Physics of washout in RC wings

We are looking at the affects that angle of attack has on turbulence in the aileron area for RC aircraft. Washout tends to help with this and I explain how it tends to combat tipstall.

[@kiks7veliz]

Finally an easy explanation!!! Thank you so much! I kind of had an idea, but with your visual explanation I can finally put images to "just words"

[@6Sally5]

THANK YOU!! I have not been able to find anyone who has satisfactorily explained what washout is. They throw the term around in conversation without thought. I have a sailplane that tip stalls like crazy and I get comments to just put some washout in the wings...with no explanation whatsoever. Now it makes sense.

[@Migueldeservantes]

I'm very grateful, you have really increase my knowledge in a way that can actually understand.

[@andpet55]

Thank you.

[@warrentodd4848]

Very informative and easy to understand. Thank-you!

[@sajjad3]

wonderfull, and appreciatable... getting good tips in RC field... very good way to make us understand... thanks indeed

[@Observ45er]

Not too bad in general, but it is better to point-out the following. Turbulance near the trailing edge indicates the wing is *already in stall*. Turbulance is not desired, nor expected anywhere on a good wing *out of stall*. A lowered aileron is effectively an increase in angle of attack (AOA) and increased lift for the aileron section of the wing and a raised aileron is an effective reduction in AOA and reduced lift. ... *Near stall*, not in stall and *before* the turbulance forms near the trailing edge, a lowered aileron effectively increases the AOA and can actually stall its section of the wing before the root, therefore dropping that tip. Also near stall, the opposite, raised aileron will reduce the effectice AOA, thus reduce turbulance, and take it out of stall, which will raise that tip rather than lowering it. This was called 'aileron reversal' in early aircraft before they figured this out. Washout was added to prevent it. .. The net effect is the same, but the causes are a little different than you explain. Cheers P.S. It also isn't actually the "longer path" over the top that reduces the pressure. It is because the air has no choice but to follow the convex curve (if it didn't, there'd be a vacuum there) . The so often (way too often) repeated and incorrect explanation of fast air creating low pressure and the air having to meet at the trailing edge is not the case. Upper air beats the lower air by a significant amount. Fast air does not create low pressure -- air moves from a higher pressure region to a lower pressure region because there is more pressure behind it than ahead; which is a net force forward (into the lower pressure region). Try this for understanding Bernoulli: How do wings work - Common misconception on lift His slides: drive.google.com/file/d/0B0JABuFvb_G_MkpBZHJmRGo3UkU/edit?usp=sharing Click the download Icon if you get only part of the slides.

[@jakedassan4117]

Great video and techniques for demonstrations

[@gluebox1]

One of the key features of the Extra 300 is that it's just as capable inverted as it is upright, so you would never put washout it. Instead you would add vortex generators (on both sides), which achieves same effect

[@icerinkdad]

Great info for a lifting airfoil on a plane that spends most of it's time upright. Wouldn't this make things worse upside down?

[@andpet55]

Good point. Washout is typical for regular flight but if you spend much time upside down you would want a symmetrical airfoil with no washout. This is the reason that the ailerons are so much larger on planes such as the 540 and 330s. They also extend much closer to the fuse than do the larger planes not intended for stunt flight.

[@Paulo_Paulistano]

Nice video very ease to understood! Have you heard about Coanda Efect?

[@andpet55]

thanks