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Wing Tip Deformation in flight

DonJr

Active Member
Patron
Has anyone noticed any type of deformation of their wing tips while in flight. I stumbled into another builders site - which will remain anonymous, who claimed that he noticed some deformation/flexing of the fiberglass while inflight. Hence he was modifying his wing tips by adding an additional crossmember within the tip to strengthen it from the external pressures created during Va for his plane. This may be a one off but was curious if others have noticed this phenomenon.
 
I have a -7A and have never noticed any in-flight deformation, although I did notice how flexible the top of the wing tips were and was a little concerned. Turns out, there was some basis for my concern, as people naturally tend to place their hands on the wing tips, sometimes applying enough pressure to deform them. I eventually started getting hairline cracks in the paint, so added a single ply of fiber glass inside the tip in the critical area to give it a bit more stiffness. Turned out just right, just wished I had done it earlier.
 
My RV-8 has the WD-715-1 wing tips (not sure what the -14 has) and they deform slightly in-flight as shown in the pic below. After 1170 hours there is no cracking in the paint or the glass.

i-Tvc2ccP-L.jpg
 
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Thanks for the pic Carl. The comments made on the builders site implied that he was more concerned about the thickest area of the tip and not the area next to the trailing edge. He was adding the new crossmember in the thickest part of the tip. Closer to the CG point. He did not provide any pictures to support his claim. That's why I was asking here.
 
wingtip

I noticed on my -10, when it is warm outside, the middle portion on the tip becomes very flexible...and I have talked to some that have had paint cracking if people inadvertently push on it.

I decided to layup one strip of SORIC in this area, prior to painting...
 
Thanks for the pic Carl. The comments made on the builders site implied that he was more concerned about the thickest area of the tip and not the area next to the trailing edge. He was adding the new crossmember in the thickest part of the tip. Closer to the CG point. He did not provide any pictures to support his claim. That's why I was asking here.

Yes, the whole wingtip is very flexible (WD-715-1 wing tips). I try not to push down anywhere on the tip skins, as they flex easily, even when just wiping them down. The aft third does deform in-flight due to air loads as shown in the pic above. The tip of the TE deforms upward a smidge and the upper skin buckles downward slightly. The overall effect is a 'squeezing' of the aft third of the wing tip.

If you're in Arlington, WA, you're welcome to stop over and see for yourself.
 
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Dowels

I glassed 1/4" dowels (2) top and bottom. Bonded them with flox then applied a layer of fiberglass. I drilled tiny holes and tied them in place with waxed lashing string till the flox cured. String pulls right out. A bit of micro filled the holes. Finished product is pretty stiff.
 
You would flex too if you were in a 180 mph wind. :)

You're right I would! :eek:

But the earlier flat top Hoerner-style tip (W-415) on my previous RV-8 didn't flex a bit. Those are pretty stiff compared to the latest W-715-1 wingtips.
 
Yes, the whole wingtip is very flexible (WD-715-1 wing tips). I try not to push down anywhere on the tip skins, as they flex easily, even when just wiping them down. The aft third does deform in-flight due to air loads as shown in the pic above. The tip of the TE deforms upward a smidge and the upper skin buckles downward slightly. The overall effect is a 'squeezing' of the aft third of the wing tip.

If you're in Arlington, WA, you're welcome to stop over and see for yourself.

So the -14 wing tip instructions now call out a W-1015 Wing Tip. NOT having a completed set of wings for my plane yet. I'm assuming someone else can provide input on how this version of wing tip performs @ 180 or while on the ground while wiping? Quick Build wing kit on order since March 2021.
 
My RV-8 has the WD-715-1 wing tips (not sure what the -14 has) and they deform slightly in-flight as shown in the pic below. After 1170 hours there is no cracking in the paint or the glass.

i-Tvc2ccP-L.jpg

Hi,
I put foam blocks in the wing tip , but I can see deformation , rather ugly. I ´ll remove them because I think a light deformation in flight is not an issue IMHO.
 
i Used dense foam to stiffen up the tip

I glued in dense foam cut in to two 3x3 x 30 inch long strips.
Using polyurethane sealer I glued these to the top inside surface of the tip
The foam weighs nothing and really did a great job of stiffening up the tip :)
 
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