GB1190812A - Improvements relating to Aircraft Air Intakes - Google Patents

Abstract

1,190,812. Jet propulsion engine air intakes. BRITISH AIRCRAFT CORP. Ltd. July 1, 1968 [April 18, 1967], No.17813/67. Headings F1G and F1J. A variable area air intake to a supersonic aircraft jet propulsion engine has a variable centre body 12 formed by forward and rearward expandable portions 16, 25 comprising respectively axially extending, circumferentially over-lapping, strips 17, (18), Fig.2 (not shown), and 171, 181. The forward strips 17, (18) are pivoted at their upstream ends at 19 to a part 14 fixed to the side of the aircraft fuselage 15 while the strips 171, 181 are similarly pivoted at the downstream ends to a fixed part 26. The forward and rearward strips over-lap at 29 in the region of their connection to an actuating linkwork comprising two sets of links 21, 27 whose inner ends are pivoted to respective spiders 22, 28 on a member 23 guided for axial movement by a slide 24. The outer end of each link 27 is connected by a lug 33 and pivot pin 35 to a strip 171 and the strips 181 are connected with the adjacent links 27 through pins 351, lugs 331 and scissor-like links 42. The links 21 are similarly connected to the forward strips 17, (18) and further links 30 inter-connect the links 21, 27 so that they move in unison. The connection between each link 27 and its respective lug 33 is slotted at 32 and a cam 34 secured to each link 30 guides the pivot pin 35 in the slot 32 to prevent flutter of the strip 171. When the member 23 is moved axially, the linkwork 21, 27 etc. causes the centre body 12 to expand or contract radially to thus vary the flow area of the hemi-annular air intake passage 11 defined between the body and a scoop 10 at the side of the fuselage 15. Axial movement of the member 23 is effected by an actuator, such as an electric motor 40, driving a lead screw 37 engaging a nut 36 in the member. The actuator 40 can be controlled manually by the pilot or may be connected to a pilot system so as to function automatically in dependence upon air speed and Mach number. Reference has been directed by the Comptroller to Specification 915, 941.