Rutan Ski-gull

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by lear999wa, Mar 31, 2013.

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  1. Jul 24, 2015 #121

    rv6ejguy

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    The Ski-Gull is not really typical of your average light aircraft- folding, higher aspect ratio wing and a very large fuel fraction compared to most. Rutan has a lot of real world experience with these design compromises on his two round the world designs and he's stated this aircraft must be robust to take a bit of pounding. Probably has his reasons for struts.
     
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  2. Jul 24, 2015 #122

    jetblackaircraft

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    It looks to me from the photos that the reason for the struts is that his wing is super high above the cabin to get it away from the water and clear the propeller. If he didn't have a strutted wing he'd be looking at a seriously heavy pylon to attach the fuselage to the wing. Look at the front view, it's a really thin structure as it is. If he didn't have support from the struts he'd have a massive, beefy structure that would add weight and unless he tried to keep it thin, also drag.
     
  3. Jul 25, 2015 #123

    autoreply

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    Pylon loads (unstrutted) are tiny; simply do the math yourself or look at the attachment points of a sailplane and compare to the spar.
    Pylon can be much thinner as the main spar. With high AR and high wing mass, yaw loads are the biggest issue. Struts don't do anything there...
     
  4. Jul 25, 2015 #124

    Kiwi303

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    I notice the wing tips are swept, I would have expected epileptic wings for nest L/D and ratio, sort of like the Spitfires, but stretched. That is what I have seen on most of the gliders I have been around.

    Is this a design element of being a MOTORglider vs a straight glider?
     
  5. Jul 30, 2015 #125

    KevinThorp

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    Rutan likes to hot-wire wing cores from foam blocks. You fasten airfoil profiles to both ends and "trace" around them with the hot wire. Using this method you can create straight or tapered wings, but not elliptical. A 2 part straight/tapered wing approximates an ellipse, but is much simpler to construct.

    Years ago I was disappointed to hear Burt had given up designing small aircraft for the GA market. This new plane is pretty exciting. Can't wait to see it fly.
     
  6. Jul 31, 2015 #126

    CutieDarkFae

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    CNC machines are getting cheaper and more available every year. You can get your cores CNC'd now easily, so I don't see how ellipses aren't possible with modern tech.

    I agree that the plane is exciting, but I can wait to see it fly, I have no choice :(
     
  7. Jul 31, 2015 #127

    H.Evan'sRV7A

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    As I understood him at the PADA presentation, the strut were needed at least in part because the wings fold.
     
  8. Jul 31, 2015 #128

    Jay Kempf

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    The gain in efficiency between a triple taper wing and an elliptical wing is not even measurable in the real world. Double tapers can be close to optimal structurally and aerodynamically and that with a large portion of the span with no taper at all.
     
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  9. Jul 31, 2015 #129

    Riggerrob

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    Those swept wing tips are the current fashion for Formula One and Sportsman class racers at the Reno Air Racers. We have also seen similar swept wing tips on recently-desigend competition sailplanes. Scaled Composites has long had the tools to cut elliptical wings since they have been using CNC cutters since at least 1993.
     
  10. Aug 6, 2015 #130

    harrisonaero

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  11. Nov 4, 2015 #131

    harrisonaero

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    Here's an update on SkiGull design progress...

    Rutan
     
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  12. Nov 4, 2015 #132

    Topaz

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    Thanks very much for posting that. Interesting news. One of the things I like about Rutan is that he doesn't expect perfection on the first go, and is open to making changes based on actual tests. Not as risk-averse as we, as a society, seem to have become in general.
     
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  13. Nov 10, 2015 #133

    henryk

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  14. Nov 24, 2015 #134

    harrisonaero

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    First flight of the SkiGull today in Coeur d'Alene, ID. Great flight with very nice handling qualities- going to be quite a plane.

    Couple of my pics from from the chase plane.

    Joa_HarrisonAero_SkiGull_1.jpg Joa_HarrisonAero_SkiGull_2.jpg
     
  15. Nov 24, 2015 #135

    Jay Kempf

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    AWESOME!

    Was the first flight from and to water?
     
  16. Nov 24, 2015 #136

    henryk

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  17. Nov 24, 2015 #137

    berridos

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    Did he match the expected cruise speed?
     
  18. Nov 24, 2015 #138

    Kingfisher

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    I agree, yours is quite similar. I was also reminded of the Centaur/Gull aircraft, except these guys have been tinkering around with the concept for a long time, while Rutan got his off the ground already.
    17700.gif.jpeg
     
  19. Nov 24, 2015 #139

    rv6ejguy

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    Congrats Joa! Nice to see it flying after all the work and testing. Did you end up with an engine/ EFI from Edge Performance?
     
  20. Nov 24, 2015 #140

    Victor Bravo

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    What strikes me about the photos of the pilot sitting in the cockpit, and the group photo of everyone standing in front of it.... is how small the airplane is. I had wrapped my head around the idea that it was a larger aircraft. Looks like the cockpit is about the size of a Long-EZ.

    It sure looks cool.
     
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