Wing "Washout" defined

[jdoran]

Help me understand the concept here:

If the mounts for a wing are fixed (non adjustable) where they attach to the fuselage, and the front strut (mid wing) is non adjustable, that only leaves the rear mid wing strut as an adjustment point.

What is the goal here, to sort of twist the wing to change the angle of attack by adjusting the rear strut up or down?

Is it more important to have both wings the same, or is there a specific angle for both wings to have, and for both wings to match??

[Len Petterson]

Re: Wing "Washout" defined

You need a manual for the aircraft and a acurat 4 foot Level to do it righ.
Len

[flyguy]

Re: Wing "Washout" defined

Within reason you pretty much adjust it to fly wings level--at least on a plane that flys pretty much ok already. Mine flew left wing low when I got it, I just tweaked it a couple of turns (as I remember) and it pretty much flies straight an level hands off now. Of course it will change depending upon which tank has gas in it and whether I have a passenger, ect. Yep you are just changing the trailing edge up or down a tiny amount which does just what you would think it does.
DC

[jgerard]

Re: Wing "Washout" defined

You adjust washout (wing tip at a reduced A.O.I. than the root) by adjusting the length of the rear wing strut. The "Jurry Struts" (small vertical struts) are there to support the wing struts, not put the twist in the wing.

Washout is used for many reasons such as to cause the root to stall first or correct for a heavy wing and or nose/tail heavyness. Example: 2 turns in on my rear struts reduced the washout of the wing enough to reduce the nose heavyness felt at max fwd C.G. power off w/full nose up trim glide speed by allmost 5 mph. The plane now lands much better and has a more solid feel in slow flight and still stalls straight ahead.

I heard of a Piper Pacer in CA. that had all the diheadral taken out and no washout. It flew faster and stalled like a stock Pacer. Those that have flown Clip wing Tcrafts may wish to comment on the behavior of those modified flat wings.

Forrest was a test pilot, he could probably enlighten us with how they adjusted the planes setup up durring factory test flights.

[Forrest Barber]

Re: Wing "Washout" defined

Actually that is 30" level. 4ft works too! The manual has the prodcedure to use fro the initial settings , then after flight test(s) you tweak it so she flys straight & level, hands off at cruise. Basicaaly the thoughts are that the ends are "washed out" so the stall is progressive. The clip wings have all been done different, ours had a wee bit of dihedral ( or the wings look like they have a droop "anhedral") . The leading edge of the stabs are raised 3/4 to 1 in to decrease the built in angle of incidence. WE did have one F-19 that had the trailing edges up too high due to a new guy in assembly, She had a very high cruise but a high "minimum trim speed " also.
Today is my Birthday, I am finishing a presentation for the American Legion tomorrow, it is titled "Taylorcraft,the War Years" I just got busy this week, flew a NA T-28B, finished a new Sport Pilot transition for a Student, many aerial photos, making calls on parts for Taylorcrafts, trying to keep ahead of the situation in Brownsville. Soooo I am out of here back Sunday.

[Chet Peek]

Re: Wing "Washout" defined

Forrest, may you have a happpy birthday and many more. I think you and I are much blessed. My 86th will be tomorrow, November 11. I plan to go over and get the DC-65 into the air.
Chet

[flyguy]

Re: Wing "Washout" defined

Forrest, Thanks for the info about the "up tweaked" wing and high cruise speed. Bill B. and I were just talking here about some way to dump some lift to get the tail down (streamline the fuselage) on aircraft that have enough power to cruise at a higher speed.
I think i might have a problem applying that concept as my adjustments are all the way "up" on one side and "down" on the other. Maybe go back and start from scratch as most everything else was either misadjusted or hooked up backwards on this plane when I got it. It is really great to have your input on here!
Darryl

[paulnuss]

Re: Wing "Washout" defined

WOW! A T-28B! Sounds pretty neat! I have heard they fly light and like a dream, at least for a big ol' iron bird.

It has been a while, but I seem to remember the wash-put adjustment had a complication: the aileron cables are becoming either shorter or longer when the adjustments are made, need to be loosened first, the wash-out changed, then aileron cables re-tightened and safety wired. That added quite a lot to the job. And explains why I might have settled for good-enough instead of perfect.

And, that brings up the hands-off flying; my ship is just about hands off when I am alone in the airplane in the left seat, and needs some aileron correction when there is a passenger in the right. The balance is affected by the left-of-center weight distribution sole occupant. (That may be the only thing left-of-center I have ever been associated with in my whole life!) So the decision must be made, to adjust for solo flight if that is more common, or adjust for passenger aboard if that is more common. Anyone else note this?

[flyguy]

Re: Wing "Washout" defined

Yep, I mentioned the change with gas in the right tank too. Changes pitch trim when you lean forward. Sometimes I do that in cruise for temporary mild pitch adjustment LOL. Interesting point on the aileron cables.
I made an error in saying that my adjustments were ALL the way up/down. They are more/mostly/whatever up on one side and more down on the other.
DC

[crispy critter]

Re: Wing "Washout" defined

Yep, I mentioned the change with gas in the right tank too. Changes pitch trim when you lean forward. Sometimes I do that in cruise for temporary mild pitch adjustment LOL. Interesting point on the aileron cables.
I made an error in saying that my adjustments were ALL the way up/down. They are more/mostly/whatever up on one side and more down on the other.
DC

DC,
Do you have any splices on your wing struts? I had a T-craft once that had the same problem,turns out it had a splice on one of the wing struts and aparently they didn't jig it properly and the wing strut with a splice on it was 1/8 of an inch shorter then the other. The same can apply if you have a bowed strut too. The easiest way to determin if this is the problem is to trade sides with the strut that is spliced or looks bowed and see if it reverses the problem.(i.e. if it now flies right wing heavy then reversing them shoud make it fly left wing heavy).Then you know you need to straighten,replace,or repair a strut.

[flyguy]

Re: Wing "Washout" defined

Kevin, I may have made it sound extreme. There may be more adjustment left there than I think. I have to check it out someday. Flies pretty well now depending upon how it is loaded. There must be 100 things that will change the flight characteristics of the wing, but it is interesting to tweak in little changes and see what happens. My struts appear to be cherry.
DC

[VictorBravo]

Re: Wing "Washout" defined

Kevin, I may have made it sound extreme. There may be more adjustment left there than I think. I have to check it out someday. Flies pretty well now depending upon how it is loaded. There must be 100 things that will change the flight characteristics of the wing, but it is interesting to tweak in little changes and see what happens. My struts appear to be cherry.
DC

On an airplane with a long wing like a T-craft, a dent on one leading edge out near the tip can make a difference. The leading edge skin being screwed in to the ribs with a bulge in it could do something. The fuselages were built in jigs, but I believe the rest of the Tayorcraft was hand-built and there are probably differences from one to another. One wing could have a new spar that weighs less or more than the other wing. You could chase all this stuff down for the rest of your life. Composite sailplane wings that were vacuum-bagged into molds could come out different from one glider to another. someone could have shrunk the fabric tighter on one wing than the other and that would make a huge difference...