The US Marine Corps is in the early stages of a Sikorsky CH-53X service life extension/ product improvement programme.

According to Sikorsky, the USMC operates around 160-165 CH-53E heavylift cargo helicopters, each powered by three 3,265kW (4,380shp) General Electric T64-416 engines.

USMC studies show that some aircraft will reach their maximum service life of 6,500 flight hours within two years. However, the bulk of the CH-53Es will need to be retired or subjected to a service life extension in 2010-13. Sikorsky says between 110-140 of the aircraft could be candidates for a service-life extension programme (SLEP).

Sikorsky has briefed Lt Gen Fred McCorkle, the USMC's deputy commandant for aviation, on the CH-53X, and the USMC's leadership is said to endorse the SLEP/product improvement project. Funding issues remain unresolved, but Sikorsky, USMC and US Navy officials are working together on a plan to initially fund the remanufacturing work beginning in fiscal year 2003.

Sikorsky expects to be under contract within a year. After engineering and flight testing of new components, limited production would begin in fiscal year 2009, with plans for 15 aircraft to be remanufactured annually.

As planned, the CH-53X Future Stallion would have commonality with the Bell Boeing MV-22 tiltrotor and the remanufactured Bell UH-1Y utility helicopter, offering performance enhancements and reduced cost of ownership. Feasibility studies indicate that the MV-22's 4,470kWRolls-Royce T406-499 turboprop can be substituted, while retaining the drivetrain. "There are challenges, but it is a workable solution," says an official of the helicopter company.

Ultimately, a powerplant emerging from the US Joint Turbine Advanced Gas Generator technology demonstrator project might be introduced. Other proposed enhancements include new main rotor blades, an elastomeric rotor head and an electric blade-fold system. The CH-53X's modernised cockpit would come from either the MV-22 or the UH-1Y.

Development of a new drivetrain could follow, leading to a stretched fuselage for internal cargo carriage. This would eliminate speed restrictions while carrying slung-loads.

Meanwhile, the new CH-53 Super Stallion model is also being pitched as an interim and long-term solution for the US Army's emerging advanced heavy lift requirement. Sikorsky believes the further improved CH-53 could satisfy US Army plans for a Future Transport Rotorcraft.

Source: Flight International