Improvements in exhaust nozzle structures

865,540. Jet propulsion nozzles. GENERAL ELECTRIC CO. March 26, 1958, No. 9774/58. Class 110 (3). A jet-propulsion nozzle comprises a variable area convergent nozzle combined with means providing an exterior air passage surrounding the nozzle so that an air wall is developed surrounding an area adjacent to the convergent nozzle which air wall combines with the exhaust gases to provide controlled divergence in supersonic operation. The tailpipe 10 is provided with pivoted members 11 having protruberances 11a or an internal axially movable bullet to form a variable area convergent nozzle. This nozzle is surrounded by an axially movable shroud 14 which forms a passage 15 whereby ram air is supplied to the area adjacent the convergent nozzle. This air is formed into a divergent cone inside shroud 14 by the exhaust gases. This cone forms a wall for the exhaust gases. The cone 14 should extend between sixto nine-tenths of the diameter of the nozzle beyond the end of the nozzle. The members 11 and 14 may be controlled by means 24 either independently or together. The means 24 may be responsive to different variables to initiate proper actuation of the shroud 14 and members 11.