A method of manufacture of rotor blade spars for helicopters or rotating wing aircraft

摘要

623,824. Making screw propellers. DE HAVILLAND AIRCRAFT CO., Ltd., and BROWN, G. H. F. Feb. 11, 1947, No. 3994. [Classes 83 (ii) and 83 (iv)] Forging; extruding.-A spar for making a blade for a helicopter having a part 1 of uniform cross-section and another 2 which is not, is produced by forcing metal through an extruding die into a pressure die to form the part 2 and then allowing the dies to separate while the part 1 is extruded. A hollow billet 13, Fig. 4, in a matrix 8 is forced through a die 9 by an annular plunger 12, the extruded metal being received in a preferably split die 7. When this is full the mandrel 10 is pushed into the position shown by a plunger 11. The die 7 is then released from the matrix and preferably positively traversed over a roller top table while extrusion is continued to form a uniform section 1, e.g. as shown in Fig. 2. The end of the part 2 may then be upset 6, Fig. 1, and the part 1 may be flattened to taper towards the tip T, Fig. 5, e.g. by passing through suitable dies. The centre line 16 of the part 2 may also be at an angle α to that of the part 2. This may have flanges 18 to receive a separately-formed fairing 5.