Whats the purpose of a larger flap on the outside wing...would it be the same for equal length wings and longer inside wings.if you have equal length wings the flaps would be the same length if its a longer inside wing the inside flap would be longer than the outside flap.you could make the flap narrower to get the same effect

 The outboard wing carries the tip weight. If you have a lot of weight onboard, it may tend to cause the model to drop that wing in a corner. A bigger flap will help keep the wing up. Some guys start out with even flaps and then add a tab to the flap if needed. Some just make the flap a bit wider out at the tip end and try to blend it in to the wing shape. Been done a long time.
  Type at you later,
  Dan McEntee

Quote from: Dan McEntee on May 04, 2026, 09:22:43 AMThe outboard wing carries the tip weight. If you have a lot of weight onboard, it may tend to cause the model to drop that wing in a corner. A bigger flap will help keep the wing up. Some guys start out with even flaps and then add a tab to the flap if needed. Some just make the flap a bit wider out at the tip end and try to blend it in to the wing shape. Been done a long time.
  Type at you later,
  Dan McEntee

So if you had a 1 inch longer inner wing you would need a wider outer flap

Quote from: doug coursey on May 04, 2026, 10:23:04 AMSo if you had a 1 inch longer inner wing you would need a wider outer flap

   Not necessarily. The reason for tab is to control the lateral CP shift, you determine it by experiment. "Equal-span wings" are not really a thing since the 80's.   The velocity gradient is very real and not "fixed" by naive sorts of ideas like equal span. All it does is wind you up with 3 ounces of tipweight, which is just dead weight.

    The extra span on the inboard would give more *inboard* flap if you didn't do something to even it out, so evening out the area would require a wider outboard flap in any case. How much more is debatable, that's why you have to experiment with the tab.

   But I think there is an effect beyond that, however. Exactly why is a matter for debate, my opinion after experimenting is that while you are adjusting the wing to put the CP in the middle, you aren't doing the same with the stabilizer - which also has a velocity gradient from side to side. My next airplane will have about 1 1/4" asymmetry in the wing, and about 1/2 in the tail, and will start with roughly similar inboard and outboard flap area.

    Brett

Quote from: doug coursey on May 04, 2026, 10:23:04 AMSo if you had a 1 inch longer inner wing you would need a wider outer flap

   Yeah, possibly. Test flying and observation tells the tale. Notice most modern designs don't have much or hardly any offset? The theory is that the outboard wing flies farther and faster than the inboard wing, and thus should be making more lift, so in the old days, they made the inboard wing longer to counter that, plus hold up the weight of lines and such on that side. I think the All American Senior had 2 or 3 inches of offset/asymmetry? George Aldrich's '52 Nobler had a lot more asymmetry that the green box version did, almost 2 inches I think. If you have and or can find one of the Tom Morris PAMPA Old Time and Classic Design books, flip through there and you'll see a lot of variation. Modern power plans seem to be  one of the thing that helped make get wings more even on each side, and models just look better also.
  Type at you later,
  Dan McEntee