GB960657A - Helicopter control mechanism - Google Patents

Abstract

960,657. Helicopter rotors. POWER JETS (RESEARCH & DEVELOPMENT) Ltd. Dec. 12, 1962 [Dec. 28, 1961], No. 46397/61. Headings B7G and B7W. [Also in Division F2] An aircraft has a two-bladed helicopter rotor on which lift is generated or enhanced by blowing and is varied by varying the width of a blowing slot. In one embodiment each blade is of circular section (Fig. 3), and has four slots 41-44 through which air is blown to provide lift, and a fifth slot 45 through which air is blown in the reverse direction. Two turbine jetpropulsion engines, preferably of the by-pass type are provided, air being bled from their compressors and passed through an annular channel 31 to the blowing slots. The exhaust gases of one of the engines may be deflected either to produce forward thrust, or to flow through the hollow interior 33 of the blades to tip jets. The lift on the blades is varied by varying the width of the slots 44 and 45; a draw-bar 72 (Fig. 7), extending and movable longitudinally of the blade has wedge-shaped cams 88, detachably mounted on it, which each actuate a pivoted follower member 85 connected to a flexible strip 82 defining one edge of the slot. The draw-bars of the slots 44 and 45 are coupled together to move in opposite directions (alternatively, one draw-bar with the sets of cams may be provided) and are operated by a swash plate (Figs. 2 and 4, not shown), coaxial with the rotor hub, and which may be tilted for cyclic control and moved axially for collective control. The cams 88 are so profiled that the cyclic variation of lift does not produce vibration. The draw-bars and cams may be divided longitudinally (Fig. 12), with the cams arranged so that if one of the draw-bar halves fails it will move along the blade under centrifugal force and its cams will disengage the roller follower 90 and assume the dotted-line position cf Fig. 12. The slots 44, 45 may alternatively be of fixed width towards the rotor hub, and of variable width towards the tip. The cams may each have a flat 89b, 89c (Figs. 14(a), 14(b), at one of their extreme ends, so arranged that no lift is developed by the blades when the followers are on them. The draw-bars preferably decrease in section, in steps, towards the blade tips. In cruising flight the aircraft is supported by wings, and the rotor is retracted axially so that the blades nest in recesses in the fuselage and fin (see Fig. 1, not shown). In another embodiment, the blades are of elliptical section and have a variable width slot on each side of the trailing edge. In a further embodiment, only one slot is provided, and lift is generated on the jet flap principle. Specifications 883,865, 913,754, 944,010, 948,947 and 956,013 are referred to.