Short question: EQUAL FLAPS?

[Claudio Chacon]

Hello guys,
There's a topic I'm still confused with:
When you have a wing with equal span panels, the outboard flap area should be:

- Equal to the inboard flap?
- Larger than the inboard flap?
- Smaller than the inboard flap?

Help!
Thanks,
Claudio.

[Randy Powell]

Claudio,

I used equal span panels with equal flaps for years. Takes more tip weight. Recently I've moved to an asymmetrical wing (about 5/8" for the span I'm using) and equal flap area. Sometimes this is accomplished by making the flaps the same span but increasing the tip chord and sometimes, as with the current plane I'm building, the flaps are exactly the same and I just adjust at the wing tip. In either case, it's important to balance the lift generated by the flaps.

Or you can go all weird like Howard Rush and play with movable tabs.   

[Claudio Chacon]

Thanks Randy,
The reason you now changed for an asymmetrical wing was to save the extra tip weight needed in a symmetrical one?
Other?

Cheers,
Claudio.

[Randy Powell]

Claudio,

Partly. Of course, the inboard wing travels a bit slower than the outboard and benefits from a little more area. I tried making the outboard wing slightly large, but never managed to get the thing to turn flat. The last couple of planes I've gone to equal flap areas and it's made trimming a bit easier.

Nothing wrong with equal span wings and flaps, but I felt that the additional weight needed to keep the outboard wing from wanting to roll in was causing some problems with hinging (at least for the planes I built). It's just easier to trim the way I'm doing it now. Takes some of the elements out of the equation.