Wingtip shape (rounded, squared)

Discussion in 'Technical' started by gjs238, Feb 11, 2011.

  1. gjs238

    gjs238 Well-Known Member

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    What are the advantages and disadvantages of the different wingtip shapes?
    Why did some designs choose one over the other?

    Thanks
     
  2. drgondog

    drgondog Well-Known Member

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    There existed a perception that aerodynamically a rounded wingtip lessened the intensity of the vortex at the wingtip. Although this concept is true, it is negligible in in subsonic flow.

    At the end of the day, the taper ratio is more important - primarily for low speed roll control/delay tip stalls.
     
  3. Grampa

    Grampa Member

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    Is that the reason why Messerschmitt chosed to build the Me 109 F and later version whit rounded wingtip instead of the old square version?
     

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  4. davebender

    davebender Well-Known Member

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    The Me-109F and Me-109G were about 50mph faster. Perhaps that is a factor.
     
  5. drgondog

    drgondog Well-Known Member

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    It is hard to say how much contribution to Reducing tip vortex, and thereby mitigating induced drag, the rounded wing tip contributed. Horner for example estimates that the rounded tip effectively decreased aspect ratio by 2% but I can't (yet) see a discussion on corresponding effect of a 'square' tip.

    Willy must have seen a benefit because the rounded tip should be a little more expensive. Having said this you have to think that the empirical results were not conclusive as neither the Mustang of the HellCat, etc had rounded wingtips in any version.

    The increase in speed from E to F/G was a lot more about Hp than the extremely small possible contribution to reduced induced drag by the wing tip geometry. At max speed the Drag is overwhelmingly due to Parasite Drag than Drag due to lift - as the AoA and corresponding CL is at a minimum at max speed.
     
  6. davparlr

    davparlr Well-Known Member

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    I suspect that any advantages of rounded wing tips disappears with increased airspeed which would imply it is part of induced drag. It appears that very few, if any, unlimited racers have rounded wing tips where every mph is a valuable asset. Like spinners, huge increases in hp makes any advantages negligible.
     
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