New Products Flash Sale
Thread Tools
Old Oct 26, 2012, 07:11 PM
Mopar92 is offline
Find More Posts by Mopar92
Motorized lawn dart
Mopar92's Avatar

Easiest way to make a cowl?

What's the easiest way to make a cowl for my 50" Kitfox project? Balsa and hollow it out? Or make a plug and vacuum?
Sign up now
to remove ads between posts
Old Oct 26, 2012, 07:42 PM
AndyKunz is online now
Find More Posts by AndyKunz
AndyKunz's Avatar
They're all easy ways. I like making big ones from a foam block (usually several layers of sheet) then carving/sanding to shape and covering with glass. Then I remove the excess foam (sometimes all, depends on the plane).
Site Sponsor
Old Oct 26, 2012, 08:02 PM
turbojoe is offline
Find More Posts by turbojoe
M0unt@in M0del$ minion
turbojoe's Avatar
Hey Andy, that would make a great "how to" thread for the new forum. Hint, hint, nudge, nudge.

Old Oct 27, 2012, 10:55 PM
Wehrdo is offline
Find More Posts by Wehrdo
Not failing=Not trying enough
Wehrdo's Avatar
If weight is of the essence, you can make one from plastic.

Make a foam plug like Andy said by carving/sanding a chunk or sheets of foam. I like to glue it to the firewall with hot glue and just sand with ~60 grit sandpaper OUTSIDE(foam dust is terrible).

Then cover the nose of the plane with masking tape where you want your cowl to cover. This part is similar to fiberglassing. Some also apply car wax to make it come off easier. Now, instead of putting glass cloth and resin, use paper mache. i.e. paper dipped in a glue/water mix. Try to use as little glue as possible so it dries quicker. Once all dry, pull off the plane. You might have to dig out the foam. It will be kind of flexible. Then fill with plaster of paris, and once cured, you can tear off the paper mache. Voila, a solid plug for shrinking.

For the shrinking, there's lots of info about that around. To shrink with a bottle, you need to find a PET plastic bottle that fits around your plug. Then you can heat with a heat gun to shrink. Or I've heated it over an electric stove.

Actually, if you have a vacuum former you can get away with just using the foam plug. If you're shrinking a bottle, the foam will get crushed by the force of the shrinking bottle and will deform.
Old Oct 28, 2012, 12:34 PM
mnowell129 is offline
Find More Posts by mnowell129
I'm not as bad as they say.
Epoxyglass over foam has it's merits. You can make fun parts like this.

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion What's the best way to make a mold for a cowl? whowhatwhere The Builders Workshop 15 Jul 30, 2012 06:19 PM
Discussion Best/easiest way to remote trigger NEX5N? aForcefulThrust Multirotor Electronics 2 Jul 18, 2012 08:54 PM
Discussion Easiest way to launch a DLG for a beginner nph Hand Launch 10 Apr 03, 2012 12:17 PM
Discussion Easiest way to make a fiberglass tube? gobigkahuna Composites Fabrication 29 Mar 12, 2010 10:19 AM
Discussion what is easiest way to make 3s2p ? submarco Batteries and Chargers 2 Sep 10, 2006 09:27 AM