US Military Going Beyond Helicopters

The Sikorsky–Boeing SB-1 Defiant is built and will make its first flight early in 2019.

The SB-1 Defiant will have a cruise speed of 250 knots (460 km/h). It will initially will have less range due to using the “old” T55 engine. A new engine, the future affordable turbine engine (FATE), will enable it to meet the range requirement of 229 nmi (424 km).

The Bell V-280 Valor is competing for the Future Vertical Lift program. In October 2018, the V-280 reached 250 knots (460 km/h) at 80% proprotor cruise speed. It was also flown to a 45° bank angle at up to 200 kn (370 km/h), achieved a 4,500 ft/min (23 m/s) climb rate at 160 kn (300 km/h), exceeded 200 kn (370 km/h) with less than 50% torque, and recorded a peak load factor of 1.9g. Its longest flight covered 270 mi (230 nmi; 430 km).

The V-280 is designed for a cruising speed of 280 knots (320 mph; 520 km/h). It will have a top speed of 300 knots (350 mph; 560 km/h), a range of 2,100 nautical miles (2,400 mi; 3,900 km), and an effective combat range of 500 to 800 nmi (580 to 920 mi; 930 to 1,480 km). Expected maximum takeoff weight is around 30,000 pounds (14,000 kg)

19 thoughts on “US Military Going Beyond Helicopters”

  1. Well there was DARPA LightningStrike, but that got cancelled before the full up prototype got built out. They did make the 1MW generator that was to be matched with the honeywell turboshaft engine though, and distributed propulsion using boxfans is mostly understood via the subscale prototype…

  2. Coaxial rotors neutralize the tendency of a single-rotor craft to spin its airframe in the opposite direction of the rotor above. (This is why many “simple” helis have that little whizzing tail-rotor: mostly to counteract body spin, but also to allow yaw (intentional spin around center-of-gravity axis). 

    THe tree-strike potential of the pusher propeller is overplayed. It is a propeller, contained in the overall frontal envelope of the craft. Its fine. 

    Tilt-rotor craft are wickedly noisy. There is essentially no stealth that they’re capable of. The smaller (total) rotor area requires thrusting the smaller columns of air to higher velocities to achieve the same static lift. Higher velocities equal higher turbulence, equal higher propwash pressures, equal higher modal noise. Counter-rotating the pair of props helps a lot in vectoring the craft without “Corialis” effects and anisotropic (asymmetric) speed-vs-lift issues. 


  3. ScaryJello says it, and there is another answer too. 

    A helicopter ‘works’ by accelerating a column of air “down”, so as to produce lift. When that air column isn’t directly “down”, but is tilted, then the copter also gets a transverse thrust. Forward, backward, sideways.  

    The reason why conventional copters only have one big rotor is because of the word “one”. One of anything is almost always less complicated than “two or more” of those things. Except when it isn’t. Airplanes have TWO wings, because, well, one would be a disaster. The tail “fin-thing” usually has 2 or more winglets. For the same reason: should one be damaged, the whole aircraft doesn’t need to fall out of the sky like a damaged bumblebee. 

    Given the very real complexity of the “contraption at the top” of a helicopter, which actually slightly twists the individual rotor blades as they spin about their radial axis (giving offset or non-homogeneous lift), having to make one tough, competent, armored “thing” is a heck of a lot cheaper (and easy to control by the pilot) than 2 or more. 

    Quadracopters (and higher order) helis abstract the complexity of controlling them all interdependently by using fast real-time sensor-and-computation algorithms. This abstraction lets “ordinary mortals” fly the things with simple joysticks and other finger controls. Such real-time computation wasn’t thought desirable or defensible when helis were evolving in the 1950s-thru–80s. 


  4. “if we can imagine it, it must be eventually possible, right?”

    Rule 34 doesn’t quite go like that. Close, but not quite.

  5. Because real helicopters use 5,000 hp gas turbines and gear boxes to turn the rotor(s) and not rinky dink cordless drill motors powered by batteries.

  6. Yes the Osprey can have problems landing.

    For my money’s worth I would reconfigure Ospreys to be mini AC-130 gunships for close fire support for troops. It can loiter longer due to wings.

  7. And the tilt rotor doesn’t have the ability to do precision helicopter like landings well. Apples and Oranges unfortunately. Range & speed vs putting special operators where they are supposed to go.

  8. V-280 and Defiant are already winners- the problem is that they are winners at different things.

    Defiant is clearly going to dominate at low speeds with excellent maneuverability because it is a helicopter. V-280 will carry more and be faster.

    Question is what does the Army need more?

  9. Actually, why are all the tiny drones quad or hexa copters, while large helicopters usually have just one or two large rotors? Presumably which is better depends on scale, but why?

  10. I think the tilt rotor is less efficient in the hover and its downwash can be damaging. Not good for rescue or stealthy insertion. We really need both.

  11. The question lis why coaxial rotors. Yes they allow you to go faster…however it a maintenance nightmare. And the pusher prop is a treestrike waiting to happen. This restricts NOE operations. The 280 however in helicopter mode can get in the trees and rivers…low level…then pop up…tilt the rotors in seconds…and be gone at 300+…carries more weight…longer range… Better fuel consumption…critical on deep insertions. Capability of quick change out to an AH version. Coming from the spec op world…I know where I’d put my money. Wish we had the 280s down south in the 80s

  12. [irony]Where’s my Quadracopters? Or hexacopter? How about those flying battleships, ever so popular on PowerDude SciFi films?  I mean … if we can imagine it, it must be eventually possible, right? [/irony] Happy new year.GoatGuy

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