[Captain Avgas]

I've posted a photo of the channel formed on the inside of the counterbalance arm on the elevator of my RV7A.

I've noticed that some builders fill this in with fibreglass...and some do not.

The advantages of filling it in may be aesthetics and aerodynamics. The disadvantage is that if it is not done properly it may dislodge and obstruct elevator travel (with very serious ramifications).

Does anybody have any recommendations on a secure method for filling in this channel.

 

[RV7Guy]

Foam

Hi scuffed the inside with the wire brush wheel with my Dremel. I used a piece of foam and cut to fit. I secured it with microfiller and epoxy, then used glass cloth over the foam and approx 1" over the skin.

Looks great but I'm not sure I'd go to the trouble again.

 

[DGlaeser]

Foam and F/G

I wrapped a piece of styrofoam with glass cloth for a filler and then used epoxy with microballoons to fill the channel. Checking those areas will be part of the preflight, but don't forsee any problems with it coming loose.

 

[WSBuilder]

What kind of foam?

Is the closed-cell, blue foam the best way to go? What about the open cell, insulating foam-in-a-can since it's going to get a ply of glass? The spray foam has good adhesion.