Turbine engines on U.S. military aircraft, in addition to their manufacturer-given names, receive separate designations (consisting of J [for turbojets], F [for turbofans; formerly TF], or T [for turboprops], followed by a number) for internal military use (examples: JT3C/J57, JT4A/J75, JT3D/TF33, JT8A/J52, JT9D/F105, PW2000/F117, JT12A/J60, CJ805-3/J79, CJ610/J85, CF700/TF37, CF34/TF34, CFM56/F108, CF6/F103), even if the military engine is completely unchanged from the civilian version known universally by the manufacturer-given name.

For most engines, information on their various names is readily available; however, I have been unable to find the military designations of two Pratt & Whitney turbofans currently-or-formerly-used on U.S. military aircraft (the JT8D low-bypass turbofan, used on the T-43, C-9, and YC-15, and the PW4000 high-bypass turbofan, used on the KC-46). Does anyone here know the answers to this puzzle?


Two versions of license built military JT8D is called RM-8A and RM-8B.

PW4062 is a military version of PW4000 used in Boeing KC-46 Pegasus.

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    $\begingroup$ This doesn't answer the question as asked - what are the U.S. military's TF-/F- designations for the JT8D and PW4000? $\endgroup$ – Vikki - formerly Sean Jan 16 at 21:16

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