ailerons that run from the tip to the root

[parrot pilot]

What are the advantages and disadvantages to ailerons that run from the tip to the root?
Also I was wondering if there is a typical amount of wing washout (in degrees) for a wing. It’s a large wing, a lot of lift. I understand that it would change depending on a lot of different factors, just looking for a ballpark idea for a Mud Duck 2 I’m building. Normally according to the instructions you just push down on the tips before attaching the struts, but I’m making a wing without struts. I guess I could just push down the same way, but the way I’m making them, that might be difficult.
Dan
I'm new at this, :o Please try to type in small words that I can understand!

[ADB2]

Wing washout is used to avoid tip stall, afaik. It does depend on a lot of variables (airfoil, wing loading, intended usage, etc), so I don't think there is a "typical" amount, each design has a recommended amount, found either by trial and error or estimated during the design phase and corrected after flight tests.
Running the ailerons all the way from tip to root is one way to increase control surface (hence control effectiveness). I guess the main disadvantage is exactly the fact that the aileron carries higher loads, so it requires more attention wrt to its mechanical properties. Also of course ailerons are more effective at the tips, so the part of the aileron nearer the root is less effective (and also suffers from being next to the fuselage wake); on the other hand it is nearer to the prop wake, so you get some roll control in slow flight (and hovers) for example. As before, it depends on the intended flight profile.

[Brandano]

There is an advantage in having the ailerons only in the outer portion of the wing. You can arrange the linkages or trim them in such a way that will give you some wing washout if the amount in the original design wasn't sufficient, or to reduce it if it was excessive. You can achieve the same twisting the wing (which could be difficult to do) or twisting the strip ailerons (which will be easier, but still harder than just acting on trims or linkages). It's better to have the flaps in the inboard portion, because this will increase the camber of the center portion of the wing and it is this section that will stall first. I think the best compromise would be to have conventional ailerons mixed with spoilers and conventional flaps mixed with ailerons, so that you can use them in opposite directions as crow brakes and synchronously as ailerons. That said, RC models already have impressive roll rates with normal ailerons, thanks to their low inertia compared to a full size plane.

[MudDuckAviation]

"...according to the instructions you just push down on the tips before attaching the struts, but I’m making a wing without struts. I guess I could just push down the same way, but the way I’m making them, that might be difficult."


Hey Dan,

Actually the instructions do not require you to add washout for the MkII anymore. You are referring to the wing building video which showed how to add washout. with the old style wing. In actuality, the old wing used a "Y" strut and the new one uses an "I" strut, which wouldn't hold in the washout anyway.

That is my fault, I really need to esit that video to note that is is the "old" style wing. I only have it posted for the purpose of giving potential customers the proof how fast and easy it is to build the plane, and I really need to make an updated one.

So for your one-piece wing, don't bother trying to add washout, it doesn't need it. If for any reason you feel it would benefit from it, refer to Brandano's response and add "up" aileron in the neutral trim postition if you were to keep the "barn door" ailerons. If you choose to go to full-length ailerons and want to add in washout later (I can't see you needing it) you can always "warp" your ailerons so the outboard sections are "warped" up a bit and that will also work (as long as you do both sides evenly). I have "warped" full length balsa ailerons on old planes that I couldn't get the entire wing to warp (by heating the covering while twisting the wing and letting it cool) but you probably can't warp FFF effectively, so this explanation might be fruitless, but it is good to know for built up models you may aquire ( I'm an auction junkie).

Greg

[parrot pilot]

Thanks all. I understand now, I'm sure with the duck, there would not be any benefit or need for washout. I did run the ailerons the length of the wings (I linked a video in another post here). With my duck, I'm looking for some nice relaxing flying. My design goals have changed since I decided to go with the Weed Eater engine. Weight is a little less of a concern since I'm not going electric and will I'll have more than enough power with the 31ccs. Still I think I'll come in around 8 pounds, not too bad for as strong as it's turning out.

I almost forgot, good to have you back Greg, Hope your feeling OK.
Dan