GB797874A - Variable configuration discharge nozzles for propulsive jets - Google Patents

Abstract

797,874. Jet propulsion nozzles. POWER JETS (RESEARCH & DEVELOPMENT), Ltd. Feb. 20, 1956 [March 1, 1955], No. 6098/55. Class 110 (3). A variable area jet propulsion nozzle defined by number of wall elements extending longitudinally in the direction of fluid flow and flexible in a radial plane containing the longitudinal axis of the nozzle has means to vary the nozzle flow area in one or more planes consisting of connecting members extending between successive pairs of adjacent wall members or bands attached to the wall members to locate each in the radial direction, the circumferential length or disposition of which may be varied. The nozzle, Fig. 1, consists of an outer row of peripherally consecutive wall elements 1 and a similar inner row of wall elements 2. The upstream ends 3 of the wall elements of a row are of arcuate section and abut each other to form a ring. The abutments of the outer ring are staggered with respect to the abutments of the inner ring. The rings are in radial abutment with one another or with an intermediate ring and are spigotted and rigidly attached to a recess in the downstream end of the duct 4. For the remainder of their length the wall elements are of arcuate cross-section with outwardly projecting flanges 5. The flanges 5 of the inner ring members carry sealing strips 6. At a number of intermediate transverse planes A, B, C, E, F each wall element has a partspherical spigot 7 which forms a common pivot for a pair of crossed links 8. The ends of the links 8 associated with each adjacent pair of spigots are jointed by pins 9 to form a linkage of lattice or lazy-tongs form. Pivoting of the links 8 alters the peripheral length of the linkage and so varies the diameter of the nozzle. Each linkage is activated by one or more hydraulic jacks connected to the pins 9. By appropriate adjustment of the degree and sense of variation of the diameters of the linkages the nozzle may be modified from the convergent arrangement shown to a convergent-divergent arrangement. In the plane D the nozzle diameter remains constant. The supporting ring 11 to which the wall elements are rigidly attached is supported in mounting blocks 13 by opposed spigots 12. The wall elements may be attached to the ring 11 by spherical spigots, in which case the ring 11 is made in two parts fastened together and recessed to form the spherical seatings for the spigots. The moment of inertia of the wall elements may be reduced at 14. The hydraulic jacks 10 for actuating the linkage consist of a central cylinder block 15 with an integral piston 16, a double-ended piston 17 and two end cylinder blocks 18 united by tie bars. The cylinder block 15 and piston 17 have bosses 20, 21 to which are attached the pins 9. Connections 22, 23 are supplied with pressure fluid to vary the position of the jack. Adjustable stops limiting the outward and inward movements of the jack may be provided. The connections 22, 23 of the jacks may be connected to common manifolds to give a particular nozzle configuration when fluid is supplied to one or other of the manifolds.