GB707770A - Improvements in helicopter rotors - Google Patents

Abstract

707,770. Blades for aircraft rotors. DEHN, S. G. (Bell Aircraft Corporation). Oct, 3, 1951, No. 23067/51. Class 4 A rotor blade for a rotary wing aircraft comprises a beam-like structure disposed interiorly of the contours of the blade, said beam like structure including beam flange portions formed of relatively strong wood and extending in spaced relation along the respective trailing and entire leading edge portions of the blade, a beam web portion formed of relatively strong wood and lying substantially chordwise of said blade and interconnecting said flange portions, and filler members formed of relatively light weight wood connected to said beam-like structure and co-operating therewith to define the exterior surfaces of the blade. The blade, which is of composite wood construction, comprises a laminated birchwood beading edge member 10 having a steel plate 12 embedded therein and terminating in a blade attachment eye portion 14, the birchwood and the plate being bushed at 15, a laminated spruce trailing edge member 20 which terminates at point 32 on the trailing edge and is formed with a bifurcated forward extension 22 bonded to the member 10. The remaining portions of the blade are formed from cemented balsa blocks 23 and the joint between the portions 10 and 22 is reinforced by plywood plates 24. The members 10, 22 and 20 are connected by plywood panels 28, 30 which instead of being positioned at the surfaces of the blade may be replaced by a single web lying on the chord line of the blade so that the web and the members 10, 20 constitute an I beam. The outer surface of the blade is covered with a woven glass fabric overlapped at the leading edge by a protective metal plate 36.