Bell shaped lift distribution

Discussion in 'Hydrodynamics and Aerodynamics' started by container, May 19, 2020 at 2:10 PM.

  1. DCockey
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    DCockey Senior Member

    An exception would be to use a symmetric foil section with no twist, and design the planform section to provide the desired spanwise load distribution. In that case the shape of the load distribution would be independent of the angle of attack. A disadvantage of that approach is the symmetric foil section will have higher drag than a section with optimized camber. Also the required planform shape may have drawbacks for structural and/or manufacturing reasons.
     
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  2. container
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    container Junior Member

    One would have to assume the ideal planform shape would be that of a soaring albatross or seagull? Obviously their wings are perfectly suited to bell shape load distribution so it makes sense. I am already using a gull wing shape for my elliptically loaded foils, I much prefer the feel of a 'cranked' wing over a traditional straight H/A foil.
     
  3. Doug Halsey
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    Doug Halsey Senior Member

    Maybe if your planform has to fold, flap, and encounter all the same mix of conditions that the birds do.

    Otherwise, maybe not.
     
  4. patzefran
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    patzefran patzefran

    It was just a reference to Jesus !
     
  5. container
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    container Junior Member

    I disagree, gull wings feel amazing to fly compared to straight or anhedral wings. I have no numbers or data to back that up other than the fact I have used alot of different foils, production ones and my own designs, and in my opinion without a doubt the gull wing is the smoothest, most forgiving and most maneouverable to ride.
    Seagulls arent flapping or folding their wings when gliding or performing a diving turn, so i think its relevant. Hawks and eagles have to do the same flapping and folding but use a drastically different wing shape, must be something to do with flight characteristics
     

  6. Doug Halsey
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    Doug Halsey Senior Member

    It's not surprising that birds' wings would have evolved to provide the favorable qualities that you mention. However, I doubt if their lift distributions are perfectly bell-shaped, and I've got to believe that they would be shaped somewhat differently if they didn't have to fold or flap.
     
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