BOEING SIKORSKY has completed the second flight of the first prototype RAH-66 Comanche scout/attack helicopter, some seven months after the first flight. The 54min flight took place at Sikorsky's West Palm Beach, Florida, flight-test centre on 24 August. The first flight took place on 4 January.
The second flight was delayed after a gear failed in the propulsion-system testbed, a ground-based test rig for the Comanche dynamic system (Flight International, 7-13 August, P17). Sikorsky says that the resonance which caused the input bevel-gear to disintegrate is still being investigated, but tests have determined that the aircraft can be flown safely, but with a power limit to avoid encountering the resonance in flight.
This will allow the flight envelope to be opened up to a forward speed of 160kt (300km/h), the manufacturer says. On the second flight, the aircraft was flown to 20kt forward airspeed, and 10kt rearward, and was put through hover manoeuvres, completing a total of five take-offs and landings. A new transmission is to be installed in November, enabling the flight envelope to be expanded fully.
Source: Flight International
