GB792962A - Improvements in or relating to jet-nozzle arrangements - Google Patents

Abstract

792,962. Jet propulsion nozzles. ROLLS-ROYCE, Ltd. March 29, 1955 [April 1, 1954], No. 9652/54. Class 110 (3). A jet propulsion nozzle comprising a number of axially extending nozzle elements pivoted at their upstream edges to stationary structure has rollers provided externally of the nozzle elements and co-operating therewith and a hoop member, encircling the nozzle elements and co-operating with the rollers to move the elements into an orifice-restricting position. The jet pipe 10 is double-walled, the walls 10a, 10b being spaced apart to form a cooling air passage 11. A cast ring 12 provided with cooling air holes 14 is attached direct to the wall 10b and by a flange 13 to the wall 10a. The nozzle elements 17, 18 are pivoted to the lugs 15 on the ring 12 by lugs 21, 24 and pins 16. The nozzle elements 17 are the main nozzle elements which alternate with the sealing nozzle elements 18. Each sealing nozzle element 18 has a sealing strip 19 along its axially-extending edges which co-operate with wings 17a of adjacent main nozzle elements. Each main nozzle element 17 comprises a framework including two circumferentially-spaced pairs of axially-extending channel girders 23 and an inner skin free to expand relative to the framework which engages a rubbing pad 22 carried by the cast ring 12. Each pair of the girders 23 carry, at their upstream ends, a lug 24 which receives one of the pivot pins 16, and, at about mid-length, a roller 25. A hoop 27 encircles the nozzle elements 17, 18 and is movable axially of the nozzle by rams 31. The hoop member has sixteen panels 27a, 27b, the panels 27a being arranged to correspond to each of the main nozzle elements 17 and the others 27b corresponding to the sealing nozzle elements 18. Each panel 27a carries a bracket 28 carrying one part of a universal coupling 29 by which it is connected to the piston-rod 30. The panels 27a are formed along their axiallydirected edges with inwardly-facing channels 32 in which are mounted hard metal tracks 33 which co-operate with a pair of rollers 25 of one main nozzle element. The sides of the channels 32 co-operate with the rollers 25 to keep the hoop member 27 concentric with the nozzle. Each panel 27a also has projecting from its inner surface a pair of hooked members 34 which engage flanges on the girders 23 to prevent the main nozzle elements 17 falling away from the hoop members. A circumferentially-extending bar 35 attached to the sealing nozzle elements 18 overlaps the adjacent portions of the elements 17 to prevent falling away of the sealing elements. The nozzle elements and operating mechanism may be enclosed by overlapping outer flaps 36 pivoted to fixed structure 38 and connected at their downstream edges by links 37 to the main nozzle elements 17.