I'm not really a beginner but this belongs in the beginners forum.

I have a plane with CA hinges that had a small accident. After a closer inspection I found that one of the CA hinges was damaged on the rudder. The fabric that is sandwiched on each side of the plastic came off leaving the fabric in the wood and the plastic on the outside. Whatever the solution I think I will end up having to cut the other hinges to be able to fix the problem.

Has anyone had to replace CA hinges and what was your solution?

Cut the other hinges, and sand both surfaces back down to smooth (actually, just sand the existing CA hinges, or carve with a knife, until you can't feel them anymore). Then, cut new slots just above or below the old slots, insert new hinges, and glue back into place. It's that simple. It will be impossible to replace one CA hinge without damaging the others, and chances are their integrity was compromised anyway!

Depends on the airplane. If its just a trainer or a general sport flying plane what 2 slow said is perfect. If you want the hinges to be prefectly centered again you can cut out the spot where the hinge was and replace the balsa. That is a pain in the butt though and probably not worth the trouble.

Sometimes you get lucky and there is just the right amount of space beside the original hinge location to put the new hinges. I have tried all 3 ways but prefer the latter if possible. I just dont want my hinge lines to be offcenter high or low.

Gents,

What I have done is to completely remove all the C/A hinges from a model that was given to me and replaced them with nylon hinges. I just used my Slot Machine with the thin blades installed and cut along both sides of each C/A hinge. The remaining slots are too over sized for C/A hinges but just fine for the thicker nylon hinges with a thick hinge glue.

JC

Hi,

There are many ways to skin a cat. I have had success in replacing CA hinges by cutting them flosh and replacing with Robart Hinge points by simply drilling through the centre of the old hinges.

Cheers,

Colin

Let's do this properly and neatly. Use a #11 blade to cut to either side of the hinge. Use a pair of needle nose pliers or hemostats to pull the hinge out. Fill the now wallowed-out slot with balsa and glue in place. Cut a new slot with your #11 and install new hinges.
There are several rules to follow for an easy, correct CA hinge installation. These rules are good for hinges from different manufacturers, including Great Planes and Radio South. I’ve used them on many planes from pylon racers to Unlimited class Fun Fly planes to even a giant scale Stinger (the 1/4 scale size hinges). I have never seen an in-flight failure using this procedure.

I have seen only two in-flight hinge failures. One failure was from catastrophic flutter, which also destroyed the wing panel. The other was due to doubled hinges and the use of thick CA.

Here we go:

Use a #11 blade to cut the slots.
Cut only once per side/per hinge.
Use only thin CA.
Do not double the hinges.
Do not use “kicker”.
Install after covering.

1. Slot the wood pieces, install the hinges, and mount the control surface. Gently push the pieces together.
2. Flex the control surface both ways for the maximum amount of travel you expect to use. This will automatically create the proper hinge line gap.
3. Slowly drop 2-3 drops of CA on each hinge at the hinge line on one side only. If any CA puddles in the hinge line, blot it with a paper towel.
4. When that is dry, apply 2-3 drops of CA to the other side of each hinge.
5. When both sides are dry, flex the control surface both ways.

That’s it! The wood will pull out before the hinge will let go. The surface will tend to stay centered and will not flop around. Both will help prevent flutter.

A simpler repair is to make up a few strips of covering as rolling hinges, thread them through the gap and iron in place. See the thread at http://www.rcuniverse.com/forum/m_11...tm.htm#1169731

Thanks guys! These are all great ideas!

I thought I would complete this thread by saying I repaired my plane. I used the Robart hinge idea and it worked very good.