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Will the Defiant Be the Helicopter That Finally Replaces the Black Hawk?

By David Grossman Popular Mechanics

SIKORSKY-BOEING

Two American giants of military development, Sikorsky and Boeing, have teamed up for what they are calling a revolutionary helicopter design. The SB>1 Defiant, in the works for years, is finally getting a debut in pictures. According to a press release, the Defiant is “designed to fly at twice the speed and range of today’s conventional helicopters and offers advanced agility and maneuverability.”

The actual flight launch is scheduled for 2019, even as early as next month.

The companies hope that the Defiant is the culmination of a decade-long effort known as the Future Vertical Life (FVL). Started in 2008 as a response to legacy helicopters crashing in Iraq and Afghanistan, the goal was to develop an entirely new rotorcraft system, as opposed to just continually upgrading Black Hawks and Apaches.

First made public in 2017, the Defiant “has great potential,” according to Swami Karunamoorthy, a professor of engineering at Washington University in St. Louis with a speciality in helicopter dynamics. The strengths that the Defiant brings, Karunamoorthy says, lies in that fact that it doesn’t rely on one singular style of propulsion. It’s “a hybrid system,” he tell PopMech over email.

The hybrid system has a “coaxial rotor design for vertical flight” Karunamoorthy says, “and a pusher propeller system to increase the forward flight speed.” A coaxial helicopter design features two sets of helicopter rotors and has been a concept in flight design before flight was a reality, dating back to the 1700s. Working in tandem with a propeller system “may be twice the current speed record as it claims,” he says.

However, not everyone was as optimistic. A retired Army experimental test pilot who asked for anonymity pointed towards Sikorsky’s uneven history with coaxial, specifically a smaller project known as the S-97 Raider. Under development since 2011, a Raider test in 2017 ended in an inauspicious hard landing. It’s begun testing again this year.

A front-facing shot of the Defiant.
SIKORSKY-BOEING

“While Lockheed/Sikorsky has likely learned from their S-97 experience,” says the former test pilot, “getting this larger scale to achieve all of the goals in a mission configuration that is representative of a combat aircraft is unlikely.”

To get a Defiant to double the speed of a conventional helicopter would require it to fly at 280 knots, or a little over 322 mph. The former test pilot says this is “unlikely.”

Sikorsky-Boeing SB>1 Defiant

And the Defiant isn’t the only FVL around—there’s competition from the already flying Bell V-280 Valor, which has nearly a year of flight tests under its belt. Karunamoothy believes that both the Defiant and the Valor have the potential to “break the barrier in both forward and vertical flight.”

For the Defiant to succeed, says the former test pilot, Sikorsky and Boeing must have made sure it is “sized properly to achieve all of the Army’s design goals,” which they point to as a failure of the S-97.

With its test flights next year, the Defiant will soon have a chance to prove its worth.

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