The Rolls-Royce Pegasus powered the Harrier vertical and short take-off aircraft.
The Pegasus was a turbofan engine developed for the Hawker Siddeley Harrier and its later variants. Its unusual design used swivelling exhaust nozzles, allowing thrust to be directed downward for vertical take-offs and landings or angled for conventional flight.
Four rotatable nozzles were central to the Harrier’s capability. The forward pair directed air from the engine’s cold section, while the rear pair directed hot exhaust from the core. Coordinating those flows allowed the aircraft to hover and transition between hover and forward flight.
The Pegasus was developed by Bristol Siddeley and later produced and supported by Rolls-Royce after corporate consolidation. It is sometimes confused with the Adour, another vectored-thrust turbofan used in aircraft such as the SEPECAT Jaguar, but the Harrier’s signature engine was the Pegasus.