The Pegasus vectored-thrust turbofan is a two-shaft design featuring three low pressure (LP) and eight high pressure (HP) compressor stages driven by two LP and two HP turbine stages respectively.
Unusually the LP and HP spools rotate in opposite directions to greatly reduce the gyroscopic effects which would otherwise hamper low speed handling.
LP and HP fan blading is titanium, the LP fan blades operating in the partly supersonic region, and airflow is 432 lb/s.
The engine employs a simple thrust vectoring system that uses four swiveling nozzles, giving the Harrier thrust both for lift and forward propulsion, allowing for STOVL flight.

Combustion system is an annular combustor with ASM low-pressure vaporising burners.

Engine starting was by a top-mounted packaged combined gas turbine starter/APU.
The Pegasus vectored-thrust turbofan is a two-shaft design featuring three low pressure (LP) and eight high pressure (HP) compressor stages driven by two LP and two HP turbine stages respectively. Unusually the LP and HP spools rotate in opposite directions to greatly reduce the gyroscopic effects which would otherwise hamper low speed handling. LP and HP fan blading is titanium, the LP fan blades operating in the partly supersonic region, and airflow is 432 lb/s. The engine employs a simple thrust vectoring system that uses four swiveling nozzles, giving the Harrier thrust both for lift and forward propulsion, allowing for STOVL flight.
Combustion system is an annular combustor with ASM low-pressure vaporising burners.
Engine starting was by a top-mounted packaged combined gas turbine starter/APU.
Rolls-Royce Pegasus