| 摘要 |
611,941. Boundary layer control. ARMSTRONG WHITWORTH AIRCRAFT, Ltd., Sir W. G., LLOYD, J., and MURRAY, C. V. May 13, 1946, No. 14459. [Class 4] In order to reduce the tendency for tip stalling, particularly in tailless aircraft with swept-back wings and powered by an internal combustion turbine unit, the turbine intake is arranged along a streamlined passage provided with shutter means normally forming part of the passage wall but movable to a position partially blocking the passage, so as to cause a depression or reduction of pressure therein, the region of the depression being in communication with an opening in the upper surface of the wing, near the tip thereof, whereby air will be drawn in from that portion of the wing surface, partly by the depression and partly by the suction of the power unit, when the shutter is so moved from its normal position. In the form illustrated, an aircraft is powered by two turbine units 12, one in each wing, the intake 16 of each being provided with shutter flaps 18, 19 connected by a link 20, and operable by the pilot's main control member 36 and the throttle lever 37 through a hydraulic servomotor 21. The shutters move to the positions 18a, 19a, Fig. 5, when either of the controls 36, 37 is moved to the fully back position, and to the positions 18b, 19b when both controls are moved back simultaneously. The regions 23, 24 of the intake near the shutters are placed in communication with openings in the upper tip surfaces of the respective wings by ducts 25, 28, in order that should one of the turbine units fail the other will serve to remove the boundary layer from the upper surfaces of both wing tips. The supply of liquid to the jack 21 is controlled by piston valves 39 operated by the control levers 36, 37. In addition to reducing the tendency to tip stalling, the arrangement ensures that the turbines receive sufficient input of air.
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