Could someone please explain Stall, Washout, and incedance. I have been trying to figure these terms out for a while, and they are used so frequently and in different context, I am having trouble understaning them.. Thanks.

esanger, I'll try to give a brief non-tech answer.

Stall: commonly, the point when forward motion is slowed enough that the plane wants to fall out of the air. This point will vary with the same plane depending on how it is set up and the angle of the wing to flight path.

Washout: take a peace of paper and hold it up so you are looking at one end. Now imagine that the end furtherest from you is attached to the plane at the fuse. Now imagine that the left end of paper closest to you is the rear of the wingtip. Bend just the left end of the paper up. That would be washout. If you bend it down that would be wash in. The thinking behind this is the center of the wing would STALL first allowing the plane to kinda mush forward instead of STALLING at a wingtip causing the plane to drop to the side. The bad side is that when flying inverted you have just the opposite.

Incidence: If you were to draw a straight line down the side of the plane and compare the angle of the rear stab, wing and engine to it you would have the incidence. I use the rear stab as 0 degree. If the front of the wing is higher in relation to the line (and the rear of the wing lower) then it is said to have positive incidence. If the centerline of the engine is up at the prop end then it is said to have upthrust. If viewed from above it can also have right or left thrust.

Maybe by moving this back up to the top of the threads someone who has had more sleep than me will jump in with a better answer. Hope this helps.
Ed M.

bentgear gave good explanations, but I'm going to take a shot at it in English.

Stall - Your aircraft stopped flying and is now falling from the sky.

Washout - Wing tips are twisted so the leading edge is lower at the tip than at the center and trailing edge is higher than at the center. This makes the wingtips keep flying after the center of the wing has stalled and prevents your plane from flipping over on its back.

Incidence. Incidence is the angle at which your wing or stabilizer is mounted when viewed from the side. Zero = level. Positive numbers indicated the leading edge is higher than the trailing edge. Negative indicates the trailing edge is higher than the leading edge. Same goes for stabilizer.

SO TRUE......

esanger,

Stall is simply when your wing stops producing lift, or at least stops producing enough lift. This generally happens when the angle of attack gets too large, or when the airspeed gets too small.

Washout is more complicated. Usually, washout means reducing the angle of attack toward the tip of the wing, by building it with some downward twist toward the tip. There are other ways of getting an equivalent effect without actually having geometric twist. Generally, the goal is to cause the outboard part of the wing stall after the inboard part of the wing ( in other words, to avoid tipstall ).

Incidence is the angle of the wing ( or horizontal stabilizer ) to some reference line on the fuselage. The reference line can be anything, in principle, but it is usually something close to the geometric center line down the middle of the fuselage.

banktoturn

Pretty much everything is covered already, but if you are wondering what washout looks like i believe the F-18 is a great example. look at the tip of the wing. It looks like it is pointed down at a very significant angle. Also, if you want more information on the angle of incedence, you should try searching for "angle of attack" or "alpha level"

Hope this helps
Sherm

Geez, and I always thought washout was the 50% of my flight school class that didn't graduate. hehe