PAUL LEWIS /STRATFORD
CH-53E modernisation to include re-engining with options to build new airframes
Sikorsky is studying an evolutionary approach to modernising the US Marine Corps' CH-53E heavylift helicopters, starting with re-engining the existing fleet to address the most immediate need for additional payload range with later options to build new airframes and dynamic components to significantly lower operating costs.
The USMC has identified eight key areas for improvement, encompassing a new engine, improved main rotor blades, cargo system, elastomeric rotor hub, transmission, new cockpit, survivability and structural life extension. A final decision on the scope of work awaits completion of an analysis of alternatives by June and the subsequent release of an operational requirements document in time for a 2004 start.
Top of the USMC priority list is a replacement powerplant for the CH-53E's three General Electric T64-416 turboshafts following the recent Afghanistan conflict. "Flying over 12,000ft [3,660m] passes put heavy loads on the engines and I want to put a new motor in before I add one extra radio," says Lt Gen Michael Hough, USMC deputy commandant aviation.
Sikorsky's spiral approach would consist of re-engining and the repair of critical airframe components, as an initial Block 1 modernisation. Candidate engines include either an uprated T64-419B or new GE38, Honeywell T55, Pratt & Whitney Canada PW150 and Rolls-Royce AE1107C. "Requirements will determine the changes we make. If it is to carry 14,500kg [32,000lb] over 50nm [93km] at sea level there is no significant change in performance, but to achieve 12,700kg over 370km, then you need major changes," says John Wakefield, Sikorsky CH-53 programme manager.
Block 2 would include re manufactured or all-new fuselages, fly-by-wire flight controls, re-wiring, a new cockpit, cargo handling and enhanced defensive systems. The oldest of the USMC's 152 CH-53Es is nearing the end of its 6,600h fatigue life, and, based on the experience of the Sikorsky MH-60R programme, it may be more cost effective to build new airframes. "If you make the decision at the start, Block 1 and 2 could run concurrently over the same four years," says Jason Durno, Sikorsky CH-53E chief engineer.
Block 3 would include all-new composite main rotor blades, transmissions and an on-condition rotorhub using S-92 technology, but with flight testing it will take six years to complete.
Source: Flight International