DEVELOPMENT OF THE SEA KING COMPOSITE MAIN ROTOR BLADE

The existing metal blade for the Sikorsky S61 family of helicopters, of which the Westland Sea King forms part, was designed in the 1950’s and does not measure up to the ruggedness required for service in the 1980’s. Westlands chose composite materials with a replaceable metal erosion shield as the means of meeting the requirements for an improved life blade. The aim was to provide a blade with matched aerodynamic and dynamic properties allowing true retrofitting to be carried out on existing aircraft. Being a true retrofit blade it was considered desirable to develop a bolted root end for the blade, but this root end design could not be allowed to degrade the fatigue advantages of the composite construction. The blade is designed with pre-impregnated composites which have been shown suitable for manufacture of high quality composites by automated techniques. The paper discusses the technical problems and achievements of the Sea King Composite Main Rotor Blade programme in the design and manufacture fields which have led to the availability of this blade for the Sea King Helicopter.