GB638079A - Improvements in or relating to aircraft gas-turbine-engine power plants - Google Patents

Abstract

638,079. Propellers. ELLIOTT, A. G. July 4, 1947, No. 17751. [Class 114] [Also in Group XXVI] In a gas-turbine plant of the type comprising an airscrew and a compressor arranged to take in air through an unscreened intake duct, means are provided to deliver hot gas to a duct structure carried by and rotating with the airscrew. A gas-turbine engine drives through a reduction gear 14 a pair of counterrotating airscrews 12, 13 which carry portions 18a, 18b of a spinner forming a continuation of the inner defining wall 15 of the air intake 16 of the power plant compressor and portions 19a, 19b of a hollow outer annular fairing forming a continuation of the outer defining wall 17 of the air intake. The root portions 12a, 13a, where they cross the space 16a, are enclosed in fairings 20, 21 which are inclined to assist in the delivery of air into the engine compressor or to effect zero work on the air entering the space 16a. Hot gas extracted from the engine is led through conduits 23 to an annular manifold 24 formed in the leading edge of the engine nacelle 11. From the manifold 24, the hot gases pass into the outer annular fairing 19a, 19b part then passes into the root fairings 20, 21 from which it enters the air intake 16, 16a though outlets 25 and part passes to the leading edge of the portion 19a and enters the intake through outlets 26. The manifold 24 is provided with lips 27 to transfer the hot gas to the rotating fairing 19b and seals 34 prevent excessive leakage. A ring of guide blades 28 directs the gas forward into the fairing and scoops are provided to guide the gas round the blade roots 13a to a port leading into the leading edge of the aerofoil fairing 21. A second pair of lips 32 provided with seals 33 is used to transfer the hot gas from the fairing 19b to the portion 19a. The root fairings 20, 21 are formed along their leading edges with ducts 37 to receive the hot gases and have double skins so as to confine the hot gas flow to the outlets 25 to the surfaces of the fairings. The shells 19a, 19b are preferably formed as double-skinned structures, the outer skin being formed of aluminium and the inner skin of steel to avoid excessive heat radiation and damage by heat to the surface skin. In a modification as applied to a single airscrew the hot gases from the engine are led to a stationary manifold on the inner wall of the intake and then pass into a rotating manifold attached to the inside of the spinner 18b. From the rotating manifold the gases pass partly through a duct formed at the trailing edge of the root fairing 20 and partly through pipes to a further manifold connected to a duct formed at the leading edge of the root fairing. The gases passing through the leading edge duct pass into the outer fairing 19a and then into the air intake duct 16a through openings 26. The gases passing through the trailing edge duct pass through openings 25 into the air intake. An arrangement in which this modification is applied to a power plant with counter-rotating airscrews is also described. Part of the hot gas may also be led to the nose of the spinner. Specification 624,402, [Group XXVI], is referred to. Reference has been directed by the Comptroller to Specification 636,612, [Group XXVI].