Joint Staff to conduct "paper review" before giving go-ahead for the development of CH-53 replacement

The US Marine Corps has clarified its acquisition strategy for the engines and cockpit for its Heavy Lift Rotorcraft (HLR), formerly CH-53X, even as the service awaits a final go-ahead from the US Joint Staff within four weeks.

Funding of $103 million to launch the system development and demonstration phase in fiscal year 2005, which began on 1 October, is waiting to be released to Sikorsky, maker of the CH-53E Sea Stallion, which is to be replaced after 2015. Programme manager Col Paul Croisetiere says the Joint Staff is set to conduct a "paper review" rather than a formal meeting, which often indicates there are relatively few objections being raised.

The USMC plan calls for buying at least 154 HLRs in an effort to replace the CH-53E with an identical footprint and vastly improved lifting capability. Shipboard operating restrictions prevent the service from building a larger aircraft, so HLR will attempt to maximise the performance capability of the CH-53E airframe, says Croisetiere. The proposed number of HLRs matches the existing fleet of CH-53Es, but, Croisetiere notes, the service is "short on -53s as it is" and more aircraft could be added later.

Michael Wynne, undersecretary of defence for acquisition, technology and logistics, has already intervened in the USMC's acquisition strategy on several points.

Most notably, he has directed Sikorsky to select a powerplant for the three-engined heavylifter, ruling against a bid by the USMC to manage an engine competition separately.

Engine manufacturers watched the selection strategy closely. The USMC is believed to favour the 6,150shp (4,580kW) Rolls-Royce Allison AE1107C now installed on the Bell Boeing V-22 Osprey. Other likely competitors include a growth version of the 4,380shp General Electric T64-416, a turboshaft derivative of the Pratt & Whitney Canada PW150 and a 6,000shp-class Honeywell T55-715B.

Also, a new rotor blade design may provide up to 2,300kg (5,000lb) of extra lift, says Croisetiere. The innovative design includes dihedral-anhedral "cathedral" blade tips, which first rise then slope down. The HLR is expected to carry a 13,600kg external load at least 205km (110nm), with a take-off altitude at 3,000ft (900m) and temperature at 33°C (91.5°F).


Source: Flight International