GB751109A - Improvements in rotors for rotary wing aircraft - Google Patents

Abstract

751,109. Rotary wing aircraft. SAUNDERS-ROE, Ltd. Dec. 14, 1954 [Jan. 21, 1954], No. 1840/54. Class 4. A rotary wing aircraft rotor hub comprises a hollow beam 10 centrally supported by a see-saw mounting 11 on the rotor shaft 14, blade attachment members 18 at the ends of the beam which are rotatable for pitch charges, and a pre-tensioned torsion bar 30 within the beam and attached at its opposite ends to the members 18. The shaft 14 includes passages 15, 16 for fuel, and 17 for starting air for blade tip pulse jet engines, and has a rubber buffer 38 to limit the rocking of the beam. Each blade attachment member comprises a sleeve mounted on the beam by thrust bearings 19, 20, and alignment bearings 21 and terminating in forks 28 formed with sockets 29 for attachment of the blades. The axes X-X of each pair of sockets 29 are inclined so that when stationary the blades are coned upwards. The torsion-bar 30, which may consist of a plurality of sectorshaped members 31, or a plurality of spring plates, or a hollow slotted cylinder, is threaded at each end 32 to receive a nut 33 abutting the end of each sleeve 18, so that the nuts 33 can put the bar 30 in tension, preferably so that at normal rotative speed, the centrifugal load is taken entirely by the bar 30. Horns 34 secured by straps 36 and removable shear pins 35 extend from each sleeve for attachment to pitch change mechanism, cyclic pitch changes rotating bar 30, and collective pitch changes applying torque. In a modification, the axes X-X of sockets 29 are made at right-angles to the sleeve 18, but the beam 10 is kinked so as to incline upwardly at each side. Bar 30 may then be similarly kinked.