The Sikorsky-Boeing SB-1 Defiant compound helicopter is still on track for its first flight before the end of 2018, despite difficulties setting up automated fiber placement tooling to manufacture the aircraft’s composite rotor blades.
The partners say they have installed a powertrain systems testbed at its West Palm Beach, Florida facility and by the end of October it plans to use it to test the Defiant’s dynamic systems, such as its turbines, transmission and rotors. Ground-based powertrain systems tests will proceed the helicopter’s first flight.
The aircraft was supposed to have flown for the first time last year, but the composite blade manufacturing process has delayed this. At the request of the US Army, Sikorsky-Boeing used an automated fiber placement machine to manufacturer the helicopter’s blades.
“To set the precedent for the future of being a low-cost aircraft we went right in with an automated approach,” said Ken Eland, Future Vertical Lift programme manager for Boeing. “As I put it to someone in the Army, the first spar took us two years to build; the last spar took us 11 days.”
The Sikorsky-Boeing team plans to make ground runs with the Defiant in November. And while the pace of the Defiant’s flight envelope testing will depend on how initial evaluations of the aircraft go, Eland says once the aircraft flies, 6 months would not be an unrealistic window to reach speeds above 200kt (370 km/h).