Patent GB-728062-A (GB)
Title: Improvements relating to helicopters, rotorchutes and the like
Inventor: LUX HORST DIETER
IPC: B64C27/26
Filed: 1952-04-09
Abstract: 728,062. Helicopter rotors. MACKENZIE, M. April 7, 1953 [April 9, 1952; Oct. 9, 1952; Dec. 9, 1952], Nos. 9105/52, 25358/52 and 31208/52. Class 4. A helicopter or rotorchute or the like rotor comprises at least one blade arranged on a main shaft and subdivided into a plurality of parts including a root, a tip, and an intermediate part, the two latter being foldable upon the root and unfoldable by centrifugal force to an extended position, means for effecting such folding, and means drivingly connecting said root section to said main shaft. Preferably, as shown in Fig. 1, the rot- or comprises two blades subdivided into separate sections 43, 47, 48, 49, 53, formed with internal bores through which is fed an endless steel cable 51 adapted to restrain the blades against centrifugal force. As shown in Fig. 14, bosses 56 are fitted to the outer ends of each section, co-operating with recesses in the inner end of the next section, preventing twisting of the extended blade. The blade of Fig. 1 is mounted on hinges 29 and 34 for dragging and flapping and have pitch change levers 26, 27, and the inner section 43 is slidable on rods 39, 40, so that it can move inwards to slacken cable 51 to permit collapsing of the sections. In the modification of Fig. 6, rods 40<SP>1</SP> are fitted with a ratchet, engaged by a pawl 64 on section 43 urged into contact with the ratchet by a spring 70, so that the blade, once extended, cannot collapse. Folding in this case is accomplished as shown in Fig. 8, where pulley 71 is adapted to wind in cables 73, 74, attached to the outer edge of the blades, and the outer edges of alternate sections, thus collapsing the blades as shown. The cables 73, 74, are attached to pawls 64, so that tightening of the cables raises the pawls. The pulley 71 is driven by a shaft 72 inside the rotor shaft 21, shaft 72 being driven by an electric motor 79 through a clutch 70. The flapping axes of the blades may be inclined to provide change of pitch without flapping. Fig. 14 shows a rotary wing parachute embodying the invention. The blades are carried by a member 94 forming a double cone bearing with member 98 and the tapered roller bearings 95, 96. Member 92 is screwed onto an extension of member 98 and supports the load. The blades have pitch change levers 27 operated by link 113 and rod 114. A disc fast to rod 114 compresses a spring 119, and is retained in position by an explosive head 122 on the end of rod 114 abutting a plate 123. An electrical firing equipment is provided, connected to head 122 by a flexible cable 124. An electrical contact is adapted to be made between member 139 and a plunger 143 having a contact 138 at its end. Plunger 143 is urged upwards by a spring 136. Initially, contacts 138 and 139 are closed, but switch 132 is open. On launching the parachute, weight 141 pulls down the plunger breaking contact 138, 139, and closing switch 132. When weight 141 strikes the ground, spring 136 raises the plunger, making contact, and firing the explosive head 122. Spring 119 then raises rod 114 to increase the pitch of the blades to retard the descent of the parachute before landing.