Boeing KC-97 Stratotanker











The Boeing KC-97 Stratotanker was a strategic tanker aircraft. For many years, it was the backbone of the USAF's tanker fleet until replaced by the KC-135.

History

The United States Air Force operated the KC-97 from 1950 until being phased out in favor of the KC-135 beginning in 1956. KC-97s were transitioned to the Air Force Reserves and Air National Guard units and were finally retired completely in 1978, when the Texas and Utah Air National Guards exchanged their KC-97Ls for KC-135s. A total of 816 KC-97s were purchased from Boeing, as opposed to only 74 of the C-97 base cargo version. The KC-97 had piston engines, powered by gasoline, but was carrying jet fuel for its refueling mission, so it had to have independent fuel systems for both types of fuel. Two jet engines were added to increase speed and altitude, making the tankers more compatible with high performance jet aircraft. These tankers were vitally important to the world-wide B-47 strategic mission. An example is the support of over-the-arctic reconnaissance flights from Thule Air Base. The struggle to start and operate this complex airplane from a deep freeze of minus 40 F was a triumph. Navigation in the arctic night/winter requires great skill.

Development

The KC-97 Stratotanker is a Boeing Model 367 aerial refueling tanker variant of the C-97 Stratofreighter and the Boeing 377 Stratocruiser airliner greatly modified with all the necessary tanks, plumbing, and \"flying boom\". The cavernous main (upper) deck was capable of accommodating oversize cargo accessed through a very large left-side door; OR transferrable jet fuel was contained in tanks on the lower deck. Both decks were heated and pressurized for high altitude operations.

Variants

  • KC-97A - Three C-97As were converted into aerial refueling tankers. After the design was proven, they were converted back into the standard C-97A configuration.
  • KC-97E - 60 production aircraft were factory-built as aerial refueling tankers.
  • KC-97F - 159 production aircraft were factory-built as aerial refueling tankers.
  • KC-97G - 592 production aircraft were factory-built as dual-role aerial refueling tankers/cargo transportation aircraft. KC-97G models carried underwing fuel tanks. Many models were converted into full transport (i.e. aeromedical) or rescue roles.
  • GKC-97G - Five KC-97Gs were used as ground instruction airframes.
  • JKC-97G - One aircraft was modified to test the underwing J47 jet engines, and was later designated KC-97L.
  • KC-97H - One KC-97F was experimentally converted into a hose-and-drogue refueling aircraft.
  • KC-97L - 81 aircraft were modified with a pair of turbojet engines for greater thrust.


General characteristics ( KC-97L )

  • Crew: five (two pilots, navigator, flight engineer, boom operator)
  • Capacity: 9,000 gal (34,000 L) of jet fuel
  • Length: 117 ft 5 in
  • Wingspan: 141 ft 2 in
  • Height: 38 ft 4 in
  • Empty weight: 82,500 lb
  • Loaded weight: 153,000 lb
  • Max takeoff weight: 175,000 lb
  • Powerplant
    • 2 x General Electric J47-GE-23 turbojets, 5,790 lbf (kN) each
    • 4 x Pratt & Whitney R-4360-59 radial engines, 3,500 hp (kW) each


Performance ( KC-97L )

  • Maximum speed: 400 mph
  • Cruise speed: 230 mph
  • Range: 2,300 mi
  • Service ceiling: 30,000 ft