In a rotary‐winged aircraft, wherein the control in roll is effected by operating on the rotor either by tilting it bodily or by controlling the pitch angles of the rotor blades to produce a lateral tilting of the path swept by the rotor blades, one or more fixed aerofoil surfaces are situated within the slipstream of the airscrew and so disposed angularly to the slip stream that the effective angle of incidence to the slip stream of the whole or part of such surface on one side of (or above) the longitudinal axis of symmetry of the aircraft differs from that on the other side of (or below) the axis so that an aerodynamic couple is produced tending to neutralise the airscrew reaction torque. As shown, the autorotative rotor 38 may be rocked about transverse or longitudinal pivots by links 51, 47, operated by hand control 44. The motor 32 of the tractor airscrew 33 may drive the rotor 38 when desired through gearing 103x and 85. A rudder bar 55 is connected by cables 67 to steer the tail wheel 64. The rear end of the aircraft body is provided with a horizontal tailplane comprising right‐ and left‐hand valves 57, 57a, Fig. 2, an upper central fixed vertical tail fin 53 and a lower fin 54. The angle of incidence of the part 57 of the tail plane is opposite to that of the other part 57a so that a couple is developed due to the slip stream in the opposite sense to that developed by the reaction torque of the propeller 33. The tail plane pivots about a transverse axis 58 and is provided with upturned tips 56 which effect a stabilising effect in roll, yaw and pitch. The tips 56 are provided with adjustable trailing flaps 71 and the tailplane with flaps 72, while the vertical fin 53 carries an adjustable flap 73. Since the adjustable flaps 71, 73 lie outside and inside the slip stream respectively, correct yawing trim can be obtained at all speeds and throttle openings, and by adjustment of the flaps 72 the rolling couple produced by the tailplane may be made equal and opposite to the airscrew reaction torque. The fins or surfaces for correcting the reaction torque may be arranged cither vertically or horizontally and may be combined with fins or surfaces provided for other purposes, e.g. they may consist of a pair of small horizontal fixed wings incorporated in the wheel undercarriage or in the support for lateral floats, or they may consist of vertical surfaces forming fairings around members of the undercarriage below the body and round a member or members constituting the rotor‐supporting structure above the body, or they may consist of vertical tail fins disposed above and below the body having a differential incidence setting. Specification 393,976 is referred to.
(1935), "Month in the Patent Office: A Selection of the More Important Aircraft and Engine Specifications Published Recently", Aircraft Engineering and Aerospace Technology, Vol. 7 No. 5, pp. 130-130. https://doi.org/10.1108/eb029936
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