Boeing KC-135 Stratotanker


In 1954 the United States Air Force (USAF) announced its intention of buying a fleet of 800 jet tankers to support the B-52 and B-58 bombers of Strategic Air Command (SAC). Boeing had already been experimenting with a 'flying boom' aerial refuelling system, and this, allied with its Model 367-80 (the prototype of the Boeing 707 commercial airliner) led to an order being placed with them for the KC-135A Stratotanker, Boeing model number 717. Between 1956 and the ending of production in 1965 820 KC-135s had been built, including over 50 C-135 Stratolifter pure transport variants.

Based on the Boeing 707 platform, the KC-135A actually incorporates many structural differences, including a narrower fuselage, and other alterations led to the two aircraft sharing little more than the basic wing box.

The Stratotanker could carry up to 80 passengers on its upper deck, with its 22 fuel tanks in the lower fuselage and wings giving a refuelling capacity of 114,320 litres (30,200 US gal). Originally it was equipped solely with the ‘flying boom’ type of refuelling equipment fitted to SAC bombers, but was later upgraded with a drogue and probe attachment giving it commonality to the fighters of Tactical Air Command (TAC) and the US Navy, as well as aircraft from other nations.

During its long service career, numerous variants of the KC-135 appeared, and it served in theatres all over the world. The KC-135s form the backbone of the Air Force tanker fleet, meeting the aerial refuelling requirements of bomber, fighter, cargo and reconnaissance forces, as well as the needs of the Navy, Marines, and allied nations. By 1992, the vast majority of the fleet had been upgraded to either KC-135E or KC-135R standard with turbofan engines and improved avionics. It is expected to soldier on as the USAF’s prime aerial tanker until the 2040s.

Further Reading

Jane’s All the World’s Aircraft 1959-60; Boeing 707, Douglas

DC8 & Vickers VC10 by Stewart Wilson

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