3-Axis "Trike"?

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Aerowerx, Nov 29, 2019.

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  1. Nov 29, 2019 #1

    Aerowerx

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    Something I have been wondering about.

    Traditionally a "Trike" is considered a weight shift flying wing design. Like this...
    [​IMG]

    Why not build something that looks like this, except with 3-axis control?

    I'm talking about the basic layout, with rigid fabric covered or aluminum covered wing. Maybe with drag rudders, or (horrors!;)) tip rudders with elevons.

    Looks like it would be an easy structure to build.
     
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  2. Nov 29, 2019 #2

    henryk

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    -thanks todays composites technology it is possible to build light flying wings,
    no wires,no struts (RIGID WINGS)...

    modern "trike" with rigid wing=simple interceptors or elevones for axial controll
    and CG shift for longitudal controll.

    f.e.= SILENT GLIDER +IMPACT, ATOS atc.

     

    Attached Files:

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  3. Nov 29, 2019 #3

    Battler Britton

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  4. Nov 29, 2019 #4

    Aerowerx

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  5. Nov 29, 2019 #5

    bmcj

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    Trikes are traditionally soft flexwings. If you want to add an elevator or more, you’ll need to make the airfoil rigid enough that you reverse or change the airfoil shape when loads or airflow go negative. Negatively loading a flexible airfoil can yield drastic, and even catastrophic, aerodynamic changes.
     
  6. Nov 30, 2019 #6

    Aerowerx

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    To quote myself...
     
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  7. Nov 30, 2019 #7

    bmcj

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    Oh, then you mean this:
    148E00E6-BE13-4B54-A702-2D8CB42C5D3F.jpeg

    You pointed out the simplicity of build for the flexwing example you gave. You lose some of that simplicity when you make it a rigid wing and airfoil.
     
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  8. Nov 30, 2019 #8

    b7gwap

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    I was about to say Mitchell wing. More than a few have flown, I think Wick’s still sells kits for the B10 (wood and fabric version of the one posted above)
     
  9. Nov 30, 2019 #9

    Aesquire

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    I have been considering "updating" the Pterodactyl Ascender with a trike like single triangle cockpit & landing gear instead of the pyramid.

    https://en.m.wikipedia.org/wiki/Pterodactyl_Ascender

    lower drag & parts count. I'd keep it a 2 axis canard, a well proven design, not changing the Aerodynamics.

    But a 3 axis rigid wing would work just fine.

    The thing that complicates the idea is you don't need or want the pivot point where the trike chassis connects to the wing to pivot like a trike if you go 3 axis. A modified 'dactyl would still be wire braced, so the pylon/wing interface is a simple bolted joint. It only needs to take lift and thrust loads. If you didn't want wires, that joint has to be cantilever, taking roll, yaw and pitch loads as well.

    That's not a deal breaker, but needs to be considered.

    I do love the Silent Glider power pod design.

    http://en.a-i-r.de/atos-motorisierung/

    The control system is weight shift in pitch, and yoke/wheel in roll. Not a problem for weight shift trained pilots, I think, but not exactly what you are contemplating.
     
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  10. Nov 30, 2019 #10

    henryk

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    -or KASPERWING=simple,contant chord single surface rigid wing,
    hybrid (CG shift + aerodynamic rudders)=huge speed diapason=0-70 km/h !





     
  11. Nov 30, 2019 #11

    bmcj

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    There is one 3-axis flexwing that I can think of... the American Aerolights Eagle XL. It had its elevator control on the canard, but IIRC, the canard was always at a positive AoA, which kept the wing at a positive AoA.

    4F9B7DC3-9B46-45F8-9094-40FD6AEAB0DB.jpeg
     
  12. Nov 30, 2019 #12

    henryk

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  13. Dec 1, 2019 #13

    erkki67

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    It would make sense to me, to have a Plank with a cockpit hang beneath the wing.

    with some tundrawheels attachedeither as tricycle or taildragger layout.
     
  14. Dec 1, 2019 #14

    gtae07

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  15. Dec 1, 2019 #15

    Aerowerx

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    Exactly!

    My idea is to design it with the desired static margin while empty. This determines where the CG is, and then put the seat at that location. Fuel in the wing just above it. The result is no CG shift with load!
     
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  16. Dec 1, 2019 #16

    Andy Hughes

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    Perfect reply! Its a different aircraft. You could ask the same question, why wouldn't you take a Cessna and convert to a 2 axis flex wing. Pointless
     
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  17. Dec 1, 2019 #17

    b7gwap

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    Um so that A.I.R. Silent still looks like it uses weight shift for pitch control.. there’s nothing wrong with that except I thought the OP was after 3-axis aero control with no weight shift, is that not the case?

    either way, that is a beautiful trike.
     
  18. Dec 1, 2019 #18

    henryk

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    =full,seriouse motorglider...
     
  19. Dec 1, 2019 #19

    Aerowerx

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    My OP question has nothing to do with converting anything.

    I was just wondering about designing something along the same pattern as the weight shift trikes, but starting from scratch.
     
  20. Dec 2, 2019 #20

    Aesquire

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    Your idea of a pylon thing below a flying wing is good. The basic triangle holding seat, engine, and landing gear can be covered with a light, non structural fairing, or not, depending on drag & weather tolerance.

    just for sake of argument, I'll assume a foam core carbon fiber covered swept wing similar in planform to a SWIFT. ( you may choose a plank, or tube & fabric, or a tailed design, should make little difference to this post ) 3 axis control, for example, elevons and tip rudders.

    If you wire or strut brace the wing, the pylon structure can be minimal. But full cantilever will require a much beefier ( technical language! ;) ) pylon and spar connection at the wing. Fore & aft loads can be dealt with by adding a strut from the front of the trike frame to the nose of the wing, so in side view it's a big N.

    There's also a matter of pendulum effect on stability, good & bad.

    Overall, hanging the pilot under the wing deals nicely with one of the biggest problems with aircraft design, the desire to put the pilot ( variable load ) on the CG, where the wing spar wants to be.

    There are various setup advantages with some trike designs where you have a folding mast/pylon, standing the wing on it's nose to attach the mast, then tipping it back & securing the front triangle tube(s). Handy idea to break down for transport.
     
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