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Sikorsky-Boeing team rolls out Defiant ahead of first flight

27 December 2018
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The SB>1 Defiant will be fitted with aerodynamic rotor hub fairings ahead of its first flight, expected in early 2019. Source: Sikorsky-Boeing

The Sikorsky-Boeing team has rolled out the SB>1 Defiant co-axial compound helicopter that is being built for the US Army's Joint Multi-Role Technology Demonstrator (JMR-TD)/Future Vertical Lift (FVL) effort.

The event, which took place at Sikorsky's West Palm Beach facility in Florida, marks a major milestone ahead of the first flight, which is expected in early 2019. The helicopter will first be fitted with the aerodynamic rotor hub fairings that were missing from the roll-out.

Along with the Bell V-280 Valor tiltrotor, the Defiant was downselected in October 2014 to help the US Army develop its requirements for new utility helicopters expected to enter service in the early 2030s. Based on an upcoming 'fly-off', the army will downselect to one platform for further development of the FVL family of rotorcraft.

For the Capability Set 3 (Assault)/FVL-Medium requirement that the Defiant and Valor are geared towards, the US Army has laid down a number of key performance parameters for the competing designs. In terms of speed, the service stipulated in its 2012 Broad Area Announcement a performance of more than 230 kt while carrying 12 fully equipped troops.

To achieve this the SB>1 Defiant uses the same co-axial rotor and pusher propeller technology that Sikorsky developed for its X2 high-speed demonstrator and later its S-97 Raider. Developed by Sikorsky to cruise comfortably at 250 kt while retaining excellent low-speed handling, efficient hovering, and safe autorotation combined with a seamless and simple transition to high-speed flight, the X2 incorporated a number of advanced technologies, including fly-by-wire flight controls, counter-rotating all-composite rigid rotor blades, hub drag reduction, active vibration control, and an integrated auxiliary propulsion system that included a pusher propeller driven by the same gear box that turned the main rotors.

Weighing 6,000 lb (2,722 kg) and accommodating a crew of just two, the X2 was significantly smaller than the 32,000 lb (14,515 kg) and up to 18-person Defiant.

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