ORIGINAL: Stickbuilder
Okay, let's say that you have a biplane with both top and bottom wings (Clark-Y) set at zero (to the datum line). If built per instructions the tail will have 3 degrees positive incidence. When seen flying at cruise throttle, it appears to be dragging it's behind, while the full scale flys much as does the cub or the DC-3 (tail high). Would you say that it presents too much wing to the airstream?
Bill, AMA 4720
WACO Brotherhood #1
I'd say it drags it's behind at cruise.
As for why, there could be a bunch of reasons.
Going back to the paragraphs that describe how the wing's AOI is figured from it's AOA.............. and expanding that in light of your observed behavior from that biplane (let me guess, it's a WACO, right)...................
You've observed the final product of wing and stab rigging in cruise.
You've seen the fuselage is not level.
The first and most powerful thing flying in that assemblage of parts is the wing(s). It's going to find it's required AOA and DO IT. And all else is going along for the ride. Those two wings have found where they wish to be and they're happy. They will do that no matter what you do with all the rest. They will be influenced by other things, like the extra induced drag from a fuselage that's cocked down in back, but take that away, and those two wings won't shift their pitch enough that you'd be able to see the difference in AOA from the ground.
So the first thing I'd figure to fix was the AOI of the two wings. And I'd start by getting an accurate measurement of the wings relative to each other. And then see if I'm reading each of their AOIs correctly.
Would you say that it presents too much wing to the airstream?
It can't. The wings decide how much they want to "present" and do it. They assume whatever AOA is needed to carry whatever load that airplane is at whatever speed you've got the engine pulling with whatever load is coming from a CG that might be off or a tail that's being forced to "present too much wing" and is generating a bunch of excess induced drag.
I would WAG that the two wings are screwed up in decalage (to each other, not to the stab) and causing this problem. WACOs don't normally fly around looking like a waterskier.