washout (foam wings)

[crashbuilder]

Hi there,
Posted this in the "slope" section originally, perhaps this is a better place ......

I've got these ace wing cores here that were not cut with washout and I'm trying to figure out how to add some after the fact. The plane I'm building is a trainer and I don't want to be tip stalling etc. I'd appreciate it if you guys could take a look at this drawing and let me know if this solution will be aerodynamically effective.

[Ollie]

Your scheme for wash out gives both aerodynamic washout, by making the zero lift angle of attack more positive, and geometric washout. You won't need much because the taper ratio of your planform is moderate, not extreme.

[shaneyee]

You can actually build in the washout when you are covering or taping the wing. There is no need to cut the wing because the foam is soft and flexible without covering.

Shane

[billsmithjr]

dont cut into your foam wing .Ive found that you can add washout by sanding the leading edge some on the bottom at the root and transitioning to the top at the wing tips. Another trick -
when you glue on your balsa wing skin do the bottom first on a flat surface starting from the trailing edge and allow to dry and stiffin before doing top skin. This only works on tapered semetrical wings. because the wings thickness decreases at its center but remains constant at the trailing across its span holding it against a flat surface should induce wash out and the wing skin now becomes a stessed skin and holds this shape when dry.

[raptor22]

i've do it with the strapping tape when covering

--Alex

[airboss]

hey crash
you would have a lighter wing by building the washout into it
any of the methods previously described will work
you could quickly reform the wing using the hot iron method to straighten out bent foam wings
keep us updated on what you decide please
thanx
allen

[crashbuilder]

Thanks for all the input guys ... I appreciate it. I posted a similar thread in the slope forum and I was convinced that I should just give it a go “as is” Well being the lazy, ham fisted builder I am I just went ahead without the washout ... lets hope for the best. I’ve included a pic of the “finished” model. I say “finished” because since this pic was taken I’ve hacked off the nose and added an extra 1 1/2” in length to the model. Just wasn’t enough room in the fuse to get the required amount of lead it there ....... it’s not quite as attractive now I’ll post new pics soon and the results of the test glide .... let’s cross our fingers

[crashbuilder]

Thanks for all the input guys ... I appreciate it. I posted a similar thread in the slope forum and I was convinced that I should just give it a go “as is” Well being the lazy, ham fisted builder I am I just went ahead without the washout ... lets hope for the best. I’ve included a pic of the “finished” model. I say “finished” because since this pic was taken I’ve hacked off the nose and added an extra 1 1/2” in length to the model. Just wasn’t enough room in the fuse to get the required amount of lead it there ....... it’s not quite as attractive now I’ll post new pics soon and the results of the test glide .... let’s cross our fingers