Looking for wing final settings Kitfox III

[LSaupe]

Mounted the wings yesterday, but unfortunately my build manual does not provide guidance on checking the final wing settings. Primarily what and how to check for dihedral and washout etc.

Wings fold well and look goodto the eye (when open), though wing tips, when folded show differences.

Anyone have a check procedure for this they would be willing to post?

Larry

[Paul Z]

Your running into what we referred to as Tangency error when folding the wings.
The tangent of 1 degree is .017455 per inch. For evert inch a 1 degree variance results in a variation of + or - .017455. So if you are lookiking at a 1 degree in the pivot hinge to hinge angle you'll see a variation of

1 Degree variation in the pivot hinge to hinge angle variation would result in + or - 3.141911 inches per inch.
15 foot wings X 12 inches in a foot X .017455 = 3.141911 inches tip to tip

1/2 Degree variation the pivot hinge to hinge angle variation would result in + or - .0087275 inches per inch.
15 foot wings X 12 inches in a foot X .0087275 = 1.570955 inches tip to tip.

The location of wings folded is not all that important, you will always see variation in the wings folded position because of the Tangency errors. You physically will never be able to get the Tip to Tip to be the same when folded, because of the variation in the angle of the hole going through the pivot pins locations on the frame.

It is when the wings that are locked in for flight that is important, and that must be right.
1) Level the fuselage in both axis fore & aft, stem to stern. I would use a 4 or 6 foot digital level to do this.
2) Verify the wing tip to tip is level (same point on both wings) with wings in the inflight position. I'd use either a laser level or a 30 foot hose as a large bubble level.
3) Verify the wing tip to to the tail center line measurement is the same for left wing and right wing, measure the same points on the wing tip both wings, and the same point at the tail on the centerline. Tape measure within 1/4 inch or less.
4) Verify the wing cord is level fore and aft both wings. I'd use a Digital level.

Use the old carpenter rule measure twice cut once. Set it all up level, rig in the wings (& do the same for the horizontal stabilizer), then verify the wings & horizontal stabilizer are level & true. Walk away, close the hanger, go home, and then do it again the next day verify everything twice. Everything else is built into the wings.

I hope I got everything, and I hope this helps.

[LSaupe]

Thanks. Great information. Any info on what the dihedral and washout settings should be?

[Paul Z]

Sorry about not answering the Dihedral Washout, I missed read your post saying you didn't have them. I only have information on a Series VII dihedral and washout. Here is a lengthy thread posting on setting both. I woul look at "cgruby's" post he has a Model III.

http://www.teamkitfox.com/Forums/showthread.php?t=2492&highlight=dihedral+washout+model+III&page=3

On page three cgruby had a similar question regarding his type III. "The factory could offer no information on my plane, however said the newer planes were 1 degree.

I think I found the answer to my question in Service Letter #25. A 4 foot level beneath the front spar should read between 1.1 and 1.4 inches.

If you want to get that in degrees, then the Tangent of 1.3/48=0.0270. The angle whose tangent is 0.0270 is 1.1 degrees. That's for each wing. Mine measures 1.25 degrees. I think that's close enough for me."

I'd go read this thread, and get Service Letter #25, 25a, & 25b.
http://www.kitfoxaircraft.com/support/service_letters/sl25.htm

http://www.kitfoxaircraft.com/support/service_letters/sl25b.htm

http://www.kitfoxaircraft.com/support/service_letters/sl25a.htm

[LSaupe]

Thanks Paul.

[Paul Z]

No problem, I'm retired and retired Engineer I enjoy doing the research.