hotrod180
FRIEND
Port Townsend, WA
....Another common misunderstanding is "the only relationship that matters is that between the but rib and outer aileron bay rib so why bother to level the fuselage". Fundamental to rigging is the leveling of the aircraft at the fuselage horizontal reference. Rigging washout in the level position compensates for any variation in wing incidence that can occur, especially in older airframes....
My thought is that when rigging an airplane, you should try hard to get everything exactly right.
Whether or not you can, who knows?
My joke is that I strive for perfection but hope to at least achieve mediocrity.
What if the butt rib angle of incidence is off even when the fuselage is correctly levelled?
My impression is that adding washout to the wing is to insure that the butt end stalls before the outboard end,
thus maintaining some aileron effectiveness right down into the stall.
So IMHO getting the difference in AOA between the butt rib and the aileron rib is more important that the AOA difference between the aileron rib and the fuselage.