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How flat is flat, aileron question

Posted: Thu Jul 13, 2006 4:25 pm
by JohnR
Okay, so I bent my elevator trailing edges and had no problem. They came out what I consider to be nice and flat. I'm now working on the ailerons and using the same 2x6 brake as shown in the plans that I used on the elevators, but I am not getting the results as good as I would like. I have bent these down to where the stiffeners are touching the other skin and then as soon as I let off, BOING and they are right back up with a lot more space between the edges than what the spar fills. :bang: :bang:

I should add that they do not look that bad and may very well be acceptable. The radius is correct but when I pull the skin down to the spar and cleco it there is just a slight bulge between stiffeners. I've worked it a little with my hands and it is better but, how flat is flat? I want the thing to handle like an RV when I'm done building so don't want to settle for good-enough unless it really is good enough.

Any suggestions? Comments?

I was planning on riveting these tonight or tomorrow night but am hesitant until I know they are okay.

Thanks,

Posted: Thu Jul 13, 2006 5:41 pm
by JohnR
Okay, so I looked at the clock and noticed it was time that Van's support would be open. I called and talkedto Scott and he said not to worry about this, it was not going to effect the way the palne flew at all. Guess I get t onit-picky from time to time. :oops:

Thought I would post his response for the next person who is wondering about it.

Posted: Thu Jul 13, 2006 6:21 pm
by captain_john
John, if it makes you feel any better... I concur.

I think my ails didn't come out as "crisp" as my tails. Dunno why. I am still pleased with the result.

:) CJ

Posted: Fri Jul 14, 2006 12:51 am
by jim_geo
Here's a blast from the past.

Image

That's an elevator of course but it would work on ailerons also. Depending on the quality of the tangent I have read that the controls will either be stiff or they'll be mush.

Posted: Fri Jul 14, 2006 7:07 am
by Womack2005
I have a question regarding the wood break:

Did you guys take any precautions when storing the wood break against warping? I just bent my trailing edges on the elevators this week and am woundering how to store the wood break so it is still straight when its aileron time.

I had to dig thru the pile of 2x8s for about a half an hour at Mannards in order to find a straight one :( Don't really want to do that again.

Posted: Fri Jul 14, 2006 9:38 am
by JohnR
Thanks CJ, always nice ot hear what others have experienced.

Jim_Geo, I thought about doing that and might if I'm not happy after gettting things riveted. I believe they are going ot be just fine as is though.

Will, you have that right, finding straight boards is a real pain. I probably should have stored mine in a better place but I just slid it under the main workbench after I got done with the elevators and dug it out when I got to this point. It was still straight. My shop is heated and has AC so I'm guessing a stable environment has helped.

Posted: Fri Jul 14, 2006 9:43 am
by Wicked Stick
If you seal the wood, it will help against warping. I stained mine, and gave it a couple of coats of Polyurethane. Also certain types of wood warp less than others. Stay away from PINE if possible. A nice Hardwood is best.

Posted: Fri Jul 14, 2006 9:53 am
by Womack2005
Thanks guys. I think I will seal the wood and store inside :mrgreen:

Last night I drilled the counterweights. I was worried it would be difficult (or hit and miss) to get the hole in the center of the rib flanges - but they turned out perfect 8)

Skip the real wood...

Posted: Mon Jul 17, 2006 3:41 pm
by RV7Factory
I combed through the pile of "premium" wood at lowes for an hour to pick out the two best planks. They were very flat for the tail feathers, but since they have been sitting in the garage for a while now, they have taken on a nice warp.

I am going to rebuild them with MDF for the ailerons/flaps... MDF is much more stable over the long term.

Posted: Mon Jul 17, 2006 4:50 pm
by tshort
MDF is good ... I used poplar planks from Lowes (very straight) then sanded and sealed them with polyurethane. So far after moving from basement to new shop and high humidity they remain straight.
Should be good to go for my next project!! (flaps and ailerons are done...)

Thomas
-8 wings