After years of secrecy and CGI, we’re finally getting to see the Sikorsky-Boeing dream team’s SB>1 Defiant ultra-high-speed helicopter in real life.
Unfortunately, Defiant is still on the ground, not flying: It was supposed to take its first flight this month, but that’s been pushed back until early 2019.
But at least part of the delay is due to how revolutionary the Defiant is compared to Valor — and the difference between designs is why it’s so crucial that we see full testing of them both.
Compare the photos of the two aircraft.
Bell’s offering is a tiltrotor, a technology the company has worked on since the 1950s and mass-produced (together with Boeing) for the V-22 Osprey. It’s called a tiltrotor because the rotors tilt: They can either face up and spin like helicopter rotors, or they can face forward and spin like (oversized) propellers.
That lets a tiltrotor combine the versatility of a helicopter — the ability to hover, maneuver precisely and slowly just above the ground, and take off or land without a runway — with the speed, range, and fuel efficiency of a turboprop airplane.
The Sikorsky-Boeing Defiant, by contrast, is a compound helicopter, a technology Sikorsky pioneered on its award-winning X2 and its S-97 Raider, but which has not yet seen mass production or operational service.
At first glance, Defiant looks pretty conventional: Specifically, it looks like a lot of Russian helicopters, which — instead of a big main rotor for thrust and lift plus a small tail rotor for stabilization (like most Western choppers) — have two rotors on the same mast, turning in opposite directions to keep the aircraft from spinning like a top.
But look closer, especially at that rear view:
Where most helicopters would have a tail rotor, the Defiant has a pusher propeller.
That propeller allows Defiant to reach turboprop speeds, like a tiltrotor, but, unlike a tiltrotor, Defiant never stops being a helicopter.
Sikorsky and Boeing say that will make for a much more agile aircraft, especially at low speeds.
Now they finally have a finished prototype for testing to prove those claims.
This was first published by our partner Breaking Defense on December 26, 2018.