Aluminum wingtip damage

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V529
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Re: Aluminum wingtip damage

Post by V529 » Tue May 19, 2020 3:31 pm

I see on top of your wings you have the 3 signature bumps on the aft spar of your metalized wings. I'm certain that means those wings were metalized by Farley Vincent He was heavily involved in 120/140 restoration work and mods.(eons ago) I can guarantee you that those wrinkles were not there when he covered the wings. He did seamless work.

Is the wrinkle because of your wing tip bump or was it there prior........I don't know.

I can say this. A. wrinkled skin means something is bent underneath. B. Usually forward momentum and damage to a tip will bend the wings close to where they attach to the fuselage. Composite aircraft, (think Cirrus) when they get a tip strike will buckle(actually de-laminate) the rear spar under the aft seats inside the fuselage.

Every Airplane reacts differently to a tip strike.

Sorry to be the bearer of bad news, but take another look. Also check your carry through spars inside the cabin.

The picture may "enhance" the view of the wrinkle, but it doesn't look all that great.

8451
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Re: Aluminum wingtip damage

Post by 8451 » Tue May 19, 2020 3:37 pm

V529 wrote:
Tue May 19, 2020 3:31 pm
I see on top of your wings you have the 3 signature bumps on the aft spar of your metalized wings. I'm certain that means those wings were metalized by Farley Vincent He was heavily involved in 120/140 restoration work and mods.(eons ago) I can guarantee you that those wrinkles were not there when he covered the wings. He did seamless work.

Is the wrinkle because of your wing tip bump or was it there prior........I don't know.

I can say this. A. wrinkled skin means something is bent underneath. B. Usually forward momentum and damage to a tip will bend the wings close to where they attach to the fuselage. Composite aircraft, (think Cirrus) when they get a tip strike will buckle(actually de-laminate) the rear spar under the aft seats inside the fuselage.

Every Airplane reacts differently to a tip strike.

Sorry to be the bearer of bad news, but take another look. Also check your carry through spars inside the cabin.

The picture may "enhance" the view of the wrinkle, but it doesn't look all that great.
Victor,

I don't consider you as bearing any bad news; I know I screwed up and I just want to do what I can to determine how badly.

I can check both carry through spars next time I look. Looking at the rear spar and both connection points I didn't see any signs of damage. Is there any place else that the damage may have manifested?

8451
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Re: Aluminum wingtip damage

Post by 8451 » Tue May 19, 2020 4:55 pm

8451 wrote:
Tue May 19, 2020 3:37 pm
V529 wrote:
Tue May 19, 2020 3:31 pm
I see on top of your wings you have the 3 signature bumps on the aft spar of your metalized wings. I'm certain that means those wings were metalized by Farley Vincent He was heavily involved in 120/140 restoration work and mods.(eons ago) I can guarantee you that those wrinkles were not there when he covered the wings. He did seamless work.

Is the wrinkle because of your wing tip bump or was it there prior........I don't know.

I can say this. A. wrinkled skin means something is bent underneath. B. Usually forward momentum and damage to a tip will bend the wings close to where they attach to the fuselage. Composite aircraft, (think Cirrus) when they get a tip strike will buckle(actually de-laminate) the rear spar under the aft seats inside the fuselage.

Every Airplane reacts differently to a tip strike.

Sorry to be the bearer of bad news, but take another look. Also check your carry through spars inside the cabin.

The picture may "enhance" the view of the wrinkle, but it doesn't look all that great.
Victor,

I don't consider you as bearing any bad news; I know I screwed up and I just want to do what I can to determine how badly.

I can check both carry through spars next time I look. Looking at the rear spar and both connection points I didn't see any signs of damage. Is there any place else that the damage may have manifested?
Regarding the wrinkle being pre-existing: I reviewed my logs and the wings were metalized in '59, extensive repairs were done to both wings in '64. I would say it is plausible that it is residual damage from when the airplane was wrecked previously.

I don't have a headliner so I'll be able to look at the carry-through easily enough. I didn't look the other day but Farley installed a small inspection panel inboard of the pitot tube just under the leading edge where he stamped his name, I may be able to get a good look at the bay with the wrinkle that way.

8451
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Re: Aluminum wingtip damage

Post by 8451 » Tue May 19, 2020 5:46 pm

John or Victor,

For curiosity's sake, I was looking at the parts manual and doing some research on the wing structure and came across the entry for a complete wingtip assembly (including the last couple ribs) that Cessna sold as a complete assembly back in the day, presumably because they anticipated it to be a commonly damaged part.

On the 170 forum a user there mentioned that the tips were engineered to “break away” in the event of damage to save the rest of the structure and then just have the wing tip assembly be replaced. Are either of you familiar with this, and if it’s real did this concept apply to the engineering of the 140 type or was it afterwords for the 170?

V529
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Re: Aluminum wingtip damage

Post by V529 » Wed May 20, 2020 8:25 am

The wing tip is a separate piece. My airplane was destroyed in a wind storm in 1991. I purchased a used set of fabric wings. On one of those I had to replace the wing tip. It's a very straight forward replacement, effortless actually. (when the fabric or metalized covering is removed :x ) Cessna did supply tips as "spare parts"........back in the day.

That being said, it's held on pretty stoutly. Double row of bolts perhaps.........I'll look at my airplane the next time I'm out there.

If you can find some way with a borescope to look out there..........I would try. Also run the borescope under the area where the wrinkle is. The two areas that show damage (typically) are where the wing rib meets the spar(common enough that Cessna came out with "L" shaped doublers to rivet in those locations) and the spar itself.

V529
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Re: Aluminum wingtip damage

Post by V529 » Wed May 20, 2020 8:27 am

Where the wing bolts to the fuselage is pretty stout. I would look for damage either outboard or inboard of that location.

8451
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Re: Aluminum wingtip damage

Post by 8451 » Mon May 25, 2020 1:53 pm

I got a chance to look inside the wing with a borescope today. Both front and rear spars did not show any signs of damage (wrinkles, popped rivets/bolts, etc). The front and rear carry-through were also intact. The wingtip attach bolts appears to be flush and did not show signs of being pulled.

Really the only signs of damage I found were a couple wrinkled ribs, but they already had stiffeners on them and corresponded to a 337 I have for repairs many years ago. I looked at the bay with the wrinkled top skin and everything appeared intact - That bay did appear to have stiffeners that the skin was riveted through into the rib that I didn’t see on the other bays; I speculate it was part of previous repairs.

For what its worth, I got some pictures from last year from a friend and the skin wrinkle was indeed pre-existing.

I reviewed this with my IA and the conclusion was there was no structural damage sustained other than to my pride. John and Victor, thanks again for the pointers on where to drill down and inspect.

4945
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Re: Aluminum wingtip damage

Post by 4945 » Sat Aug 01, 2020 10:00 am

V529 wrote:
Wed May 20, 2020 8:25 am
The two areas that show damage (typically) are where the wing rib meets the spar(common enough that Cessna came out with "L" shaped doublers to rivet in those locations) and the spar itself.
I've been trying to find pictures of those doublers, which had been posted on this forum in the past. I believe those were part number 10004-58. I need about 4 or 5 of them and can't find them anywhere. I could easily make them if I could find a pattern or just a photo with some scale.

Gary

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