppressed below the oscillators resonance frequency. The response function between the gravity perturbation δg(ω) and induced test mass acceleration δa(ω) assumes the form
equation M32
where we have introduced a viscous damping parameter γ, and ω0 is the resonance frequency. Well below resonance, the response is proportional to ω2, while it is constant well above resonance. Above resonance, the supported test mass responds like a freely falling mass, at least with respect to “soft” directions of the support. The test-mass response to vibrations δα(ω) of the support is given by
equation M43
This applies for example to horizontal vibrations of the suspension points of strings that hold a test mass, or to vertical vibrations of the clamps of a horizontal cantilever with attached test mass. Well above resonance, vibrations are suppressed by ω−2, while no vibration isolation is provided below resonance. The situation is somewhat more complicated in realistic models of the support especially due to internal modes of the mechanical system (see for example [76]), or due to coupling of degrees of freedom [121]. Large mechanical support structures can feature internal resonances at relatively low frequencies, which can interfere to some extent with the desired performance of the mechanical support [173]. While Eqs. (2) and (3) summarize the properties of isolation and response relevant for this paper, details of the readout method can fundamentally impact an instrument’s response to gravity fluctuations and its susceptibility to seismic noise, as explained in Sections 2.2 to 2.4.
Next, we discuss the response to tidal forces. In Newtonian theory, tidal forces cause a relative acceleration δg12(ω) between two freely falling test masses according to
equation M54
where equation M6 is the Fourier amplitude of the gravity potential. The last equation holds if the distance r12 between the test masses is sufficiently small, which also depends on the frequency. The term equation M7 is called gravity-gradient tensor. In Newtonian approximation, the second time integral of this tensor corresponds to gravity strain equation M8, which is discussed in more detail in Section 2.4. Its trace needs to vanish in empty space since the gravity potential fulfills the Poisson equation. Tidal forces produce the dominant signals in gravity gradiometers and gravity strainmeters, which measure the differential acceleration or associated relative displacement between two test masses (see Sections 2.3 and 2.4). If the test masses used for a tidal measurement are supported, then typically the supports are designed to be as similar as possible, so that the response in Eq. (2) holds for both test masses approximately with the same parameter values for the resonance frequencies (and to a lesser extent also for the damping). For the purpose of response calibration, it is less important to know the parameter values exactly if the signal is meant to be observed well above the resonance frequency where the response is approximately equal to 1 independent of the resonance frequency and damping (here, “well above” resonance also depends on the damping parameter, and in realistic models, the signal frequency also needs to be “well below” internal resonances of the mechanical support).
Shapiro time delay Another possible gravity response is through the Shapiro time delay [19]. This effect is not universally present in all gravity sensors, and depends on the readout mechanism. Today, the best sensitivities are achieved by reflecting laser beams from test masses in interferometric configurations. If the test mass is displaced by gravity fluctuations, then it imprints a phase shift onto the reflected laser, which can be observed in laser interferometers, or using phasemeters. We will give further details on this in Section 2.4. In Newtonian gravity, the acceleration of test masses is the only predicted response to gravity fluctuations. However, from general relativity we know that gravity also affects the propagation of light. The leading-order term is the Shapiro time delay, which produces a phase shift of the laser beam with respect to a laser propagating in flat space. It can be calculated from the weak-field spacetime metric (see chapter 18 in [124]):
equation M95
Here, c is the speed of light, ds is the so-called line element of a path in spacetime, and equation M10. Additionally, for this metric to hold, motion of particles in the source of the gravity potential responsible for changes of the gravity potential need to be much slower than the speed of light, and also stresses inside the source must be much smaller than its mass energy density. All conditions are fulfilled in the case of Earth gravity field. Light follows null geodesics with ds2 = 0. For the spacetime metric in Eq. (5), we can immediately write
equation M116
As we will find out, this equation can directly be used to calculate the time delay as an integral along a straight line in terms of the coordinates equation M12, but this is not immediately clear since light bends in a gravity field. So one may wonder if integration along the proper light path instead of a straight line yields additional significant corrections. The so-called geodesic equation must be used to calculate the path. It is a set of four differential equations, one for each coordinate t, equation M13 in terms of a parameter λ. The weak-field geodesic equation is obtained from the metric in Eq. (5):
equation M147
where we have made use of Eq. (6) and the slow-motion condition equation M15. The coordinates equation M16 are to be understood as functions of λ. Since the deviation of a straight path is due to a weak gravity potential, we can solve these equations by perturbation theory introducing expansions equation M17 and t = t(0) +t(1) + …. The superscript indicates the order in ψ/c2. The unperturbed path has the simple parametrization
equation M188
We have chosen integration constants such that unperturbed time t(0) and parameter λ can be used interchangeably (apart from a shift by t0). Inserting these expressions into the right-hand side of Eq. (7), we obtain
equation M199
As we can see, up to linear order in equation M20, the deviation equation M21 is in orthogonal direction to the unperturbed path equation M22, which means that the deviation can be neglected in the calculation of the time delay. After some transformations, it is possible to derive Eq. (6) from Eq. (9), and this time we find explicitly that the right-hand-side of the equation only depends on the unperturbed coordinates1. In other words, we can integrate the time delay along a straight line as defined in Eq. (8), and so the total phase integrated over a travel distance L is given by
equation M2310
In static gravity fields, the phase shift doubles if the light is sent back since not only the direction of integration changes, but also the sign of the expression substituted for dt/dλ.
Gravity induced ground motion As we will learn in Section 3, seismic fields produce gravity perturbations either through density fluctuations of the ground, or by displacing interfaces between two materials of different density. It is also well-known in seismology that seismic fields can be affected significantly by self-gravity. Self-gravity means that the gravity perturbation produced by a seismic field acts back on the seismic field. The effect is most significant at low frequency where gravity induced acceleration competes against acceleration from elastic forces. In seismology, low-frequency seismic fields are best described in terms of Earth’s normal modes [55]. Normal modes exist as toroidal modes and spheroidal modes. Spheroidal modes are influenced by self-gravity, toroidal modes are not. For example, predictions of frequencies and shapes of spheroidal modes based on Earth models such as PREM (Preliminary Reference Earth Model) [68] are inaccurate if self-gravity effects are excluded. What this practically means is that in addition to displacement amplitudes, gravity becomes a dynamical variable in the elastodynamic equations that determine the normal-mode properties. Therefore, seismic displacement and gravity perturbation cannot be separated in normal-mode formalism (although self-gravity can be neglected in calculations of spheroidal modes at sufficiently high frequency).
In certain situations, it is necessary or at least more intuitive to separate gravity from seismic fields. An exotic example is Earth’s response to GWs [67, 49, 47, 30, 48]. Another example is the seismic response to gravity perturbations produced by strong seismic events at large distance to the source as described in Section 4. It is more challenging to analyze this scenario using normal-mode formalism. The sum over all normal modes excited by the seismic event (each of which describing a global displacement field) must lead to destructive interference of seismic displacement at large distances (where seismic waves have not yet arrived), but not of the gravity amplitudes since gravity is immediately perturbed everywhere. It can be easier to first calculate the gravity perturbation from the seismic perturbation, and then to calculate the response of the seismic field to the gravity perturbation at larger distance. This method will be adopted in this section. Gravity fields will be represented as arbitrary force or tidal fields (detailed models are presented in later sections), and we simply calculate the response of the seismic field. Normal-mode formalism can be avoided only at sufficiently high frequencies where the curvature of Earth does not significantly influence the response (i.e., well above 10 mHz). In this section, we will model the ground as homogeneous half space, but also more complex geologies can in principle be assumed.
Gravity can be introduced in two ways into the elastodynamic equations, as a conservative force −∇ψ [146, 169], or as tidal strain The latter method was described first by Dyson to calculate Earth’s response to GWs [67]. The approach also works for Newtonian gravity, with the difference that the tidal field produced by a GW is necessarily a quadrupole field with only two degrees of freedom (polarizations), while tidal fields produced by terrestrial sources are less constrained. Certainly, GWs can only be fully described in the framework of general relativity, which means that their representation as a Newtonian tidal field cannot be used to explain all possible observations [124]. Nonetheless, important here is that Dyson’s method can be extended to Newtonian tidal fields. Without gravity, the elastodynamic equations for small seismic displacement can be written as
equation M2411
where equation M25 is the seismic displacement field, and equation M26 is the stress tensor [9]. In the absence of other forces, the stress is determined by the seismic field. In the case of a homogeneous and isotropic medium, the stress tensor for small seismic displacement can be written as
equation M2712
The quantity equation M28 is known as seismic strain tensor, and λ, μ are the Lamé constants (see Section 3.1). Its trace is equal to the divergence of the displacement field. Dyson introduced the tidal field from first principles using Lagrangian mechanics, but we can follow a simpler approach. Eq. (12) means that a stress field builds up in response to a seismic strain field, and the divergence of the stress field acts as a force producing seismic displacement. The same happens in response to a tidal field, which we represent as gravity strain equation M29. A strain field changes the distance between two freely falling test masses separated by equation M30 by equation M312. For sufficiently small distances L, the strain field can be substituted by the second time integral of the gravity-gradient tensor equation M32. If the masses are not freely falling, then the strain field acts as an additional force. The corresponding contribution to the material’s stress tensor can be written
equation M3313
Since we assume that the gravity field is produced by a distant source, the local contribution to gravity perturbations is neglected, which means that the gravity potential obeys the Laplace equation, equation M34. Calculating the divergence of the stress tensor according to Eq. (11), we find that the gravity term vanishes! This means that a homogeneous and isotropic medium does not respond to gravity strain fields. However, we have to be more careful here. Our goal is to calculate the response of a half-space to gravity strain. Even if the half-space is homogeneous, the Lamé constants change discontinuously across the surface. Hence, at the surface, the divergence of the stress tensor reads
equation M3514
In other words, tidal fields produce a force onto an elastic medium via gradients in the shear modulus (second Lamé constant). The gradient of the shear modulus can be written in terms of a Dirac delta function, equation M36, for a flat surface at z = 0 with unit normal vector equation M37. The response to gravity strain fields is obtained applying the boundary condition of vanishing surface traction, equation M38:
equation M3915
Once the seismic strain field is calculated, it can be used to obtain the seismic stress, which determines the displacement field equation M40 according to Eq. (11). In this way, one can for example calculate that a seismometer or gravimeter can observe GWs by monitoring surface displacement as was first calculated by Dyson [67].
Coupling in non-uniform, static gravity fields If the gravity field is static, but non-uniform, then displacement equation M41 of the test mass in this field due to a non-gravitational fluctuating force is associated with a changing gravity acceleration according to
equation M4216
We introduce a characteristic length λ, over which gravity acceleration varies significantly. Hence, we can rewrite the last equation in terms of the associated test-mass displacement ζ
equation M4317
where we have neglected directional dependence and numerical factors. The acceleration change from motion in static, inhomogeneous fields is generally more significant at low frequencies. Let us consider the specific case of a suspended test mass. It responds to fluctuations in horizontal gravity acceleration. The test mass follows the motion of the suspension point in vertical direction (i.e., no seismic isolation), while seismic noise in horizontal direction is suppressed according to Eq. (3). Accordingly, it is possible that the unsuppressed vertical (z-axis) seismic noise ξz(t) coupling into the horizontal (x-axis) motion of the test mass through the term ∂xgz = ∂zgx dominates over the gravity response term in Eq. (2). Due to additional coupling mechanisms between vertical and horizontal motion in real seismic-isolation systems, test masses especially in GW detectors are also isolated in vertical direction, but without achieving the same noise suppression as in horizontal direction. For example, the requirements on vertical test-mass displacement for Advanced LIGO are a factor 1000 less stringent than on the horizontal displacement [22]. Requirements can be set on the vertical isolation by estimating the coupling of vertical motion into horizontal motion, which needs to take the gravity-gradient coupling of Eq. (16) into account. Although, because of the frequency dependence, gravity-gradient effects are more significant in low-frequency detectors, such as the space-borne GW detector LISA [154].
Next, we calculate an estimate of gravity gradients in the vicinity of test masses in large-scale GW detectors, and see if the gravity-gradient coupling matters compared to mechanical vertical-to-horizontal coupling.
One contribution to gravity gradients will come from the vacuum chamber surrounding the test mass. We approximate the shape of the chamber as a hollow cylinder with open ends (open ends just to simplify the calculation). In our calculation, the test mass can be offset from the cylinder axis and be located at any distance to the cylinder ends (we refer to this coordinate as height). The gravity field can be expressed in terms of elliptic integrals, but the explicit solution is not of concern here. Instead, let us take a look at the results in Figure Figure1.1. Gravity gradients ∂zgx vanish if the test mass is located on the symmetry axis or at height L/2. There are also two additional ∂zgx = 0 contour lines starting at the symmetry axis at heights ∼ 0.24 and ∼0.76. Let us assume that the test mass is at height 0.3L, a distance 0.05L from the cylinder axis, the total mass of the cylinder is M = 5000 kg, and the cylinder height is L = 4 m. In this case, the gravity-gradient induced vertical-to-horizontal coupling factor at 20 Hz is
equation M4418
This means that gravity-gradient induced coupling is extremely weak, and lies well below estimates of mechanical coupling (of order 0.001 in Advanced LIGO3). Even though the vacuum chamber was modelled with a very simple shape, and additional asymmetries in the mass distribution around the test mass may increase gravity gradients, it still seems very unlikely that the coupling would be significant. As mentioned before, one certainly needs to pay more attention when calculating the coupling at lower frequencies. The best procedure is of course to have a 3D model of the near test-mass infrastructure available and to use it for a precise calculation of the gravity-gradient field.
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Figure 1
Gravity gradients inside hollow cylinder. The total height of the cylinder is L, and M is its total mass. The radius of the cylinder is 0.3L. The axes correspond to the distance of the test mass from the symmetry axis of the cylinder, and its height above one of the cylinders ends. The plot on the right is simply a zoom of the left plot into the intermediate heights.
Gravimeters
Gravimeters are instruments that measure the displacement of a test mass with respect to a non-inertial reference rigidly connected to the ground. The test mass is typically supported mechanically or magnetically (atom-interferometric gravimeters are an exception), which means that the test-mass response to gravity is altered with respect to a freely falling test mass. We will use Eq. (2) as a simplified response model. There are various possibilities to measure the displacement of a test mass. The most widespread displacement sensors are based on capacitive readout, as for example used in superconducting gravimeters (see Figure Figure22 and [96]). Sensitive displacement measurements are in principle also possible with optical readout systems; a method that is (necessarily) implemented in atom-interferometric gravimeters [137], and prototype seismometers [34] (we will explain the distinction between seismometers and gravimeters below). As will become clear in Section 2.4, optical readout is better suited for displacement measurements over long baselines, as required for the most sensitive gravity strain measurements, while the capacitive readout should be designed with the smallest possible distance between the test mass and the non-inertial reference [104].
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Figure 2
Sketch of a levitated sphere serving as test mass in a superconducting gravimeter. Dashed lines indicate magnetic field lines. Coils are used for levitation and precise positioning of the sphere. Image reproduced with permission from [96]; copyright by Elsevier.
Let us take a closer look at the basic measurement scheme of a superconducting gravimeter shown in Figure Figure2.2. The central part is formed by a spherical superconducting shell that is levitated by superconducting coils. Superconductivity provides stability of the measurement, and also avoids some forms of noise (see [96] for details). In this gravimeter design, the lower coil is responsible mostly to balance the mean gravitational force acting on the sphere, while the upper coil modifies the magnetic gradient such that a certain “spring constant” of the magnetic levitation is realized. In other words, the current in the upper coil determines the resonance frequency in Eq. (2).
Capacitor plates are distributed around the sphere. Whenever a force acts on the sphere, the small signal produced in the capacitive readout is used to immediately cancel this force by a feedback coil. In this way, the sphere is kept at a constant location with respect to the external frame. This illustrates a common concept in all gravimeters. The displacement sensors can only respond to relative displacement between a test mass and a surrounding structure. If small gravity fluctuations are to be measured, then it is not sufficient to realize low-noise readout systems, but also vibrations of the surrounding structure forming the reference frame must be as small as possible. In general, as we will further explore in the coming sections, gravity fluctuations are increasingly dominant with decreasing frequency. At about 1 mHz, gravity acceleration associated with fluctuating seismic fields become comparable to seismic acceleration, and also atmospheric gravity noise starts to be significant [53]. At higher frequencies, seismic acceleration is much stronger than typical gravity fluctuations, which means that the gravimeter effectively operates as a seismometer. In summary, at sufficiently low frequencies, the gravimeter senses gravity accelerations of the test mass with respect to a relatively quiet reference, while at higher frequencies, the gravimeter senses seismic accelerations of the reference with respect to a test mass subject to relatively small gravity fluctuations. In superconducting gravimeters, the third important contribution to the response is caused by vertical motion ξ(t) of a levitated sphere against a static gravity gradient (see Section 2.1.4). As explained above, feedback control suppresses relative motion between sphere and gravimeter frame, which causes the sphere to move as if attached to the frame or ground. In the presence of a static gravity gradient ∂zgz, the motion of the sphere against this gradient leads to a change in gravity, which alters the feedback force (and therefore the recorded signal). The full contribution from gravitational, δa(t), and seismic, equation M45, accelerations can therefore be written
equation M4619
It is easy to verify, using Eqs. (2) and (3), that the relative amplitude of gravity and seismic fluctuations from the first two terms is independent of the test-mass support. Therefore, vertical seismic displacement of the reference frame must be considered fundamental noise of gravimeters and can only be avoided by choosing a quiet measurement site. Obviously, Eq. (19) is based on a simplified support model. One of the important design goals of the mechanical support is to minimize additional noise due to non-linearities and cross-coupling. As is explained further in Section 2.3, it is also not possible to suppress seismic noise in gravimeters by subtracting the disturbance using data from a collocated seismometer. Doing so inevitably turns the gravimeter into a gravity gradiometer.
Gravimeters target signals that typically lie well below 1 mHz. Mechanical or magnetic supports of test masses have resonance frequencies at best slightly below 10 mHz along horizontal directions, and typically above 0.1 Hz in the vertical direction [23, 174]4. Well below resonance frequency, the response function can be approximated as equation M47. At first, it may look as if the gravimeter should not be sensitive to very low-frequency fluctuations since the response becomes very weak. However, the strength of gravity fluctuations also strongly increases with decreasing frequency, which compensates the small response. It is clear though that if the resonance frequency was sufficiently high, then the response would become so weak that the gravity signal would not stand out above other instrumental noise anymore. The test-mass support would be too stiff. The sensitivity of the gravimeter depends on the resonance frequency of the support and the intrinsic instrumental noise. With respect to seismic noise, the stiffness of the support has no influence as explained before (the test mass can also fall freely as in atom interferometers).
For superconducting gravimeters of the Global Geodynamics Project (GGP) [52], the median spectra are shown in Figure Figure3.3. Between 0.1 mHz and 1 mHz, atmospheric gravity perturbations typically dominate, while instrumental noise is the largest contribution between 1 mHz and 5 mHz [96]. The smallest signal amplitudes that have been measured by integrating long-duration signals is about 10−12 m/s2. A detailed study of noise in superconducting gravimeters over a larger frequency range can be found in [145]. Note that in some cases, it is not fit to categorize seismic and gravity fluctuations as noise and signal. For example, Earth’s spherical normal modes coherently excite seismic and gravity fluctuations, and the individual contributions in Eq. (19) have to be understood only to accurately translate data into normal-mode amplitudes [55].
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Figure 3
Median spectra of superconducting gravimeters of the GGP. Image reproduced with permission from [48]; copyright by APS.
Gravity gradiometers
It is not the purpose of this section to give a complete overview of the different gradiometer designs. Gradiometers find many practical applications, for example in navigation and resource exploration, often with the goal to measure static or slowly changing gravity gradients, which do not concern us here. For example, we will not discuss rotating gradiometers, and instead focus on gradiometers consisting of stationary test masses. While the former are ideally suited to measure static or slowly changing gravity gradients with high precision especially under noisy conditions, the latter design has advantages when measuring weak tidal fluctuations. In the following, we only refer to the stationary design. A gravity gradiometer measures the relative acceleration between two test masses each responding to fluctuations of the gravity field [102, 125]. The test masses have to be located close to each other so that the approximation in Eq. (4) holds. The proximity of the test masses is used here as the defining property of gradiometers. They are therefore a special type of gravity strainmeter (see Section 2.4), which denotes any type of instrument that measures relative gravitational acceleration (including the even more general concept of measuring space-time strain).
Gravity gradiometers can be realized in two versions. First, one can read out the position of two test masses with respect to the same rigid, non-inertial reference. The two channels, each of which can be considered a gravimeter, are subsequently subtracted. This scheme is for example realized in dual-sphere designs of superconducting gravity gradiometers [90] or in atom-interferometric gravity gradiometers [159].
It is schematically shown in Figure Figure4.4. Let us first consider the dual-sphere design of a superconducting gradiometer. If the reference is perfectly stiff, and if we assume as before that there are no cross-couplings between degrees of freedom and the response is linear, then the subtraction of the two gravity channels cancels all of the seismic noise, leaving only the instrumental noise and the differential gravity signal given by the second line of Eq. (4). Even in real setups, the reduction of seismic noise can be many orders of magnitude since the two spheres are close to each other, and the two readouts pick up (almost) the same seismic noise [125]. This does not mean though that gradiometers are necessarily more sensitive instruments to monitor gravity fields. A large part of the gravity signal (the common-mode part) is subtracted together with the seismic noise, and the challenge is now passed from finding a seismically quiet site to developing an instrument with lowest possible intrinsic noise.
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Figure 4
Basic scheme of a gravity gradiometer for measurements along the vertical direction. Two test masses are supported by horizontal cantilevers (superconducting magnets, …). Acceleration of both test masses is measured against the same non-inertial reference frame, which is connected to the ground. Each measurement constitutes one gravimeter. Subtraction of the two channels yields a gravity gradiometer.
The atom-interferometric gradiometer differs in some important details from the superconducting gradiometer. The test masses are realized by ultracold atom clouds, which are (nearly) freely falling provided that magnetic shielding of the atoms is sufficient, and interaction between atoms can be neglected. Interactions of a pair of atom clouds with a laser beam constitute the basic gravity gradiometer scheme. Even though the test masses are freely falling, the readout is not generally immune to seismic noise [80, 18]. The laser beam interacting with the atom clouds originates from a source subject to seismic disturbances, and interacts with optics that require seismic isolation. Schemes have been proposed that could lead to a large reduction of seismic noise [178, 77], but their effectiveness has not been tested in experiments yet. Since the differential position (or tidal) measurement is performed using a laser beam, the natural application of atom-interferometer technology is as gravity strainmeter (as explained before, laser beams are favorable for differential position measurements over long baselines). Nonetheless, the technology is currently insufficiently developed to realize large-baseline experiments, and we can therefore focus on its application in gradiometry. Let us take a closer look at the response of atom-interferometric gradiometers to seismic noise. In atom-interferometric detectors (excluding the new schemes proposed in [178, 77]), one can show that seismic acceleration δα(ω) of the optics or laser source limits the sensitivity of a tidal measurement according to
equation M4820
where L is the separation of the two atom clouds, and is the speed of light. It should be emphasized that the seismic noise remains, even if all optics and the laser source are all linked to the same infinitely stiff frame. In addition to this noise term, other coupling mechanisms may play a role, which can however be suppressed by engineering efforts. The noise-reduction factor ωL/c needs to be compared with the common-mode suppression of seismic noise in superconducting gravity gradiometers, which depends on the stiffness of the instrument frame, and on contamination from cross coupling of degrees-of-freedom. While the seismic noise in Eq. (20) is a fundamental noise contribution in (conventional) atom-interferometric gradiometers, the noise suppression in superconducting gradiometers depends more strongly on the engineering effort (at least, we venture to claim that common-mode suppression achieved in current instrument designs is well below what is fundamentally possible).
To conclude this section, we discuss in more detail the connection between gravity gradiometers and seismically (actively or passively) isolated gravimeters. As we have explained in Section 2.2, the sensitivity limitation of gravimeters by seismic noise is independent of the mechanical support of the test mass (assuming an ideal, linear support). The main purpose of the mechanical support is to maximize the response of the test mass to gravity fluctuations, and thereby increase the signal with respect to instrumental noise other than seismic noise. Here we will explain that even a seismic isolation of the gravimeter cannot overcome this noise limitation, at least not without fundamentally changing its response to gravity fluctuations. Let us first consider the case of a passively seismically isolated gravimeter. For example, we can imagine that the gravimeter is suspended from the tip of a strong horizontal cantilever. The system can be modelled as two oscillators in a chain, with a light test mass m supported by a heavy mass M representing the gravimeter (reference) frame, which is itself supported from a point rigidly connected to Earth. The two supports are modelled as harmonic oscillators. As before, we neglect cross coupling between degrees of freedom. Linearizing the response of the gravimeter frame and test mass for small accelerations, and further neglecting terms proportional to m/M, one finds the gravimeter response to gravity fluctuations:
equation M4921
Here, ω1, γ1 are the resonance frequency and damping of the gravimeter support, while ω2, γ2 are the resonance frequency and damping of the test-mass support. The response and isolation functions R(·), S(·) are defined in Eqs. (2) and (3). Remember that Eq. (21) is obtained as a differential measurement of test-mass acceleration versus acceleration of the reference frame. Therefore, δg1(ω) denotes the gravity fluctuation at the center-of-mass of the gravimeter frame, and δg2(ω) at the test mass. An infinitely stiff gravimeter suspension, ω1 → ∞, yields R(ω; ω1, γ1) = 0, and the response turns into the form of the non-isolated gravimeter. The seismic isolation is determined by
equation M5022
We can summarize the last two equations as follows. At frequencies well above ω1, the seismically isolated gravimeter responds like a gravity gradiometer, and seismic noise is strongly suppressed. The deviation from the pure gradiometer response ∼ δg2(ω) − δg1(ω) is determined by the same function S(ω; ω1, γ1) that describes the seismic isolation. In other words, if the gravity gradient was negligible, then we ended up with the conventional gravimeter response, with signals suppressed by the seismic isolation function. Well below ω1, the seismically isolated gravimeter responds like a conventional gravimeter without seismic-noise reduction. If the centers of the masses m (test mass) and M (reference frame) coincide, and therefore δg1(ω) = δg2(ω), then the response is again like a conventional gravimeter, but this time suppressed by the isolation function S(ω; ω1, γ1).
Let us compare the passively isolated gravimeter with an actively isolated gravimeter. In active isolation, the idea is to place the gravimeter on a stiff platform whose orientation can be controlled by actuators. Without actuation, the platform simply follows local surface motion. There are two ways to realize an active isolation. One way is to place a seismometer next to the platform onto the ground, and use its data to subtract ground motion from the platform. The actuators cancel the seismic forces. This scheme is called feed-forward noise cancellation. Feed-forward cancellation of gravity noise is discussed at length in Section 7.1, which provides details on its implementation and limitations. The second possibility is to place the seismometer together with the gravimeter onto the platform, and to suppress seismic noise in a feedback configuration [4, 2]. In the following, we discuss the feed-forward technique as an example since it is easier to analyze (for example, feedback control can be unstable [4]). As before, we focus on gravity and seismic fluctuations. The seismometer’s intrinsic noise plays an important role in active isolation limiting its performance, but we are only interested in the modification of the gravimeter’s response. Since there is no fundamental difference in how a seismometer and a gravimeter respond to seismic and gravity fluctuations, we know from Section 2.2 that the seismometer output is proportional to δg1(ω) − δα(ω), i.e., using a single test mass for acceleration measurements, seismic and gravity perturbations contribute in the same way. A transfer function needs to be multiplied to the acceleration signals, which accounts for the mechanical support and possibly also electronic circuits involved in the seismometer readout. To cancel the seismic noise of the platform that carries the gravimeter, the effect of all transfer functions needs to be reversed by a matched feed-forward filter. The output of the filter is then equal to δg1(ω) − δα(ω) and is added to the motion of the platform using actuators cancelling the seismic noise and adding the seismometer’s gravity signal. In this case, the seismometer’s gravity signal takes the place of the seismic noise in Eq. (3). The complete gravity response of the actively isolated gravimeter then reads
equation M5123
The response is identical to a gravity gradiometer, where ω2, γ2 are the resonance frequency and damping of the gravimeter’s test-mass support. In reality, instrumental noise of the seismometer will limit the isolation performance and introduce additional noise into Eq. (23). Nonetheless, Eqs. (21) and (23) show that any form of seismic isolation turns a gravimeter into a gravity gradiometer at frequencies where seismic isolation is effective. For the passive seismic isolation, this means that the gravimeter responds like a gradiometer at frequencies well above the resonance frequency ω1 of the gravimeter support, while it behaves like a conventional gravimeter below ω1. From these results it is clear that the design of seismic isolations and the gravity response can in general not be treated independently. As we will see in Section 2.4 though, tidal measurements can profit strongly from seismic isolation especially when common-mode suppression of seismic noise like in gradiometers is insufficient or completely absent.
Gravity strainmeters
Gravity strain is an unusual concept in gravimetry that stems from our modern understanding of gravity in the framework of general relativity. From an observational point of view, it is not much different from elastic strain. Fluctuating gravity strain causes a change in distance between two freely falling test masses, while seismic or elastic strain causes a change in distance between two test masses bolted to an elastic medium. It should be emphasized though that we cannot always use this analogy to understand observations of gravity strain [106]. Fundamentally, gravity strain corresponds to a perturbation of the metric that determines the geometrical properties of spacetime [124]. We will briefly discuss GWs, before returning to a Newtonian description of gravity strain.
Gravitational waves are weak perturbations of spacetime propagating at the speed of light. Freely falling test masses change their distance in the field of a GW. When the length of the GW is much larger than the separation between the test masses, it is possible to interpret this change as if caused by a Newtonian force. We call this the long-wavelength regime. Since we are interested in the low-frequency response of gravity strainmeters throughout this article (i.e., frequencies well below 100 Hz), this condition is always fulfilled for Earth-bound experiments. The effect of a gravity-strain field equation M52 on a pair of test masses can then be represented as an equivalent Newtonian tidal field
equation M5324
Here, equation M54 is the relative acceleration between two freely falling test masses, L is the distance between them, and equation M55 is the unit vector pointing from one to the other test mass, and equation M56 its transpose. As can be seen, the gravity-strain field is represented by a 3 × 3 tensor. It contains the space-components of a 4-dimensional metric perturbation of spacetime, and determines all properties of GWs5. Note that the strain amplitude h in Eq. (24) needs to be multiplied by 2 to obtain the corresponding amplitude of the metric perturbation (e.g., the GW amplitude). Throughout this article, we define gravity strain as h = ΔL/L, while the effect of a GW with amplitude aGW on the separation of two test mass is determined by aGW = 2ΔL/L.
The strain field of a GW takes the form of a quadrupole oscillation with two possible polarizations commonly denoted × (cross)-polarization and +(plus)-polarization. The arrows in Figure Figure55 indicate the lines of the equivalent tidal field of Eq. (24).
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Figure 5
Polarizations of a gravitational wave.
Consequently, to (directly) observe GWs, one can follow two possible schemes: (1) the conventional method, which is a measurement of the relative displacement of suspended test masses typically carried out along two perpendicular baselines (arms); and (2) measurement of the relative rotation between two suspended bars. Figure Figure66 illustrates the two cases. In either case, the response of a gravity strainmeter is obtained by projecting the gravity strain tensor onto a combination of two unit vectors, equation M57 and equation M58, that characterize the orientation of the detector, such as the directions of two bars in a rotational gravity strain meter, or of two arms of a conventional gravity strain meter. This requires us to define two different gravity strain projections. The projection for the rotational strain measurement is given by
equation M5925
where the subscript × indicates that the detector responds to the ×-polarization assuming that the x, y-axes (see Figure Figure5)5) are oriented along two perpendicular bars. The vectors equation M60 and equation M61 are rotated counter-clockwise by 90° with respect to equation M62 and equation M63. In the case of perpendicular bars equation M64 and equation M65. The corresponding projection for the conventional gravity strain meter reads
equation M6626
The subscript + indicates that the detector responds to the +-polarization provided that the x, y-axes are oriented along two perpendicular baselines (arms) of the detector. The two schemes are shown in Figure Figure6.6. The most sensitive GW detectors are based on the conventional method, and distance between test masses is measured by means of laser interferometry. The LIGO and Virgo detectors have achieved strain sensitivities of better than 10−22 Hz−1/2 between about 50 Hz and 1000 Hz in past science runs and are currently being commissioned in their advanced configurations [91, 7]. The rotational scheme is realized in torsion-bar antennas, which are considered as possible technology for sub-Hz GW detection [155, 69]. However, with achieved strain sensitivity of about 10−8 Hz−1/2 near 0.1 Hz, the torsion-bar detectors are far from the sensitivity we expect to be necessary for GW detection [88].
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Figure 6
Sketches of the relative rotational and displacement measurement schemes.
Let us now return to the discussion of the previous sections on the role of seismic isolation and its impact on gravity response. Gravity strainmeters profit from seismic isolation more than gravimeters or gravity gradiometers. We have shown in Section 2.2 that seismically isolated gravimeters are effectively gravity gradiometers. So in this case, seismic isolation changes the response of the instrument in a fundamental way, and it does not make sense to talk of seismically isolated gravimeters. Seismic isolation could in principle be beneficial for gravity gradiometers (i.e., the acceleration of two test masses is measured with respect to a common rigid, seismically isolated reference frame), but the common-mode rejection of seismic noise (and gravity signals) due to the differential readout is typically so high that other instrumental noise becomes dominant. So it is possible that some gradiometers would profit from seismic isolation, but it is not generally true. Let us now consider the case of a gravity strainmeter. As explained in Section 2.3, we distinguish gradiometers and strainmeters by the distance of their test masses. For example, the distance of the LIGO or Virgo test masses is 4 km and 3 km respectively. Seismic noise and terrestrial gravity fluctuations are insignificantly correlated between the two test masses within the detectors’ most sensitive frequency band (above 10 Hz). Therefore, the approximation in Eq. (4) does not apply. Certainly, the distinction between gravity gradiometers and strainmeters remains somewhat arbitrary since at any frequency the approximation in Eq. (4) can hold for one type of gravity fluctuation, while it does not hold for another. Let us adopt a more practical definition at this point. Whenever the design of the instrument places the test masses as distant as possible from each other given current technology, then we call such an instrument strainmeter. In the following, we will discuss seismic isolation and gravity response for three strainmeter designs, the laser-interferometric, atom-interferometric, and superconducting strainmeters. It should be emphasized that the atom-interferometric and superconducting concepts are still in the beginning of their development and have not been realized yet with scientifically interesting sensitivities.
Laser-interferometric strainmeters The most sensitive gravity strainmeters, namely the large-scale GW detectors, use laser interferometry to read out the relative displacement between mirror pairs forming the test masses. Each test mass in these detectors is suspended from a seismically isolated platform, with the suspension itself providing additional seismic isolation. Section 2.1.1 introduced a simplified response and isolation model based on a harmonic oscillator characterized by a resonance frequency ω0 and viscous damping γ6. In a multi-stage isolation and suspension system as realized in GW detectors (see for example [37, 121]), coupling between multiple oscillators cannot be neglected, and is fundamental to the seismic isolation performance, but the basic features can still be explained with the simplified isolation and response model of Eqs. (2) and (3). The signal output of the interferometer is proportional to the relative displacement between test masses. Since seismic noise is approximately uncorrelated between two distant test masses, the differential measurement itself cannot reject seismic noise as in gravity gradiometers. Without seismic isolation, the dominant signal would be seismic strain, i.e., the distance change between test masses due to elastic deformation of the ground, with a value of about 10−15 Hz−1/2 at 50 Hz (assuming kilometer-scale arm lengths). At the same time, without seismically isolated test masses, the gravity signal can only come from the ground response to gravity fluctuations as described in Section 2.1.3, and from the Shapiro time delay as described in Section 2.1.2.
EAST CHINA SEA (Jan. 11, 2020) MH-60S Sea Hawk helicopters assigned to the Island Knights of Helicopter Sea Combat Squadron (HSC) 25 land on the flight deck of amphibious assault ship USS America (LHA 6). The America Expeditionary Strike Group, 31st Marine Expeditionary Unit team is operating in the U.S. 7th Fleet area of operations to enhance interoperability with allies and partners and serve as a ready response force to defend peace and stability in the Indo-Pacific region. (U.S. Navy photo by Mass Communication Specialist 3rd Class Vincent E. Zline)
en.wikipedia.org/wiki/Washington_National_Cathedral
The Cathedral Church of Saint Peter and Saint Paul in the City and Diocese of Washington, commonly known as Washington National Cathedral, is an American cathedral of the Episcopal Church. The cathedral is located in Washington, D.C., the capital of the United States.[1][2] The structure is of Neo-Gothic design closely modeled on English Gothic style of the late fourteenth century. It is the second-largest church building in the United States,[3] and the fourth-tallest structure in Washington, D.C. The cathedral is the seat of both the Presiding Bishop of the Episcopal Church, Michael Bruce Curry, and the bishop of the Diocese of Washington, Mariann Edgar Budde. Over 270,000 people visit the structure annually.[4]
The Protestant Episcopal Cathedral Foundation, under the first seven Bishops of Washington, erected the cathedral under a charter passed by the United States Congress on January 6, 1893.[5] Construction began on September 29, 1907, when the foundation stone was laid in the presence of President Theodore Roosevelt and a crowd of more than 20,000, and ended 83 years later when the "final finial" was placed in the presence of President George H. W. Bush in 1990. Decorative work, such as carvings and statuary, is ongoing as of 2011.[needs update] The Foundation is the legal entity of which all institutions on the Cathedral Close are a part; its corporate staff provides services for the institutions to help enable their missions, conducts work of the Foundation itself that is not done by the other entities, and serves as staff for the board of trustees.
The cathedral stands at Massachusetts and Wisconsin Avenues in the northwest quadrant of Washington. It is an associate member of the recently organized inter-denominational Washington Theological Consortium.[6] It is listed on the National Register of Historic Places. In 2007, it was ranked third on the List of America's Favorite Architecture by the American Institute of Architects.[7]
Contents
1 History
1.1 Construction
1.2 National role
2 Major events
2.1 Major services
2.2 2011 earthquake
2.3 Lee-Jackson stained glass windows
3 Financial concerns
4 Architecture
4.1 Architects
4.2 Images of architectural details
5 Leadership and funding
5.1 List of deans
6 Worship
7 Music
8 Burials
9 Schools
10 Media
11 See also
12 References
13 Bibliography
14 External links
History
Construction
In 1792, Pierre L'Enfant's "Plan of the Federal City" specified a site for a "great church for national purposes". However he defined it as non-sectarian and nondenominational. Hamilton modified that plan and eliminated the "church" and several other proposed monuments and that plan was never reproduced. The working plan for the new city was subsequently produced by Andrew Ellicott and it varied in many respects from L'Enfant's although the essence remained. National Portrait Gallery now occupies that site. In 1891, a meeting was held to begin plans for an Episcopal cathedral in Washington. On January 6, 1893, the Protestant Episcopal Cathedral Foundation of the District of Columbia was granted a charter from Congress to establish the cathedral. The 52nd United States Congress declared in the act to incorporate the Protestant Episcopal Cathedral Foundation of the District of Columbia that the "said corporation is hereby empowered to establish and maintain within the District of Columbia a cathedral and institutions of learning for the promotion of religion and education and charity."[8] The commanding site on Mount Saint Alban was chosen. Henry Yates Satterlee, first Episcopal bishop of the Diocese of Washington, chose George Frederick Bodley, Britain's leading Anglican church architect, as the head architect. Henry Vaughan was selected supervising architect.
Construction started on September 29, 1907, with a ceremonial address by President Theodore Roosevelt and the laying of the cornerstone. In 1912, Bethlehem Chapel opened for services in the unfinished cathedral, which have continued daily ever since. When construction of the cathedral resumed after a brief hiatus for World War I, both Bodley and Vaughan had died. Gen. John J. Pershing led fundraising efforts for the church after World War I. American architect Philip Hubert Frohman took over the design of the cathedral and was thenceforth designated the principal architect. Funding for Washington National Cathedral has come entirely from private sources. Maintenance and upkeep continue to rely entirely upon private support.
National role
From its earliest days, the cathedral has been promoted as more than simply an Episcopal cathedral. Planners hoped it would play a role similar to Westminster Abbey. They wanted it to be a national shrine and a venue for great services. For much of the cathedral's history, this was captured in the phrase "a house of prayer for all people." In more recent times the phrases "national house of prayer" and "spiritual home for the nation" have been used. The cathedral has achieved this status simply by offering itself and being accepted by religious and political leaders as playing this role.[9]
Its initial charter was similar to those granted to American University, The Catholic University of America, and other not-for-profit entities founded in the District of Columbia around 1900. Contrary to popular misconception, the government has not designated it as a national house of prayer.
During World War II, monthly services were held there "on behalf of a united people in a time of emergency."[10] Before and since, the structure has hosted other major events, both religious and secular, that have drawn the attention of the American people, as well as tourists from around the world.
Major events
Major services
The 2004 state funeral of the 40th President, Ronald Reagan
State funerals for four American presidents have been held at the cathedral:[11][12][13]
34th President Dwight D. Eisenhower (1969): lay in repose at the cathedral before lying in state
40th President Ronald Reagan (2004)
38th President Gerald Ford (2007)
41st President George H. W. Bush (2018)
Memorial services were also held at the cathedral for the following presidents:[11]
(29th) Warren G. Harding
(27th) William Howard Taft
(30th) Calvin Coolidge
(33rd) Harry S. Truman
(37th) Richard Nixon
Presidential prayer services were held the day after the inaugurations for:[14]
32nd President Franklin D. Roosevelt's second inauguration in January 1937
40th President Ronald Reagan's second inauguration in 1985
41st President George H. W. Bush's inauguration in 1989
43rd President George W. Bush's first and second inaugurations in 2001 and 2005
44th President Barack Obama's first and second inaugurations in 2009 and 2013
45th President Donald Trump's inauguration in 2017[15]
46th President Joe Biden's inauguration in 2021
Prayer and vigil for the March for Our Lives rally, March 23, 2018
Other events have included:
Funeral for former first lady Edith Wilson (1961)[11]
Memorial service for former first lady Eleanor Roosevelt (1962)[11]
Memorial service for the casualties of the Vietnam War on November 14, 1982
Public funeral for Chief of Naval Operations, United States Navy, Admiral Jeremy Michael Boorda (1996)
Funeral for Secretary of Commerce Ronald Brown (1996)
Funeral for U.S. Ambassador to France Pamela Harriman (1997)
Funeral for The Washington Post newspaper publisher Katharine Graham (2001)
Memorial service for the victims of the September 11, 2001 attacks
Special evensong for the victims of the Virginia Tech shooting
Funeral for educator and national civil rights leader Dorothy Height (2010)
Memorial service for NASA astronaut and first person on the Moon Neil Armstrong (2012)
Funeral for Senator Daniel Inouye of Hawaii, President Pro Tempore of the Senate, and Medal of Honor recipient (2012)
Funeral for Charles Colson, founder of Prison Fellowship (2012)[16]
Memorial service for former South African President and anti-apartheid activist Nelson Mandela (2014)
Interfaith service of Prayer and Remembrance: The Fifteenth Anniversary of the September 11, 2001 attacks, Sunday September 11, 2016
March for Our Lives Prayer Vigil: A vigil for "activists, students and pilgrims" participating in the March for Our Lives anti-gun violence rally in Washington, D.C. and other cities, Friday March 23, 2018[17]
Funeral for U.S. Senator John McCain of Arizona (September 1, 2018)
Service of Thanksgiving and Remembrance for Matthew Shepard (October 26, 2018).[18]
Funeral for U. S. Army General (Ret.), Former Chairman of the Joint Chiefs of Staff and former Secretary of State Colin Powell (November 5, 2021).
Funeral for U.S. Senator Bob Dole of Kansas (December 10, 2021)
It was from Washington National Cathedral's "Canterbury Pulpit" that the Reverend Martin Luther King Jr. delivered his final Sunday sermon on March 31, 1968, just a few days before his assassination in April 1968.[19] A memorial service for King was held at the cathedral later the same week.
2011 earthquake
Washington National Cathedral undergoing repairs in 2017
The cathedral was damaged in August 2011 during the Virginia earthquake. Finial stones on several pinnacles broke off, and several pinnacles twisted out of alignment or collapsed entirely. Some gargoyles and other carvings were damaged, and a hole was punched through the metal-clad roof by falling masonry. Cracks also appeared in the flying buttresses surrounding the apse. Inside, initial inspections revealed less damage, with some mortar joints loose or falling out.[20] The cathedral, which had no earthquake insurance, struggled to cope with the cost of the damage.[21]
Washington National Cathedral closed from August 24 to November 7, 2011,[20] as $2 million was spent to stabilize the structure and remove damaged or loose stone.[21] Safety netting was erected throughout the nave to protect visitors from any debris that might fall from above.[22] The cathedral reopened for the consecration and installation of Mariann Budde as the ninth Bishop of Washington on November 12, 2011.[23] At that time, estimates of the cost of the damage were about $25 million.[23]
Identifying the full extent of the damage and construction planning and studies over the next two years consumed another $2.5 million.[21] In 2011, the cathedral received a $700,000 preservation work matching grant from the Save America's Treasures program, a public-private partnership operated by the nonprofit National Trust for Historic Preservation. The program, which is federally funded, required the cathedral to match the grant dollar-for-dollar with private funds and use the money solely for preservation work.[24]
The Reverend Canon Gary R. Hall was chosen to be the 10th dean of Washington National Cathedral in July 2012.[25]
Although fundraising to repair the damage began soon after the earthquake, it took the cathedral three years to raise the $15 million to complete the first phase of repairs.[21] In August 2013, the cost of the repairs was re-estimated at $26 million. About $10 million had already been raised by this date to pay for the repairs, half of that coming from the Lilly Endowment.[26] The cathedral began charging a $10 admission fee for tourists in January 2014, and started renting out its worship and other spaces to outside groups to raise cash.[27] The cathedral also transformed the Herb Cottage (its old baptistry building adjacent to the cathedral) into a for-profit coffeehouse operated by the Open City café chain.[28]
Phase I of the restoration, which cost $10 million,[21] repaired the internal ceiling's stone and mortar and was completed in February 2015. The planned 10-year, $22 million Phase II will repair or replace the damaged stones atop the cathedral.[29]
In June 2015, Washington National Cathedral leaders said the church needed $200 million, which would both complete repairs and establish a foundation to give the cathedral financial stability. The cathedral began working on a capital fundraising campaign, which The New York Times said was one of the largest ever by an American religious institution, to begin in 2018 or 2019. Hall said that the cathedral also planned to reopen its continuing education college and its Center for Prayer and Pilgrimage (a space on the cathedral's crypt level dedicated to prayer, meditation, and devotional practice). After three years of deficit spending, however, the cathedral also announced additional cuts to music programs to balance its budget.[21]
Lee-Jackson stained glass windows
See also: Modern display of the Confederate flag and Removal of Confederate monuments and memorials
In June 2016, after an examination by a five-person task force it was announced that two Confederate battle flag images would be removed from stained glass windows commemorating the lives of Confederate generals Robert E. Lee and Stonewall Jackson. The windows were installed in 1953 after lobbying by the United Daughters of the Confederacy. In its report, the task force wrote that it "is unanimous in its decision that the windows provide a catalyst for honest discussions about race and the legacy of slavery and for addressing the uncomfortable and too often avoided issues of race in America. Moreover, the windows serve as a profound witness to the cathedral's own complex history in relationship to race."[30]
On September 6, 2017, the cathedral, in a statement signed by the Right Rev. Mariann Edgar Budde, bishop of the Episcopal Diocese of Washington, the Very Rev. Randolph Marshall Hollerith, dean of the cathedral, and John Donoghue, chair of the cathedral chapter, announced its decision to deconsecrate and remove the stained glass windows honoring Lee and Jackson.[31]
Financial concerns
In January 2003, the Reverend Nathan D. Baxter, dean of the cathedral, announced his retirement effective from June 30, 2003. Baxter had led the cathedral since 1991.[32] After an 18-month search, Samuel T. Lloyd III was named dean and began his tenure on April 23, 2005.[33] Using a $15 million bequest the cathedral received in 2000, Lloyd rapidly expanded the cathedral's programming.[34][21] Meanwhile, the cathedral deferred maintenance and declined to make needed repairs.[21] Construction also began in summer 2005 on a $34 million, four-level, 430-car underground parking garage. It opened in 2007.[35][21] The structure was pushed by John Bryson Chane, bishop of the Episcopal Diocese of Washington, and was mostly funded by debt. Payments on the garage were $500,000 per year, with a major increase in the annual debt service beginning in 2017.[36] In early 2008, the National Cathedral Association, the church's fundraising donor network, was disbanded after cathedral leaders concluded that the building was "finished" and it was no longer necessary to raise significant funds for construction.[21][37]
The 2008–2009 Great Recession hit the cathedral hard. By June 2010, the cathedral cut its budget from $27 million to $13 million, outsourced the operation of its gift shop, shut its greenhouse, cancelled its plans to replace the Skinner organ in the sanctuary, and ceased operation of the College of Preachers that had provided Episcopal clergy nationwide with continuing theological education. The cathedral also laid off 100 of its 170 staff members, including its art conservator and its liturgist (who researched and advocated the use of liturgies at the cathedral).[38] It also significantly cut back on programming, music performances, and classes.[39] To help stabilize its finances, the cathedral began an $11 million fundraising campaign and used $2.5 million of its $50 million endowment to plug budget holes.[38] The National Cathedral Association was recreated as well.[36]
In June 2010, the cathedral announced that it was exploring the sale of its rare book collection, the value of which was estimated to be several million dollars.[38] It sold a number of books to a private collector in 2011 for $857,000[21] and in 2013 donated most of the remaining collection to Virginia Theological Seminary.[21][40]
As the economic downturn continued, a report by cathedral staff identified $30 million in needed maintenance and repairs.[21] Among the problems were cracked and missing mortar in the oldest sections of the building; broken HVAC, mechanical, and plumbing systems throughout the structure; extensive preservation needs; and a main organ in disrepair. Repointing the building was estimated to cost at least $5 million, while organ repair was set at $15 million.[36]
Architecture
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Looking east, looking up to the choir of the cathedral
Nave vaulting facing east
The cathedral's final design shows a mix of influences from the various Gothic architectural styles of the Middle Ages, identifiable in its pointed arches, flying buttresses, a variety of ceiling vaulting, stained-glass windows and carved decorations in stone, and by its three similar towers, two on the west front and one surmounting the crossing.
The structure consists of a long, narrow rectangular mass formed by a nine-bay nave with wide side aisles and a five-bay chancel, intersected by a six bay transept. Above the crossing, rising 301 ft (92 m) above the ground, is the Gloria in Excelsis Tower; its top, at 676 ft (206 m) above sea level, is the highest point in Washington.[3] The Pilgrim Observation Gallery—which occupies a space about 3/4ths of the way up in the west-end towers—provides sweeping views of the city. Unique in North America, the central tower has two full sets of bells—a 53-bell carillon and a 10-bell peal for change ringing; the change bells are rung by members of the Washington Ringing Society.[3] The cathedral sits on a landscaped 57-acre (23 ha) plot on Mount Saint Alban.[3] The one-story porch projecting from the south transept has a large portal with a carved tympanum. This portal is approached by the Pilgrim Steps, a long flight of steps 40 feet (12 m) wide.
Most of the building is constructed using a buff-colored Indiana limestone over a traditional masonry core. Structural, load-bearing steel is limited to the roof's trusses (traditionally built of timber); concrete is used significantly in the support structures for bells of the central tower, and the floors in the west towers.
The pulpit was carved out of stones from Canterbury Cathedral; Glastonbury Abbey provided stone for the bishop's formal seat, the cathedra. The high altar, the Jerusalem Altar, is made from stones quarried at Solomon's Quarry near Jerusalem, reputedly where the stones for Solomon's Temple were quarried. In the floor directly in front of that altar are set ten stones from the Chapel of Moses on Mount Sinai, representing the Ten Commandments as a foundation for the Jerusalem Altar.
There are many other works of art including over two hundred stained glass windows,[3] the most familiar of which may be the Space Window, honoring mankind's landing on the Moon, which includes a fragment of lunar rock at its center;[3] the rock was presented at the dedication service on July 21, 1974, the fifth anniversary of the Apollo 11 mission.[41] Extensive wrought iron adorns the building, much of it the work of Samuel Yellin. A substantial gate of forged iron and carbon steel by Albert Paley was installed on the north side of the crypt level in 2008. Intricate woodcarving, wall-sized murals and mosaics, and monumental cast bronze gates can also be found. Most of the interior decorative elements have Christian symbolism, in reference to the church's Episcopal roots, but the cathedral is filled with memorials to persons or events of national significance: statues of Washington and Lincoln, state seals embedded in the marble floor of the narthex, state flags that hang along the nave, stained glass commemorating events like the Lewis and Clark expedition and the raising of the American flag at Iwo Jima.
The cathedral was built with several intentional "flaws" in keeping with an apocryphal medieval custom that sought to illustrate that only God can be perfect.[dubious – discuss] Artistically speaking, these flaws (which often come in the form of intentional asymmetries) draw the observer's focus to the sacred geometry as well as compensate for visual distortions, a practice that has been used since the Pyramids and the Parthenon.[citation needed] The architects designed the crypt chapels in Norman, Romanesque, and Transitional styles predating the Gothic, as though the cathedral had been built as a successor to earlier churches, a common occurrence in European cathedrals.[citation needed]
Numerous grotesques and gargoyles adorn the exterior, most of them designed by the carvers; one of the more famous of these is a caricature of then-master carver Roger Morigi on the north exterior of the nave. There were also two competitions held for the public to provide designs to supplement those of the carvers. The second of these produced the famous Darth Vader grotesque which is high on the northwest tower, sculpted by Jay Hall Carpenter and carved by Patrick J. Plunkett.[42]
The west facade follows an iconographic program of Creation rather than that of the Last Judgement as was traditional in medieval churches. All of the sculptural work was designed by Frederick Hart and features tympanum carvings of the creation of the Sun and Moon over the outer doors and the creation of man over the center. Hart also sculpted the three statues of Adam and Saints Peter and Paul. The west doors are cast bronze rather than wrought iron. The west rose window, often used as a trademark of the cathedral, was designed by Rowan LeCompte and is an abstract depiction of the creation of light. LeCompte, who also designed the clerestory windows and the mosaics in the Resurrection Chapel, chose a nonrepresentational design because he feared that a figural window could fail to be seen adequately from the great distance to the nave.
The cathedral contains a basement, which was intentionally flooded during the Cuban Missile Crisis to provide emergency drinking water in the event of a nuclear war.[43]
Architects
The cathedral's master plan was designed by George Frederick Bodley (founder of Watts & Co.), a highly regarded British Gothic Revival architect of the late-19th and early-20th centuries, and was influenced by Canterbury. Landscape architect Frederick Law Olmsted Jr. contributed a landscaping plan for the cathedral close and Nellie B. Allen designed a knot garden for the Bishop's Garden. After Bodley died in 1907, his partner Henry Vaughan revised the original design, but work stopped during World War I and Vaughan died in 1917. When work resumed, the chapter hired Boston architecture firm Frohman, Robb and Little to execute the building. Philip Hubert Frohman, who had designed his first fully functional home at the age of 14 and received his architectural degree at the age of 16, and his partners worked to perfect Bodley's vision, adding the carillon section of the central tower, enlarging the west façade, and making numerous smaller changes. Ralph Adams Cram was hired to supervise Frohman, because of his experience with the Cathedral of St. John the Divine in New York City, but Cram insisted on so many major changes to the original design that Frohman convinced the Cathedral Chapter to fire him. By Frohman's death in 1972, the final plans had been completed and the building was finished accordingly.
The Beechcraft UC-43 Staggerwing was a military version of the popular Beechcraft Model 17 Staggerwing biplane. It was used by the United States Army Air Corps during World War II for transportation and liaison duties. The UC-43 Staggerwing featured a distinctive staggered upper and lower wing design, giving it excellent stability and handling characteristics.
RD16605. The 2ft gauge Ffestiniog Railway's 2-4-0ST/T BLANCHE departing from Tanybwlch with a train from Porthmadog to Blaenau Ffestiniog.
BLANCHE was built as an 0-4-0ST for the 1ft 10¾in gauge Penrhyn Quarry Railway to transport slate from the quarry in the hills at Bethesda to the coast at Port Penrhyn where it was transferred to waiting ships.
Following the closure of the PQR in the early 1960s, BLANCHE and sister locomotive LINDA were purchased by the nearby Ffestiniog Railway where they were re-gauged to 1ft 11½ins and had tenders added. Later, the were also fitted with pony trucks to improve stability.
Thursday, 21st June, 2018. Copyright © Ron Fisher.
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