repair help...
 

Hey all,
Well, I broke the glue joint on my h. stab today, and i'm trying to figure out how to repair it. The fin is still attached, as is the dorsal fin to the fuse. How should I go about seperating the parts. Should I cut the dorsal fin off the fuse, or cut the vert. stab off the dorsal fin.
Thanks
-John

RE: repair help...
 

It might help to know what kind of model you have.

RE: repair help...
 

Sorry. GP PT-40
-John

pics here. http://www.rcuniverse.com/forum/fb.asp?m=4095267 Not of damage, just the tail config.

RE: repair help...
 

If I understand correctly what you said it sounded like you just broke the glue joint. Is that correct?? Not the actual wood? If so remove enough covering so you can access the joint and reglue into place.

Ken

RE: repair help...
 

Yes, that's correct. So I just kind bend it enough to squish some epoxy under it?

RE: repair help...
 

Sure, if you can get it back together that way go ahead and do it. Was it an epoxy joint that broke???

Ken

RE: repair help...
 

Ya, suprisingly enought it was a 30 min. epoxy joint. Hehe, I actually didn't notice it till I was leaving. I thing I did it, on a take off, where the wind threw it 90 degrees after lift off (cross wind), instructor took control but had the throttle at idle when flipped the switch. Plump;) Lol. I thought everything was ok, so fired it up and went back up. STill cranked when it broke ground, but no problems. Leveled it, and just kept climbing. Uneventful flight. Did a little slow speed work, keeping it stationary in a kinda harrier position into wind, then brought it down for a pretty smooth landing, if a little bit far down the runway. Then when I was cleaning it to put it car, I notice the horizontal stab is wiggling. Ooops. Lol. I'll see if I can get some epoxy under there.
Thanks
-John

RE: repair help...
 

That seems to be a weak joint. I had the same problem on a PT-40 about 18 years ago, when the plane was first introduced. Think about reinforcing the joint with some tri-stock. Check the C.G. after the repairs.

RE: repair help...
 

Do like nickj mentioned. Epoxy it back in place and then reenforce it with some tri-stock to keep it from happening again.

Hope this helps

Ken

RE: repair help...
 

You named the real problem. 30-minute epoxy is too thick to properly soak into the balsa. This creates a "surface bond" joint that looks and feels strong until extra force is applied. Then it breaks. I have not used any type of epoxy for construction in my planes in the last 20 years. I use exclusively thin and thick CA. To date, I've had no in-flight structural failures on sport planes, pylon racers, warbirds, and giant scale planes.

Cut the joint apart, peel/scrape off all the epoxy, and reattach using thin CA. The tristock mentioned by other posters is a good reinforcement method and can also be CAed in place.

Dr.1

RE: repair help...
 

Hi guys
sounds as if that joint needs strnghthening i would remove the stab and refix it with a cocktail stick inside it glued in with epoxy and when the joint is closed run some cyano in.