The SB-1 Defiant helicopter, a new rotary-winged aircraft design developed by Sikorsky-Boeing, flew for the first time on Friday, March 21, 2019.
The Defiant uses a unique propulsion system, ditching the tail rotor of conventional helicopters and adding a push propeller. The result is an aircraft the manufacturer touts as faster and better handling than other choppers, which could result in faster and more agile U.S. Army helicopter force.
The Defiant uses an unusual propulsion system that utilizes a pusher propulsor instead of the traditional tail rotor. Its makers say the result is a craft with superior handling that will change the face of the U.S. Army helicopter force.
The flight lasted around 30 minutes and didn’t include any particularly daring maneuvers, but marked an important developmental step for the prototype aircraft that leans heavily on Sikorsky’s Advancing Blade Concept rotor design. The idea is to use two stacked rotors that spin in opposing directions to produce lift, with a pusher-propeller to add thrust at high speeds. The Defiant prototype that flew last week is only the fourth aircraft Sikorsky has fitted with such a means of propulsion.
The Defiant is an entrant in the U.S. Army’s Joint Multi-Role-Medium Technology Demonstrator program, whose goal is to develop a new medium transport aircraft to replace the UH-60 Blackhawk helicopter. The Blackhawk has been in continuous service since the early 1980s, and although it’s had a successful tenure, the Army decided now is the time for something new. New aviation technologies developed since the UH-60’s introduction could allow for faster, longer-range aircraft with greater performance in high-altitude environments such as Afghanistan.
The SB-1 Defiant capitalizes on technology originally introduced on the X-2 technology demonstrator, and then the S-97 Raider scout helicopter. Instead of using a conventional helicopter layout with main rotors and a stabilizing tail rotor, the Defiant uses two sets of counter-rotating main rotors and a rear-facing propulsor propeller for forward thrust. The SB-1 would have a crew of four, carry 12 combat troops, and reach speeds of up to 250 knots, or 287 miles an hour. That’s more than a hundred mph faster than the latest version of the UH-60 Blackhawk, the UH-60M, can fly.
The Joint Multi-Role-Medium Technology Demonstrator program should produce a viable Blackhawk replacement by the late 2020s, with first fielding of the aircraft in the early 2030s. An attack helicopter version to replace the AH-64 Apache is also envisioned.