General Electric today announced finalizing the design of the 7,500shp GE38 turboshaft engine selected to power the US Marine Corps Sikorsky CH-53K.

Completing the critical design review clears the GE to begin full-engine testing.

Rig tests of the full engine are scheduled for the first half of this year. In all, GE will build 20 engines to power the five prototype CH-53Ks over a four-year, 6,000h flight test phase.

The three-engine, 84,000lb CH-53K is expected to enter service in Fiscal 2015, replacing an aging fleet of CH-53D Sea Stallions.

But the CH-53K could be only the beginning for the GE38.

The engine manufacturer projects the GE38-1B could form the building block for a family of engines in the same class that could fill a strategic gap in power ranging from about 7,000shp to 10,000shp.

GE is looking beyond the military helicopter market to encompass new commercial turboprops that may enter service over the next decade.

The GE38 is derived from the GE27 modern technology demonstrator engine and the T407 engine, but adds 3-D aerodynamics and improved cooling to offer 15-20% more power and reduced lifecycle cost.