GB848912A - Engine for producing a propulsive jet - Google Patents

Abstract

848,912. Gas turbines. COLVIN, R. H. Dec. 19, 1956 [Dec. 22, 1955], No. 38682/56. Class 110 (3). A gas turbine jet-propulsion engine comprises a compressor supplying air to a combustion chamber which discharges through a restricted outlet into a duct in which air is caused to flow by the jet so as to drive a turbine, located upstream of the combustion chamber outlet, arranged to drive the compressor. The jet propulsion engine shown comprises a tubular casing 10 spaced from inner casing 11 by struts 12, 13 to form an annular air duct leading from an inlet diffuser 14 to a rear duct 15. A conical guide member 16 forms with the portion 17 of the casing 11 a combustion chamber 18 which is supplied with compressed air by a centrifugal compressor 21 which may, if desired, be a multi-stage compressor. The outlet of the combustion chamber 18 is defined by a Venturi-shaped restriction 27 in casing 11 which co-operates with an axially-adjustable plug 28 to control the pressure in the combustion chamber. The plug 28 has threads 30 which engage corresponding threads in a cylindrical casing 53 and is rotated from a control-shaft 59 through gearing 58, 60 and splined rod 55. The combustion-chamber may have a deformable discharge outlet for varying the outlet area instead of the plug 28. The plug 28 may be cooled by air passing through ports 31 into the interior of the plug 28. Cooling fins 27a may also be provided. The combustion gases from the outlet 51 caused an air flow to be induced in the passages between the casings 10, 11. This air flow is used to drive a turbine 47 provided with adjustable stator blades 48. This turbine drives the compressor 21 through multiplying gear 35, 36, 38, 39. A starting- motor is connected to the shaft 34 by an overrunning clutch 50. Reference has been directed by the Comptroller to Specification 800,261.