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Thread: Advantages of tapered wings

  1. #1
    Registered User handprop's Avatar
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    Advantages of tapered wings

    I was wondering if you folks could enlighten me on the subject of tapered wings. I hope you can all excuse me for probably being a little ignorant when it comes to design but building a tapered wing for a homebuilt to me seems like it lacks any real benefit. Part of my ignorance stems from my lack to fully understand some of the charts and what not. Iíve been spending each night trying to work through the math of airfoils and wing plan forms but it seems to be coming a little slow.

    As some of you know I have decided to build my own version of a Tipsy Nipper and with just the basic reference drawing done the wing is the next area of study. The original wings are tapered and from what I have learned so far the airplane is quite wonderful for aerobatics. Some searches online have revealed that many aerobatic monoplanes use some sort of taper in the wing.

    On my version Iíve been thinking about letting aerobatics play second fiddle to everything else on the plane. In an ideal world I would like the airplane to be a good all around airplane that handles fairly well and is capable of simple aerobatics.

    When researching tapered wing plan forms I just canít seem to figure out why people want to build taper into wings. Every bit of information I have found has made me conclude that the typical Hershey bar wings actually make for a great wing. Based on my reading here are the only benefits I have found so far for using a tapered wing for a homebuilt.

    1. Lower drag
    Helps with overall speed
    Better lift distribution

    2. Improved Maneuverability

    3. Structurally
    More structurally efficient with root.
    Lighter overall structure

    From my perspective this seems to be great but upon reading, looking and studying a host of airplanes with Hershey bar wings it seems that normal Hershey bar wings can very well have low enough drag, great maneuverability, and structurally they can be built just as strong. Now, I realize some of the larger any faster airplanes out there may have a strong case to support the tapered wing plan form but for basic moderate speed homebuilt I have found some real problems with tapered wings. Iíll explain what I have discovered.

    Working backwards here Iíll first talk about my thoughts on weight. I realize everyone in the realm of aviation works to avoid weight but realistically it seems to me that an airplane must have a wing and any wing regardless of type weighs a certain amount thatís simply unavoidable. So right off the bat a designer knows that if a Hershey bar type wing weighs ď X ď than a tapered wing should be less than ď X ď. OK, from my calculations the difference in weight on a tapered wing canít really amount to much, especially when you consider the extra time involved in creating a taper vs a simple rectangle. In order to create a tapered wing the wing has to be larger ( scale effect ) thus creating an increase in weight, cancelling out the overall difference.

    The second point is structurally. Spending time studying airplanes made in the last 30 or so years makes me wonder whatís wrong structurally with a rectangular wing plan form. I am really having a hard time buying into the fact that the difference structurally between the two wings is worth talking about.

    On the topic of maneuverability airplanes like the RV series or any type of airplane in that class has pretty darn good maneuverability all things considered, and all have straight wings.

    I can understand why designers like the tapered wing as it concerns lift distribution but at the same time along with lift distribution come the fact that tip stall also comes with the territory, and since ailerons just so happen to be mounted on the tips of the wings they also can loose effectiveness and potentially the airplane can end up in a spin.

    On the topic of speed, again I fail to see any advantage here because speed is relative to so many other factors that the overall percentage of benefit that tapered wings have with speed is rather small.

    Could anyone tell me if Iím on to something here, I have tons more reading to do on this subject so I could be way off base in my thinking but so far I see nothing wrong with a basic rectangular wing. Mike
    Where am I? ó Charles Lindbergh, upon arrival in Paris.

  2. #2
    Formerly Unknown Target Inverted Vantage's Avatar
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    Re: Advantages of tapered wings

    As far as I understand it, one of the advantages to a tapered wing, besides sharper looks, is that the "ideal" form of lift distribution along the wing's planform is that of an ellipse; with a tapered wing, the lift distribution is much closer to this ideal shape.

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    Registered User bmcj's Avatar
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    Re: Advantages of tapered wings

    Hershey bar wings surprisingly get pretty close to the ideal lift distribution on their own and can be taylored with washout and airfoil selection. Tapered can benefit you structurally in that the root and the airfoil at the root are larger and give you more "beef" where the bending loads are highest. Also, with less area toward the tips, most of the lift is inboard, which further reduces bending loads at the root. On the other hand, tapered are more work to build, and in cases of extreme taper, I suspect that the small, thin airfoil at the tip might suffer some aerodynamic or tip stall issues (Orion would better be able to answer this point). Also, tapers usually mean that the ailerons are not perpendicular to the airflow (for what that's worth).

    For simplicity, I would go with the straight wing... easier to build and good basic aerodynamic qualities.

    Bruce

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    Registered User handprop's Avatar
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    Re: Advantages of tapered wings

    Thanks, I thought I was having trouble mathematically. In the world of tradeoffs A homebuilt with a cruise of about 120-130 mph seems to warrant a straight wing. For the life of me I calculate the benefits of taperd wings on a homebuilt of this type are so small that it's just not worth it. Like I said earlier Bruce, when a fella spends time looking at all the great airplanes out there most of them have hershey bar wings. Thanks for your response. Mike
    Where am I? ó Charles Lindbergh, upon arrival in Paris.

  5. #5
    Registered User handprop's Avatar
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    Re: Advantages of tapered wings

    Unknown Target, as far as "ideal" form of lift distribution, I have read and studied that, but my math seems to indicate rectangular wings are not that far from being "ideal". What confuses me is why so many people try to put all kinds of taper and sweep on wings when according to a little math, I keep coming up with the fact that a hershey bar wing is actually ideal on normal sport type airplanes. The only thing I can think of as to why some designers put wild looking wings on airplanes is because the very design must be cutting edge and almost requires such an endeavour. I don't know, I guess I'm still a little confused. Back to the books. Mike
    Where am I? ó Charles Lindbergh, upon arrival in Paris.

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    Registered User Mac790's Avatar
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    Re: Advantages of tapered wings

    Handprop please use search options, we were discussing about wings shape many times.
    You will find some info about tapered wigs shape in those threads.
    http://www.homebuiltairplanes.com/fo...selection.html
    http://www.homebuiltairplanes.com/fo...cal-wings.html

    Seb
    Amor Patriae Nostra Lex

    "Time, training, training, training and more training is the key to any success."
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    Registered User BBerson's Avatar
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    Re: Advantages of tapered wings

    The late John Thorp wrote an article for EAA "Tapered wings are for birds... and very large airplanes". Might be in the EAA archives.
    BB

    I vote for no taper.

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    Registered User handprop's Avatar
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    Re: Advantages of tapered wings

    mac790, thanks, I have searched and read through past threads but The questions I have are a little different. One of the problems I was having was trusting my math because of lack of experience. I keep coming up with more negatives (IMO) for the tapered wing than a standard hershey bar set-up. I think I understand why people try to build tapered wings but on the same hand companies like Vans and Sonex use a standard wing with great results.

    If Sonex replaced the hershey wing with a tapered one I'm willing to bet the advantages would be tiny compared to the simplicity of just building a simple wing that works great. Thanks again, Mike
    Where am I? ó Charles Lindbergh, upon arrival in Paris.

  9. #9
    Registered User handprop's Avatar
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    Re: Advantages of tapered wings

    BB, just found and read the article. Thats just what I was thinking. Hershey wings for this cat. Thanks for the tip, Mike
    Where am I? ó Charles Lindbergh, upon arrival in Paris.

  10. #10
    Registered User handprop's Avatar
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    Re: Advantages of tapered wings

    Flying Magazine - Rectangular Wings

    Here is a link to an article on tapered vs hershey wings if anyone is interested. Mike
    Where am I? ó Charles Lindbergh, upon arrival in Paris.

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    Super Moderator orion's Avatar
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    Re: Advantages of tapered wings

    Quote Originally Posted by handprop View Post
    If Sonex replaced the hershey wing with a tapered one I'm willing to bet the advantages would be tiny compared to the simplicity of just building a simple wing that works great.
    Your research and conclusions are quite good, a fact borne out not only in the math but also by the many well flying examples. One of the difficulties when considering the various aspects of airplane design is that many in the field will tend to get locked in on one aspect of the design and try to "optimize" that aspect to death, regardless of the fact that for most GA applications, that optimization will rarely if ever be realized by the airplane or for that matter, even be measurable.

    We all try to optimize for a particular goal but it's important to also recognize the limitation of that work, as well as the possible negative aspects that might arise.

    In short, there is absolutely nothing wrong with Hershey bar wings and for the vast majority of GA product lines, using them may cost you just a bit in aesthetics, but rarely in anything else.
    "To live is to learn; to learn is to live" (author unknown)

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    Registered User handprop's Avatar
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    Re: Advantages of tapered wings

    Orion, Thanks for you thoughts on this matter. I always look forward to your wisdom. Engineering is something that can be a little tough for me but I sure try hard, it just takes me a little longer than most, but hey I'm having fun so what the heck.

    I always tend to start out looking at any problem with a bit of common sense. Than try to ask myself " Is there any problem in the first place" I'm real happy the math I'm doing works. But then I kept doubting myself because it seems so many people strive for fancy wings and such. But then I sit back and re-evaluate whats been done in the past and keep saying to myself the good old wings are really a good compromise all things considered. Again, thanks. Hershey bar wing it is.

    Now I'm off to start reading my "Theory of wing sections" book I bought. This really aught to be interesting for a plumber. I had my four wisdom teeth pulled out Friday morning so I'm stuck on my couch this weekend with my laptop, pile of books, and some ice cream. What could be better? Mike
    Where am I? ó Charles Lindbergh, upon arrival in Paris.

  13. #13
    Super Moderator orion's Avatar
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    Re: Advantages of tapered wings

    All four? - Ouch.

    And if you add a bit of Oxycontin or similar to your current situation, those design ideas might get really out of this world!
    "To live is to learn; to learn is to live" (author unknown)

  14. #14
    Registered User handprop's Avatar
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    Re: Advantages of tapered wings

    And here I thought my ideas were already wacky! Ha, man when the Vicodin kicks in the "Theory of wing sections" becomes almost funny. Mike
    Where am I? ó Charles Lindbergh, upon arrival in Paris.

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    Registered User BBerson's Avatar
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    Re: Advantages of tapered wings

    The real question to ask... what about a wing that is wider at the tip than the fuselage?
    Reverse taper. Anybody done that? It could have some of the good points promised from forward sweep (less flow toward tip) without any of the downside.
    BB
    Last edited by BBerson; May 9th, 2009 at 05:11 PM. Reason: spelling

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