Sikorsky Aircraft, Stratford, Conn., has completed the initial phase of testing for the composite main and tail rotor blades manufactured for the U.S. Marine Corps CH-53K heavy lift helicopter program. At 35 ft span length, and almost 3 ft chord width, the CH-53K main rotor blade has 12% more surface area than the CH-53E blade. A fourth-generation aerodynamic design adds unique airfoils, twist, and taper to the new blade to accommodate 71% greater power generated by the CH-53K aircraft’s three 7500-shaft-horsepower GE38-1B engines.
Included in the span length is an advanced blade tip to improve hover performance, and a composite cuff attachment feature that will allow maintainers to quickly attach each of the seven CH-53K blades directly to an elastomerically articulated titanium rotor head without the need for specialized tools or multiple redundant fasteners. When attached to the nearly nine-foot-diameter main rotor hub, the blade radius extends to 39.5 ft.
The four 10 ft. long CH-53K tail rotor blades have 15% more surface area than the same tail rotor blades on the CH-53E helicopter. On the CH-53K aircraft, the tail rotor blades collectively produce as much thrust as the main rotor blades on Sikorsky’s 11,000 lb S-76 helicopter. Designed specially to help meet the Marine Corps requirement to lift the aircraft’s maximum gross weight of 88,000 lb, the all-composite blades are the largest and most technologically advanced ever produced by Sikorsky, a subsidiary of United Technologies Corp.
