Boeing C-97 Stratofreighter

C-97 Stratofreighter
Role Military transport aircraft
Manufacturer Boeing
First flight 9 November 1944
Introduction 1947
Retired 1978
Primary users United States Air Force
Israeli Air Force
Produced 1944–1952
Number built 77 (total of 888 in all variants)
Unit cost
$1,205,000
Developed from Boeing B-29 Superfortress
Boeing B-50 Superfortress
Variants Boeing KC-97 Stratofreighter
Boeing 377 Stratocruiser
Aero Spacelines Pregnant Guppy
Aero Spacelines Super Guppy
Aero Spacelines Mini Guppy

The Boeing C-97 Stratofreighter is a long-range heavy military cargo aircraft developed from the B-29 and B-50 bombers. Design work began in 1942, with the prototype's first flight being on 9 November 1944, and the first production aircraft entered service in 1947. Between 1947 and 1958, 888 C-97s in several versions were built, 811 being KC-97 tankers.[1][2] C-97s served in the Berlin Airlift, the Korean War, and the Vietnam War. Some aircraft served as flying command posts for the Strategic Air Command, while others were modified for use in Aerospace Rescue and Recovery Squadrons (ARRS).

Design and development

The C-97 Stratofreighter was developed towards the end of World War II by fitting an enlarged upper fuselage onto a lower fuselage and wings which were essentially the same as those of the B-29 Superfortress with the tail, wing, and engine layout being nearly identical.[3] It was built before the death of Boeing president Philip G. Johnson. It can be easily distinguished from the 377 Stratocruiser by the "beak" radome beneath the nose and by the flying boom and jet engines on later tanker models.

The prototype XC-97 was powered by the 2,200 hp (1,600 kW) Wright R-3350 engine, the same as used in the B-29. The XC-97 took off for its first flight on November 9, 1944.[4]

The tenth and all subsequent aircraft were fitted with the taller fin and rudder of the B-50 Superfortress.[3] The C-97 had clamshell doors under its tail, so that a retractable ramp could be used to drive in cargo. However, unlike the later Lockheed C-130 Hercules, it was not designed as a combat transport which could deliver directly to primitive forward bases using relatively short takeoffs and landings. The rear ramp could not be used in flight for air drops.

YC-97 Stratofreighter 45-59590 with the shorter fin of the B-29 (1947)

On 9 January 1945, the first prototype, piloted by Major Curtin L. Reinhardt, flew from Seattle to Washington, DC in 6 hours 4 minutes, an average speed of 383 mph (616 km/h) with 20,000 lb (9,100 kg) of cargo, which was for its time impressive for such a large aircraft. Production models featured the 3,500 hp (2,600 kW) Pratt & Whitney Wasp Major engine, the same engine as for the B-50.

The C-97 had a useful payload of 35,000 lb (16,000 kg) and could carry two normal trucks, towed artillery, or light tracked vehicles such as the M56 Scorpion. The C-97 was also the first mass-produced air transport to feature cabin pressurization, which made long range missions somewhat more comfortable for its crew and passengers.

The civilian derivative of the C-97 was the Boeing 377 Stratocruiser, a very luxurious transoceanic airliner which featured a lower deck lounge and could be fitted with sleeper cabins. The first Stratocruiser flew on July 8, 1947. Only 56 were built.[5]

Operational history

One YC-97A (45–9595) was used in the Berlin Airlift during April 1949 operating for the 1st Strategic Support Squadron. It suffered a landing gear accident at Rhein Main Air Base and by the time it was repaired, the Soviet Blockade was lifted.

C-97s evacuated casualties during the Korean War. C-97s also participated in the Biafran airlift, delivering relief materials to Uli airstrip in Biafra during the Nigerian Civil War. Flying under the cover of darkness and at treetop level to evade radar, at least two C-97s were lost.[6]

Boeing KC-97G Stratofreighter of the Minnesota Air National Guard in 1971 after service as part of Military Airlift Command

The USAF Strategic Air Command operated C-97 Stratofreighters from 1949–1978. Early in its service life, it served as an airborne alternative SAC command post. While only 77 C-97 transports were built, 811 were built as KC-97 Stratofreighters for inflight refueling. Many KC-97s were later refitted as C-97G transports and equipped several squadrons of the US Air National Guard.

Two C-97s are still airworthy at the present day, one (s/n 52-2718, named "Angel of Deliverance") operated as a privately owned warbird, the other operated as a fire bomber in the United States.

The Israelis turned to Stratocruisers and KC-97s when they could not buy the highly regarded C-130. They adapted Boeing 377 Stratocruiser airliners into transports, including many using C-97 tail sections including the loading ramp. Others were adapted with swiveling tails and refueling pods. One Israeli C-97 was downed by an Egyptian SA-2 Guideline missile on 17 September 1971, while flying as an electronic counter-measures platform some 12 miles from the Suez Canal.[7][8]

Variants

XC-97
military designation of the prototype Boeing 367, three built.
YC-97
cargo transport, six built.
C-97A Stratofreighter 49-2607 of Minnesota Air National Guard (1960)
YC-97A
troop carrier, three built.
YC-97B
fitted with 80 airliner-style seats, later redesignated C-97B, in 1954 became C-97D, retired to MASDC 15 December 1969.[9]
C-97A
transport, 50 built.
KC-97A
Three C-97As were converted into aerial refueling tankers with rear loading door removed and a flight refueling boom added. After the design was proven, they were converted back into the standard C-97A.
C-97C
Second production version, 14 built; those used as medical evacuation transports during the Korean War were designated MC-97C.[10]
VC-97D
staff transport and flying command post conversions, three C-97As converted.[11]
C-97E
KC-97Es converted to transports.
KC-97E
aerial refueling tankers with rear loading doors permanently closed; 60 built.
C-97F
KC-97Fs converted to transports.
KC-97F
3800hp R-4360-59B engines and minor changes; 159 built.
C-97G
135 KC-97Gs converted to transports.
EC-97G
ELINT conversion of three KC-97Gs. 53–106 was operated by the CIA for covert ELINT operations in the West Berlin Air Corridor.
KC-97G
dual-role aerial refueling tankers/cargo transportation aircraft. KC-97G models carried underwing fuel tanks; 592 built.
GKC-97G
Five KC-97Gs were used as ground instruction airframes.
JKC-97G
One aircraft was modified to test the underwing General Electric J47-GE-23 jet engines, and was later designated KC-97L.
HC-97G
KC-97Gs converted for search and rescue operations; 22 converted.
KC-97H
A YC-97J, an experimental turboprop-powered variant, in flight
One KC-97F was experimentally converted into a probe-and-drogue refueling aircraft.
YC-97J
KC-97G conversion with four 5,700 hp (4,250 kW) Pratt & Whitney YT34-P-5 turboprops, two converted.
C-97K
27 KC-97Gs converted to troop transports.[12]
KC-97L
81 KC-97Gs modified with two J47 turbojet engines on underwing pylons.

Operators

Military Operators

 Israel
 Spain
 United States

U.S. Air Force Units

The following Air Force wing organizations flew the various C-97 models at some time during their existence:[13]

Air National Guard

Boeing C-97G of the Foundation for Airborne Relief at Long Beach Airport, California, in 1973

Civil Operators

Accidents and incidents

Survivors

Specifications (C-97)

Data from Boeing C-97 Stratofreighter[47][48][49]

General characteristics

Performance

See also

Related development
Aircraft of comparable role, configuration and era
Related lists

References

Notes
  1. Bach, p. 7
  2. Bowers 1989, p. 353-359.
  3. 1 2 Swanborough / Bowers 1989, p. 125.
  4. Bowers 1989, p. 353.
  5. Bach, p. 40
  6. "ASN Aviation Safety Database." Aviation Safety Network, Flight Safety Foundation. Retrieved: 27 April 2009.
  7. Rubinstein and Goldman 1979, p. 89.
  8. "East of the Suez". Israeli Air Force official website. Retrieved 19 February 2013.
  9. Bowers 1989, p. 357.
  10. Bowers 1989, p. 358.
  11. Bowers 1989, p. 362.
  12. Bowers 1989, p. 364.
  13. Ravenstein, Charles A., ed. Air Force Combat Wings: Lineage and Honors Histories, 1947–1977. Washington, D.C.: United States Air Force Historical Research Center, Office of Air Force History, 1984. ISBN 0-912799-12-9.
  14. "A Mission of History, Education and Remembrance." Spirit of Freedom, 2011. Retrieved: 21 October 2011.
  15. Accident description for 43-27472 at the Aviation Safety Network. Retrieved on 26 January 2013.
  16. Accident description for 48-0398 at the Aviation Safety Network. Retrieved on 26 January 2013.
  17. Union News, Springfield, Massachusetts, 16 October 1951.
  18. Accident description for 48-0413 at the Aviation Safety Network. Retrieved on 26 January 2013.
  19. Accident description for 52-2654 at the Aviation Safety Network. Retrieved on 2015-06-30.
  20. Accident description for 53-0110 at the Aviation Safety Network. Retrieved on 2015-06-30.
  21. Accident description for 51-0220 at the Aviation Safety Network. Retrieved on 2015-06-30.
  22. Accident description for 52-0222 at the Aviation Safety Network. Retrieved on 2015-06-30.
  23. Accident description for 50-0702 at the Aviation Safety Network. Retrieved on 26 January 2013.
  24. Accident description for 52-2737 at the Aviation Safety Network. Retrieved on 2015-06-30.
  25. Accident description for 52-2711 at the Aviation Safety Network. Retrieved on 2015-06-30.
  26. Accident description for 49-2597 at the Aviation Safety Network. Retrieved on 26 January 2013.
  27. Accident description for 52-2703 at the Aviation Safety Network. Retrieved on 2015-06-30.
  28. Accident description for 51-0363 at the Aviation Safety Network. Retrieved on 2015-06-30.
  29. Accident description for 52-2738 at the Aviation Safety Network. Retrieved on 2015-06-30.
  30. Accident description for 52-2773 at the Aviation Safety Network. Retrieved on 2015-06-30.
  31. Accident description for 52-907 at the Aviation Safety Network. Retrieved on 2015-06-30.
  32. Accident description for 52-0904 at the Aviation Safety Network. Retrieved on 2025-06-30.
  33. Accident description for N52676 at the Aviation Safety Network. Retrieved on 26 January 2013.
  34. Accident description for 4X-FPS/037 at the Aviation Safety Network. Retrieved on 2015-06-30.
  35. Accident description for 4X-FPR/033 at the Aviation Safety Network. Retrieved on 2015-06-30.
  36. "Accident Report: Boeing C-97 Stratofreighter G, 30 July 1987." Aviation Safety Network. Retrieved: 21 October 2011.
  37. "C-97G AF Serial No. 52-898." aeromuseum.org. Retrieved: 13 November 2010.
  38. "C-97G AF Serial No. 52-2626." pimaair.org. Retrieved: 13 November 2010.
  39. "C-97G AF Serial No. 52-2718 'Angel of Deliverance'." spiritoffreedom.org. Retrieved: 13 November 2010.
  40. http://www.airfields-freeman.com/WI/Airfields_WI_SW.htm#dodgeville
  41. Leuw, Rudi. "C-97G AF Serial No. 52-2764 showing civil registry N227AR." ruudleeuw.com. Retrieved: 13 November 2010.
  42. "C-97G AF Serial No. 53-0272." pimaair.org. Retrieved: 13 November 2010.
  43. "Israeli Air Force Museum Unofficial Museum Guide." aeroflight.co.uk. Retrieved: 8 November 2011.
  44. "Boeing C-97G Stratofreighter USAF Serial Number 53-0218" Retrieved: 23 December 2012
  45. "Boeing – History – C-97 Stratofreighter." Boeing. Retrieved: 27 April 2009.
  46. Hansen, Dave. "Boeing C-97 Stratofreighter." Warbird Alley, 27 April 2009.
  47. "C-97 Stratofreighter Specifications." GlobalSecurity.org, 27 April 2009.
  48. Bridgman, Jane's 1952–1953, p. 184.
Bibliography
  • Rubinstein, Murray and Richard Goldman. The Israeli Air Force Story London: Arms & Armour Press, 1979. ISBN 0-85368-462-6.
  • Martin Bach: Boeing 367 Stratofreighter, Boeing 377 Stratocruiser, Aero Spacelines Guppies. NARA Verlag, Allershausen 1996, ISBN 3-925671-18-8.
  • Peter M Bowers: Boeing Aircraft since 1916. Putnam Aeronautical Books, London 1989, ISBN 0-85177-804-6.
  • Gordon Swanborough und Peter M Bowers: United States Military Aircraft since 1909. Putnam Aeronautical Books, London 1989, ISBN 0-85177-816-X.
  • Leonard Bridgman: Jane's All The World's Aircraft, 1952–53. Sampson Low, Marston & Company, London 1964.

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