U.S. Patent Specifications

For propelling an aeroplane, a gas turbine engine comprising a compressor assemblage having a low‐pressure air compressor and a high‐pressure air compressor, combustion equipment to receive compressed air from said compressor assemblage means to supply fuel to said combustion equipment, and a pair of independently rotatablc turbine rotors to receive in turn the hot products of combustion from the combustion equipment, each of said turbine rotors driving one of the air compressors, in combination with an apparatus for producing a braking thrust on the aeroplane said apparatus comprising a combustion chamber separate of the combustion equipment, means for supplying fuel to said chamber, a duct to convey compressed air from the compressor assemblage upstream of the high‐pressure stage thereof to said combustion chamber, and a nozzle from which the combustion products arc adapted to be discharged as a high velocity jet in a direction to produce said braking thrust.