C-17 Pratt & Whitney F117-PW-100
Two engines on a US Air Force C-17.
The C-17 is powered by four Pratt & Whitney F117-PW-100 turbofan engines, which are based on the commercial Pratt and Whitney PW2040 used on the Boeing 757. Each engine is fully reversible and rated at 40,400 lbf (180 kN) of thrust. The thrust reversers direct engine exhaust air upwards and forward, reducing the chances of foreign object damage by ingestion of runway debris, and providing enough reverse thrust to back the aircraft up on the ground while taxiing. The thrust reversers can also be used in flight at idle-reverse for added drag in maximum-rate descents.
Canadian Aviation Blog