I am building the H9 XT 40 plane and I have a question about gluing the hinges on the ailerons/wings. It say to install the hinges using a T-pin to make sure it’s halfway in the slot and then remove the pins and while holding the aileron and wing together, then apply CA to both the top and bottom joint areas. Would it be better to first glue the wing hinges in place while holding the wing upright “to let the CA wick into the slot and hinge. Let dry, then put the aileron on and glue them on while holding the aeilon upright. I just think that more CA will wick into the slot my way then just CA’ing the hinges all at once.

Thanks in advance--------------Stashu

Absolutely not. If you try it your way you are going to wind up with and aileron (or other control surface) that you can't attach to the plane any longer. As soon as you apply CA to the hinge it wicks to the ENTIRE hinge and seals the fibers. When you apply the aileron and put CA on it the adhesive can no longer attach to the fibers of the hinge. This will cause the aileron to not adhere to the hinge, which can be very bad in flight because the aileron will pull off in flight. You need to think of the CA hinges as a "one time only" material. You only have one chance to apply CA to them.

You need to follow the instructions completely when installing the hinges. Otherwise you're going to wind up with the plane in a trash bag. Do exactly as they instruct you to do.
1. Install a pin on the halfway mark in the hinge.
2. Insert the hinge in the wing all the way to the pin
3. Install the aileron on the hinges and push all the way to the pins
4. Flex the aileron away from you.
5. Apply CA to all of the hinges and wait for a few minutes
6. Turn the wing over and flex the aileron away from you
7. Apply CA to all of the hinges and wait for a few minutes
8. Now flex the aileron back and forth several time to flex the hinges.
9. Pull on the aileron to ensure that it is firmly attached to the wing.

Doing it any other way will result in disaster

Hope this helps

Ken

CA Hinge Installation

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.

Dr.1

Thanks for setting me straight on the hinges. I will take your "and the orginal instructions" information and do it that way. I did not realize the ENTIRE hinge wicks up the CA, making a bad joint if done my way.

THANKS again!! Stashu

THANKS for the info!!


Stashu

Wow I was just doing this job on a Chinese ARF trainer. All the directions say is to use CA on the hinges - thats it!

I had to recut every single hinge slot so I could get the hinges in all at the same time.

Then I put it all together dry and marked the hinge centers with a felt tip pen.

I then put glue on one half of the hinges and sliped them into place.

Next I put glue on the other half of the hinges and tried to put the eleveator etc on. I knew this was going to be hard to do in 20 seconds before the CA set! It sure was hard to get the hinges to slip in all the slots at onece. I had to re apply the glue and clean out the slots again with the knife.

ARE YOU TELLIING ME THAT I CAN ASSMBLE IT DRY AND JUST PUT THE CA ON THE OUTSIDE AND IT WILL SOAK UP INTO THE SLOTS?!!!!? Wow would that be easier!!! It just doesn't seem like the glue would get in there where it needs to. Also I was worried about the hinge getting stiff if I got glue into the part the flexes.

Please let me know if I have this right. I still need to do the Ailerons and they need epoxy and CA at the same time and I couldn't figure out how I was going to do that!

My elavator locked up slightly off to one side. How hard is is to re-hinge if I cut the hinges. Is it possible to dig them out and start over?

chevy, That is the same way I did my very first ARF too. I didn't know any better. It cost me that airplane over a year later when I finally got to where I could fly it, the elevator halves came off in air after only about 10 flights. I do them the right way now. They come out looking great, they're stronger than ever & only take a few minutes to do. Talk about learning the hard way huh?[sm=idea.gif]

Is the slot that is in the hinge for the glue to get down into the wood?

Chevy,

If the control surface isn't cocked too much, leave it. The servo will center it. You can dig the hinge out of the wood by slicing on either side of the hinge and pulling it out with needle nose pliers. Then glue in some scrap wood to fill the slot and re-cut it.

Dr.1

Dr1, Would it be better rather than try to dig the old hinge out, just to to re-slot & hinge next to the bad hinge? Then he could just cut the bad hinge off flush at the hinge line. Just a thought, because I tried to dig one out once too. I ended up butchering the aileron so bad I had to break down & bought a new set.[&:]

I believe digging the old hinge out would be the right way to repair this. If he works slowly, there shouldn't be too much damage to the wood. Gluing the new hinge in the same place as the old one might inhibit the flexing. CA hinges don't like sharp edges and stiff/too much glue. It might be possible to cut all the old hinges apart and glue new ones right next to the old ones.

Dr.1

Yes, That is what I was thinking. He would defenitely need to get the old one cut down flush to the control surfaces or as you said, any remaining lip of a hinge sticking out would cause a bind. Thanks for the quick reply.

Ya know I've been coming in here for over a year now & I've learned most of what I know right here on RCU, but I still learn new stuff in here all the time!

grump, I've been in R/C over 20 years, and I still learn new things. RCU is a great open format for information, reviews, and techniques. There are always several ways to do something, and there USUALLY isn't one RIGHT way. Each person uses whatever method they find workable and easy. The keyword there is "workable". It HAS to work first and foremost.

Dr.1

I heard that drawing a line in white crayon will prevent the ca from wicking into the portion of the hinge that has the line on it. This would be good for prventing the hinge line from getting stiff.

CA hinges are designed to get CA in them and still flex. After the CA sets give the surface a couple of moves back and forth and the hinge line will be freed up so that it has plenty of flex in it. Drawing with crayon on the hinge has no effect to keep the CA out because the CA will just wick up under the wax from the crayon.

Ken

Chevy, Yes, that's exactly what that slot in the hinge is for.

If the hinges you are using are not slotted (Most aren't) you can drill a 1/8" hole in the center of the hinge slot to achieve the same thing.

Guys, please take a minute to read the "How To" I did a few years ago on CA hinges.

Just click on the link below:

[link=http://www.rcuniverse.com/magazine/article_display.cfm?article_id=55]How to install CA Hinges[/link]

I’d like to add one more thing on the hinge question. I was looking at a bottle of thin CA stored in the cellar opened up about 4 months ago. I compared it to a NEW unopened bottle of thin CA and the old bottle appeared a little thicker. I guess it thickens up over time "moisture"??—Anyway I am going to use the NEW bottle to be sure it wicks into the hinge.

Thanks !! Everybody for all info!! Stashu

CA can get old and thicken up, especially in a humid atmosphere. Store it in a refrigerator.

Dr.1