Boeing KC-135R Stratotanker
Facing the increasing age of their KC-135A fleet, along with the type’s less fuel efficient, smoky, and noisy JT3D turbojet engines, the USAF embarked on a program to either modify or replace the 700 or so KC-135s in service beginning in 1980. The KC-10A Extender proved to be an adequate supplement, but cost concerns and the sheer size of the USAF’s tanker fleet meant that completely replacing the KC-135 with the KC-10 was not feasible; likewise, a partial re-engining to KC-135E standard, which used TF33 turbofans taken from 707 airliners, likewise would not be cost-effective for the entire fleet.
Therefore the USAF decided instead to modify the KC-135As to KC-135R standard. Like the KC-135Es, the old turbojets would be replaced by turbofans, but these were state-of-the-art high-bypass CFM56 types, twice the diameter of the older JT3Ds. The CFM56, designated F108 in USAF service, doubled the thrust of the KC-135A, yet was cheaper and more fuel efficient to operate, far more quiet, and allowed the offload of half again as much fuel as the A model. This extended not only the range of the KC-135 force, but also further extended the reach of tactical fighters it would refuel. An auxiliary power unit (APU) was added as well, allowing the KC-135R to operate with a minimum of ground equipment from unprepared airstrips, and the airframe was reskinned, taking the fleet back to essentially zero flight hours. The 360 KC-135Rs were therefore practically new aircraft, and were projected to serve until at least 2010 or possibly longer.
KC-135Rs entered service in 1983 and rapidly replaced nearly all KC-135As in service; SR-71 dedicated KC-135Qs were reengined as KC-135Ts. The first combat use of the R model was in Panama in 1989, followed by Operation Desert Storm in Iraq in 1991; since then, KC-135Rs have supported every peacetime and war deployment by the US, the most recent being Operation Odyssey Dawn over Iraq in 2011. With the retirement of the KC-135E in 2009, the R model is now the only KC-135 variant operated by the USAF. The entire fleet went through the Pacer CRAG update in the late 1990s, adding GPS and additional navigational equipment to the KC-135. A few were further modified as KC-135RTs, which themselves can be refuelled in flight; several more have also had underwing fuel tanks added to allow for three-point refuelling—one via the USAF-standard boom/plug, the other two utilizing US Navy style probe/drogue.
Though much of the KC-135R fleet has been found capable of operating until 2040 (when the youngest airframe will be approaching eighty years old), obviously a replacement would be needed at some point; this was recognized by the USAF in the late 1990s and accelerated by the higher strain of constant wartime deployments over Iraq and Afghanistan since 2001. A long, drawn-out, and bitter competition between Boeing’s 767 and Airbus’ A330 over the past ten years finally came to an end in 2011, when the USAF selected Boeing’s KC-767 proposal over the Airbus KC-30; designated KC-46, the new tanker will begin replacing the KC-135R about 2015.
This KC-135R, 58-0098, was at Malmstrom AFB in 1987 to provide familiarization for base personnel, as the 301st Air Refueling Wing was due to arrive later in the year. It was assigned to the 28th Strategic Bomber Wing at Ellsworth AFB. This view shows the earlier overall SAC gray scheme used on its tankers, complete with Strategic Air Command stripe on the fuselage and the 28th's tail stripe. 58-0098 is still around, today serving with the 101st Air Refueling Wing (Maine ANG) at Bangor, Maine.
Boeing KC-135R Stratotanker
Facing the increasing age of their KC-135A fleet, along with the type’s less fuel efficient, smoky, and noisy JT3D turbojet engines, the USAF embarked on a program to either modify or replace the 700 or so KC-135s in service beginning in 1980. The KC-10A Extender proved to be an adequate supplement, but cost concerns and the sheer size of the USAF’s tanker fleet meant that completely replacing the KC-135 with the KC-10 was not feasible; likewise, a partial re-engining to KC-135E standard, which used TF33 turbofans taken from 707 airliners, likewise would not be cost-effective for the entire fleet.
Therefore the USAF decided instead to modify the KC-135As to KC-135R standard. Like the KC-135Es, the old turbojets would be replaced by turbofans, but these were state-of-the-art high-bypass CFM56 types, twice the diameter of the older JT3Ds. The CFM56, designated F108 in USAF service, doubled the thrust of the KC-135A, yet was cheaper and more fuel efficient to operate, far more quiet, and allowed the offload of half again as much fuel as the A model. This extended not only the range of the KC-135 force, but also further extended the reach of tactical fighters it would refuel. An auxiliary power unit (APU) was added as well, allowing the KC-135R to operate with a minimum of ground equipment from unprepared airstrips, and the airframe was reskinned, taking the fleet back to essentially zero flight hours. The 360 KC-135Rs were therefore practically new aircraft, and were projected to serve until at least 2010 or possibly longer.
KC-135Rs entered service in 1983 and rapidly replaced nearly all KC-135As in service; SR-71 dedicated KC-135Qs were reengined as KC-135Ts. The first combat use of the R model was in Panama in 1989, followed by Operation Desert Storm in Iraq in 1991; since then, KC-135Rs have supported every peacetime and war deployment by the US, the most recent being Operation Odyssey Dawn over Iraq in 2011. With the retirement of the KC-135E in 2009, the R model is now the only KC-135 variant operated by the USAF. The entire fleet went through the Pacer CRAG update in the late 1990s, adding GPS and additional navigational equipment to the KC-135. A few were further modified as KC-135RTs, which themselves can be refuelled in flight; several more have also had underwing fuel tanks added to allow for three-point refuelling—one via the USAF-standard boom/plug, the other two utilizing US Navy style probe/drogue.
Though much of the KC-135R fleet has been found capable of operating until 2040 (when the youngest airframe will be approaching eighty years old), obviously a replacement would be needed at some point; this was recognized by the USAF in the late 1990s and accelerated by the higher strain of constant wartime deployments over Iraq and Afghanistan since 2001. A long, drawn-out, and bitter competition between Boeing’s 767 and Airbus’ A330 over the past ten years finally came to an end in 2011, when the USAF selected Boeing’s KC-767 proposal over the Airbus KC-30; designated KC-46, the new tanker will begin replacing the KC-135R about 2015.
This KC-135R, 58-0098, was at Malmstrom AFB in 1987 to provide familiarization for base personnel, as the 301st Air Refueling Wing was due to arrive later in the year. It was assigned to the 28th Strategic Bomber Wing at Ellsworth AFB. This view shows the earlier overall SAC gray scheme used on its tankers, complete with Strategic Air Command stripe on the fuselage and the 28th's tail stripe. 58-0098 is still around, today serving with the 101st Air Refueling Wing (Maine ANG) at Bangor, Maine.