Firewall damage help

[darkwing52]

I was on my third outing with my Cub and have suffered a nasty crash. After a small tumble I didn't notice that one side of the elevator was bent slightly down so when I launched it again I had trouble keeping it up and straight ending in a glorious nose dive. Learned my lesson to do better inspections after even a small tumble.

I now have a wing snapped in half, smashed cowl, bent elevator and bent prop. The motor itself looks okay and when I spin it without a prop I don't see any wobble in the shaft. I did notice a crack in the firewall on the one side. It isn't bent out of shape but there are definite cracks.

My question is would it be okay to try to apply glue to the cracks to reinforce them or do I need to replace the firewall?

Thanks
Darren

[renard80]

Yes, you can repair a firewall. But you may find that its configuration has altered subtly, which could adversely affect the prop thrust angle and therefore your plane's performance.

Don't take my word for it, though. Wait for confirmation from one of the more experienced modellers on here.

If you do have to replace it, be extremely careful not to damage the underlying foam. Use a scalpel or other fine-bladed knife and take as long as it needs.

Do not use strong glues like epoxy or CA to apply a new firewall. They can damage the foam next time you have to remove it. I prefer silicone, the stuff used to caulk around baths, showers etc.

[flydiver]

You can try but nothing but heaps of epoxy seem to stick to the plastic and then that needs to be stuck to the foam. Makes an ugly mess that is awful to remove when you bust it again, and you will because it's not as strong as before, and it's in a vulnerable spot.

Replace as described above.

[nightflyer]

Also, clear packing tape or duck tape w/ popsicle sticks worked well for me

[darkwing52]

I managed to build up the courage to replace the firewall. It really wasn't that difficult at all. I carefully cut the old silicone with an exacto knife and gently pulled. I cleaned the old silicone and installed the new firewall using white kitchen and bath silicone caulking. It went back on straight and it seems really secure.

My plane is all back together again and I took the time to modify a few things like the battery box. I am just waiting for my new wing which I should have in a couple of days. I hope to be flying again by the weekend. ;D

Cheers
Darren

[renard80]

Pleased to see the job went well, Darren. I'm sure you did the right thing by replacing, not repairing.

[scubajohnny37]

Hey I'll give you a new firewall and save you the trouble!