Boeing KC-97L Stratofreighter
The range of the B-29 Superfortress immediately interested Boeing in developing a passenger version for postwar use; this would make transatlantic and Hawaii flying routes economical for the first time. Since the standard B-29 fuselage would be inadequate for passengers, Boeing designers added a larger-diameter fuselage atop the old B-29 fuselage, resulting in a “double-bubble” appearance. The tail and engines of the B-50 advanced version of the Superfortress were adapted to what would become the Model 377 Stratocruiser. While only 55 Model 377s entered airline service, quickly eclipsed by the jet age, they were considered luxurious for their time, with the lower deck being used for airborne lounges or sleeping compartments, all in pressurized comfort—a first for the airline industry.
The USAF developed the C-97 Stratofrieghter version of the Model 377 at the same time, which differed from the airliner version by being used for cargo missions, with undernose weather radar and clamshell doors in the rear fuselage. The C-97 arrived just too late for the Berlin Airlift, but was used extensively in Korea. Like the Stratocruiser, only 60 dedicated C-97 transports were built: by the time the aircraft reached the USAF in numbers, the Lockheed C-130 Hercules was already in development.
Where the Stratofreighter would truly shine was as an airborne tanker: over 800 KC-97s would be built as the first purpose-built airborne tankers in the world. The clamshell doors were deleted, though cargo capacity was retained on the upper deck, giving the KC-97 a dual role. Fuel tanks were added to the lower deck, along with a station for the Boeing flying boom attached to the rear fuselage. The aircraft had to have separate fuel systems, as the KC-97 used piston engines and the jets it refueled would need a different type. The use of piston engines was to prove problematic for the KC-97 as well: by the time it entered service in 1950, it was far slower than the jets it would need to refuel. The complicated Wasp Major engines were also difficult to maintain, notorious for spraying oil at startup, and prone to catastrophic fires. At least two KC-97s were lost to engine explosions, something that had plagued the Model 377 as well. As the B-50 was retired in the early 1960s, J47 jet engines were removed and attached to Stratofreighters as the KC-97L variant.
The KC-97 could still be called a success, despite all of its problems and the fact that technology threatened to render it obsolete as soon as it entered service. Replaced in frontline service by the KC-135 Stratotanker, the KC-97 was relegated to Air Reserve and Air National Guard units in the mid-1960s, where it freed up KC-135s for service in Vietnam. Even with jet augmentation, the KC-97 was clearly obsolete by the 1970s, but a few KC-97Ls soldiered on until 1978, when it was finally withdrawn from service. A few briefly served with the Spanish Air Force during the 1970s, while Israel modified theirs to essentially KC-97 standard and utilized them in the Yom Kippur War of 1973. At least 26 KC-97s still exist in museums, and two are known to be airworthy.
53-0354 started off as a KC-97G, assigned to the 9th Bomb Wing at Mountain Home AFB, Idaho. In 1965 it was modified to a KC-97L, and reassigned to the 134th Air Refueling Group (Tennessee ANG) at McGhee-Tyson; the 134th set a record for transitioning into the KC-97, doubly impressive as they had been in F-104 Starfighters! 53-0354 participated in Operation Creek Party deployments to West Germany, and was retired in 1976. It was stored at MASDC in Arizona, but in 1984 was donated to the Castle Air Museum, and flown by a volunteer crew to the base.
Today (or at least in May 2021), 53-0354 is displayed as a "plain Jane" KC-97, with no unit markings. It is showing some wear and tear, but probably will be restored in the not-too-distant future.
Boeing KC-97L Stratofreighter
The range of the B-29 Superfortress immediately interested Boeing in developing a passenger version for postwar use; this would make transatlantic and Hawaii flying routes economical for the first time. Since the standard B-29 fuselage would be inadequate for passengers, Boeing designers added a larger-diameter fuselage atop the old B-29 fuselage, resulting in a “double-bubble” appearance. The tail and engines of the B-50 advanced version of the Superfortress were adapted to what would become the Model 377 Stratocruiser. While only 55 Model 377s entered airline service, quickly eclipsed by the jet age, they were considered luxurious for their time, with the lower deck being used for airborne lounges or sleeping compartments, all in pressurized comfort—a first for the airline industry.
The USAF developed the C-97 Stratofrieghter version of the Model 377 at the same time, which differed from the airliner version by being used for cargo missions, with undernose weather radar and clamshell doors in the rear fuselage. The C-97 arrived just too late for the Berlin Airlift, but was used extensively in Korea. Like the Stratocruiser, only 60 dedicated C-97 transports were built: by the time the aircraft reached the USAF in numbers, the Lockheed C-130 Hercules was already in development.
Where the Stratofreighter would truly shine was as an airborne tanker: over 800 KC-97s would be built as the first purpose-built airborne tankers in the world. The clamshell doors were deleted, though cargo capacity was retained on the upper deck, giving the KC-97 a dual role. Fuel tanks were added to the lower deck, along with a station for the Boeing flying boom attached to the rear fuselage. The aircraft had to have separate fuel systems, as the KC-97 used piston engines and the jets it refueled would need a different type. The use of piston engines was to prove problematic for the KC-97 as well: by the time it entered service in 1950, it was far slower than the jets it would need to refuel. The complicated Wasp Major engines were also difficult to maintain, notorious for spraying oil at startup, and prone to catastrophic fires. At least two KC-97s were lost to engine explosions, something that had plagued the Model 377 as well. As the B-50 was retired in the early 1960s, J47 jet engines were removed and attached to Stratofreighters as the KC-97L variant.
The KC-97 could still be called a success, despite all of its problems and the fact that technology threatened to render it obsolete as soon as it entered service. Replaced in frontline service by the KC-135 Stratotanker, the KC-97 was relegated to Air Reserve and Air National Guard units in the mid-1960s, where it freed up KC-135s for service in Vietnam. Even with jet augmentation, the KC-97 was clearly obsolete by the 1970s, but a few KC-97Ls soldiered on until 1978, when it was finally withdrawn from service. A few briefly served with the Spanish Air Force during the 1970s, while Israel modified theirs to essentially KC-97 standard and utilized them in the Yom Kippur War of 1973. At least 26 KC-97s still exist in museums, and two are known to be airworthy.
53-0354 started off as a KC-97G, assigned to the 9th Bomb Wing at Mountain Home AFB, Idaho. In 1965 it was modified to a KC-97L, and reassigned to the 134th Air Refueling Group (Tennessee ANG) at McGhee-Tyson; the 134th set a record for transitioning into the KC-97, doubly impressive as they had been in F-104 Starfighters! 53-0354 participated in Operation Creek Party deployments to West Germany, and was retired in 1976. It was stored at MASDC in Arizona, but in 1984 was donated to the Castle Air Museum, and flown by a volunteer crew to the base.
Today (or at least in May 2021), 53-0354 is displayed as a "plain Jane" KC-97, with no unit markings. It is showing some wear and tear, but probably will be restored in the not-too-distant future.