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1:72 Saab J29D (Flygande) Tunnan; “Röd Rudolf” of the Swedish Air Force F1 Kungliga Västmanlands Flygflottilj, 1st Jaktflygdivision; Hässlö Flygplats/Västerås, central Sweden, 1964 (Whif/Heller kit conversion)

+++ DISCLAIMER +++

Nothing you see here is real, even though the model, the conversion or the presented background story might be based historical facts. BEWARE!

 

 

Some background:

In the aftermath of the Second World War, Sweden required a strong air defense, utilizing the newly developed jet propulsion technology. This led to a pair of proposals being issued by the Saab design team, led by Lars Brising. The first of these, codenamed R101, was a cigar-shaped aircraft, which bore a resemblance to the American Lockheed P-80 Shooting Star. The second design, which would later be picked as the winner, was a barrel-shaped design, codenamed R 1001, which proved to be both faster and more agile upon closer study.

 

The original R 1001 concept had been designed around a mostly straight wing, but after Swedish engineers had obtained German research data on swept-wing designs, the prototype was altered to incorporate a 25° sweep. In order to make the wing as thin as possible, Saab elected to locate the retractable undercarriage in the aircraft's fuselage rather than into the wings.

 

Extensive wind tunnel testing performed at the Swedish Royal University of Technology and by the National Aeronautical Research Institute had also influenced aspects of the aircraft's aerodynamics, such as stability and trim across the aircraft's speed range. In order to test the design of the swept wing further and avoid any surprises, it was decided to modify a single Saab Safir. It received the designation Saab 201 and a full-scale R 1001 wing for a series of flight tests. The first 'final' sketches of the aircraft, incorporating the new information, was drawn in January 1946.

 

The originally envisioned powerplant for the new fighter type was the de Havilland Goblin turbojet engine. However, in December 1945, information on the newer and more powerful de Havilland Ghost engine became available. The new engine was deemed to be ideal for Saab's in-development aircraft, as not only did the Ghost engine had provisions for the use of a central circular air intake, the overall diameter of the engine was favorable for the planned fuselage dimensions, too. Thus, following negotiations between de Havilland and Saab, the Ghost engine was selected to power the type instead and built in license as the RM 2.

 

By February 1946 the main outline of the proposed aircraft had been clearly defined. In Autumn 1946, following the resolution of all major questions of principal and the completion of the project specification, the Swedish Air Force formally ordered the completion of the design and that three prototype aircraft be produced, giving the proposed type the designation J 29.

On 1 September 1948, the first of the Saab 29 prototypes conducted its maiden flight, which lasted for half an hour. Because of the shape of its fuselage, the Saab J 29 quickly received the nickname "Flygande Tunnan" ("The Flying Barrel"), or "Tunnan" ("The Barrel") for short. While the demeaning nickname was not appreciated by Saab, its short form was eventually officially adopted.

 

A total of four prototypes were built for the aircraft's test program. The first two lacked armament, carrying heavy test equipment instead, while the third prototype was armed with four 20mm automatic guns. Various different aerodynamic arrangements were tested, such as air brakes being installed either upon the fuselage or on the wings aft of the rear spar, along with both combined and conventional aileron/flap arrangements.

The flight test program revealed that the J 29 prototypes were capable of reaching and exceeding the maximum permissible Mach number for which they had been designed, and the flight performance figures gathered were found to be typically in excess of the predicted values.

 

In 1948 production of the type commenced and in May 1951 the first deliveries of operational production aircraft were received by F 13 Norrköping. The J 29 proved to be very successful and several variants and updates of the Tunnan were produced, including a dedicated reconnaissance variant and a dedicated all-weather fighter with an on-board radar, the J 29D.

 

The J 29D variant originally started its career as a single prototype to test the Ghost RM 2A afterburner turbojet with 27.5 kN (2,800 kgp/6,175 lbf). The new engine dramatically improved the Tunnan’s performance, esp. concerning the start phase, acceleration and climb, and was eventually adopted for the whole J 29 fighter fleet in an update program, leading to the J 29F variant.

 

However, at the time of the RM 2A trials, Sweden was more and more in need for a suitable all-weather aerial defense for its vast, neutral airspace in the vicinity of the Soviet Union. Only a single flight of the Swedish Air Force, F1 in Hässlö, operated roundabout thirty radar-equipped fighters, and these were outdated De Havilland Mosquito night fighters (locally designated J 30).

 

The highly successful J 29 was soon considered as a potential air-intercept radar carrier, offering a much more up-tp-date performance and deterrent potential against would-be intruders. Consequently, Saab started the development of an indigenous all-weather fighter on the basis of the Tunnan (originally coded “J 29R”). The work started with aerodynamic trials of different radome designs and placements on a Tunnan’s nose, e .g. inside of the circular air intake opening or above it. No major drawbacks were identified, and in 1955 the decision was made to convert thirty J 29B daylight fighters for the all weather/night fighter role. These machines officially inherited the designation J 29D.

The J 29D’s compact radar, called the PS-43/T, was designed by CSF (Compagnie Generale de Telegrahpi Sans Fil) in France after the Swedish specification. It had a wavelength of 3 cm with an effect of 100 kW, and it was to have a spiral scan pattern. Range was 15-20 km, only a slight improved against the Mosquitos’ bulky SCR-720B radar set, which only had a range of 12-16km. But the system’s compact size and the ability to be operated by the pilot alone meant a serious step forward. 34 sets were delivered together with blueprints in 1956, and the PS-43 radar system was later modified and adapted to the Saab 32 Lansen, too.

 

The structural modifications for the radar-equipped Tunnan were carried out in the course of the ensuing J 29F update program, which had started in 1954. Beyond the afterburner engine and dogtooth wing updates for the day fighters, the J 29D also received a re-designed nose section which now featured a thimble radome for the PS-43/T, integrated into the upper air intake lip, reminiscent of the F-86D’s arrangement. The air intake itself kept the original circular diameter, but the opening was slightly wider, raked forward and featured a sharper lip, for an improved airflow under the radome. Overall performance of the J 29 did not suffer, and the conversion took place swiftly thanks to a simple replacement of the nose section in front of the windscreen and the installation of a shielded tracking monitor in the cockpit.

 

Experiments with a heavier cannon armament (consisting of four, long-barreled 30mm guns in the lower fuselage) for the J 29 in general were conducted in parallel, too. But, despite showing no negative effect on the J 29’s handling or performance, this upgrade was not introduced to any of the J 29 variants in service and so the J 29D kept its original four 20mm cannon as main armament, too. Additional ordnance consisted of optional racks with 75 mm/3 in air-to-air rockets under the inner wings against large aerial targets like bombers. A pair of drop tanks could be carried on the outer pylons, too, and they were frequently carried in order to extend range and loiter time. Other loads, including bombs or unguided air-to-ground missiles, were possible, but never carried except for in practice.

 

The last converted J 29D was delivered back to the Swedish Air Force in late 1956, just in time to replace the last active J 30 Mosquitos in service, which had been gradually phased out since 1953. In parallel, the radar-equipped J 33 Venom was introduced into service, too, since the small number of J 29Ds had in the meantime turned out to be far from sufficient to effectively cover the Swedish air space against large numbers of ever faster jet bombers and reconnaissance aircraft. The J 29D fulfilled its role and duty well, though, and was just as popular as the daylight fighter versions.

 

Initially, all J 29D were delivered in bare metal finish, but they were soon adorned with additional markings on fin and wing tips for easier recognition and formation flights. A few all-weather fighters of F1 Flygflottil experimentally received the blue/green camouflage which had been adopted for the S 29C reconnaissance aircraft, but this was found to be ineffective at the typical altitudes the interceptors would operate. As a consequence, the scheme was quickly changed into the much lighter livery of the former J 30 and J 33 fighters, although the bare metal undersides and the formation markings under the wing tips were retained – even though this practice was confined to F 1 and not consequently carried out among all of the fighter squadron's J 29Ds. Some J 29D furthermore carried various forms of black ID bands for quick identification in war games, but unlike the day fighters, these markings were limited to the undersides only.

 

From 1963 onwards all frontline J 29Fs were equipped with AIM-9 Sidewinder infrared-seeking air-to-air missiles, designated Rb 24 in Swedish service. This update was also carried out among the J 29D fleet, and the new, guided missiles considerably improved the aircraft’s capabilities.

 

Anyway, the J 29D’s small number remained a fundamental problem that prevented bigger success or even export sales, and due to the quick technical advances, the J 29D remained only a stopgap solution. The much more capable Saab 32 Lansen had been under development and its dedicated all-weather fighter variant, the J 32B, had already entered service in 1958, replacing the mixed and outdated lot of radar-equipped fighters in Swedish service.

Nevertheless, the J 29D soldiered on, together with the rest of the J 29F and S 29C fleet, until 1970, even though not in front line duties anymore.

 

 

General characteristics:

Crew: 1

Length: 10.80 m (35 ft 4 1/2 in)

Wingspan: 11.0 m (36 ft 1 in)

Height: 3.75 m (12 ft 4 in)

Wing area: 24.15 m² (260.0 ft²)

Empty weight: 4,845 kg (10,680 lb)

Max. takeoff weight: 8,375 kg (18,465 lb)

 

Powerplant:

1× Svenska Flygmotor RM2B afterburner turbojet, rated at 6,070 lbf (27 kN)

 

Performance:

Maximum speed: 1,060 km/h (660 mph)

Range: 1,100 km (685 mi)

Service ceiling: 15,500 m (50,850 ft)

Rate of climb: 32.1 m/s (6,320 ft/min)

 

Armament:

4x 20mm Hispano Mark V autocannon in the lower front fuselage

Typically, a pair of 400-liter (106 US gallon) or 500-liter (132 US gallon) drop tanks was carried on the outer “wet” pylons

Further air-to-air ordnance initially consisted of 75 mm (3 in) air-to-air rockets, from 1963 onwards the J 29D could also carry up to 4x Rb 24 (AIM-9B Sidewinder) IR-guided air-to-air missiles.

Optionally (but never carried in service), the J 29D could also deploy a wide range of bombs and unguided missiles, including 145 mm (5.8 in) anti-armor rockets, 150 mm (6 in) HE (high-explosive) rockets or 180 mm (7.2 in) HE anti-ship rockets

 

 

The kit and its assembly:

Sweden is a prolific whiffing territory, and the Saab 29 offers some interesting options. The all-weather Tunnan was a real Saab project, and things actually got as far as the aforementioned radome shape test stage. But eventually the project was fully dropped, since Saab had been busy with standard J 29 production and conversions, so that this aircraft never materialized, just as the projected side-by-side trainer Sk 29 of the same era.

 

However, I recently came across a nice Saab 29 book which also covers some projects – including drawings of the radar-equipped Tunnan that never was. My converted model with the thimble radome and the raked air intake is based on these drawings.

 

The basic kit is the Heller Saab 29, which I deem superior to the Matchbox Tunnan, with its mix of raised and engraved panel lines and overall rather soft detail (despite the surprisingly nice cockpit). Anyway,, the Heller kit has its flaws, too, e. g. a generally weak material thickness, lack of locator pins or other stabilizing aids and some sinkholes here and there.

 

The kit was built mostly OOB, with as much lead in the gun tray as possible - and it actually stands on its own three feet/wheels! The only major change is the modified nose section. It sounds simple to graft a radome onto the Tunnan's nose, but the rhinoplasty was challenging. The whole front end had to be renewed, based on the profile drawings and sketches at hand.

 

The thimble radome is actually a recycled drop tank front end from a Hasegawa F6F Hellcat. The raked, lower aitr intake lip comes from a Matchbox Mystère IVA - but it lost its splitter, was reshaped and had the OOB air intake duct glued into place from behind. Once the intake was glued into its place, a wedge opeing was cut into the area in front of the canopy and the drop tank radome adapted to the gap, a step-by-step approach, since I wanted to have the radome slightly protrude into the airtake, but also keep a staright line in front of the windscreen.

 

Additional details include new pitots on the wing tips and some additional antennae. The heat shield for the afterburner engine is OOB, as well as the streamlined drop tanks and their pylons. I just added an additional pair of pylons (from an Acedamy MiG-23) to the inner wing, holding a pair of AIM-9Bs.

 

 

Painting and markings:

Finding a suitable, yet “different” scheme for the J 29 night fighter was not easy; most J 29 were left in bare metal, some carried dark green upper surfaces and some S 29C wore a paint scheme in olive green and dark blue. I eventually settled for the RAF style paint scheme that had been adopted with the J 30 Mosquito and J 33 Venom night fighters – not spectacular, but different from the Swedish early Sixties norm, and it subtly underlines the J 29D’s role.

 

The scheme was lent from RAF Venom night fighters (which was used on the Swedish J 33, too), and of the upper surfaces I used RAF tones, too: Humbrol 163 (Dark Green) and 165 (Medium Sea Grey). However, I did not want to use the grey on the lower surfaces, since I found that scheme a bit too uniform and British, so I painted the lower surfaces in NMF, with a waterline at medium height - higher than the camouflaged S 29C’s and lower than the early, camouflaged J 29A fighters (with an experimental all-green upper surface).

 

The bare metal finish was created with acrylic Aluminum (Revell 99) and Polished and Matt Aluminum Metallizer (Humbrol) added on top, highlighting single panels. Around the engine bay and the exhaust, a base with Iron (Revell 91) was laid down, with Steel Metallizer (Modelmaster) on top.

Under the wing tips, green formation markings (again Humbrol 163) were added, as well as black ID stripes (cut from generic decal sheet material). Other, Swedish adornment, like the roundels, codes or squadron markings, was taken from the OOB sheet, a PrintScale sheet for the J 29 and leftover decals from a Heller J 21.

 

Interior details were painted according to Swedish standard, thankfully there are many good pictures available. The cockpit interior became grey-green (Revell 67 comes very close to the real thing) with light grey dashboard and side consoles. The landing gear wells medium (Revell 57) grey with some dry-brushed Aluminum, while the wheel discs became grey-green, too.

 

 

An interesting result, through relatively little effort: the dog nose changes the look of the tubby J 29 a lot, it looks much sleeker and somewhat German now – but somehow also more retro than the original aircraft? The different paint scheme looks unusual, too, despite being relatively down-to-earth. This will certainly not be my last modified J 29, a two-seat trainer would certainly be another cool and reality based Tunnan whif?

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Uploaded on October 13, 2017
Taken on October 11, 2017