KC-135 / C-135

[Davef68]

Originally Posted by megan

Dave, I wonder if the 1962 change didn't apply to those aircraft because of the use to which they were put, VIP transportation, particularly President and Vice President etc. All went to the 89th Military Airlift Wing which took over from the 1254th ATW in 1966. Logic to me to have the aircraft assigned the same designation for maintenance purposes if nothing else, since except for the two EC, all aircraft were operated by the one unit supplying VIP transportation. There is always an outlier in these things, or "what about". The designation covered nine aircraft
.

It generally didn't apply to any USAF aircraft already in development or service (The Phantom was one of the exceptions) - so C-130, C-141 etc all retained their original designation (in the case of the C-130 even to this day). Someone in the project office obviously thought there was a good reason to ask for a new designation for the 707-derived airframes

[Martin the Martian]

The C-135A (Boeing 717-157) was bought by the USAF as an interim jet transport while studies into what would become the C-141 StarLifter were carried out. Initially 50 aircraft were approved but ultimately only fifteen were ordered, along with the conversion of three KC-135As on the production line. Thirty C-135Bs (Boeing 717-158) made up the balance, being near identical but with TF33 engines rather than J57s. The C-135 featured the deletion of the air refuelling system, a strengthened cargo floor and the addition of a fuel dumping capability. Although the C-135 offered much over the piston and turboprop transports then in service it was less flexible due to the side loading cargo door, while the C-135A required water injection and a long runway when fully loaded, curtailing its usefulness. In addition it only had an endurance of five-six hours, fine for crossing the Atlantic but not the Pacific. Ultimately Secretary of Defense Robert McNamara directed the USAF to find other uses for them once the C-141 was available.

And they certainly did. All C-135As were converted into different configurations, including KC-135A-II tankers, JC-135A nuclear test support aircraft, and EC-135N Apollo Range Instrumented Aircraft (ARIA). C-135Bs lasted longer as transports, though many of them were converted as test range telemetry aircraft, WC-135B weather reconnaissance aircraft, VC-135B VIP transports or assorted RC-135s. The USAF certainly had its money's worth.

All info c/o The Boeing KC-135 Stratotanker- More Than A Tanker (Robert S. Hopkins III), Crecy Publishing 2017