Cowl Madness: How do you stretch a cowl ?

[dsmithlib]

I have been blazing through the my RV7 cowl project with Skybolts and thought I had it pretty well under control. I fitted the attach strips and then thought I should pull the cowl up to the spinner plate (as opposed to leaving it resting on the various supports).

When I got the 1/4" at the top of the spinner, I was horrified to find that I now had over 3/8" at the joint between cowl halves. I was not clear what I should do to finihsh the uneven joint between cowl halves or just leave them.

Worse, I now have over .040 at the firewall and I have not done the finish sanding. So, the bottom line is that my cowl is too short (overtrimmed).

Van's claims that over 3/8" at the spinner will appear excessive. The .040 at the firewall is more gap than I had planned. So, what is the best solution to stretch the cowl here?

1. leave it, its fine
2. get the firewall joint correct and the do what up front
3. keep the spinner gap to 1/4" and come up with a filler solution for the firewall

I will have an 0360, Vans mounts and Catto......... and plan to set my spinner flush to the cowl.

Thanks,
Dave

[Jeff R]

I ended up overcorrecting my top cowl by 3/16" or so and simply reglassed it to built it back up again. I ran a couple layers of duct tape along the outer edge to form the outside surface, then applied some flox and epoxy-wetted glass tape from the inside to build the edge back up. You may need to go back to get the outside surface smooth and level later, but it all files/sands down fairly easily. For 3/8", you may need to do things a little different (reinforce even more with glass tape where the fasteners will go to ensure they won't break through), but it really isn't hard. It was my first attempt at glass repair and I suppose there are better ways of doing it, but it worked.

This was discussed a little bit on an earlier thread a few months ago. But, yeah, you aren't the only one!

[Vlad]

Dave check this thread http://www.vansairforce.com/communit...lass+grow+back I had some problems with cowling and got good feedback.

[mburch]

I had a similar problem on my 9 when I switched to an MT prop - different spinner, big gap between spinner and firewall (more like 3/4" if I recall correctly). I extended the nose of the cowl by gluing on some rings I cut out of foam, sanded them to the right contour, glassed over them, and faired in with micro. Worked great!

good luck,
mcb