| 摘要 |
<p>1,103,803. Jet propulsion plant. BOEING CO. Jan. 14, 1966 [Jan. 15, 1965], No. 1921/66. Headings F1G and F1J. A circular, elliptical, semi-circular or semielliptical air intake for a jet engine, e. g. turbojet, pulse jet or ram jet, has a core with laterally expandable and contractible parts 4, 5, 6 for varying the width of the air inlet passage. The core is shown in its fully expanded position in which a throat 9 is formed. In the fully contracted position the cross-sectional area of the air inlet passage is substantially constant throughout its length. The walls of the core parts 4, 5, 6 are formed from a number of overlapping strips 10, 11, the edges of the strips 10 having deep grooves into which the strips 11 are telescoped, Figs. 9 to 14 (not shown). The strips 10 each have an inwardly extending strengthening rib to which is attached a toggle member 15 at the junctions between the core parts 4, 5, 6. Additionally, each toggle member 15 is attached to slides 18 movable along a stationary core support sleeve 7 to expand or contract the core. The slides 18 are moved by a reciprocable thrust rod 19, Figs. 4 and 6 (not shown), inside the sleeve 7 by a pneumatic or hydraulic jack 22. The jack may positively move the thrust rod in both directions, or the core expansion direction only in which case the pressure of the incoming air in the cowl 1 forces the core back to its contracted position. The jack may be replaced by a screw and nut actuator. The thrust rod may be moved manually or automatically in accordance with velocity, or static pressure in the cowl 1, engine power requirements or power lever setting. The core may be contracted when the aircraft exceeds Mach 1 by a predetermined amount, or when the power requirements are less than half that available and thereby reduce compressor noise. At supersonic aircraft speeds with the core fully expanded, shock waves are deflected at a sufficiently small angle from the tip of the nose cone 2 to extend inside the cowl lip 3 and thence are reflected back and forth between the cowl and core, see dash lines in Fig. 2 (not shown), until they are substantially normal to the air flow and at sonic velocity in the throat 9. The cowl may have relief valves and/or bypass doors downstream of the throat 9.</p> |
