GB1427158A - Composite helicopter blade - Google Patents

Abstract

1427158 Helicopter rotor blades UNITED AIRCRAFT CORP 30 May 1973 [31 May 1972 (2)] 25652/73 Heading B7W A helicopter rotor blade has a primary structure comprising two half-components 36a, 36b joined by bonding on the chordal plane 38. Each component has a lightweight core 40 extending substantially from root to tip bonded to a half-spar along its length, each spar comprising bonded span-wise extending fibres extended from the tip towards the root where they are looped over a tear-drop section part 74 of a root attachment fitting 60 and then carried back to the tip, thereby forming a tensileload-carrying member 41. The structure is assembled by bonding the two core halves and the two root fittings to give a unitary spar structure, bonding profiled filler material 110 to the aft face of this to form the trailing portion of the blade, positioning profiled nose balance weights 112 and enclosing the whole by a skin 90 formed by diagonally laid strips. A splice cap 116 may be applied to the abutted leading edge portions and an abrasion strip 118 may be provided. In an alternative construction (Figs. 12, 13, not shown) the spar is made up as an oval section member with the outer skin acting as a tube with filler insert, the trailing edge fairing being shaped on its forward face to accommodate the spar profile. In a still further embodiment the spar has a single spanwise extending looped strip with a pin passed through the loop and secured to a forked fitting on the rotor head (Fig. 19, not shown).