SB-1 Defiant helicopter set for take-off

The Sikorsky-Boeing SB-1 Defiant prototype, in competition with the Bell V-280 Valor to replace the U.S. Army’s UH-60 Black Hawk and AH-64 Apache helicopters, is to make its maiden flight


SB-1 DEFIANT: Flight demonstrator builds on Sikorsky’s coaxial rotor and pusher propeller
technology

Rotor fairings
Reduce drag

Composite fuselage

Retractable undercarriage


Coaxial rotors: Two rotors spin in opposite directions, offsetting each other’s torque – eliminates need for tail rotor to produce stable flight conditions

Engine
Lycoming/Honeywell T55

Fly-by-wire
Electronic flight-control system with digital engine controls allows greater manoeuvrability

Propeller: Driven by same gear box that turns main rotors, generates thrust in similar way
to fixed-wing aircraft

Active vibration control: Reduces rotor shake


All-composite rigid rotor blades

V-280

Tiltrotor technology allows V-280 to be more fuel-efficient in long-range flight

Bell and Sikorsky both claim their aircraft is more agile – crucial when landing troops in
tight spaces


Specifications	UH-60		V-280		SB-1
comparison	Black Hawk	Valor		Defiant

Speed		280km/h		520km/h		463km/h
Combat radius	600km		1,480km		426km*
Payload		4,540kg		5,440kg		Tbc
Crew		4		4		4
Troops		11		14		12

*Achieved with forthcoming FATE powerplant


Sources: IHS Markit, Lockheed Martin, Boeing, Bell
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