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Thread: Wittman Wingtips

  1. #1
    ironnerd's Avatar
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    Goggles Wittman Wingtips

    I find the Tailwind and Buttercup to be fascinating aircraft. But I always wonder about the effectiveness of the Trapezoidal Wing Tips. I have read that Steve did a test flight with just one tip installed, and that the wing with the tip rose first and required aileron input to counter. But that could be attributed to the additional span. So I'm wondering about their effectiveness. I don't think Mr. Wittman would ever keep something that made the plane (any plane) slower, but not sure how he felt about handling.

    Have any forum members flown a Tailwind without and with the tips and noted the performance and/or flight control changes?

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    John P. Adams
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  2. #2
    Airmutt's Avatar
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    All of his designs were about speed. His wingtip design was probably meant to improve cruise performance at altitude. Not sure why he picked the triangular shape but at the end of the day, the reduction in induced drag due to the span increase is most likely greater than the increased drag of wetted area of the extension. That’s my opinion and I’m sticking with it.
    Dave Shaw
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  3. #3
    planecrazzzy's Avatar
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    Not only did he change the Wing tips...
    The Buttercup Empenage was different...rounded.
    The Tailwind has the Trapezoid shape also... less drag
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    I see modern Fighter jets with this style too.
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    I changed my Buttercup Tail... I kept the same Square inches ( or more )

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    Gotta Fly...
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  4. #4
    Airmutt's Avatar
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    Looks good! Nice workmanship.
    John Monnett offered a design option for his Sonerai using straight leading and trailing edges as a time saver. To my knowledge it made no observable difference in performance. I also remember seeing a pic of one of the factory planes with Wittman style wingtips (1980s??) but it was never adopted. I don’t know why.
    Dave Shaw
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  5. #5
    ironnerd's Avatar
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    Quote Originally Posted by planecrazzzy View Post
    Not only did he change the Wing tips...
    The Buttercup Empenage was different...rounded.
    The Tailwind has the Trapezoid shape also... less drag
    .
    I see modern Fighter jets with this style too.
    .
    I changed my Buttercup Tail... I kept the same Square inches ( or more )

    .
    Gotta Fly...
    I do like Wittman's designs. Innovative, bare-bones, and efficient. Almost like they were designed by a racer Of the Buttercup, Wittman once said it was the only plane he designed that went faster than he thought it would.

    FWIW @planecrazzzy, I do prefer the sharp, trapezoid tail on your BC. Are the tail feathers flat or airfoil?

    I read an article that stated the wingtips reduce stall speed and increase cruise (at something like 9,000').

    From what I gather the Tailwinds fly a like the AA-1A I am accustomed to. When I look at the differences between the Tailwind and Buttercup, I do lean more towards the Buttercup. From what I have read the BC has a shorter TO distance then the Tailwind. Since I like to FLY as opposed to go fast on the ground, that suits me quite well. The AA-1 takes a month of Sundays to get into the air.

    Of course, someone took Wittman a step further [LINK]
    Last edited by ironnerd; 12-18-2020 at 10:47 AM.
    John P. Adams
    EAA 1379403
    Team Hi-Max (in process)
    If it flies and puts a smile on your face, it's the best plane in the world.

  6. #6
    planecrazzzy's Avatar
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    Take the shot

    My Horizontal Stabilizers have an inverted Airfoil... Normal it's symmetrical.
    In this picture , Only the top has fabric , you can see the slight airfoil I added.
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    I'm doing what I can for STOL

    They are set in the neutral position for first flight.
    Other holes are in place to lower the front of the HS leading edge if it needs it.
    .
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    Here's a picture of an F-22

    Trapezoids all over this thing .
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    Gotta Fly...
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    Last edited by planecrazzzy; 12-19-2020 at 03:24 AM.

  7. #7
    ironnerd's Avatar
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    I built F-22s for a while. Nice plane, but a little expensive. Most of the trapezoids are for stealth (look at how many parallel leading edges there are on the thing).

    But... Trapezoidal surfaces are also all over the P-51 (and Tailwind ), so you may be on to something. Besides, Steve liked to Simplicate when he could, and a trapezoid is easier to fabricate than a curved stabilizer.

    I like the airfoil empennage. The Bearhawks have that as well to help provide more control authority from the same square footage., or conversely to get the same authority from less sq footage (and therefore a bit less drag).
    Last edited by ironnerd; 12-20-2020 at 11:00 AM.
    John P. Adams
    EAA 1379403
    Team Hi-Max (in process)
    If it flies and puts a smile on your face, it's the best plane in the world.

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