The Sikorsky-Boeing SB-1 Defiant rotorcraft demonstrated the ability to lift a 2,400kg (5,300lb) sling load in a recent test flight.
The co-axial helicopter with a pusher propeller is still undergoing flight tests as the US Army reportedly recently sent out request for proposals for its Future Long Range Assault Aircraft (FLRAA) to the Sikorsky-Boeing team and Bell. The SB-1, as well as Bell’s V-280 Valor, were developed under a demonstration programme for the service.
Whereas the Bell V-280 tiltrotor wrapped up its demonstration programme in June, after about 3.5 years of flight testing, the SB-1 is trying to make up for lost time. It didn’t reach first flight until 2019, due to issues with its composite rotor blade manufacturing process and transmission gears.
“The flight, carrying a 5,300lb Guided Multiple Launch Rocket System training load, took place last week at the Sikorsky Development Flight Center in West Palm Beach, Florida,” says the Sikorsky-Boeing team on 22 July. “The lifting power demonstrated by SB-1 Defiant equates to an Infantry Squad Vehicle or hundreds of thousands of rounds of ammunition – resupply vital to soldier survival in a contested environment – further displaying Defiant’s suitability for the Army mission.”
The demonstration also showed the SB-1’s ability to carry troops at the same time as hauling a heavy sling load, the joint development team says.
FLRAA is intended as the US Army’s replacement for the Sikorsky UH-60 Black Hawk utility helicopter. The service wants to equip its first unit with the new rotorcraft no later than 2030.
The US Army wants FLRAA to have a maximum cruise speed of 280kt (519km/h). It also wants the aircraft to have an unrefuelled combat radius of 300nm (556km), and a one-way unrefuelled range of at least 2,440nm.