Wednesday February 16, 2005

Did it again - cowl rework Geez my wife is going to kill me. So the fiberglass cowl off my Pitts S1 is causing the firewall flange to gradually fail, because the shape isn't quite right and it prestresses the flange. Then throw in a couple hundred hours if high-G pulls and pushes and the thing starts to fail. So for annual, I pulled the cowl off for some quick reshaping so that it matches the firewall. I can never get it through my thick skull that nothing in fiberglass land is "quick". steps:

1. create a female pattern of the firewall
2. transfer it to plywood
3. mount the cowl to the plywood to force the correct shape
4. fill the cowl with expanding urethane foam
5. Cut a good size section out of the cowl
6. reshape it with Bondo or sheetrock compound, making sure exit area is correct
7. apply mold release
8. lay in 3-4 bid of glass/carbon/whatever
9. tear out plug
10. Fill and finish glass
11. repaint
12. reinstall