Rogallo wing question

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by cluttonfred, Feb 14, 2020.

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  1. Feb 14, 2020 #1

    cluttonfred

    cluttonfred

    cluttonfred

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    Does anyone have a good reference for the characteristics of a standard Rogallo wing that I could use to estimate the performance and power requirements of something like this? I am having a hard time finding information as basic as the effective lift coefficient of the wing as a whole. Thanks!

    leonardino 2.jpg
     
  2. Feb 14, 2020 #2

    BJC

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  3. Feb 14, 2020 #3

    flywheel1935

    flywheel1935

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    Many years ago (1983 ) I met up with Francis Rogallo at his home in Kitty Hawk. We were sort of 'pen-pals' and he helped me with fitting spoilers to a Klaus Hill Hummer
    that flew like pile of cr*p. Once we sorted out the "Tailerons" and made it a full 3 axis microlight, it flew half decently.
    Best I can offer is glide ration of his wing is about 4 to 1 ???
     
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  4. Feb 14, 2020 #4

    cluttonfred

    cluttonfred

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    Thanks, guys. I have been through most of the papers in BJC's link and most of them focus on L/D. I am looking for CL so I can get a handle on the surface area required for a given speed and weight, but haven't found anything so far. I am also musing and sketching on non-Rogallo but still low aspect ratio wings that could also suit this general arrangement: circular, Zimmerman, rhomboidal, etc.
     
  5. Feb 14, 2020 #5

    BJC

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  6. Feb 14, 2020 #6

    cluttonfred

    cluttonfred

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    Thanks, I'll check it out. I suspect that I will eventually end up with like the Weller ULI NG below (maybe with struts), but it's fun to explore options.

    weller uli ng.jpg
     
  7. Feb 15, 2020 #7

    Aesquire

    Aesquire

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    Eipper Flexi Floater, 19' leading edges & keel tube, 80 degrees nose angle.

    Page for the near identical Standard from LEAF.
    http://all-aero.com/index.php/compo...63-hang-glider-paraglider/17301-leaf-standard

    Here's the improved Flexi II, I had the 245 sq. Ft. Version.
    http://all-aero.com/index.php/63-hang-glider-paraglider/17045-eipper-formance-flexi-2

    6/1 is generous. At 1 pound per sq. Foot a 290 fpm sink rate was about right. Looks primitive, but I flew mine several flights over an hour, and 30 miles cross country.

    here's some nice planform drawings.
    https://everardcunion.com/hang-gliding-2/paintings/

    Hopefully you can guesstimate the c/l from the above numbers.

    However, I strongly discourage flying anything based on a Standard Rogallo unless they are experienced, and at a small training hill, for nostalgia. First practical mass produced hang glider doesn't mean it's safe. Not by any modern standards. Performance is like a Space Shuttle final approach but much slower. Aka a brick.

    The current tech version is... https://www.willswing.com/hang-gliders/falcon-4/ or https://www.willswing.com/alpha/

    which are easily capable of soaring, safer by orders of magnitude. HGMA testing ihttp://hgma.net and voluntary compliance. The faq may interest you.
     
  8. Feb 15, 2020 #8

    Aesquire

    Aesquire

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    To pick just one reason not to build a Standard Rogallo, the problem of "full luff dives" comes to mind. If you dive too steeply, and it may take a whip stall to get this far, the sail luffs, streams like a flag. This removes all stability from wing twist and reflex and is recoverable only by luck and a higher drag on the wing than the pilot. Maybe. Tie a weight to a rag and toss into the air. Looks like that.

    That got solved... And the list of subsequent problems and solutions is a years long saga that I lived through.
     
  9. Feb 15, 2020 #9

    jedi

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    Me to. But then I quit during the dangerous years. Went back when the "modern" hang glider was developed. But then paragliding took over the loss of control issue. Not to worry. Airplanes have LOC issues too.

    You all be carefull out there.
     
  10. Feb 15, 2020 #10

    BJC

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  11. Feb 15, 2020 #11

    cluttonfred

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    The appeal of the basic Rogallo is simplicity and the idea is that the added tail surfaces could be rigged to prevent luffing and allow recovery if it did happen. That could literally mean setting the horizontal tail and limiting the control throw such that you can pull up but only push forward a little to the lowest safe angle of attack. I would not want to try to fabricate a modern, high aspect ratio flexible wing as a homebuilder.
     
  12. Feb 15, 2020 #12

    Aesquire

    Aesquire

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    A fixed horizontal stabilizer was one of the solutions, a triangle of cloth and one additional short length of tubing, attached to the lower rear flying wires from the control bar to the rear of the keel tube. No need to limit control authority.

    Better yet, just buy a used post 1995 glider and build a framework to hold the engine. There are pictures and video here of an Eastern European design that would be easy to copy.

    The frame of even a modern glider is easy to make. Aluminum tubing & commercially available brackets and parts. Sixth gen often uses a carbon fiber cross spar more complex than just tubes, and Carbon fiber to replace aluminum parts at the competition/optional cost level.

    The sewing of the sail is a skilled job, tight tolerances for a sail maker, & the detail of the design fairly complex. More than I'd tackle tiday, and I built first, second, third & fourth generation Rogallos.

    Defined as... First generation, all fabric and suspension lines derived from the original Rogallo kites. Second generation, ridgid leading edges, keel, and cross bar, conical wing design, hang cage or triangle bar, wire or strut braced. Third generation, higher aspect ratio, battens/ribs in sail to control flutter & shape airfoil. Multiple variants including truncated tips for washout control, sail leech & roach, stability control & dive recovery with luff lines, leading edge sure bracing, and enlarged leading edge pockets to improve airflow. Fourth generation, raised keel pockets & floating cross spar, or bowsprit wiire bracing replacing cross spar. Fifth generation, buried cross spar in double surface sail, elimination of external leading edge wire bracing. Sixth generation, elimination of king post and upper wires, heavier internal dive recovery systems & reinforced cross spar to take negative G loading.

    Every commercial modern Flex wing glider is Fifth and Sixth gen. Afaik.
     
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  13. Feb 15, 2020 #13

    Bill-Higdon

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    The solution I was going to try was developed by Ryan for their Rogallo work it was a small canard surface above the wing with a positive angle of attack compared to the keel tube. I played with it on some kites,with out it they did a great plummet straight down once the air bubble escaped. With it they would pitched up nose & re-inflate the kite. Oh yes I had a deflation accident when I was flying, I was lucky I was real close to the ground just bruised & banged up.
     
  14. Feb 15, 2020 #14

    jedi

    jedi

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    Like this:

    https://en.wikipedia.org/wiki/Platz_glider

    [​IMG]
     
  15. Feb 15, 2020 #15

    Bill-Higdon

    Bill-Higdon

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    As a side note look ar Barry H (Hill) Palmer flew some early powered Rogallo aircraft. https://web.archive.org/web/20030417010117/http://members.aol.com/hiitec/kite/trike.html
     
  16. Feb 18, 2020 #16

    Sockmonkey

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    Like something sort of kite-shaped for a simple STOL plane?
     
  17. Feb 18, 2020 #17

    Aesquire

    Aesquire

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    On a classic conical Rogallo wing C/L = "some". ;)

    What's your proposed speed range? Pt. 103?

    If it's 35-100 mph, look at the low aspect ratio Trike wings.
    http://evolutiontrikes.com/wings/
    can you get a ballpark C/L from these specs?

    One blast from the past is the Bowsprit wings.
    https://everardcunion.files.wordpress.com/2010/05/upmsqito.jpg

    https://everardcunion.files.wordpre...awtingPlanView_SouthdownSailwingsSigma11m.jpg

    When the Primary Need is light weight, this tubing & cable structure is excellent. Drag, however, with all the cable bracing, goes up in a steep curve dominated by parasitic drag. With a 55 knot limit, one would be a good choice for reducing weight to accommodate a "24 up 4 Stroke" flying machine.

    If you want aerodynamic controls, extend the keel tube act to a horizontal stabilizer. You can treat the wing as a rigid wing. A basic landing gear, pilot & engine pod underneath, ( arranged as you see fit ) viola! Better would be an Atos composite D-tube cantilever wing. But not as light as a bowsprit wing. Drag/weight....

    At the low speed end, it's been proven on the Gossamer Condor and Gossamer Albatross.
     
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