The first flight of the Sikorsky S-92 Helibus medium-weight helicopter is now planned to take place in late December, three months later than expected, says Randy Oliver, Sikorsky's S-92 flight test director.

Delivery of the first of five prototypes of the twin-turbine helicopter, the ground-test vehicle (GTV), to Sikorsky's West Palm Beach, Florida, flight-test centre, slipped from March to June. The second prototype, the first flight test aircraft, will not arrive until the middle of November. "We've lost a little bit of time, but we're still making it our goal to fly by the end of the year," says Oliver.

The GTV and first flight test aircraft will be powered by CT7-6Ds, as General Electric is still developing an improved compressor for the CT7-8s planned for the production aircraft. The first S-92 to be powered by the -8 will be the second flying prototype. Oliver says type certification is still expected in the third quarter of 2000 after completion of a 1,600h flight-test programme with four aircraft.

Sikorsky and its partners, which include Mitsubishi Heavy Industries, Gamesa and Embraer, will not decide whether to launch production of the S-92 until flight testing begins. The production decision could be announced at Heli-Expo '99, which takes place in Dallas, Texas, on 21-23 February.

The S-92 will be available in two versions: a 19-passenger civil transport, the S-92C; and a military utility model, the S-92IU.

Discussions have taken place on qualification of the Rolls-Royce Turboméca RTM322 with the S-92, but a formal agreement will not come until a customer steps forward.

The CT7-8 turboshaft is rated at 1,790kW (2,400shp). The RTM322-01 is rated at 1,565kW, with growth potential to 2,608kW.

"The RTM322 turboshaft is an attractive option to our customers. We think the engine enhances the market for the S-92," Oliver says.

Source: Flight International