Rolls-Royce Pegasus

The Rolls-Royce Pegasus is a British vectored-thrust turbofan built for V/STOL aircraft, first designed as the Bristol Siddeley Pegasus and manufactured by Rolls-Royce plc after its takeover of Bristol Siddeley. Its four swivelling nozzles let the engine direct both fan air and hot turbine exhaust downward, so a lightly loaded aircraft can take off and land vertically and then fly forward like a conventional jet. It is a two-shaft design with three low pressure and eight high pressure compressor stages, an annular combustor, and low and high pressure spools that turn in opposite directions to cut gyroscopic effects at low speed. Water injection raises thrust for take-off in hot conditions. The engine powers every version of the Harrier family, and in United States service it is designated F402. The latest and most powerful version, the Pegasus 11-61, provides 23,800 pounds-force (106 kilonewtons) of thrust.