Elytron 2S - the first commercial tiltrotor?

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Xanadrone, Jul 28, 2014.

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  1. Jul 28, 2014 #1

    Xanadrone

    Xanadrone

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    Elytron 2S: The out-of-the-box tiltrotor concept
    ...shows a rather interesting concept of tiltrotor VTOL craft (it will be presented at Oshkosh too on the 3th of August), even if it's not totally new.

    The boxwing "Prandtl" scheme at least it's not new at all, maybe just the smaller rotating wing (100 degrees span) "in-between", supporting two nacelles/engines with fixed pitch props if I remember it well.

    What's your opinion about it? Let alone the recognised difficulty of the transition flight-phases (maybe easier to resolve with the actual hi-tech electronics), I wonder if this concept is viable and maybe less prone to test-crashes, like the V-22 Osprey was.

    elytron-6.jpg
     
    Last edited: Jul 28, 2014
  2. Jul 28, 2014 #2

    TFF

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    I doubt it is VTOL with the limited tilt. With any tilt rotor the two problems are going to be keeping both power plants going and having one rotor in a settling with power situation which can happen with a slow hovering crosswind turn. Minor other problems making hp per pound. Ambitious. Agusta 609s have been around for a long time; no one has liked the cost overruns which have been about a million a year per example if someone would buy one; they need to sell 20 before they will release.
     
  3. Jul 28, 2014 #3

    kenkad

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    Looks nice. Seems I have seen that kind of design in a single passenger concept that has dual counter rotating ducted fans. I did contact them and asked how they computed the NP for that joined wing since I could not get any useful information on HBA. I am curious if they will respond.
    kenkad
     
  4. Jul 28, 2014 #4

    Jay Kempf

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    I ain't gonna sit in that cabin looking at those blades right next to my body. Looks like a food processor. It would seem that four rotors would be a better solution but then there is the idea that you need collective rotor heads to control it. I thought this sort of stuff was already ruled out due to control issues and power to weight. Quad copters deal with control with very reactive motors and fancy electronics. If this thin is a turbine how could they possibly control it in hover? Transition with control, etc...?

    As concepts go this one seems to have every bad idea in one platform. Just my opinion. I have been looking closely at multirotor VTOL concepts of late due to some UAV things I am working on. Looks like someone did a tiny bit of math about power and disc loading and convinced themselves that this is viable. I think tilt rotors are viable but this seems like it has too many points of single failure designed in. The box wing seems completely out of place and counter to the rest of the design intent.
     
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  5. Jul 28, 2014 #5

    Jon Ferguson

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    First time I saw an A-26 I thought the same thing... Those props look mighty close.
     
  6. Jul 28, 2014 #6

    autoreply

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    Lots of fancy renderings, but whether there is any solid engineering behind it?


    Propwash/wing interaction is going to be interesting.

    Non-cyclic props work just fine on a small scale, but you run into a brick wall at higher inertias. Not sure where those values would be and a hybrid with light composite props in this range might actually be do-able.

    Overall I like the concept.

    Now let's see one flying.
     
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  7. Jul 28, 2014 #7

    revkev6

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    this plane is similar in concept to the canadair Cl-84.... which was a successful aircraft, just not landing any contracts.

    this plane has two glaring issues imo. the article claims their will be no cyclic or collective control of the blades. the cl-84 had collective control that was connected to the throttle. the engines could not react fast enough to maintain precise power in a hover so they changed blade angle to make it faster. the engine governors would then level out the control and reduce the pitch change of the prop.

    even though the cl-84 did not have cyclic it did have a tail rotor and a horizontal stabilizer that changed incidence to maintain pitch control in hover and transition.

    this plane is just a sketch that will never work correctly IMO.
     
  8. Jul 29, 2014 #8

    ultralights

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  9. Jul 29, 2014 #9

    TFF

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    I hope they get more prop to that than the toy ones on there, if the plan to hover.
     
  10. Jul 30, 2014 #10

    Topaz

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    How exactly is this thing controlled during hover and, more importantly, during transition? They say it has "four control surfaces" on the little stub wings, but that's not going to be much control power compared to the moments generated by induced flow and gusts on the (much larger) box-wing.

    I don't know enough about this design, really, but if that's their only means of control in powered-lift flight and transition, I think these guys have vastly underestimated the three-axis control power they'll need for this thing during such critical phases of flight.
     
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  11. Jul 30, 2014 #11

    Topaz

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    Ya think? :speechles
     
  12. Jul 30, 2014 #12

    Apollo

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    Well, at least they're building hardware. That's further than some of us get :)

    But yeah, not very workable IMO.
     
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  13. Jul 30, 2014 #13

    Topaz

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    I would've liked to see them spend a little less on such a "flashy" demonstrator and instead build more of a hover and transition "mule" first. I don't mind the box wing. I don't even necessarily mind the box wing with the stub-wing prop-rotors. But control power during hover and transition seems... iffy at best. If I can see them make a full transition from hover to horizontal flight and back again, then I'll be a believer.
     
  14. Jul 30, 2014 #14

    BBerson

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    What booth?
    I am at Oshkosh.

    edit: I think I found the location, heading that way.
     
    Last edited: Jul 30, 2014
  15. Jul 30, 2014 #15

    Apollo

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    I'd be satisfied with a video of a quarter-scale model showing the transition from hover to flight and then back again. Of course it doesn't exist. Outfits like this want investors' money without any significant proof that their concept is viable. I'm not going to feel sorry for the investors though, who obviously didn't perform any due diligence.
     
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  16. Jul 30, 2014 #16

    revkev6

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    the website claims several quarter scale models were built... still don't see it working well as shown
     
  17. Jul 31, 2014 #17

    BBerson

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    I looked at the full size mockup yesterday. Will attend their forum today(4pm).
    The RC model does fly, a bit rough but works.

    It is has motorcycle engine with shafts to twin props. Looked like ordinary props.
    More info later.
     
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