Inflatable apparatus for maintaining continuity of a variable contour of an adjustable jet pipe

1,114,140. Jet propulsion nozzles. SOCIETE NATIONALE D'ETUDE ET DE CONSTRUCTION DE MOTEURS D'AVIATION. Dec.13, 1965 [Dec.14, 1964], No.52896/65. Heading F1J. The invention relates to means for maintaining continuity of the variable external contour of an adjustable jet propulsion nozzle having adjustable flaps, the means comprising inflatable members secured to the external surfaces of the nozzle fixed structure and adjustable flaps at each side of the pivotal points of the flaps. The jet nozzle shown comprises a fixed portion 1 and a fixed portion 2 which define therebetween an opening 5 for flow of ambient air during the subsonic phase as shown in Fig. 3, the flaps 3 being pivoted outwardly to close the opening 5 during the supersonic phase, Fig. 4. An inflatable member 13 is secured to the fixed structure 1 and flaps 3 in outwardly-facing recesses at either side of the pivotal point 4, the member 13 being uninflated in the position shown in Fig. 3 but inflated in the position shown in Fig. 4 whereby the external surface is rendered substantially continuous. Variable area flaps 7 are pivotally mounted at the downstream end of the fixed structure 2 at pivotal points 6a, 6b and an inflatable member 14 is secured to the external surfaces of the structure 2 and flaps 7 at either side of the pivotal point 6b, the member being uninflated in the subsonic phase, Fig. 3, but inflated in the supersonic phase, Fig. 4. The jet pipe comprises also an inner wall 8 which defines with the structure 1 an annular passage 10 for flow of secondary air. Variable area flaps 9 are pivotally mounted at the downstream end of the wall 8. The members 13, 14 may be inflated by air under pressure tapped from the engine compressor.