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Top skin oil canned after using wing jack

P

petersb

Well Known Member
My shiny new RV7A now has an oil can top skin, there is a noticeable deprecation.

I used a wing jack, the official way to lift the plane, for fitting of wheel pants.

You could see oil canning forming the second bay in as the plane was lifted, however, on lowering the plane it remained.

I may be able to glue in a stiffener , or possible it may reset next flight

Will never use a wing jack again !

Bummer
 
Last edited:
Lower pressure above the wing combined with pulling G's will do it even worse. You should see my -10 wings at gross weight in cruise on a hot sunny day.
 
I am trying to picture the load path that would cause this? Is there something lose or broken on the rear cary through spar?
 
I would get a camera or scope inside that wing. Oil canning is not normal under any circumstance. Like Bret, I can't imagine what load path would cause this. You may have a deeper problem. This could end up being a blessing in disguise.
 
petersb said:
My shiny new RV7A now has an oil can top skin, there is a noticeable deprecation.

I used a wing jack, the official way to lift the plane, for fitting of wheel pants.

You could see oil canning forming the second bay in as the plane was lifted, however, on lowering the plane it remained.

I may be able to glue in a stiffener , or possible it may reset next flight

Will never use a wing jack again !

Bummer
Click to expand...

Can you confirm that you used something threaded into the tie-down point as the jack point?
 
Kyle Boatright said:
Can you confirm that you used something threaded into the tie-down point as the jack point?
Click to expand...

Yes. a bolt was threaded into the tie-down point.

Another thread reported a slight buckling of the skin during jacking which then came back out when the jack was removed.

Structure has been checked and there is no internal damage to structure. A slight push from the inside temporarily pops the skin out.

We are possibly seeing the results of a minor flexing of the spar during lifting which just tipped the skin into a new relaxed position when the load is released.

Aircraft has 30 hours to date

Peter
 
Reckon a -3G bunt would flex it enough in the opposite direction to pull the skin tight again?
 
Skin oil canned

Unless the front spar is exactly parallel with the jack piston, you will add a twisting motion to the spar. Level the wing bottom before jacking.
 
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