What's new
Van's Air Force

The definitive Van's Aircraft support community! Buying, building or flying an RV? Join our exclusive family of mentors and enthusiasts!

Self healing wing dent

CJT

CJT

Well Known Member
On September 1st, it was a calm wind day at Gaithersburg, ground temperature around 20*c, I flew between 3000-4000 feet in calm winds, on landing, noticed a fist size dent in right wing just beyond fuel tank, I had not noticed any impact at ant time. The edges were smooth, no paint damage. After parking and post flight, which took about 30 minutes, the dent magically vanished.
Anyone with similar experience?
As it is common nowadays to consult AI, This what Grok said;
Thermal Expansion/Contraction, most common cause
Fuel Tank Pressure/Venting, may be due to blocked vent
Structural Flexing- Not likely
Any thoughts?

a7bf6f3b-01d5-496f-ac33-7430d8cabf86.jpeg
 
well, that is an interesting one, well done :)

Now it ain't located in the middle between ribs (right?), and that makes it even more of an enigma.
I once assisted in load testing of an RV-4 wing many moons ago, the skin sure started to dent >4G, but all this happened mid rib span (and returned to normal once the test was over).
Yep, thermal retraction/contraction sounds good, how cold was your fuel?
 
I have no theory on the cause but I've experienced something similar regarding the "fix". I picked up dents on my leading edges from hail in Alaska. You can't pull them like you can with steel as you'll just trade dents for pimples. Someone told me to try dry ice - no luck. Someone told me to try a hair dryer - no luck. Someone told me to try pressure in the tank - no luck, though maybe I was too chicken to apply enough pressure, not wanting to create a real problem while addressing a cosmetic problem. Then some crusty old dude (imagine this in geezer voice) said: Just park it facing East in the morning and turn it around at noon.
Within a few days most of the dents were gone entirely and even the worse were 90% gone.
 
Being it’s beyond the fuel tank, I’m struggling with thermal contraction and expansion as the cause especially at the stated temp and altitudes.. Definitely a head scratcher.
 
Just confirming, the dent was still there right after landing with no aero loads on the wing?

Were there any tipped or sheared rivets on the upper or lower skins next to the tank?

ds
 
Dark surface, warm day, direct sun after a flight at 3000’?

I’d bet on solar heating of the upper surface while everything else was still nice and cool. I used to see that on my Tomahawk, which had dark leading edges.
 
As an experiment- next hot sunny day, park the plane so that area is exposed to the sun. After it is heated up press down in the affected area & see if it pops in. If so it's a thermal expansion issue.
My maybe unorthodox repair suggestion would be to bend a length of .063x1" to the skin contour & glue it to the inside skin surface with proseal or other structural achiesive, will probably require tank removal to get at that area.
 
Kyle Boatright said:
Dark surface, warm day, direct sun after a flight at 3000’?

I’d bet on solar heating of the upper surface while everything else was still nice and cool. I used to see that on my Tomahawk, which had dark leading edges.
Click to expand...
20C/68F OAT, how hot would the top surface get in flight with the airflow over it? (I would guess not much)
 
Walt said:
20C/68F OAT, how hot would the top surface get in flight with the airflow over it? (I would guess not much)
Click to expand...

I bet it warmed up after landing when there was little/no airflow around the wing. My Tomahawk would do that 30 seconds after dragging it out of the hangar on a sunny day.
 
Kyle Boatright said:
I bet it warmed up after landing when there was little/no airflow around the wing. My Tomahawk would do that 30 seconds after dragging it out of the hangar on a sunny day.
Click to expand...
I've seen similar on my RV-6 wings that have black leading edges. Pull the plane out of a cool hangar into bright sunlight and *bong*, a dimple can occur. This is a rare occurrence, has to be just the right circumstances, but sure got my attention first time it happened!

But if it looks like this photo..........you hit a duck!!

IMG_20210501_122103930_HDR.jpg
 
For the past 28-years, my RV-6 would do similar on one wing every once in a while but not as big as yours.
 
Hard for me to tell due to the reflections in the pic but it appears that it wasn't a direct leading edge collision. Almost a slight downward angle or descending ricochet impact to it. The lack of blood or feathers leads me to believe a plugged fuel vent is to blame if that is the top fuel tank skin. Either that or you hit a drone that was dropping to get out of your way. :)
 
Last edited:
You must log in or register to reply here.
Back
Top