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Questions on CA Hinges

Old 01-14-2008, 02:48 PM
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FLAPHappy
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Default Questions on CA Hinges

I have a question on CA hinges. Are they suitable for Large and Giant scale aircraft? Please advise me on this. CA hinges, In my estimation are a tad on the light side. P.S. I also pin both sides of the hinges, nylon or CA. Good and bad points in the CA hinge?
Thanks for your input
Old 01-14-2008, 03:02 PM
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Missileman
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Default RE: Questions on CA Hinges

I have never had a problem with CA hinges on my birds up to my Super Stearman with 25cc gas engine.
Included are a Showtime 90 and 1/4 scale RV-4 that have both been wrung out repeatedly.
Old 01-14-2008, 03:19 PM
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MinnFlyer
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Default RE: Questions on CA Hinges

I have used CA hinges on 150 size airplanes with no problem.
Old 01-14-2008, 03:33 PM
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Default RE: Questions on CA Hinges

The pattern guys use them all the time on their 2 meter planes.. I have them on my planes, Excelleron 90 and Venus II, both 120 size pattern planes. The Goldberg Tiger 120 has them, as well as the Seagull Super Star 120.

They work fine. Just use more than they suggest.. if they call for 4 of them on the ailerons, then use 5.

CGr
Old 01-14-2008, 04:31 PM
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Default RE: Questions on CA Hinges

Properly installed CA hinges I've found to be problem free.

As many advise, I drill a small tunnel down each slot to help allow the CA to wick deeply into the wood and hinge.

FWIW I really like the Radio South 1/4 scale blue hinges on anything larger.
Old 01-14-2008, 05:04 PM
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Dr1Driver
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Default RE: Questions on CA Hinges

I've used them on a 72" Fokker Dr.1 and a Giant Stinger. No problems. Use CA hinges specifically made for giant planes. Follow the installation carefully.

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 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 3-4 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 3-4 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.
Old 01-15-2008, 12:02 AM
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agexpert
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Default RE: Questions on CA Hinges

CA hinges are JUNK. On one glow plane I lost one aileron, one rudder and two elevator halves, (at different times), ...on a single plane. (If you count them all, I have had AT LEAST 18 CA hinges fail in-flight.

Before I went to gas and giant scale, I switched to Robart hinge points on my glow stuff. All of my gassers have pinned hinges wih Gorilla Glue and, if needed, CF pins through the balsa.

CA hinges are nothing more than a cheap way to sell an ARF. Upgrade your hinges or learn to fly with a broken control surface or two...very quickly.

There is one exception, Radio South has some Mylar CA hines which are excellent, but I still use pinned hinges in all my planes.


There will be many more who say that CA hinges are fine, and they ARE, if you don't actually USE them.


Run away....FAST. Get a Robart hinge-point drill guide and some hinges. Get some Gorilla-glue and keep on flying.

Have FUN!!
Old 01-15-2008, 12:17 AM
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Jarrah
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Default RE: Questions on CA Hinges

I would not recommend using these on giant scale espcially aerobats. why? well why take the risk. these have been known to fail on a lot smaller planes and i have personally had a whole aileron snap off (not pull out) using these hinges on a 90 size plane. Personally i wouldnt take the risk using these on a big model, grab some robarts
Old 01-15-2008, 02:11 AM
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Herb Brown
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Default RE: Questions on CA Hinges

The suggestions made by DR Driver are excellent regarding installation of CA hinges. One additional little trick is to draw a line on the hinge line on both sides with a wax pencil or crayon, before installing the hinge. After the hinge is installed and thin CA is applied, the CA will not penetrate the hinge line and the hinge will remain very flexible.
The heavy duty CA hinges from Radio South are very good for use on large scale models.
Old 01-15-2008, 06:13 AM
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Default RE: Questions on CA Hinges

One of the most important things to remember about CA hinge installation is NOT to apply the CA twice to a side. Once you have let the 3 to 5 or so drops of CA to wick in, do NOT add more to that side. Go on to do the other side and don't do anything further with the CA. Double additions will only cause the hinge to come apart inside where it had formerly bonded with the balsa. I had that happen to me on my Tiger 60 and ended up re-hinging the ailerons because of it.

CGr.
Old 01-15-2008, 08:32 AM
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Dr1Driver
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Default RE: Questions on CA Hinges

(If you count them all, I have had AT LEAST 18 CA hinges fail in-flight.

Then you're not installing them correctly.

Dr.1
Old 01-15-2008, 08:43 AM
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Default RE: Questions on CA Hinges

I must agree.. sorry Agexpert.. but the main problem with installation of CA hinges is not installed properly. That's not intended to be an affront to you, just a reality of what happens. Most of the problems I've heard of, both here and at the field, is when someone does the CA to them twice. The second application actually de-bonds the hinge and they come out, or become brittle and break or tear.

The big boys at our club all use the CA hinges with confidence.

Now, that's not to take away from pined hinges, and other types, just that I've had good experiences with them once I learned how to install them properly.

CGr.
Old 01-15-2008, 08:50 AM
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Dr1Driver
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Default RE: Questions on CA Hinges

I gotta say, in 25+ years I've seen CA hinges on trainers, sport planes, competition fun fly planes, sport models, giant scale, and even pylon racers. They work.

Dr.1
Old 01-15-2008, 09:57 AM
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Default RE: Questions on CA Hinges

Yup, Dr. They do work, and work well. As I said, my Tiger 60 had a loose hinge (think two of them, in fact) as a direct result of the double application of CA. I ended up removing the ailerons and re-hinging them. That plane still flys today.. and it's several years and many many flights old... and pretty well abused.. it was my second plane after solo and I surely abused that thing. Fortunately, the ones that broke were close to the fuselage and I noticed them right away.

CGr.
Old 01-15-2008, 10:33 AM
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flyX
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Default RE: Questions on CA Hinges

don't use CA on the CA hinges
mmm.. unless you're young and super dooper fast, fast or love the art of re sloting hinge slots.

I don't know...i like my control surface to be posistion as perfect as posisable.
By the time you set the CA bottle down...it's too late to adjust it.lol

You know how they say...apply CA to wood to make the wood hard...in the build process.
Will if you makie the hinges hard and then have a crazy notion of wanting to flex it a million times after.
I imagine a crack will develope.

I never had any problems with them in my .60 size model.
mmm..I don't know...I make extra slots here and there and prepare the hinge area accordingly.

Just makeusre it's done properly. Makesure the slots are clean...especially if you're using an exto knife.
Sometimes there's small slices of wood in there....so the glue will only bond to that slice.
That's where tooth pick or pins comes in to play.
Old 01-15-2008, 10:53 AM
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Default RE: Questions on CA Hinges

Again.. I don't know about that. If you plan ahead and do the hinge and surface right the first time, when you get ready to set the hinge with CA, you should already be there.

I have built quite a few lately with CA. One comment I got from the 'club pro', who has been building for over 35 years now, was that he was very impressed with my aileron, rudder, and elevator hinging on my Seagul Super Star 120. The gap was almost non-existent and the flexibility was there with complete movement available on all three surfaces. There will always be a gap present no matter what hinge you use, realizing the need for gap fillers, or covering that will eliminate the gap for better performance.

A lot of this is completely dependent on the initial setup and the proper slotting of the hinge line on the movable and fixed surface. Centering is really what it is all about, and having the centers really on center is very important. Of course, that goes for all sorts of hinging jobs, be it pinned, CA or whatever else you may want to do.

The nice thing about CA hinges is that you don't have to worry about geting epoxy in the hinge itself.. I know.. preventative measures are required, but it doesn't happen with CA hinges.

It again becomes a ford - chevy discussion. There are many people for CA hinges and many against as well as as many arguements for and against them. I prefer them, and will use them, and I ain't a spring chicken either...

CGr.
Old 01-15-2008, 10:58 AM
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flyX
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Default RE: Questions on CA Hinges

I don't mind a little gap here and there...if there was to be a gap...I like for the gaps to be same size gaps.lol
Old 01-15-2008, 11:23 AM
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Default RE: Questions on CA Hinges

Gap fetish, eh?
Old 01-15-2008, 12:52 PM
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Default RE: Questions on CA Hinges

I have them on models up to a 27% (43cc) Ultimate. Zero failures since I have been using them. I also like the removable pinned plastic hinges but CA is good enough for most applications. Check out MinnFlyer's tutorial. Drilling the pilot hole (I always do) and exposing the bare wood on either side of the slot appears to help a lot. I have destruction tested control surfaces on crashed models (can't blame a mid-air or a low roll ground strike on a hinge) and even after hard slams they outlast the surrounding balsa. I also use FRESH thin CA when it is time to hinge. Pin the center so you know you have equal amounts in both surfaces and drip 4 to 6 drops per side depending on size.

http://www.rcuniverse.com/magazine/a...?article_id=55
Old 01-15-2008, 01:01 PM
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MinnFlyer
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Default RE: Questions on CA Hinges


ORIGINAL: Dr1Driver

(If you count them all, I have had AT LEAST 18 CA hinges fail in-flight.

Then you're not installing them correctly.

Dr.1
Ditto.


ORIGINAL: flyX

By the time you set the CA bottle down...it's too late to adjust it.lol
Then you too are not installing them properly. They should be adjusted BEFORE the glue is applied.

I am amazed at how many people do not install CA hinges properly, and then discredit the hinges.

See the link Charlie posted above. Installing them is easier than any other hinge method I have ever used - and I have used them all
Old 01-15-2008, 01:06 PM
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Default RE: Questions on CA Hinges

Minn.. have you ever heard of what I mentioned about "double application of CA on hinges"? Meaning, applying the 5 - 6 drops of CA, turning the surface over, flexing the surface and applying 5 - 6 drops on the other side.. then leaving it alone.. double application comes in when people go back and add more CA after the original application?

CGr.
Old 01-15-2008, 01:44 PM
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Charlie P.
 
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Default RE: Questions on CA Hinges

Another note - they are Great for reenforcing attachment points for cowls. CA them inside the cowl centered on the screw holes.
Old 01-15-2008, 03:19 PM
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Default RE: Questions on CA Hinges

I have been using them for over 20 years, since they were the new hinge, and have never had a failure. Of course I'm the guy that reads the car's owner manual too! All of the failures I have seen is directly attributable to improper installation. The wax pencil\crayon tip is good, I'll try that. I also put two pins on the center line when I install them so the hinge doesn't push too far in one side or the other.
Old 01-15-2008, 03:33 PM
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Dr1Driver
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Default RE: Questions on CA Hinges

By the time you set the CA bottle down...it's too late to adjust it.lol
Go back and read my method. You adjust the gap BEFORE you apply the CA.

I imagine a crack will develope.

You imagine wrong. CA hinges are made of mylar with a cloth bonded to it. The CA soaks into and sticks to the cloth, it does not stick to the mylar which is the actual hinge material.

To restate my directions:
The CA should only be applied once to each side.
Only thin CA should be used.
The CA should not be allowed to puddle on the hinge or in the hinge gap.

Dr.1
Old 01-15-2008, 03:44 PM
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MinnFlyer
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Default RE: Questions on CA Hinges

Actually, the wax pencil/crayon trick really doesn't do anything.

If anything It's NOT a good idea.

Look at it this way. A CA hinge is a plastic ribbon with a fibrous coating on both sides. When you add CA, it wicks its way into the fibers.

When you draw a wax line on it, that line sits on top of the fibers - so the CA will still wick under it, but now you have created a barrier on top where CA can "pool" because it can't wick into the fibers like it's supposed to.
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