Enlarge / The Sikorsky-Boeing SB-1 Defiant. (credit: Sikorsky/Boeing)
The Sikorsky-Boeing SB-1 Defiant, one of two aircraft competing for the US Army's Future Long Range Assault Aircraft program, has finally made its first flight—a short bit of hovering around an airfield at a Sikorsky facility in West Palm Beach, Florida. The flight comes over 15 months after the Bell V-280 Valor (the other competitor for the program to replace the Sikorsky UH-60 Blackhawk) took flight. But the reasons for the delay are pretty straightforward: the SB-1 prototype is only the fourth actual aircraft ever built using Sikorsky's Advancing Blade Concept rotor design, while the V-280 is based on the (relatively) mature technology behind the V-22 Osprey tilt-rotor.
The Defiant helicopter uses two stacked, contra-rotating rigid composite rotors for its lift and a pusher propeller for thrust at high speeds. Since it is a true helicopter, it has a much smaller footprint than the V-280, which has two tiltrotors positioned at its wingtips. At least in theory, the Defiant will handle more like a traditional helicopter when maneuvering in tight quarters, such as the urban environments that the Army has placed particular emphasis on in its future war planning. Manipulation of the pitch of the rotors could make for more agile maneuvering.
That, however, remains theory.
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