Air Platforms

AAAA 2019: Sikorsky-Boeing targets SB>1 Defiant envelope expansion

15 April 2019

The Sikorsky-Boeing SB>1 Defiant co-axial compound helicopter team is planning to expand the aircraft's flight envelope after the upcoming third flight test slated for next week, according to a company official.

Bill Fell, Defiant test pilot, told reporters on 15 April that the aircraft, so far, has reached 10 kt speed during two previous test flights. The Defiant team plans to increase the aircraft's speed in 40 kt increments on an upcoming test flight to verify simulation models. Fell said increasing the aircraft's speed in smaller increments will help provide confidence that simulation models are accurate.

To prepare for this envelope expansion, the Sikorsky-Boeing team will invest additional hours on its propulsion system test bed (PSTB) after the third test flight.

Want to read more? For analysis on this article and access to all our insight content, please enquire about our subscription options at

(145 of 399 words)