CH-53K helicopter rotor blades undergo testing

The first main and tail rotor blades produced by Sikorsky for the US Marine Corps' (USMC’s) CH-53K heavy lift helicopter have undergone initial testing. This first set of blades will be attached to the CH-53K Ground Test Vehicle at Sikorsky's Developmental Flight Center.

The new blades have been designed to help meet the USMC’s requirement to lift the aircraft's maximum gross weight of 88,000 pounds. The main rotor blade has 12 percent more surface area than the CH-53E blade, at 35 feet span length, and almost three feet chord width. The new design adds unique airfoils, twist and taper to the new blade so as to accommodate 71 percent greater power generated by the CH-53K aircraft's three 7,500-shaft-horsepower GE38-1B engines.

The four 10 ft. long CH-53K tail rotor blades have 15 percent more surface area compared to 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-pound S-76 helicopter.  

Mike Torok, vice president, Sikorsky's CH-53K Program, said: ‘These new blades are an important feature of the CH-53K helicopter's ability to lift almost three times the payload compared to the CH-53E Super Stallion aircraft it will replace later this decade. Advanced geometric shaping, high strength composite materials and a flaw tolerant design all come into play to provide unmatched performance, reliability, and survivability.’

Both main rotor blades and tail rotor blades are now undergoing qualification testing. Tests completed to date include spinning of the blades on whirl towers to measure balance, and initial fatigue tests to determine structural strength. Blade qualification testing will continue over several years to include stress and fatigue tests, and additional whirl tower testing to validate aerodynamic stability, tip deflection, and rotational twist along each blade's length.