The 'daydreamers' thread...post your craziest designs and concepts here

Discussion in 'Hangar Flying' started by Floydr92, Apr 12, 2016.

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  1. Apr 30, 2016 #101

    Swampyankee

    Swampyankee

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    I think that a tilt-wing or a tilt-rotor could be viable homebuilt projects, with a lot of ifs, not excluding somebody willing to design and built controllable pitch propellers with flapping and (probably) lead-lag hinges, either real ones or virtual ones (hingeless rotors have a soft-in-bending section in place of mechanical hinge). (Check out the VTOL Wheel for more fun homebuilding ideas; I rather like this one: 40.jpg ). Once one leaves out helicopters and compound helicopters, VTOL becomes hard, and for many of them, I'd want to have a zero-zero ejection seat, not just a ballistic parachute.

    Neither the tilt-wing nor tilt-rotor configuration is particularly easy, and both have disadvantages. I suspect (which means that I've not done a full-blown analysis) that the structural issues of a tilt-rotor are easier (for one thing, the wing doesn't need to move) but the aerodynamic ones of the tilt-wing are easier; it ends up being a trade study. Bell Helicopter had a lot of experience with tilt-rotors, so the V-22 was a tilt-rotor; had Hiller or LTV been major players, the JVX may have been a tilt-wing.

    Bluntly, I would not trust my life in any kind of tail-sitter, especially one powered by a piston engine. Give me a robust, well-proven gas turbine engine any day!
     
  2. Apr 30, 2016 #102

    RPM314

    RPM314

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    There's a class of aircraft in RC called a "hotliner", which is basically what happens when you take a competition sailplane and put a motor on it more typically found on pylon racers, with a folding prop. They're built for energy retention at high speeds, vertical climbouts, etc. I highly recommend Youtubing it.

    I know of course that there are power loading limits as you scale up, but I wonder how far you could get at general aviation scale, using the peculiarity that composite wings get lighter as AR goes up. Maybe a 2 stroke to get in as much HP as possible, and easier starts/stops?
     
  3. May 18, 2016 #103

    delta

    delta

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    This one stems from pedal powered crafts I've seen turning a very large slow turning prop. Decavitator and Aug. 23, 1977: Pedal-Powered Gossamer Condor Flies Into Record Books | WIRED I figure a 20hp Briggs with a massive reduction would keep it in the air longer than I could. An electric motor on the rear wheels for ground operation would get me to a restaurant or service station. If I could keep the weight down, I'm sure the top speed would not exceed part 103. Using bicycle wheels instead of motorcycle wheels might help it be street legal but a reverse trike configuration would be easy enough. Air cylinder/shocks, would adjust the ground angle of attack to facilitate take off or hugging the road. The thing would be so quiet the park service might not even hear you when you buzz the Grand Canyon.
     

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  4. May 24, 2016 #104

    delta

    delta

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    I amuse myself sometimes...
     

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  5. May 27, 2016 #105

    Tiger Tim

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    This one comes from an older sketchbook but I don't think I've posted it here before. The idea started with the thought of jazzing up the basic concept of the Affordaplane and one thing led to another, finally settling on the Afforda-Stang:
    [​IMG]
    Don't dig too deep into it, it's only a concept.
     
  6. May 27, 2016 #106

    Floydr92

    Floydr92

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    Nice sketching skills, wish i could do that. I can do good engineering drawings, but i find sketching difficult. Frustrating with so many 'napkin sketches' in my head. Haha. So, a napkin sketch for me is usually a computer rendering of some kind. Usually x-plane comes first.
     
  7. May 28, 2016 #107

    bifft

    bifft

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    Since this thread is still alive, thought of another impractical one. "The ellipse" Elliptical wing, with elliptical polyhedral. Elliptical full flying ruddervators. Would be way too hard to build, and how would you hinge any control surfaces on the wing? Would look kinda pretty.

    ellipse.jpg
     
  8. May 28, 2016 #108

    delta

    delta

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    A ring wing would be nice structurally and aerodynamically (maybe), but talk about a nightmare to build...
     

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  9. May 28, 2016 #109

    Tiger Tim

    Tiger Tim

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    Thanks Floyd, that's the result of spendingyears doodling. I always found it was too hard to pull out a laptop and design in X-plane during math class...
     
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  10. May 28, 2016 #110

    Twodeaddogs

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    @delta, they look like aircraft from Dasterdly and Muttley:gig:
     
  11. May 29, 2016 #111

    deskpilot

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    I've often wondered if this ring wing ever flew
    round-wing ultralight.jpg
     
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  12. May 29, 2016 #112

    delta

    delta

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    I saw that one at Oshkosh I believe in 2004. I didn't see it fly and haven't heard a word about it since. I didn't look real close at the time, but I'm also curious now how he hinged the curved control surfaces. The F4U Corsair flap system may contain some ideas in that regard, but it's probably not very simple or light.
     
  13. May 29, 2016 #113

    Swampyankee

    Swampyankee

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    I've seen some proposals for ring-wing airliners, but, like a lot of these designs, there are a lot of practical problems, including where to put things like landing gear and fuel.
     
  14. May 29, 2016 #114

    delta

    delta

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    Here's another one from my file of dreams...
     

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  15. May 30, 2016 #115

    deskpilot

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    Delta, I like your style. What cad program are you using?
     
  16. Jun 1, 2016 #116

    delta

    delta

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    Thanks Doug. It's all Rhino's fault. I got a students edition quite awhile back off ebay and it's been way to much fun.
     
  17. Jun 2, 2016 #117

    Giggi

    Giggi

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    Have you ever modeled something with a straight line in it? :gig:
     
  18. Jun 2, 2016 #118

    delta

    delta

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    Most of the RC models I've made were straight as an arrow, because they were made with CF arrows and golf club shafts.:gig:
     

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  19. Jul 20, 2016 #119

    delta

    delta

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    The "What replica warbird would you like to see" poll didn't allow the p-38 because it had two engines... not fair... I would love to see a reasonable representation of a p-38 in the works. The configuration is sound, and with a couple of turbocharged vw's it'd scoot pretty good at altitude.
    I had to add a couple of delta delta wings just for drill.
     

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  20. Jul 20, 2016 #120

    BJC

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    IIRC, it had control surfaces only on the strut/wing that supported the back half of the ring-shaped wing.


    BJC
     

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