Gap in Rudder Trailing Edge

[Wilkie]

Hi Gang,

I'm building the -7 and I just got done glueing the rudder trailing edge together using T-88 epoxy (it's what I had handy).

I spread a thin layer on both sides of the trailing edge wedge using a popsicle stick, and then clecoed the whole affair to my pre-drilled aluminum angle. I used a straightedge to confirm that the trailing edge was indeed straight and then set the assembly out of the way to allow the epoxy to cure. So far so good...........

My question is this: I went over to the rudder to admire my handiwork and I noticed a gap between the rudder skins at the trailing edge. It measures about 1/32nd, which doesn't seem like much, but it sure is visible to the naked eye. I don't recall whether or not this gap was present when I first glued the thing together or not- probably because I didn't look.

At any rate, is this a common gap or should I rip the trailing edge apart before the epoxy cures completely and then maybe try to use a thinner mixture of epoxy?

[Peetie the Pilot]

My RV-9A has the same condition on ALL the control surfaces. It is flying and it makes no diference in the flying characterics. It could be filled in with any substance that will hold paint and you won't know it is even there. The problem occured due to the position of the "wedge" between the skins. Don't be tearing it apart.

Good Luck
Peter
RV-9A C-GRVN 90491
Flying

[Wilkie]

Thank you for the encouragement. I debated whether or not to tear it apart but as the minutes ticked by, the epoxy got harder and harder.

I decided to go ahead and rivet the trailing edge. The rivets turned out great and the trailing edge is straight, and yes- the gap between the skins is still there. If anything, it may have even widened somewhat now that the rivets are set. I don't know what I may have done incorrectly as the holes are all matched drilled anyhow.

Thanks Again,
Wilkie

[CFI1513840]

I have exactly the same gap in my rudder after using pro-seal. I plan on filling it before painting, possibly with epoxy/cotton flox.

[ChrisL]

I just did mine this past weekend and noticed a similar gap. No matter what I did, I couldn't get the 2 skins and the wedge to meet at a perfect point. Instead, I had a consistant 1-2/32 gap along the edge. I countersunk everything deep enough (bordering on too deep), so I just don't know what the trick is.

Anyone else have additional thoughts on this?

Thanks,
Chris

[WilburD2]

Sounds like a job for them side grip cleco's. I'd suggest after the glue is in and you cleco'd the rivet holes, use the side grips to close any errant gaps. One word of caution tho: Make sure to put something (wax paper, popsicle sticks) between the skin and side grips to preclude the excess glue from gluing the side grips to the skin

my .02 dollars worth

[alpinelakespilot2000]

If you are getting big gaps that were not there when you did the initial drilling and fitting, the probable cause is using too much proseal. You need to scrape off as much as you can, leaving just a very thin (almost transparent) coating. Remember, the proseal is not there to hold the parts together permanently; it's only there to keep things secure without clecos while the riveting happens. The only places I have any similar gaps is on my first control surface where I learned this lesson. Hope this helps. Good luck.

[FredMagare]

I noticed the same problem when I was building. Went to the store and bought about a hundred wooden clothes pins to grip the area between the clecoes. It may also require a little bit of tape in order to keep them from slipping off (especially if you get the adhesive on them - they won't grip the aluminum). My trailing edges (mostly) look good.

[hempy.4]

I have seen rudder skin dimples hit each other. I filed mine down a little.
Dan Hempy
7A emp tips about done
wings on the way