First Flight of the SB-1 Defiant, a Potential Blackhawk Helicopter Replacement

Popular Mechanics ^ | March 26, 2019 | Kyle Mizokami

[C19fan]

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.

[C19fan]

Where is the jet power boosting???? [Airwolf reference]

[Bishop_Malachi]

Looks similar to the Russian Ka-50 Blackshark/Werewolf.

[Darteaus94025]

Went the way of Jan Michael Vincent.

[Yo-Yo]

First flight was a simple hover, with no power to the pusher propeller.

[Openurmind]

Cool... How does it turn around when at a static hover? torque convertors on the counter rotating hubs? Asymmetric pitch in the tail rotor? Or can it only turn when flying forward like a plane?

[SJSAMPLE]

Dissymmetry of torque caused by opposite changes in the pitches of each rotor.

[Sacajaweau]

100 miles faster than the Blackhawk....wow

[McGruff]

The Sikorsky S-69 is an experimental co-axial compound helicopter developed by Sikorsky Aircraft as the demonstrator of the Advancing Blade Concept under US Army and NASA funding. Wikipedia

First flight: July 26, 1973

[SJSAMPLE]

New aviation technologies developed since the UH-60’s introduction ...

Like the counter-rotating rotors of the 40+ year-old Kamov, or the pusher prop from the cancelled 1967 AH-56 Cheyenne?

[Psalm 73]

Nice post - have done nothing but rotorcraft for nearly 40 years.
At 287 miles an hour - more than a hundred mph faster than the UH-60M - this will change the nature of helicopters for ever.

[going hot]

The rotors give opposite torque to the shaft which is connected to the frame, thus the tail rotor is needed to counteract the torque of the blades.

With two rotor discs, the tail rotor is not needed, as the net torque cancels.

I think if one set of rotors were to be given a little bit more of pitch, and the other set a little less, the bird would stay as same altitude, but the net torque to the shaft would no longer be neutral, thus causing the tail to come around.

I have not quit my current day job, so this is just speculation based on previous infor from another life. (!)

[PLMerite]

[Openurmind]

Thank you. That makes sense. I knew counter forces had to applied somewhere to spin it.

[Openurmind]

Thank you! SJSAMPLE explained the same principle. :)

[clueless_expert]

But it doesn’t look anywhere near as menacing as the Blackhawk. I dunno, maybe paint some shark teeth on its front or something. lol.

C_E

[Rummyfan]

[Delmarksman]

Thanks for the pic.
As a former Jet Engine mechanic, this looks to be high maintenance and difficult to repair/maintain in the field.

[Mariner]

No tail rotor required with counter-rotating top rotors.

Nice propeller boost in the rear.

250 knots?

[pfflier]

First impression: Looks like a Russian design knockoff.

Second impression: Those are some kind of beefy rotor hubs.

[BenLurkin]

ping