Patent GB-332892-A (GB)
Title: Improvements in or relating to aircraft
IPC: B64C3/54
Filed: 1929-01-26
Abstract: 332,892. Wragg, C. A. Jan. 26, 1929. Planes, arrangement and disposition of.-A compound aircraft wing comprises a basic wing a, Fig. 2, and an auxiliary wing b having a chord considerably smaller than that of the basic wing and which is disposed, with its leading edge slightly to the rear of a vertical plane containing the trailing edge of the basic wing and set close below it. The upper forward surface of the auxiliary plane is of low camber and its under forward surface is either symmetrical therewith or more convex. The under surface may be of concavoconvex section. A sesquiplane type of aeroplane is described in which compound wings of narrow chord are set at a large dihedral angle below a main plane. Steering, balancing, and regulating altitude; non-automatically. The auxiliary wing may be pivotally mounted or have its rear portion adjustable whereby its angle of incidence relative to that of the basic wing may be varied. Fig. 4 shows a basic wing a having auxiliary wings b and ailerons h mounted on a fuselage f. A centrally-cranked tubular member b<4> constitutes the main spar for the wings b and is journaled in brackets f<1> coaxial with hinges b<3>. The ailerons h may be separate sections of the wings b, alternatively the wings b may extend the full width of the span and wing tip ailerons be fitted, or the wings b may project laterally beyond the tips of wing a and be fitted with balance portions. Adjustment of wing b may be effected manually by a lever adjustable in a quadrant fitted in the cockpit and coupled by a rod to a lever on the tubular member b<4>, or the wing b may be fitted with a horn and operated by chain and cable from the control column, or alternatively control may be effected as shown in Fig. 7. Rotation of the wings b in the same or in opposite senses may be effected by the controls shown in Fig. 8 in which control wires l<1>, l<2> from the port and starboard sides of the aeroplane, are led to coaxially mounted drums m<1>, m<2>. The drum m<2> is fixed to a central shaft n universally mounted at n<1> and the drum m<1> is fixed to a sleeve n<2> mounted coaxially with the shaft. n. The shaft n and sleeve n<2> carry opposing bevel pinions p<1>, p<2> of a differential gear, the intermediate pinion of which, p<3>, can be rotated by a milled head or hand-wheel q<1> at the top of the control column q. Rotational movement of the head q<1> causes the drums m<1>, m<2> to rotate in opposite directions whereby simultaneous operation of the members b in the same sense is obtained. Differential control is obtained by rocking the control column sideways causing the drums m<1>, m<2> to rotate in the same direction. In an alternative arrangement, Fig. 10, the drums m<1>, m<2> are loosely mounted on the control shaft and carry pulleys r<1>, r<2> which are connected by wire-drives q<6>, q<7> with corresponding pulleys q<3>, q<4> mounted on a hand-wheel operated spindle at the upper end of the control column. The wire q<7> is crossed so that rotation of the hand-wheel spindle causes opposite rotation of the drums m<1>, m<2>. Small sections such as w, Fig. 14, supported by short struts w<1> upon the member b may be used to augment the work of the compound wing. At normal flying angles the section w may occupy either the position shown in full, or that shown in dotted lines; it may be flexibly or movably attached to the wing b to allow of independent movement of the latter through small angles. Alternatively, the sections w may be independently controlled. Similar members may be used for balancing the air forces on the wings b. One or more flaps x, Fig. 14, may be nested in the wing a and be hinged at their leading edges to the main spars and adapted to be turned downwardly in conjunction with the wing b. The wings b may be set at a large negative angle to neutralize the lifting effect of gusts when the aeroplane is upon the ground. Automatically. Automatic control of the member b may be effected by utilizing the pressure of the relative wind upon a disc s, Fig. 11, to operate a piston valve s<2> which controls the passage of fluid under pressure to one end or the other of a cylinder t, thus controlling the setting of a double-acting piston t' connecting by linkage t<2> to the member b. At normal flying speeds the pressure on the disc s is balanced by the pressure of a spring s<3> ; at air-speeds above normal the spring s<3> is further compressed, causing a decrease in the angle of incidence in the member b, and at air-speeds below normal to reverse occurs. In an alternative arrangement a small air screw is substituted for the disc s and drives a centrifugal governor, to the sliding collar of which is. attached a link coupled intermediate of its length to the piston valve s<2>; the hinge about which the link turns is adjustable manually to alter the mean position of the member b to be adjusted. The governor may, alternatively, be driven from the engine. According to a further arrangement, a small aerofoil or flat hinged to allow of vertical movement may be used to operate the servo-motor valve. The controlling members in the above arrangements are placed as far forward as possible in the aircraft. A glider may be operated by the use of these arrangements by utilizing the effect of gusts impinging upon the controlling member before reaching the main planes. Operation of the member b may be made dependent upon altitude by controlling a servo-motor from an altimeter, or upon attitude by utilizing a gravity-operated pendulum for opening the valve s<2>. In all cases a cut-out is provided to allow of non-automatic adjustment of the wings b. Stopping way.-The wings b may be placed in the position shown at b<2> in Fig. 2 when required to serve as air brakes. Specifications 135,829 and 216,115 are referred to.