ASME-Landmark:Pegasus 3 Engine BS 916

The Pegasus 3 is the earliest surviving example of the prototype engine for vertical/short takeoff and landing (V/STOL) jets, namely the Royal Air Force's Harriers and US Marine Corps' AV-8Bs. Owned by the Rolls- Royce Heritage Trust (a company-sponsored history and preservation society), the landmark engine is an early developmental model of the Pegasus 3 engine, the first to fly with sufficient thrust to prove the vectored-thrust concept for V/STOL jet aircraft, in 1960.

The Harrier design is the first and only operational fixed-wing V/STOL aircraft in the western world. These aircraft can operate from small fields, such as ships at sea, and are effective as land- and sea-based fighters, air support, and reconnaissance craft. Wartime vulnerability of airfields and aircraft carriers motivated post-WWII objectives for vertical-takeoff aircraft. During the 1950s numerous projects and research programs were underway in the United States and Europe to achieve V/STOL concepts. Advancing gas-turbine technology encouraged the study of direct jet lift systems and the control and stability problems associated with the transition from hover to wing-borne flight.

All Pegasus engines are distinguished by four rotatable exhaust nozzles that can direct the exhaust downward to lift the aircraft, rearward to propel it during wing-borne flight, and to any angle in between to enable transitions between the two flight regimes. The engine's power is called vectored thrust because the pilot can vary both the magnitude and direction of the thrust. See ASME website for more information