GB800770A - Nozzle assemblies for jet propulsion apparatus - Google Patents

Abstract

800,770. Controlling jet-propelled aircraft. DE HAVILLAND ENGINE CO., Ltd. March 9, 1956 [March 10, 1955], No. 7109/55. Class 4. [Also in Group XXVI] A nozzle assembly for jet propulsion apparatus capable of reducing or eliminating forward thrust and/or producing deflected or reverse thrust, comprises a discharge pipe for the propulsion fluid leading to a nozzle at the end of the discharge pipe, the discharge pipe having at least one aperture of substantial area in its wall, and at least one movable part constituting a shutter and deflector member mounted for pivoting about a transverse axis so disposed that the resultant of the fluid pressure forces acting on this member passes through ar close to the pivotal axis in all positions of the member, this member having one extreme position in which it covers the aperture and constitutes part of the wall of the discharge pipe and another extreme position in which it uncovers the aperture and extends at least partially across the discharge pipe in rear of the aperture to deflect at least a substantial proportion of the fluid stream through the aperture. In Fig. 1, the jet pipe 10 which terminates in a nozzle 14 is provided with two diametrically opposed apertures which are closed by two shutter and deflector members 23. These members are each in the form of a segment of a hollow sphere and can be swung about pivots 22 to positions where they uncover the apertures in the pipe 10 and obturate the nozzle 14. In a modification, Figs. 3 and 4 (not shown), stationary deflector vanes are disposed round the outside of the apertures so that when the apertures are uncovered the streams of gas emerging from the apertures are deflected from a mainly lateral direction into a direction having both lateral and forward components thereby providing some reverse thrust. In the arrangement shown in Fig. 6 the deflector vanes 29 are retractable and are connected to the shutter members 23 by linkages 30. In an alternative arrangement, Fig. 7, the deflector member 36 covers an aperture leading to an inclined nozzle 45 so that when the aperture is uncovered the thrust has a vertical component which assists take-off and landing of the aircraft. The dispositions of the component are preferably so arranged that the line of action of the resultant thrust will always pass as nearly as possible through the centre of gravity of the aircraft. Retractable deflector vanes may be provided with this arrangement. Fig. 10 shows an arrangement suitable for a turbo-jet propulsion engine employing re-heat. A heat sheild 37 is provided within the outer wall 44 of the discharge pipe and two apertures 39 (of which one is shown) in the shield 37 can be covered by shutter and deflector members 40 whilst corresponding apertures 41 in the outer wall 44 can be closed by sliding panels 42 connected to deflector vanes 43. When the engine is to be operated with re-heat apertures 39 and 41 are closed, Fig. 9 (not shown). When the engine is to be operated without re-heat the shutters 40 are moved to the position shown in Fi.g 10, where they partly reduce the nozzle area. When the engine is required to operate with substantially reduced thrust, the members 40 are moved to the portion shown in Fig. 10 where they partly reduce the nozzle area. When the engine is required to operate with substantially reduced thrust, the members 40 are moved to uncover the apertures 39 completely, and the panels 42 are moved rearwardly, uncovering apertures 41, and the deflector vanes 43 are moved across these apertures.