RV-10 Right Elevator Flexing/Oil Canning

[drewhottub]

For a video of my problem please click here ---> http://www.youtube.com/watch?v=T33ShFqh2Fo


Problem Description:

Here is my RV-10 Right Elevator Flexing/Oil Canning, as it sits in the hangar on a 92F day.

I wonder if over the life of my airplane will there be some fatigue cracks that develop because of this "oil canning" affect?

This flexing is not present on the left hand elevator!

Will you fellow aviation enthusiasts weigh in on this?

Thanks,

Andrew

 

[terrye]

Oil Canning

From the video it appears to me that particular bay MAY have had the rivets set a bit too heavily, or if you started riveting from each end of the spar, MAYBE there was just a wee bit too much skin left in that bay and that it ended up with a compressive load on it. It seems slightly bulged with no load on it. I checked my RV-9A and didn't find any bays like your video.

In any case, you can't do anything about it now so I don't think I would worry too much about it, except to make a note in your builder's log and keep an eye on it during your phase I testing.

Each of the bays on every aerodynamic surface will react in some way to air pressure and/or bending loads and I suspect the adjacent bays will also deflect. I don't think the bay in question is any more or less susceptible to fatigue effects than the adjacent bays.

 

[flion]

You need a tech counselor visit. Hard to tell from the video, but you only have some flexing, not actual 'oil-canning'. Still, the problem is to determine the cause and fix it if possible. If it was doing that after the ribs were riveted together and to the spar, then you look for the problem there. Maybe a rib was riveted with the top half on the wrong side compared to the other ribs. If it was Ok then but showed up when the trailing edge was done, then I'd suspect the closeout tabs being not quite right. If it was Ok then but showed up after the leading edge was done, then I would check the roll - maybe a bit of unevenness at the spar. But someone taking a hands-on look would probably be more helpful than my long-distance guessing.

 

[TroyBranch]

Wait until it hits the sun. Each bay will be that way. On a cold day it will tighten right up. I don't see an issue. It is the nature of sheet metal.

 

[drewhottub]

I just got off of the phone with Scott, at Vans Aircraft, and he says that he has an RV4 with over 1000 hours that has worse oil canning than what my video shows, with 0 fatigue cracks on the elevator!

He says what I showed in my video, is nothing to worry about, and to just keep building!!

This makes me feel better! Thank you all of you for weighing in on this!

Best Regards,

Andrew Boyd