After a nasty encounter with a limbo pole, I've repaired my Morris Knife. I flew it yesterday and it flys well, however....

When it hit the pole the engine ripped out. It pulled some of the wood mount rails with it. I was able to piece the mount together using the same broken parts and 30 minute epoxy. When done, it appeared very strong. After flying I noticed that the mounts were starting to crack at the very end (front of plane) along the repair area.

What is the best way to repair this? Any pictures of repairs would be great. I thought about cutting the entire mounts out and using new wood, but I don't think it would hold any better that the original because they were somewhat "interlocking" from the breaks. Thanks.

I say cut the engine mounts out and use wood glue to glue a new pair of hardwood rails to go in there, You should be able to glue it to plywood right? I don't think that balsa is up front on those, it's not on my extreme anyway. I fly a pizza box flyer and run full throttle into the ground and don't do ANY damage to the mount, the mount on a pizza box is a 20" piece of pine wood glued to 2 6" oak hardwood rails. Don't use those same mounts, replace with new. just my opinion

yep, just like Joe says. Cut them out, and glue new ones in. You can use epoxy to glue them in also. Make sure you fuel proof them so they don't get soaked with fuel and eventually weaken.

This very thing happened to my SuDoKhoi... I just removed the broken out material and squared out the mounts... Then I cut a piece of hardwood to fit the broken out area. Next I drilled some 3/16" holes thru the new wood into the old wood at an angle. Epoxed the whole mess up and it lasted great.

paulswany,

Did you put regular screws in the 3/16 holes or bolt them? Do you think I could do that with the wood I already have epoxied back together?

No, I used 3/16" hardwood dowels.

If you still have fairly solid engine rails, cut a couple strips of plywood for each rail. Sandwich each rail between two strips of plywood. Epoxy and clamp tightly. Pin the plywood with dowels for extra strength if desired. Redrill holes and mount your engine.

Rein

HOPPY, I have a wrecked knife arf, but the front is mint, you can have it if you want to piece it out. If I'm correct your only an hr away.