Inverted Aileron skins

Post by **Spike** » Wed Jan 23, 2008 12:29 pm

I'm working on the aileron skins and got the top/bottom/left/right relationships correct. What I did not get correct was the inversion of the one top skin and the one bottom skin (for the left right differences).

I ended up building one of each of them inverted, meaning I riveted the stiffeners onto the outside of the skins. I have nicely drilled all of the rivets and separated the pieces.

I can flatten out the dimples, and redo them in the opposite direction and re-rivet the stiffeners onto the skins.

The question is, is this safe to do? I already talked to Vans about this, but Im curious as to the group's thoughts.

John

cjensen · Post by **cjensen** » Wed Jan 23, 2008 12:34 pm

I'm willing to bet I know what Van's told you...I would have no problem whatsoever in flattening out those dimples, then re-dimpling the other way...I've done it, and have no worries. There is so little metal moved in a dimple (especially 3/32 holes) that a time or two of moving the metal back and forth won't work harden it enough to cause any concern. Three or four times, and it's trash, but this, I wouldn't worry about in the least.

rv8or · Post by **rv8or** » Wed Jan 23, 2008 12:58 pm

I think I would tend to agree with Chad. BUT, how much are the skins to replace...and is it really a signifcant cost in the big picture? Not that that should drive your decision, but something to think about.

I've certainly pressed on where I could have replaced, and I'm not loosing sleep. But someday when my paint chips, or a crack develops earlier than it should, I'll always wonder

Let us know what you decide.

Joe

Post by **bullojm1** » Wed Jan 23, 2008 1:18 pm

I recall hearing you can only reverse a dimple once. After that the metal is too prone to cracking.

smittysrv · Post by **smittysrv** » Wed Jan 23, 2008 2:18 pm

I think the real answer to this question is to whether you are going to be thinking about it when you are ready to fly your RV. If it worries you, replace the parts. If not, blow it off (mentally) and move on.

When it came time to overhaul my Cessna engine, all my buddies said "if it's got good compression, keep flying it". It had good compression, but I couldn't enjoy flying it from worrying the "high time" on the engine. So I had it overhauled.

cjensen · Post by **cjensen** » Wed Jan 23, 2008 2:27 pm

bullojm1 wrote:I recall hearing you can only reverse a dimple once. After that the metal is too prone to cracking.

Yep. That's what I've always abided by...first dimple is 'a time', the reverse dimple would be 'or two'...

One of my flaps was inadvertantly dimpled inside-out on one side of one skin, I reversed the dimples after talking with Van's, and moved on.

Post by **bullojm1** » Wed Jan 23, 2008 2:56 pm

If you do redo the dimples, check all of them our carefully for cracks. No cracks, build on. Cracks, order new parts!

Post by **Spike** » Wed Jan 23, 2008 4:14 pm

Van's said that they "didnt know" what would really happen. They did think that the ailerons aren't as likely to crack a they are out of the slipstream of the prop. They also suggested that I could use proseal to assist the rivets in securing the stiffeners.

John

svanarts · Post by **svanarts** » Wed Jan 23, 2008 6:20 pm

I dimpled my belly skin the wrong way when I was buiding the RV-4. I emailed Van's and Scott McDaniels replied with the following; you can re-dimple aluminum the opposite direction with no problem...once. If you have to dimple the opposite direction again, throw it away and start over.

She's still flying.

JohnR · Post by **JohnR** » Wed Jan 23, 2008 6:58 pm

I did one row of dimples the wrong way and was told the same thing, flatten them out redimple but make sure you get it right the second time. I'd have to look at my log ot see what part it was even. I have not lost much sleep over it. I think you are fine.