Jul 292010

The AVX Aircraft Company has come up with a pretty slick design for a roadable helicopter in response to the DARPA RFP for a “flying Hummer.” It’s a conveniently cubical boxy shape, with a fair deal of internal volume, with two ducted fans for forward thrust and foldable coaxial rotors.

avx_tx_flying.jpg  avx_tx_ground.jpg

I’ve always prefered the idea of a “roadable helicopter” to a “roadable airplane.” As well as providing more convenient folding of the lifting surfaces – the Terrafugia folds up into something of a mess… serviceable, but large and exposed, and vision-blocking – a roadable helicopter provides better operational versatility. Whether you’re a civilian trying to get home from the office or soldiers trying to get the hell out of Dodge, if you find yourself stuck on a highway, a roadable airplane won’t help much. But a roadable helicopter can, in principle, just pull off the road, fire up the rotors and lift off vertically.

AVX is also proposing to convert old OH-58D Kiowa airframes into coaxial/ducted pusher configurations. If their estimates are accurate, it would be a relatively cheap way to turn these old bitrds into new, fast battlefield tools.



 Posted by at 6:34 pm
  • JP

    I’ve been sketching out an idea that uses the counter rotating three blade props, it’s cool to see it’s being done by a real team. My idea is for something smaller like a one or two seat Aptera looking vehicle.

    It’d be a three wheeled design with two in the front and a driven wheel in back. That way it qualifies as a motorcycle. The size should keep it under the new FAA Sport Class vehicles.

    The rear wheel will rotate to act as a drive fan with simple adjustable blades. It will only require a hand controller and the front will have a lowering ramp so I can back my wheelchair inside!

  • Far.

    Personally, the Fairley Rotodyne seemed a more efficient and simple way to make a hovering airplane.

    Any technical info on that ?


  • Pat Flannery

    It actually looks like a workable concept.
    Kamov apparently started a trend with his superimposed three-bladed rotors; they seem to be becoming more common all the time.
    One downside of flying your helicopter/car to the mall is that parking lots are going to be huge if they have to account for rotor diameter of all the things landing.

  • admin

    > parking lots are going to be huge

    Not necessarily. The great thing about the vehicles being roadable is that you can land on a dedicated pad and then drive to the dedicated parking area (take a parking garage and make the roof “landing area only”) . Worries about congestion are unfounded, as these things are going to remain friggen’ expensive and only a tiny fraction of drivers will be chopper pilots.

  • admin

    > Any technical info on that ?

    Yes. “Louder than hell.” Almost certainly too loud to ever be allowed in-town. Plus, a coax version of the tipjet would seem tricky at best.

  • JP

    Flying to the mall would be easy and safe, you don’t land in the parking lot, you land on the roof! If the producers of aerocars were smart, they’d also produce landing pads that could be strong and light to place on roofs. The shade provided would probably help lower the temperature inside the mall/house.

    With my concept, I’d like to use high powered lightweight batteries. Primarily for noise reduction. Then the landing pad could be covered in solar panels and when the vehicle comes into land, the panels open up so they don’t get smooshed.

    In case of a power loss of loss of control, there could be a safety parachute, air bags for the passenger. If the parachute was deployed, the batteries/engine could also detach to allow for a smaller chute or parasail to deploy faster.

    I don’t have all the answers, I’m actually thinking more about the questions that flying car inventors like Moller never seemed to ask themselves before they began.

    1. How noisy is this. One hlo at night is noisy enough, but could you image even four or five of those flying low ALL DAY 24/7?? Tip jets, APJ’s are really really noisy

    2. Does it need a runway? The Terrorfuego is an airplane so it needs a runway. Most long commutes require pit stops. And the one time you drive it and someone bumps into it, you’re probably grounded. All those hinges and servos probably don’t take to well to even slight impacts.

    3. Any helo design that is heavy will require larger rotor diameters, engines and have an annoying amount of prop wash. That’s why I’m thinking roof landings with a light vehicle.

    4, Air traffic control and highway patrol. Who has jurisdiction? Where can you not fly? Granted, it’s already possible to punch in the GPS coord’s and it can autopilot it’s way there, but situational awareness is still needed (Birds don’t have transponders, just ask Sully)

    I’m sure there’s more, but I’ve got time to think sittin in my wheelchair

  • Pat Flannery

    JP wrote:
    “With my concept, I’d like to use high powered lightweight batteries. Primarily for noise reduction.”
    Apparently, you and Sikorsky think alike:
    I used to have a model of the Rotodyne when I was a kid; like Scott said, the thing was supposed to be able to blow out anyone’s eardrums in the vicinity when the rotor-tip jets were cranked up.
    They tried to redesign the nozzles on them to cut down the noise, but didn’t have much luck at it.
    It’s a a real pity they couldn’t fix the noise problem, as the aircraft would have had a lot of both civilian and military uses.
    Video of the prototype in action here:

  • Pat Flannery

    Speaking of rotor-tip jets, what has to be the most insane flying machine that ever actually got built: http://www.aviastar.org/helicopters_eng/papin.php
    Hard to even tell if it’s supposed to be a flying machine, or some sort of gigantic steampunk guitar. 😀

  • Pat Flannery

    A painting of a pilot gleefully flying it…obviously, he has no fear of death, or has had way too much Absinthe: http://www.heliport.sk/foto/01462i.jpg
    Even “Crimson Skies” has nothing half this weird in it.
    The thing that looks like a Vulcan Gatling gun attached to the front of his cockpit is an air blower that cancels out torque from the rotation the wing-rotor-compressor-thingy as it spins around him.
    Let’s put it this way; if this thing was in any way even vaguely right, the Wright brothers were completely wrong.
    I always loved the grandeur of this design also, which is about the closest thing to SHIELD’s Heli-Carrier I’ve ever seen:
    It would be astounding to see that monster come in to land, and the SA-2 missiles elevate into firing position.

  • Robin

    >I used to have a model of the Rotodyne when I was a kid;

    I’ve still got TWO, unmade…

    Anyone interested??

  • John Nowak

    I wonder about the engine, though. Doesn’t a helicopter use more power than a fixed-wing plane?

  • Pat Flannery

    That’s the case if uses a powered rotor during its entire flight; in the case of the Rotodyne, the rotor was only powered during liftoff and landing; during cruise flight the aircraft was a big autogyro with lift generated by the unpowered rotating rotor being supplemented by the aircraft’s wings.
    That being said, those are two very big turboprop engines for something that’s only capable of going 200 mph.
    I assume that the limiting speed was based on the ability of the big free-wheeling rotor in auto-rotating flight not to have one of its rotor-tips go supersonic and lose lift, just like a conventional helicopter.

  • Michael Holt

    The SHIELD Headquarters? Did they ever patent the design? I never found it, but I did find two patents that led to it. One is to a Peachy Booker, dated 1961, and titled “Flying Landing Platform” (3003717). The other — the oldest cited in Booker’s offering — is titled “Aircraft Landing,” 1874423, to Harry Clayton Belleville; it’s a deck supported by a dozen balloons.

    Like the man said, helicopters operate on the Principle of Aesthetic
    Repulsion: they are so ugly the Earth forces them away.

  • Pat Flannery

    This idea is pretty wild, although it looks top-heavy and might invert if built:

  • Anonymous

    I think the AVX TX looks very impressive. But for how much longer is it to remain a concept? I think it’s very easy to design a concept, but how about making it a commercial reality? Already the PD-2 appears to be a roadable aeroplane that works so I think it should be just a matter of time before a roadable helicopter is actually tested. But how much time? Obviously I don’t want it to remain a permanent concept. I therefore hope the roadable helicopter will be very much on the scene by the middle of the decade.

    I am very much in favour of flying cars and would even like flying cars and flying saucers to displace the conventional aeroplanes and helicopters altogether, except perhaps for special occasions.

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