GB948881A - Airscrew with automatically variable pitch, especially for light aircraft - Google Patents

Abstract

948,881. Airscrews. M. A. VURPILLOT. April 13, 1962 [April 22, 1961], No. 14411/62. Heading B7V. In an airscrew with automatically variable pitch, each blade 1 pivots freely about an axis 3 which lies in a plane perpendicular to the axis of the engine shaft and which is oblique to the longitudinal central axis of the blade, the inclination D of the pivotal axis of each blade being such that, at full throttle, the engine gives its maximum admissible continuous power in the two conditions of horizontal flight at maximum speed on the one hand, and of climbing flight on the other hand. As shown in Figs. 2 and 3, at every condition of flight the forces acting on the blade are the aerodynamic traction T and the centrifugal force F, causing the blade to take up an inclination A towards the front, to which corresponds a pitch B, so as to obtain equilibrium between the forces about the axis 3. In Fig. 5, the blades 1 are fixed in sockets 7 attached by a bolt 8 (constituting the oblique pivotal axis for the blades) to lugs 6 on the hub having a flange 10 for connection to the engine shaft. Abutments may be provided to limit the displacements of the blades. The abutments limiting displacement in the direction reducing pitch may be controlled by a manumetric capsule mounted on the airscrew hub.