U.S. Patent Specifications

A jet propulsion engine comprising an assembly including a multi‐stage high‐pressure air compressor, a combustion chamber, a multi‐stage gas turbine and an exhaust system arranged in series flow relation, said exhaust system ending with a rearwardly opening orifice, a by‐pass duct arranged in parallel flow relation with said assembly, a low‐pressure air compressor driven from said turbine and discharging into both said assembly and said duct, said compressors being so designed that the amount of air discharged by said low‐pressure compressor is substantially greater than the amount of air sucked up by said high‐pressure compressor, whereby a substantial amount of air discharged by said low‐pressure compressor flows through said duct, a balancing conduit connecting an intermediate stage of said high‐pressure compressor with an intermediate stage of said turbine, said stages being so selected that the pressures obtaining therein, at rated rotational speed of the engine, are substantially equal, and a further balancing conduit connecting another intermediate stage of said high‐pressure compressor, upstream of the first‐mentioned intermediate stage, with a part of said exhaust system upstream of said orifice, said last‐mentioned stage and said part being so selected that the pressures obtaining therein, at said speed of the engine, are substantially equal.