A team composed of Boeing and Lockheed Martin’s Sikorsky subsidiary conducted the fourth flight test of a next-generation helicopter designed to inform the U.S. Army’s requirements for future long-range assault aircraft, Defense News reported Wednesday.
The sortie, which saw the SB-1 Defiant coaxial helicopter fly at a speed of 20 knots, will be followed by a fifth flight test aimed at reaching 40-knot speeds.
SB-1 Defiant serves as a participant for the Army’s Joint Multi-Role technology demonstration program and includes modifications the team installed after finding issues with its propulsion system testbed.
“We saw a phenomenon called ‘bearing creep’ in the gearbox, and so we made a minor design tweak to keep that from becoming an issue,” said Ken Eland, director and manager of Boeing’s FLRAA program.
The Boeing-Sikorsky team completed Defiant’s first flight in March and expects the aircraft to go beyond the Army’s 230-knot speed requirement and reach 250 knots.