| 摘要 |
A composite material, variable pitch, helicopter rotor blade is made by: (i) making a preform having a part forming a foot (22) for connection to a hub and an aerodynamically profiled (20) operating part, the foot part having at least one cylindrical guidance portion (40,42); (ii) placing a peripheral metal ring (76,78) around each cylindrical guidance portion; (iii) placing the preform with the metal rings in an injection mould; and (iv) injecting liquid thermosetting resin; heating mould to cure resin. Preferably at the place where the metal rings are placed the preform has a diameter less than the internal diameter of the ring and a glass fibre band and adhesive is placed between them. Moulding is by resin transfer moulding under vacuum and progressing along the blade length. The centre of the blade is fitted with a lightweight foam of density less than 100 Kg/m<3>.
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