Boeing KC-135E Stratotanker
The Guard and Reserve re-engine — TF33 turbofans salvaged from retired 707 airliners · Re-engined in the 1980s · Retired by USAF 2009
The KC-135E came from the first of two engine-retrofit programmes of the 1980s. Around 160 Air National Guard and Air Force Reserve KC-135As (sources give 157 or 161) received Pratt & Whitney TF33-PW-102 turbofans taken from Boeing 707 airliners retired in the late 1970s and early 1980s — a cheaper alternative to new engines.
The turbofans made the E-model about 14% more fuel-efficient than the KC-135A and let it offload about 20% more fuel on long-duration flights. It was the only Stratotanker version fitted with thrust reversers, useful for aborted take-offs and shorter landing runs. Four ex-RC-135A aircraft, designated KC-135D, were brought to the same engine and cockpit standard in 1990.
Some E-models were later upgraded to KC-135R standard; the rest went into storage. The last USAF KC-135E, 56-3630 of the Maine Air National Guard's 101st Air Refueling Wing, was flown to the boneyard at Davis-Monthan AFB in September 2009. Chile took delivery of three ex-USAF KC-135Es from February 2010, and several are preserved in US museums.
