The Boeing KC-97 Stratotanker was a United States strategic tanker aircraft based on the Boeing C-97 Stratofreighter. It was succeeded by the Boeing KC-135 Stratotanker.
Design and development
The KC-97 Stratotanker was an aerial refueling tanker variant of the C-97 Stratofreighter (which was itself based on the B-29 Superfortress), greatly modified with all the necessary tanks, plumbing, and "flying boom". The cavernous upper deck was capable of accommodating oversize cargo accessed through a very large right-side door. In addition, transferrable jet fuel was contained in tanks on the lower deck (G-L models). Both decks were heated and pressurized for high altitude operations.
The USAF began operating the KC-97 in 1950. It purchased a total of 816 KC-97s from Boeing, as opposed to only 74 of the C-97 cargo version. The KC-97 used piston engines, fueled by aviation gasoline, but it carried jet fuel for its refueling mission. It therefore used independent (transfer valves) systems for both types of fuel, and was able to transfer its avgas 145 to off-load to the receiver in an emergency. (known as a SAVE)
These tankers were vitally important to the world-wide B-47 Stratojet strategic operations. An example was the support of Arctic reconnaissance flights from Thule Air Base.
While it was an effective tanker, the KC-97's slow speed and low operational altitude complicated refueling operations with jet aircraft. B-52s typically lowered their flaps and rear landing gear to slow the aircraft enough to refuel from the KC-97. In addition, a typical B-52 refueling engagement profile would involve a descent that allowed the aircraft pair to maintain a higher airspeed (220-240 knots). In the early 1960s, the Tactical Air Command added J-47 jet pods from retired KB-50 tankers to produce the KC-97L. The jet pods increased performance and made the KC-97 more compatible with jet aircraft.
In 1956, SAC began phasing out the KC-97 in favor of the KC-135. KC-97s continued operating with TAC, the Air Force Reserve, and the Air National Guard. The KC-97 was finally retired completely in 1978, when the Texas and Utah Air National Guards exchanged their KC-97Ls for C-130s and KC-135s, respectively.
- Source: AIRTime
- prototype, 3 built.
- cargo transport, 6 built.
- troop carrier, 3 built.
- fitted with 80 airliner-style seats, one in 1954 redesignated VC-97D, retired to MASDC 15 December 1969.
- transport, 50 built.
- 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.
- medical evacuation transports, 14 C-97As converted during the Korean War (also designated MC-97).
- staff transport conversions, 1 YC-97A, 2 C-97As converted, plus the YC-97B. Later designated C-97D.
- KC-97Es converted to transports.
- aerial refueling tankers with rear loading doors permanently closed, 60 built.
- KC-97Fs converted to transports.
- 3800hp R-4360-59B engines and minor changes, 159 built.
- 135 KC-97Gs converted to transports.
- ELINT conversion of three KC-97Gs. 53-106 was operated by the CIA for covert ELINT operations in the West Berlin Air Corridor.
- dual-role aerial refueling tankers/cargo transportation aircraft. KC-97G models carried underwing fuel tanks. 592 built.
- Five KC-97Gs were used as ground instruction airframes.
- One aircraft was modified to test the underwing General Electric J47-GE-23 jet engines, and was later designated KC-97L.
- KC-97Gs converted for search and rescue operations, 22 converted.
- One KC-97F was experimentally converted into a hose-and-drogue refueling aircraft.
- two KC-97G conversion with four 4250 kW Pratt & Whitney YT34-P-5 turboprops, dropped in favour of the Boeing KC-135 Stratotanker.
- KC-97Gs converted to troop transports.
- 81 KC-97Gs modified with two J47 turbojet engines on underwing pylons.
Spanish Boeing KC-97L Stratotanker at Albacete
- United States
The following USAF wing organizations flew the various KC-97 models at some time during their existence:
- 2d Bombardment Wing (Medium) - Hunter AFB, Georgia (1953–1963)
- 9th Bombardment Wing (Medium) - Mountain Home AFB, Idaho (1954–1965)
- 11th Air Refueling Wing - Altus AFB, Oklahoma (1957–1958)
- 19th Bombardment Wing (Medium) - Homestead AFB, Florida (1955–1961)
- 22d Bombardment Wing (Medium) - March AFB, California (1952–1962)
- 26th Strategic Reconnaissance Wing (Medium) - Lockborne AFB, Ohio (1953–1955; 1956–1958)
- 28th Bombardment Wing (Heavy) - Ellsworth AFB, South Dakota (1962–1964)
- 40th Bombardment Wing (Medium) Schilling AFB, Kansas(1953–1960)
- 42d Bombardment Wing (Heavy) - Limestone AFB, Maine (1955–1957)
- 43d Bombardment Wing (Medium) - Davis-Monthan AFB, Arizona (1953–1960)
- 44th Bombardment Wing (Medium) - Lake Charles AFB, Louisiana (1953–1960)
- 68th Bombardment Wing (Medium) - Lake Charles AFB, Louisiana (1953–1957)
- 70th Strategic Reconnaissance Wing (Medium) - Little Rock AFB, Arkansas (1955–1961)
- 90th Bombardment Wing (Medium) - Fairchild AFB, Washington (1955–1960)
- 91st Bombardment Wing (Medium) - Glasgow AFB, Montana (1952–1957)
- 93d Bombardment Wing (Medium) - Castle AFB, California (1953–1957)
- 96th Bombardment Wing (Medium) - Altus AFB, Oklahoma (1954–1958)
- 97th Bombardment Wing (Medium) - Biggs AFB, Texas (1954–1957)
- 98th Bombardment Wing (Medium) - Lincoln AFB, Nebraska (1954–1963)
- 100th Bombardment Wing (Medium) - Portsmouth AFB/Pease AFB, New Hampshire (1956–1966)
- 301st Bombardment Wing (Medium) - Barksdale AFB, Louisiana/Lockborne AFB, Ohio (1953–1963)
- 303rd Bombardment Wing (Medium) - Davis-Monthan AFB, Arizona (1953–1956; 1960)
- 305th Bombardment Wing (Medium) - MacDill AFB, Florida (1951–1959)
- 306th Bombardment Wing (Medium) - MacDill AFB, Florida (1951–1962)
- 307th Bombardment Wing (Medium) - Lincoln AFB, Nebraska (1955–1960)
- 308th Bombardment Wing (Medium) - Hunter AFB, Georgia (1953–1959)
- 310th Bombardment Wing (Medium) - Smoky Hill AFB/Schilling AFB, Kansas (1952–1963)
- 320th Bombardment Wing (Medium) - March AFB, California (1952–1960)
- 321st Bombardment Wing (Medium) - Pinecastle AFB, Florida (1954–1956)
- 340th Bombardment Wing (Medium) - Whiteman AFB, Missouri (1954–1962)
- 341st Bombardment Wing (Medium) - Dyess AFB, Texas (1956–1960)
- 376th Bombardment Wing (Medium) - Barksdale AFB, Louisiana/Lockborne AFB, Ohio (1953–1963)
- 379th Bombardment Wing - Homestead AFB, Florida (1956)
- 384th Air Refueling Wing (Heavy) - Little Rock AFB, Arkansas (1961–1963)
- 397th Bombardment Wing (Heavy) - Dow AFB, Maine (1963–1964)
- 407th Strategic Fighter Wing - Great Falls AFB, Montana (1957)
- 497th Air Refueling Wing - Plattsburgh AFB, New York (1962–1964)
- 499th Air Refueling Wing - Westover AFB, Massachusetts (1963–1965)
- 500th Air Refueling Wing - Selfridge AFB, Michigan (1963–1964)
- 509th Bombardment Wing (Heavy) - Walker AFB, New Mexico/Pease AFB, New Hampshire (1954–1965)
- 4397th Air Refueling Training Wing - Randolph AFB, Texas (1958–1963)
- 4397th Combat Crew Training Squadron
- 4050th Air Refueling Wing - Westover AFB, Massachusetts (1955–1962)
- 4060th Air Refueling Wing - Dow AFB, Maine/Plattsburgh AFB, New York (1955–1962)
- 4108th Air Refueling Wing - Plattsburgh AFB, New York (1961–1965
- 4045th Air Refueling Wing - Selfridge AFB, Michigan
- 4061st Air Refueling Wing - Malmstrom AFB, Montana
- 4081st Air Refueling Wing - Ernest Harmon AFB, NFLD (19?? - 1966)
Air National Guard
- 106th Air Refueling Group - Suffolk County Airport, New York (19-19)
- 126th Air Refueling Wing - O'Hare International Airport, Illinois (19-19)
- 128th Air Refueling Wing - Mitchell International Airport, Wisconsin (19-19)
- 134th Air Refueling Wing - McGhee Tyson Airport, Tennessee (19-19)
- 146th Air Transport Wing- Van Nuys, California 1962 - 1967
- 136th Air Refueling Wing - NAS JRB Fort Worth, Texas (1965–1978)
- 139th Air Refueling Group - Rosecrans Air National Guard Base, Missouri (1969–1976)
- 151st Air Refueling Group - Salt Lake City International Airport, Utah (1972–1978)
- 160th Air Refueling Group - Lockborne AFB, Ohio (1965–1975)
- 161st Air Refueling Group - Sky Harbor International Airport, Arizona (1972–1977)
- 171st Air Refueling Wing - Pittsburgh International Airport, Pennsylvania (1972–1977)
Accidents and incidents involving the KC-97
- 9 May 1957 - KC-97F-55-BO, 51-0258, c/n 16325, en route from Sidi Slimane Air Base, Morocco, to Lajes AB, Azores, ditches in the Atlantic 550 km (343.8 mls) SE of the Azores Islands following a double engine failure, no fatalities amongst the seven crew. The airplane floated for ten days and was sunk by USS Wisconsin.
- 18 July 1957 - The 380th Bomb Wing suffers its first peacetime major accident when KC-97G-28-BO, 52-2737, c/n 16768, from the 380th Air Refueling Squadron with a crew of eight explodes and crashes into Lake Champlain at 2128 hrs. when 2 of the 4 engines fail 3 minutes after take-off from Plattsburgh AFB, New York. Three survivors.
- 29 October 1957 - KC-97G-27-BO Stratotanker, 52-2711, c/n 16742, of the 509th Bomb Wing, out of Walker AFB, New Mexico, crashes 35 miles north of Flagstaff, Arizona, while on nine-hour low-level survey flight to determine minimum altitude restrictions for B-47 training routes. Aircraft was seen over Gray Mountain, Arizona, at altitude of 60 feet shortly after 0830 hrs., and then heard striking a cloud-shrouded cliff face, killing 16 crew and strewing wreckage for 200 yards along mountainside.
- 14 December 1959 - KC-97G Stratotanker, 53-0231, c/n 17113, of the 384th Air Refueling Squadron, out of Westover AFB, Massachusetts, collides with a B-52 during a refueling mission at an altitude of ~15,000 feet. The aircraft loses the whole left horizontal stabilizer and elevator, the rudder, and the upper quarter of the vertical stabilizer. Crew makes a no-flap, electrical power off landing at night at Dow AFB, Maine, seven crew okay. "Spokesmen at Dow Air Force, Bangor, said the B52 [sic] apparently 'crowded too close' and rammed a fuel boom into the tail of a 4 engined KC95 [sic] tanker plane."  Aircraft stricken as beyond economical repair. Two crew on the B-52 eject, parachute safely, and are recovered by helicopters in a snow-covered wilderness area. The bomber and remaining eight crew members continue to Westover AFB, where a safe landing is made.
- 15 April 1960 - Twenty-four airmen escape with their lives when KC-97G-23-BO Stratotanker, 52-0919, c/n 16612, of the 307th Air Refueling Squadron, 307th Bomb Wing, crashes and burns on take-off from Lincoln AFB, Nebraska, when the undercarriage collapses. The only casualties are two airmen who suffer leg fractures and 5 others who suffer minor cuts and burns.
- 27 June 1960 - A KC-97G-27-BO, 52-2728, of the 380th Air Refueling Squadron, Plattsburgh AFB, New York, suffers failure of lubrication on an engine impeller shaft, during an evening four-hour training mission to refuel a B-47 Stratojet. During rendezvous at 15,500 feet, bomber crew sees the tanker's number one (port outer) powerplant burst into flames. A burning fuel leak threatens the wing integrity. As the bomber moves away from the burning tanker, the crew tries unsuccessfully to put out the blaze. The plane goes into a spin as the wing fails outboard of the engine and crashes on Jonathan Smith Mountain, a hill east of Puzzle Mountain in Newry, Maine. The flash of the fire is seen from as far away as Lewiston and Bridgton, and several people witness the crash, including hundreds of moviegoers at the Rumford Point Drive-In. All five crew are killed - two are found wearing unused parachutes. KWF are Lt. William Burgess, commander, of Indian Lake, New York; Technical Sgt. Robert Costello, boom operator, of Springfield, Illinois; Lt. Raymond Kisonas, navigator, of Waterbury, Connecticut; Lt. Lewis Turner, co-pilot, of Spokane, Washington; and Master Sgt. Harold Young, flight engineer, of Selma, Alabama. Wreckage covers five acres and is still there.
- 17 September 1971 - KC-97G, 4X-FPR / 033, c/n 16714, of the Heyl Ha'Avir (Israeli Air Force), is shot down by Egyptian missiles over Suez, Egypt, 7 of 8 on board killed.
A number of KC-97s survive, at least two of which are potentially airworthy: 52-2718 / N117GA Angel of Deliverance operated by the Berlin Airlift Historical Foundation, and N1365N known as Tanker 97 and operated until recently as an aerial firefighting airtanker by Hawkins & Powers.
Static displays include:
- the KC-97L "Zeppelinheim" at the National Museum of the United States Air Force at Wright-Patterson Air Force Base near Dayton, Ohio
- Air Mobility Command Museum at Dover Air Force Base, Delaware
- March Field Air Museum at March Air Reserve Base in Riverside, California
- Museum of Aviation at Robins Air Force Base in Georgia
- Rogue Valley International-Medford Airport in Central Point, Oregon
- Carolinas Aviation Museum at Charlotte-Douglas International Airport in Charlotte, North Carolina
- Grissom Air Museum at Grissom Air Reserve Base in Peru, Indiana
- Dyess Air Force Base in Abilene, TX
- Pima Air and Space Museum adjacent to Davis-Monthan Air Force Base in Tucson, Arizona
- The Airplane Restaurant adjacent to Peterson Air Force Base and Colorado Springs Municipal Airport in Colorado Springs, Colorado
- Whiteman Air Force Base in Knob Noster, Missouri
- Castle Air Museum at the former Castle Air Force Base in Atwater, California
- Museo del Aire (Spain) at Cuatro Vientos Airport in Madrid, Spain
- Strategic Air and Space Museum near Offutt Air Force Base in Ashland, Nebraska
- KC-97L 52-0905 / 0905 (cn 16599) Wisconsin National Guard Museum at Volk Field Air National Guard Base in Camp Douglas, Wisconsin
In popular culture
The Stratotanker is shown in Strategic Air Command, refuelling a B-47 and in Bombers B-52 refueling B-52s.
Data from USAF Museum  and FAS.
- Crew: six (aircraft commander, copilot, navigator, flight engineer, radio operator, boom operator)
- Capacity: 9,000 gal (34,000 L) of jet fuel
- Length: 117 ft 5 in (m)
- Wingspan: 141 ft 2 in (m)
- Height: 38 ft 4 in (m)
- Wing area: ft² (m²)
- Empty weight: 82,500 lb (kg)
- Loaded weight: 153,000 lb (kg)
- Max. takeoff weight: 175,000 lb (kg)
- Related development
- Aircraft of comparable role, configuration and era
- Related lists
- ^ for KC-97: AIRTime Publishing. (2006). International Air Power Review, Vol 20. ISBN 1-880588-91-9
- ^ Rarenstein, Charles. (1984). Air Force Combat Wings: Lineage and Honors Histories 1947-1977. ISBN 0-912799-12-9
- ^ http://aviation-safety.net/database/record.php?id=19570509-1
- ^ Strategic-air-command.com: Plattsburgh AFB, NY - SAC - 380th Bomb Wing - B-47, B-52, FB111A Retrieved on 2011-12-1.
- ^ http://www.joebaugher.com/usaf_serials/1952.html
- ^ JoeBaugher.com: 1952 USAF Serial Numbers, Retrieved on 2011-12-1
- ^ Smithsonian Institute, "All That Remains", Air & Space Magazine, Washington, D.C., November 2002. Retrieved on 2011-12-1
- ^ AircraftArchaeology.com: KC-97G, #52-2711 crashed 29 Oct 1957, 35 miles north of Flagstaff., Retrieved on 2011-12-1
- ^ Associated Press, "Two Chutists Found Safe", Lincoln Evening Journal and Nebraska State Journal, Tuesday 15 December 1959, page 3.
- ^ Aviation-Safety.net Accident: 14 Dec 1959 KC-97G Stratotanker, Retrieved on 2011-12-1
- ^ http://www.joebaugher.com/usaf_serials/1952.html
- ^ http://www.lincolnkings.com/lafb/crashdigest.htm
- ^ http://www.307bwassoc.org/memberphotos2.htm
- ^ MeWreckchasers.com: REMEMBERING THE CREW OF KC-97G 52-2728, by Peter Noddin, Dirago Flyer, October 2001
- ^ Langeveld, M.Dirk, Staff Writer, "The ultimate sacrifice; wreck sites a reminder of military plane disasters", Sun Journal, Lewiston, Maine, 12 September 2010. Retrieved on 2011-12-1
- ^ SunJournal.com: Oxford Hills The ultimate sacrifice; wreck sites a reminder of military plane disasters, Retrieved on 2011-12-1
- ^ http://aviation-safety.net/database/record.php?id=19710917-1
- ^ "Boeing KC-97L". USAF Museum. http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=374. Retrieved 2011-12-02.
- ^ "KC-97 Stratotanker". Federation of American Scientists WMD Resources. http://www.fas.org/nuke/guide/usa/bomber/kc-97.htm. Retrieved 2011-12-02.