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| Boeing KC-135 Stratotanker |
Militarymedia.net - In 1952 Boeing developed a four-jet military transport project as a private company. The company hopes the U.S. Air Force (USAF) will almost certainly buy in-flight refueling tankers to support its long-range strategic bombers. Eventually this plan paid off. In 1954, the USAF announced that it would purchase the new tanker. It made its first flight in 1956. In 1957 the USAF adopted the aircraft as the KC-135 Stratotanker. It was the most numerous variant of the C-135 Stratolifter.
In total the USAF obtained a total of 732 of these tankers until production was halted in 1965. In 2001 a total of 549 aircraft remained in operation. As of 2016, the KC-135 is still the majority of the U.S. tanker fleet. The USAF operates about 400 of these aircraft, including about 160 active duty aircraft, 60 backup aircraft. Another 180 tankers were used by the Air National Guard. The variants used today are the KC-135R and KC-135T. The air refueling tanker is equipped with a larger KC-10 Extender. It is planned that the KC-135 will be replaced gradually with the new KC-46 Pegasus. But research has concluded that many of these aircraft could remain operational and fly until 2040. Kc-135 export operators are Chile, France, Singapore and Turkey, which fly a small number of these tankers.
The KC-135 is smaller than the commercial Boeing Model 707. It was the first USAF jet-powered refueling tanker. It was originally used to refuel strategic bombers. But since the Vietnam War, the KC-135 has also been used to refuel warplanes and tactical bombers. This allows fighters and tactical bombers to spend hours, not minutes, on the front lines. A number of older USAF C-135 series aircraft were converted into standard tankers.
It carries up to 90,700 kg of fuel. The main fuel transfer method is through the boom. Stratotanker uses a "flying boom" inflight refueling system patented by Boeing. But the aircraft can also be equipped with refueling pods under the wing.
The KC-135 was operated by three crew members, including the pilot, co-pilot and boom operator. Some missions are flown with additional navigators.
The aircraft has secondary transport capability. The cargo deck above the refueling system can transport passengers or mixed cargo. The maximum cargo capacity is up to 37,600 kg, depending on the configuration of fuel storage. Or it can carry up to 80 passengers.
The aircraft is powered by 4 turbofan engines. Initially it came with a Pratt &Whitney J57 turbofan engine. Then the tanker was transformed with a newer, more powerful and more fuel-efficient engine.
The KC-135A is the original production version. It is powered by Pratt &Whitney J57s engines.
KC-135B is a cross-air command post. A total of 17 aircraft were built. It then received in-flight refueling capability and was redesigned as an EC-135C.
The KC-135D was an RC-135A reconnaissance aircraft, converted into tankers. A total of 4 aircraft were converted to this standard. All of these aircraft retired in 2007.
KC-135E. It is basically a re-engined original KC-135A with TF33 turbofans. A total of 161 aircraft have been modified to this standard. All of these aircraft were retired from the USAF in 2009.
KC-135Q. It has also been re-engined with the F108 engine as the KC-135T. It was previously dedicated to refueling Lockheed SR-71 long-range reconnaissance aircraft and later F-117 Nighthawk stealth ground attack aircraft and other covert programs. It's carrying JP-7 fuel. A total of 56 aircraft have been modified to this standard. Then a total of 54 aircraft were further upgraded to the KC-135T standard.
KC-135R. This was a thorough upgrade and re-engineering of the previous KC-135A and several KC-135E with CFM-56 turbofans (F108-CF-100). At least 361 aircraft were converted to this standard.
The KC-135T is a re-engined KC-135Q, equipped with a CFM-56 engine. A total of 54 aircraft have been modified to this standard.
The C-135FR is a French air force variant of the C-135 transport aircraft, equipped with a refueling system. In terms of capability, it is broadly similar to the U.S. KC-135.
