Hi

I am putting fitting the CA hinges on a Kyosho Pitts Special.

I have read the advice in the below article.
But do not understand why I can't just apply the CA glue to one side of the hinge then insert it into the wing slot,
then apply to the other side and insert into the aleron slot. Why rely on on the glue Wicking into the slot??


http://www.rcuniverse.com/magazine/a...TOKEN=54846383

What am I missing?

The problem is, the CA will harden BEFORE you get the hinge all the way in. It pretty much bonds on contact, so you either wont get the hinges into the control surface properly, or you won't get the control surface hinged to the wing or stab correctly, because the CA gives you absolutely NO working time.

The wicking action of THIN CA is phenomenal. As an experiment, cut a short balsa stick about 1 inch long. Now place one of the long ends firmly against the end of your finger. Drop a couple of drops of THIN CA on the other end and wait a couple of seconds. It should be firmly stuck to your finger at this point. How did it do that, it wicked the length of the balsa stick.

OK, bad idea, don't try it. You may loose a little bit of skin getting the balsa stick off the finger, but I hope the mental picture works for you.

The fuzzy part of the CA hinge works just like the wood fibers in the balsa stick.

Ed M.

it's okey to ca the first part.
but i'm not fast enough for the second.

plus oil will break up CA later, espacially on the tail feathers or
on the hinges closest to the wing's root.

CA will also wick into the flexing part of the CA hinge..making it hard
and brittle. a rip or crack will develope later.
i draw a center line on the hinge with crayons to prevent epoxy from
sticking to the flex piont and clean off the epoxy as much as i can.

plus it also depends on how you cut the slot. if you used an xacto,
sometimes there's thin slices of wood in the slot. makesure you clean that out
or the hinge will only stick to that thin loose slice.

to put my mind at rest. i drilled tooth picks in the hings TE and control surface.
this will prevent any put outs.

i also seal the hing gap lines between TE and control surface with covering film
on top and bottom or both sides for the rear stabs.
it dose two things....prevent air leaks to the control surfaces
and prevents oil to the hinges

I hadn't heard this one yet. Can you provide some links to get more information about this?

Same comment. Can you point to some studies talking about this? Seems there must be thousands of planes out there about to experience catastrophic failure of hinges.

Not gonna happen with good hinges !
I have an Illusion pattern ship that was built in 1994 using Radio South
CA hinges and they're still holding strong. Most CA hinge failure is from
improper installation of inferior hinges.

tommy s

Thanks for all the replies guys.

The alerons are very small on this model 10" long and I have actually managed to apply the CA to one side of the hinge insert it into the wing slot,
then apply to the other side and insert into the aleron slot.

I probably was quite lucky to do them both on the first attempt, as you say, I could easily have been left with it set wrong.

Next time I will wick! Especially on larger models.

I would give them a good tug and hoep they don't come out. Also a good thing to do everytime you preflight. Good luck, you may need it.

Ed M.

Thanks -- here is progress so far....

Actually, I own 4 ARFS which came with these hinges and I installed them on all control surfaces by doing exactly that...I applied thin CA..I pushed em in one surface...I applied it to the other end of the hinge and pushed the surface in...all four at a time or whatever there was..3 on a rudder...4 on an aileron, etc.... all 4 plances have flown for a few years with no problems and I cant get them to come loose...also..they all went together easily and with NO gap..VERY VERY minimal gap....less gap than with the older metal hinge types...

Good luck he may need it? Read my post.....your pretty negative....the proof is in the flying for years....and I still cant get them to move......

Typed a great reply and got a server timeout. Lets try it again.

OK Sportair, educate me. Waht type and size planes have you got the CA hinges on that you jammed to no gap after you had put the thin CA on the hinge. Bet they are lightly loaded with small surface deflections.

First let me say I like CA hinges. I tend to use them on everything up to 1/4 scale. I also tend to use large surface deflections that will crack a nogap CA hinge in two.

This forum is littered with folks cussing CA hinges becasue of some type of failure, usually because of bad installation. I think if someone is going to use them they should at least learn one of the correct ways to do it. IMHO putting CA on the hinge and then putting it in the slot at some point is guarateed to lead to failure. If you have a way of doing it and making it work please make a vidio and educate me, I would like to learn how to do it.

Ed M.

What did you use to push the hinge into the slot with after you applied thin ca???
seems like the hinge would adhere to what ever you were holding it with.
Also, this would be a weak bond, although you are having success with it.
Be carefull of your control throws, if you have no gap for flex, one would
summize that the hinge would be in jeopardy of fracture not to mention you
are cutting your performance envelope with decreased throws.
Have fun flying, and stay safe.

I'm with you bentgear. The prescribed method of attaching CA hinges is the wicking method.
I would like to know how to push a strip airleron onto 4 or 5 hinges that that are wet with CA.
I don't think my hands could work that fast. At any rate, why risk the CA drying before the
control surface is in the correct position? I makes so much more sense to put the part in place
then add the CA! IMO it is a nobrainer.

Not true. Thin CA works on a capillary principle. That means it needs a porous surface to stick properly. If you put the hinge in one side and CA it in place, the CA will wick over the entire surface of the hinge and seal all of the pores. It still may stick in the other side, but the bond will not be very good.

Personally, I don't believe this theory. What's to prevent the CA from wicking UNDER the crayon? But if it blows your skirt up, I can't see that it would do any harm

Again, not true. The CA will wick into the balsa and glue the hinge to the slice, and the slice to the rest. However, it's a good idea to keep the slot clean so that the hinge doesn't push that slice in and jam things up.

The beauty of CA hinges is their ease of use. If installed properly, no pinning is needed

I use the crayon method,taking a crayon and drawing a line on each side of the CA hinge in the center,insert the hinge and "wick" it with the glue and I have never had one break,come loose,or get brittle,except in some of my crashes.[X(]
I like the CA type hinge on 40-60 size planes,they are cheap,quick and easy!