Patent GB-455023-A (GB)
Title: Improved aeroplane having a variable lifting surface
IPC: B64C3/54
Filed: 1935-04-05
Abstract: 455,023. Aircraft with variable-wing surface; control of motors. GERIN, J., 24, Rue de la Tourelle, Boulogne-sur-Seine, France. April 5, 1935, No. 10655. Convention date, April 7, 1934. [Class 4] [See also Group XXXVII] In an aeroplane having variable - area wings of the type described in Specification 399,048, a drum 2, Fig. 1, for winding up a cable 3 for extending the flexible wing surface 6 and a drum 7 for winding up or retracting the surface 6 are driven by a single reversible motor 1 through reduction gearing and free wheel devices so arranged that when the surface is being extended the free wheel device for driving the drum 7 is rotated in its free direction at a higher speed than is the free wheel device driving drum 2, the free wheel devices being rotated in the opposite sense for retracting the flexible surface. In the form shown diagrammatically in Fig. 1, free wheel 14 associated with drum 2 is driven by irreversible gearing permanently coupled to the shaft of motor 1 whilst free wheel device 22 associated with drum 7 is driven from the motor shaft through gears 17, 18 when surface 6 is being wound out and through gears 17, 19, 26, 27, 28 when. the surface is being retracted. The gear ratios chosen are such that during the winding out operation free wheel 22 is driven faster than shaft 23, which will be driven indirectly by drum 2 and that during retraction the speed of rotation of free wheel 14 is greater than that of drum 2 which is being driven by the winding up of surface 6. Cable 3 is maintained taut by the provision of brakes on drums 2 and 6. Figs 2 and 3 show an arrangement for driving two drums 7 and a single drum 2 from a motor 1. In this form, gear 17 is selectively coupled to gears 18, 19 through an intermediate gear 17a carried by a rocking lever 53 comprising two members 53a mounted on motor shaft 9 and pivoted at 54. Members 53a carry friction discs 55 engaging shaft 9. Rotation of motor shaft 9 causes angular movement of lever 53 against the resistance of a centralizing spring 57, causing engagement of gear 17a with gears 18 or 19 according to the direction of rotation of the motor shaft. The frictional connection between lever 53 and shaft 9 is broken in either engaged position of gear 17a by the action of wedge shaped contacts 61, 62 adapted to engage between the pivoted arms 53a and to spread these apart against the action of springs 63, at the same time closing the circuit of an associated electromagnet 61a or 62a which maintains the lever in its displaced position until the completion of the retracting or winding-up action as the case may be, when the motor circuit and that of the electromagnets 61a, 62a is interrupted and lever 53 is centralized by spring 57. Cables 3 are caused to wind helically on drum 2 by a screw and nut device 65. The flexible surface 6 is secured by screws 66a, 66b, Fig. 4, to a rigid wing tip 66 which is slidably mounted on fixed wing 67. Wing tip 66 comprises a carriage 68 guided on the leading edge of wing 67 by wheels 70, 71 connected by drag cables 73, 72 respectively to ribs of the flexible surface. Wing tip 66 is assembled and dis-assembled as a unit with fixed wing 67 in order to avoid disturbing the adjustment of pulling cables 3 (not shown in Fig. 4). The winding drums are housed in the aeroplane fuselage and surfaces 6 are drawn out through an aperture 78 in the fuselage side wall normally closed by a shutter 75, Fig. 8, acted on by a spring cord 81a. Shutter 75 also serves as a guide for the flexible surface. The fixed plane 67 passes through the fuselage and is reduced in chord to permit of dis engagement of the flexible surface. Shutter 75 is urged toward the closed position by an elastic cable 81 and is opened by a cable 83 passing over guide pulleys 84, 85 and terminating in an eye 86. In the position shown the latter engages a hook 87 rigid with the movable flexible surface so that movement of the latter causes opening of shutter 75. After a certain outward movement of the flexible surface eye 86 of cable 83 is disengaged from hook 87 by a pivoted trip lever 88 and maintains shutter 75 in its open position until winding-in of the flexible surface causes hook 87 again to pick up the cable eye. Elastic 81a also serves to complete the retraction of the movable surface in the event of stoppage of the electric motor before the retracting operation is fully completed. Fig. 9 is a wiring diagram for the controls of motor 100 which drives the cable winding drum and the two drums upon which the flexible surfaces are wound. Energy is supplied by battery 123 to field winding 101, the direction of rotation of motor 100 being determined by the selective energization of electromagnets 106, 107, which control the position of switches 103 and hence the direction of the armature current. The circuits of electromagnets 106, 107 are opened and closed by press button switches 116, 117, switch 116 causing rotation of motor 100 in the direction for winding out the flexible surface and switch 117 causing retraction. The flexible surfaces themselves carry contacts which cause interruption of the supply circuit on completion of their movement in either direction ; these are represented by switches 112, 113 which are closed when the flexible surfaces are retracted and opened when the flexible surfaces reach the end of their extension movement and by switches 114, 115 which are closed when the surfaces are extended and opened at the end of the retracting movement. With switches 114, 115 open as shown pressure on retracting switch 117 will not cause actuation of motor 100 but pressure on switch 116 establishes the following circuits : from positive pole of battery 123 through a master switch 122, contact 119, contact 120, wire 125, wire 126, contact 112, wire 127, contact 113, wire 128 and electromagnet 107 thus actuating switches 103 to start the motor. Lever 53 which is frictionally coupled to the motor shaft is rotated in the direction to close contact 110 by which it is mechanically declutched from the motor shaft being retained in its swung over position by electromagnet 108. Closure of contact 110 open-circuits switch 116 thus permitting its release. Motor 100 continues to rotate until switches 112, 113 are opened by the arrival of the flexible surfaces at their fully extended position or alternatively by pressure on switch 117. With the flexible surfaces in their fully extended position switches 114, 115 are closed and switches 112, 113 are open and the armature circuit can only be established by actuation of switch 117. In this case lever 53 swings in the other direction to close contact 111 and is held by electromagnet 109. A control panel is described for installation in a cockpit upon which are mounted retracting and spreading out switches for upper and lower planes, a battery charge indicator, ammeters, master control switches, and tell tale lamps of differing colours. Specification 302,277, [Class 4], also is referred to.