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, 58-0128, was one of the oldest aircraft at the Wings Over the Falls July 2022 airshow--and that includes the P-51 and the A-26! First delivered around 1959 as a KC-135A, it has served around the world, and has seen action over Bosnia and Kosovo, and possibly Vietnam and Iraq as well. 58-0128 was assigned to the 5th Bomb Wing at Minot AFB, North Dakota until 1986, when it was converted to a KC-135R, then was reassigned to the 100th Air Refueling Wing at RAF Mildenhall, UK in 1993; sometime after that, it went further east to the 18th Wing at Kadena, Japan, where it was named "Special Delivery." From 2019, it has served as a trainer for new tanker crews, assigned to the 97th Air Mobility Wing at Altus AFB, Oklahoma.
Tankers bookended the airshow in 2022, with 58-0128 on the south side of the tarmac, and a new KC-46A Pegasus on the north side--almost 60 years separate the two aircraft. Probably 58-0128 is in the twilight of its career. This was another picture that oddly got washed out by my camera, so I've tried to fix it as best I can.
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, 58-0128, was one of the oldest aircraft at the Wings Over the Falls July 2022 airshow--and that includes the P-51 and the A-26! First delivered around 1959 as a KC-135A, it has served around the world, and has seen action over Bosnia and Kosovo, and possibly Vietnam and Iraq as well. 58-0128 was assigned to the 5th Bomb Wing at Minot AFB, North Dakota until 1986, when it was converted to a KC-135R, then was reassigned to the 100th Air Refueling Wing at RAF Mildenhall, UK in 1993; sometime after that, it went further east to the 18th Wing at Kadena, Japan, where it was named "Special Delivery." From 2019, it has served as a trainer for new tanker crews, assigned to the 97th Air Mobility Wing at Altus AFB, Oklahoma.
Tankers bookended the airshow in 2022, with 58-0128 on the south side of the tarmac, and a new KC-46A Pegasus on the north side--almost 60 years separate the two aircraft. Probably 58-0128 is in the twilight of its career. This was another picture that oddly got washed out by my camera, so I've tried to fix it as best I can.