What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Does this QB RV10 wing inflite look okay?

mark manda

Well Known Member
Any input appreciated, do other rv10 wings look like this.

Thanks, mark
 

Attachments

  • F99762C1-E874-4879-B8C3-8E594ABC85BC.jpeg
    F99762C1-E874-4879-B8C3-8E594ABC85BC.jpeg
    388.4 KB · Views: 463
Yes, it's normal. It's called oil canning. Myriad factors affect it, temperature, pressure, etc. Accommodating it is built into the design.
 
Agree it's normal. I've seen many production airplanes look the same. IIRC it's the effect of lift on the top skins that you're seeing. My RV-14A wings (also QB) looked the same in flight.
 
It's very common. Heres a screen shot of a video I took in a Citation a while back.

The lift generated is sucking the skin up and causing the same pillowing.

In the video, it' pretty cool to see all that pillowing disappear the instant enough lift stops being developed right after touchdown.

If somebody has the technical mastery to post a video here I'd be happy to send them the clip. It's a .wav file about 30 seconds long.
 

Attachments

  • Screen Shot 2021-03-24 at 7.40.10 AM.jpg
    Screen Shot 2021-03-24 at 7.40.10 AM.jpg
    55.6 KB · Views: 555
Baron wing

note the oil canning on my Baron's wing - and it's built like a bank vault. Pretty normal.
 

Attachments

  • IMG_7750.jpeg
    IMG_7750.jpeg
    1.1 MB · Views: 515
Oil canning in flight is common, especially on the top surface of a wing. Sometimes you won't see it because of the ambient lighting such as flying under an overcast. However, sunlight from certain angles can really accentuate the visual effect with shadowing and make it appear startling, or one wing worse than the other when in fact, they aren't.

Oil canning on the ground, especially if you can flex or "pop" it by hand can be an indication that a surface or structure has been under stress or improperly constructed.

Flying Boeings, I had a few pax over the years express concern about seeing it on airliner wing panels, and a couple of those were GA pilots.
 
If you think of your wing as a beam carrying a load, the bottom of the wing spar is in tension and the top of the wing spar is in compression (zero stress somewhere in the middle). The bottom wing skins are also being stretched in tension, but the top skins have nothing to push against in compression, so there will be some pillowing of the skins between the ribs.
 
For most Cessna flyers, you'll never see the top of the wing in flight, so this looks weird. I was flying around with a 182 one day, crossed over top to move to the other side, and was REALLY surprised at the visual of the wing on the top side. Plenty of variation/pillowing of the skin when looked on from above.
 
Like others have said, it’s normal, but not very pretty. On a plane the gross weight of any of the RVs the structural weight to make “pretty” skins would be prohibitive.

Despite the skins being out of plane they can still carry plenty of shear. The operating stresses in most of the ribs and skins of light GA aircraft are usually very low. Other considerations like manufacturability frequently drive the choice of gauges. The lighter the plane, the harder it is to not be gauge-limited in design.

I’ve worked on many airframe structural tests. If you ever saw how severely buckled wing and fuselage skins of a light plane are are at limit load, let alone approaching ultimate, you’d be amazed. The load is removed from the test article and it looks the same as before the test (as it should). Well designed structure is remarkably resilient.
 
Back
Top