Bent Side Skin from Hard Landing

[Mel]

Originally Posted by JohnF

the best I can figure is that when using a hydraulic jack at the tie down point to raise the plane to install wheel pants brackets that somehow that flexed things enough to cause the slight damage. The 'rubber' fairing between the top of the wing and the fuselage at that point was also curled somewhat inward, suggesting the top of the wing skin was pushed upward.

I can't imagine jacking a wing could be worse than flight loads. Think about it. Jacking the airplane can never be more than 1 "g". Even normal flight loads go beyond that.

[joedallas]

Originally Posted by Mel

I can't imagine jacking a wing could be worse than flight loads. Think about it. Jacking the airplane can never be more than 1 "g". Even normal flight loads go beyond that.

Mel there is a difference in uniform and point load.
I don’t think the wing received a 1 G load that far out on the spar if flight.
In reference to the dent you are correct.

Also jacking at that point may be more than I G as the center of gravity moved.

My view

[David Paule]

Don, how about a photo or two? And could you mark the photos for your proposed mod?

Thanks!
Dave

[DonFromTX]

Not sure how to mark it, but you can see where the MLG would contact the side skin if deflected up very much. I propose to snip out that area directly above the MLG leg. This photo distorts the view actually there is about 3/4 inch between the leg and the side skin when building. The skin between the leg and the first horzontal row of rivets serves no purpose except to wrinkle the whole side in a hard landing.
[IMG][/IMG]

[rvbuilder2002]

Originally Posted by DonFromTX

The skin between the leg and the first horzontal row of rivets serves no purpose except to wrinkle the whole side in a hard landing.

I disagree.

I admit that witout a stiffening flange along the free edge, it is not a real strong load path in compression, but it is in tension. (Everyone should remember that modifications before certification are not allowed under E-LSA certification).

BTW, a 3/4" gap is huge for this location. If the gear leg is deflecting that much, that close to the top of the leg during a very hard landing, then that pilot was only a nats hair away from doing some major structural damage (my opinion anyway).

[joedallas]

Originally Posted by DonFromTX

Not sure how to mark it, but you can see where the MLG would contact the side skin if deflected up very much. I propose to snip out that area directly above the MLG leg. This photo distorts the view actually there is about 3/4 inch between the leg and the side skin when building. The skin between the leg and the first horzontal row of rivets serves no purpose except to wrinkle the whole side in a hard landing.
[IMG][/IMG]

Don
Can you use your seam tool and bend the skin outward at the point of the possible of contact to add a little more clearance

Are you sure the gear hit the skin at that point? Scratch on the paint?

The side skin is in shear in a hard landing?

Cutting of the skin may add to the problem?

My view

[nucleus]

This is actually a common issue on "regular RVs". If you don't trim the skin above where the gear leg goes into the fuselage, the gear will flex up on landing and bend the skin.

Probably the worst part is that the powdercoat on the gear leg gets damaged in the process.

Hans

[DonFromTX]

I don't pretend to know the answers, that is why I posted it, but with four known and admitted cases so far, I feel it should be addressed.. I would have no problem putting a doubler under or over the newly formed edge to replace the strength that was removed. The common solution seems to be to just ignore it after it happens, since it makes clearance when it bends up. I was hoping for an approved solution to keep it from happening.
I was never around when any of them bent, just relying on owners that related to me that it was caused by a hard landing they made. I would sure hate to replace an entire side panel because of it.
And Scott: The 3/4 inch is with no avionics, no tail cone, no engine for weight. Judging from the angle of my spindles, the distance will reduce a lot when loaded, I have none to measure fully loaded..

[David Paule]

Thanks for the photo - the whole issue is much more clear now.

Dave

[joedallas]

Originally Posted by DonFromTX

I don't pretend to know the answers, that is why I posted it, but with four known and admitted cases so far, I feel it should be addressed.. I would have no problem putting a doubler under or over the newly formed edge to replace the strength that was removed. The common solution seems to be to just ignore it after it happens, since it makes clearance when it bends up. I was hoping for an approved solution to keep it from happening.
I was never around when any of them bent, just relying on owners that related to me that it was caused by a hard landing they made. I would sure hate to replace an entire side panel because of it.
And Scott: The 3/4 inch is with no avionics, no tail cone, no engine for weight. Judging from the angle of my spindles, the distance will reduce a lot when loaded, I have none to measure fully loaded..

Don this seems to be something we need more information on.
Cutting or adding stiffener to solve a problem that is not described is not a good idea.
The crimple zone may be a good thing.
Pitchers of the damage would help.
If this has happened more than a few times Van should chime in.

My view