Hi all,

I have a 2-part question. My original CA hinges that came with my LT-40 kit, the material has separated just on the corners of the hinges. I would say about 1/32" has separated from the plastic on the corners only. I went to my LHS and bought a new package of CA hinges. So here is my question. Can I go ahead and use the original hinges or should I replace them with the new ones? My other question is, on the new CA hinges there's a oval slot in the center of the new hinges about 1/4" long and 1/16" wide. Will this cause any problems when I get ready to wick my hinges with CA on my control surfaces?

Thanks
CC

Replace them.

I'd have gotten the Radio South Pro CA hinges, they are pretty darn bullet proof but the ones you describe I had on my first Funtana and they held up very well so no the slot isnt an issue.

The one trick to installing CA hinges is take a small drill (smallest in most drill sets, I forget the size) 1/16th maybe? Anyhow drill a hole down into the wing and surface in the center of the hinge slot, this gives better access for thin CA to wick into the hinger farther.

the trick is NOT to over glue them. add 3-4 drops per side (thin CA) and that's it, don't add anymore. you'll find hundreds of people in the hobby who'll curse CA hinges for everything they are worth because they do not know how to properly install them. if you over glue them they'll get hard and brittle, and will eventually fail at the hinge line. the slotted hinges (such as the Hanger 9) do not require drilling the hole.

kc

Thanks BaracudaHockey,

Yes I did drill a hole in all of my slots. Which brings another question. I'm using monokote and noticed, that after I cut open my slots again with a hobby knife, I can barely make out the center holes I drilled. Will the CA still wick down into the slot like it should? Once I put in the new hinges (withthe slot) will I still need to wick both sides, or will that slot make the CA wick onto both sides at once? Or should I try to trim out the monokote away from the slots?

Thanks
CC

you should trim the monokote about 1/32" back from both sides of the slot and add the drops of glue to both sides, but no more then 4 drops on the top and bottom, it'll wick to both sides if you add it near the slot.

kc

Thanks BarracudaHockey, and KC36330!!!!!

The purpose of this slot is to allow an easier path for the CA to wick deeper into the hinge pocket. Be sure to orientate the hinge so that the 1/4" slot direction goes into the slot and not parallel to the trailing edge.

Replace them. The slot allows the CA to wick in easier.

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 Bruce88123 and Dr1Driver.

I'm getting real close to finishing my build, and I sure don't want to rush anything now. I appreciate all of you responding to my questions. Thanks to all of you.

CC

A few years ago this question was asked so often that I did a "How-To" with illustrations on the proper way to install CA hinges.

Give it a look, it's short and to the point!

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

PS, if your hinges have the slot, you don't need to drill the hole, but you should still add CA (THIN ONLY) to both sides