|The CH-53K on its third flight Nov. 13, 2015.
Photo courtesy of Sikorsky Aircraft
With the U.S. Marine Corps’ new heavy-lifter finally logging flight test hours, Sikorsky Aircraft hopes that recent advanced ground testing will enable the smooth ongoing development of the CH-53K.
The King Stallion prototype had flown a total of 6.7 hr in five flights by press time, including 30 min during its maiden flight Oct. 27 at Sikorsky’s Development Flight Center in West Palm Beach, Florida. The first flight had been delayed several times, most recently last year due to issues with the main gearbox. The corrective redesign was relatively straightforward, program officials said, but lead times on new components were long.
In 2006, when the Marines awarded Sikorsky the CH-53K development contract, the first flight was targeted for 2011. The Marines needed a replacement fast for the CH-53E, which was running up against critical life limits that would force aircraft retirements or costly refurbishments. They already were pulling mothballed -53Es from the “boneyard” at Davis-Monthan Air Force Base, Arizona, to meet operational requirements.
The first Kilo fitted with the new gearbox was the Ground Test Vehicle, which is anchored to the ground at West Palm Beach. Gearbox delays led program officials to expand testing of that aircraft, including envelope expansion to extreme conditions of torque and blade flapping. When the first Engineering Development Model -53K flew, the Ground Test Vehicle had 230 hr-plus of testing.
The Naval Air System Command program plans a three-year, 2,000-hr flight-test program with four CH-53Ks. A second Engineering Development Model aircraft was completing as 2015 ended; it could fly this month. The other two are in progress.
The -53K is intended to carry a 27,000-lb external load (nearly triple that of the Echo) over the same range (110 nm) in 105 deg F at sea level and 91.5 deg F at 3,000 ft while fitting in the same shipboard footprint and reducing maintenance and life-cycle costs. Three 7,500-shp General Electric GE38-1B turboshafts power the Kilo. The -53E has three 4,380-shp GE T64s. The Marines plan to buy 200 -53Ks starting in 2017 and to achieve initial operational capability in 2019.