GB423371A - Improvements relating to aircraft - Google Patents

Abstract

423,371. Aircraft with rotary wing systems. FLETTNER, A., 7, Neue Bayreutherstrasse, Berlin. Aug. 22, 1933, No. 23355. [Class 4] An aircraft having rotating wings hinged to a freely movable wing hub has its wings hinged to members rotatably mounted in the hub and furnished with levers connected by links with a movable controller. Normally the links prevent rotation of the wings about their axes as the hub tilts Provision may also be made for automatically changing the incidence of the wings from an autorotative position to one suitable for a positive drive and vice versa dependent upon the speed of rotation of the system or upon variation of torque upon the hub. Fig. 2 shows a wing 2 hinged to a member 15 journalled in a hub 14 mounted upon gimbals on a shaft 3. The member 15 has an arm 17 extending to a point in a plane passing through the shaft 3 at right angles to a plane containing the shaft 3 and member 15. The end of the lever is connected by a link 19, Fig. 3, to a controller 22 mounted on gimbals on the shaft 3 and tiltable in any direction by a ring 23 having a handle 24. Instead of the whole wing being pivoted to the member 15 only the wing tip 2<a> or a rear flap may be connected to a member 15<a> as also shown in Fig. 2. Alternatively, the main blades 2 may be hinged to the hub 14 and smaller blades placed between them connected to the control member 22. A counter propeller on a transverse axis may be provided at the rear of the machine to counteract driving torque and forward thrust may be given by a tractor propeller or by arranging the shaft 3 at a forward inclination. To ensure a change of incidence of the wings with variation of speed, each wing may be mounted to move axially along a shaft 26, Fig. 5, under control of a spring 27, screwed parts 28, 29 co-operating with screwed sleeves on the wing frame to produce a change of incidence as the wing moves axially. By using screwed parts of different pitch a helical twist can be given to the blade as the mean pitch increases. Fig. 6 shows a modification in which the wing is carried by a sleeve 32 which slides over a nut 35, axial movement being controlled by a light spring arranged between arms 37, 38. A wing tip 2a is mounted on a sleeve 34 rotating in the sleeve 32 and engaging a screw 33 on the control rod 31. The wing tip consequently changes its incidence as the wing moves axially while remaining under the control of the rod 31 and lever 17. Provision for giving a helical twist to the wing and its tip may be made. Fig. 9 shows the hub 14 connected to an extension 39 of the shaft 3 by a quick threaded screw so that failure of the driving torque causes relatively axial movement of the parts 3, 39 and the incidence of the wings is reduced through their connection to the controller 22 which is mounted as shown on the member 3. A freewheel is disposed between the engine and the shaft 3.