Patent GB-172077-A (GB)
Title: Improvements in ornithoptera, or bird-winged flying-machines
IPC: B64C33/02
Filed: 1920-08-23
Abstract: 172,077. Middleton, H. Aug. 23, 1920. Ornithopters; propelling. - Aerial machines are fitted with a pair or several pairs of flexible flapping wings the amplitude and plane of vibration of which can be varied. The machines may also carry fore and aft screw propellers, which are driven by the motors driving some of the wings, and the line of action of which can be varied in a vertical plane. Each of the wings 22, 22<1>, Fig. 1, of a pair is vibrated by an arm a, driven by bevel and chain gear 5, 4 or 5<1>, 4<1> from one of the motors 1, 1<1>, which are geared together. Each arm a slidingly engages its wing rod through ball bearings in a box 26, so that the duration of the up and the down strokes is different. Springs 12, 12<1> may be connected between arms 10, 10<1>, 11, 11<1> on the wing arms, or pneumatic or other springs may be employed to regulate the wing motion. The wing may be feathered by one of the methods described in Specifications 9725/88, 21885/91, and 131,862. In a modified construction, Fig. 9, each wing is vibrated by a crank 32 and connecting rod 31 driven by bevel and chain gear from a motor 28. There may be adjustable screw propellers fore and aft; and the twin screws described in Specification 113,833 may be used, with the shock-preventer described in Specification 18107/92, [Class 136, Velocipedes], interposed in the driving-shaft. Steering, balancing, and regulating altitude.- The amplitude of vibration of the wings shown in Fig. 1 can be varied by rotating the right and left handed screw 7 whereby the fulcra of the wing rods are moved towards or away from one another. The plane of vibration is changed by turning the wings, together with their supporting framework, about the axis of the bevel-wheels 5, 5<1> by manually-operated bevel and spur gear. The plane of vibration of the wings shown in Fig. 9 is varied by turning the wings and supporting-frame 62 about the axis 56 by means of a worm 61 and sector 60. Fore and aft screw propellers 23, Fig. 10, are supported in frames 23' which can be turned in a vertical plane by worm gearing 24, 25. Adjustable springs 27<1> counterbalance the weight of the screw and give a tendency to fly upwards when the worm gearing is disengaged. The screw 23 may be replaced by the twin propellers described in Specification 113,833, with their supporting-ring horizontal and inclinable about a transverse horizontal axis. For balancing, the pilots' seats may be movable by rack gearing, and a supplementary petrol tank 42, Fig. 9, may be moved in or out by a compressed-air cylinder 62<1>. In some cases the petrol, oil, or compressed air tanks are moved, and the movement may occur rhythmically with the wings. According to the Provisional Specification, a sliding weight may be moved when the plane of vibration of the wings is adjusted. Planes and the like, construction of.-The wings are made flexible, and bend more easily on the up-stroke than on the down-stroke. The wing may have three overlapping upper coverings 65, 66, 67, Fig. 16, supported by three corresponding seta of cross-ribs, with elastic bands 68, 69 to draw the parts together. The cross-rib 70, Fig. 17, attached to the main rib 71 is held in shape by cords 72, 72<1>, 72<11>. The upper overlapping layers of material are attached to the cross-ribs, and the under surface is supported by the cords. The cross-ribs may be in pieces, hinged together at 73 and fitted with springs 74 to draw the ends of the sections together. Or the ribs may be made of thin hollow metal of elliptical section, and compressed air may be admitted to them on the down-stroke to assist the flattening out of the ring. Starting; shock of landing, deadening. - Compressed-air cylinders 9, 9<1>, Fig. 1, may be used to incline the machine for starting. They also diminish the shock of landing; and the supporting, legs may be fitted with spiral springs. Tanks and like containers, arrangement and disposition of.-The patrol tanks 13, Fig. 1, may act as parts of the framing. A supplementary petrol tank 42, Fig. 9, can be adjusted backwards or forwards by admitting compressed air from a vessel 13<1> to a cylinder 62<1>.