The Boeing KC-135 Stratotanker is an aerial refueling military aircraft. It was the US Air Force's first jet powered refueling tanker and replaced the KC-97 Stratotanker.
Similar in design to the later and enlarged Boeing 707 airliner, it was initially tasked to refuel strategic bombers, but was used extensively in the Vietnam war and later conflicts such as Desert Storm to extend the range and endurance of both Air Force and Navy tactical fighters and bombers.
Serving with the United States Air Force since 1957, it is one of very few military fixed wing aircraft with over 50 years of continuous service with the original service.
A modification program re-engined 500 aircraft with new CFM International CFM56 (military designation: F108) engines produced by General Electric and Snecma. The CFM-56 turbofans are capable of producing approximately 22,500 lbf of thrust, nearly a 100% increase in power compared to the original J-57 engines.
The re-engined tanker, designated either the KC-135R or KC-135T, can offload up to 50% more fuel (on a long duration sortie), is 25% more fuel efficient, costs 25% less to operate and is 96% quieter than the KC-135A (sideline noise levels at takeoff were reduced from 126 to 99 decibels).
The KC-135R's operational range is 60% greater than the KC-135E for comparable fuel offloads, providing a wider range of basing options