wash-out question.

[Ron from Montréal]

I love my Alaskan struts in every way. What do you guys use has wash-out mesurement? I include the drawing from Alaska.

[Woody]

Start with that and adjust for wings level in flight.

[Hank Jarrett]

Remember this is measured on the bottom of the wing 26" in from the tip with the stab level. Start getting the wings level from there AFTER you make sure the tail surfaces are square to each other and the stab is parallel to the tube the back of the seat sling attaches to. The trailing edges at the tip should also be equal distance from the fin post at the bottom of the fin. When you measure don't worry about the fuselage being perfectly straight. They aren't. You also don't need to get all crazy about the wing incidence all along the span. I measured mine at every rib and integrated across the span to see how much the wing twisted back and forth. You DO NOT need to really worry about that, but I'm just a bit anal and wanted to know (ask anyone here). I actually calculated the span wise theoretical lift distribution. Don't bother, it will just make your head hurt. These planes were NOT built perfectly straight.When you start leveling the wings make sure it isn't the rudder rather than the wings that are causing the bank. Taylorcrafts are RUDDER planes. Try the tab on the rudder first and see if she stays level at different speeds, THEN mess with the washout. You DO NOT want a lot of difference in washout on either side. You will know you have uneven washout when your plane consistently rolls one way when it stalls. One wing is stalling first. DO NOT TAKE ALL THE WASHOUT OUT!!!! You will NOT fly faster (at least enough to see).
We aren't flying Black Birds. Our planes won't be perfect. It is also fun to measure the dihedral on each wing. Most are NOT equal. Don't sweat it. You can't adjust i anyway.
.
Hank

[PA1195]

There's lots of info in previous threads here. Many ways to accomplish the task. I ended up liking about 2 degrees of washout, and used a digital level placed at the same wing chord station to determine the inboard to outboard twist per wing.

Edit: to do that I attached a large nut on edge with nylon ties at both ends of the level (to avoid the lower wing's curve) and placed the rear nut under the rear spar. Then just measured the angle difference of the level root to tip rib.

Even then it takes some flying to get a relatively wings level takeoff and stall. The wing with the most lift (less wash) will lift off in a slight roll then later stall first if there's a marked difference in wash between wings.

In cruise flight if the nose wants to rise (takes more down elevator deflection or correcting trim than desired) then reduce overall lift by adding more washout to both wings. If the opposite is true (nose heavy which takes more up elevator deflection or trim to correct) then reduce washout in both wings. That's the recommended procedure from the F-19 Owner's Manual.

Edit: In the F-19 and F-21 Manuals they describe measuring and equalizing the dihedral of both the front and rear spar with a line level stretched wing tip to tip over the respective spars. That assumes a laterally level fuselage. There's no mention of the diagram in Post #1, just the subsequent flight test for nose heaviness or lightness I describe above. Of course if a STC approves another procedure then choose wisely.

Gary