GB861819A - Noise suppressor and thrust reverser for jet propulsion engines - Google Patents

Abstract

861,819. Jet deflection on aircraft. BOEING AIRPLANE CO. May 29, 1958 [July 29, 1957], No. 17196/58. Class 4. [Also in Group XXVI] An aircraft jet propulsion engine comprises an elongated housing having an interior duct wall terminating in a rearwardly directed jet nozzle, a bulbous plug radially divided into axially extending segments and means for radially shifting certain of the segments which are circumferentially spaced between an inner position in which they form with the remaining segments a stream lined plug spaced from the duct wall by an annular duct and an outer position in which gas discharge passages are opened along the spaces previously occupied by the shiftable segments in addition to passages formed outside the non-shiftable elements. The housing also has a terminal portion which can be shifted rearwardly to close the annular duct between the plug and the duct wall and open up a gap in the side wall of the housing for thrust reversal purposes. In Fig. 1, a central island body 90 supports a segmented bulbous plug 1. Surrounding the body is a housing 9 having an axially movable terminal portion 8, the inner wall 80 of which forms with the plug an annular duct 91a terminating in a nozzle 92. To effect noise suppression alternate segments 1a, Fig. 6 of the plug are projected radially outwards into the jet stream by means of a jack 12 and linkage 11, until they contact the duct wall 80. The jet stream is then divided into numerous smaller jets 91b, 91c, Fig. 6 allowing the ambient air to mix more freely with the jet stream, thus lowering the noise level. For thrust reversal the plug 1 has its movable segments retracted and the terminal portion 8 is moved axially downstream by telescoping actuators 82, 83, until it contacts the periphery of the bulbous plug. As shown in Fig. 4 rearward movement of the terminal portion closes the duct 91a and at the same time opens a gap 98 allowing the blocked exhaust gases to exit in a forward direction. If larger surfaces for impingement and reversal of the direction of thrust are desired louvres 85, may be employed.