This is a slightly condensed version of a Feature article by Chuck Doyle on building a Travelair cowling. See the full version.
I've been fighting the two upper cowl pieces for the
Travelair and making slow progress, First you must have a form or
buck to work with, you just can't build a piece in outer space.
Use a shot bag and forming hammer to rough out the shape for the
material before any wheeling is started, I had a difficult time
hammering mostly because I'm right handed but could only work with my
Check, pound check and recheck you rough forming, I is far easer to
work the material up to you form and if you go to far it might end up
in the scrap pile?
Select the anvil wheel that is closest to the radius of the piece your
working on, and then start wheeling with light pressure. Work out the hammer marks, do
not let the wheel fall off the edge of your work, check your work on
Don't get in a hurry, check you work on the buck and on the
airplane. Outside profile gauges are very helpful as well so you don't
over stretch your piece.
Your material will work harden after hammering and wheeling so it is
sometime necessary to anneal the piece, for this part I'm using
3003H14 0.032 thickness.
Use the standard W pattern keeping it close or you will get ripples
in your work.
Did I tell you to check your work on the buck and the airplane? than
check in once more before going back to the wheel.
I use masking tape to hold them down too eyeball for final fitting,
this is the most difficult part of the whole project and the most
important, easy as 1, 2, 3 right?
I didn't want you to think I didn't have any trouble with these so
here are just a few of my rejects! Enjoy your day and...
See ya Around the Patch!