GB740106A - Improvements in or relating to rotor blades for rotary wing aircraft - Google Patents

Abstract

740,106. Rotor blades. UNITED AIRCRAFT CORPORATION. May 3, 1954, No. 12857/54. Class 4. A metal rotor blade for rotary wing aircraft comprises an extruded hollow spar member 10 having upper and lower walls conforming to the aerofoil contour of the blade and front, rear and intermediate walls 30, 32 and 34. The spar is grooved spanwise at 70 and 72 to accommodate lipped edges of leading and trailing edge plates 74 and 76 which complete the aerofoil contour of the blade and are segmented spanwise in overlapping relationship, the trailing edge-plates being adhesively secured to spaced trailing edge formers 14 which are secured to a spanwise channel section member 80 bonded to the rear face of the wall 32. A similar channel 78 is bonded to the front face of the wall 30 and to the leading edge plates 74. The spar member 10 is secured at its root end to the rotor hub and both the spar and the fairing members are so proportioned that the chordwise centre of gravity of the spar is located substantially at the aerodynamic centre of the blade section and preferably at the chordwise neutral axis and the chordwise centre of gravity of the entire blade section. In a further embodiment, the channel member 78 is replaced by a D-section nose tube, through which hot air for de-icing purposes may be passed, and continuous plates, subdivided spanwise, are wrapped round the entire blade section with the free edges bonded together at the trailing edge and the plates bonded to the spar and other members. The nose-section may be filled with a moulded section containing deicing heating wires and in a still further embodiment the fairing plates may be divided along a spanwise joint at the channel member 80 and secured thereto by glue and rivets. The nosesection within the wrap-around plating may consist of a wooden section supporting a metal mass balancing rod.