Noobie here, first time plane assembler.

Putting together a 4star and the hinges it came with already have a slit in them. My question is, does the slit go parallel to the edge or perpendicular? The directions don't say and the photos in the manual aren't clear enough to tell.

Thanks in advance,

Don

Perpendicular

Thanks Steve

Your welcome. Have you read this article?
I don't drill the hole because I believe the capillary action is all that is needed.
http://www.rcuniverse.com/reviews.ph...ew&reviewid=55

Yeah, we read that, but it didn't say what to do with pre-slit hinges. I figured they would be weaker with the slit running parallel, but wanted to be certain. Kinda need the control surfaces to stay attached in flight.

Thanks again,

Don

Don, I rub a little crayon or candle wax along the hinge line of the hinges, about 1/8" wide, it will keep this area from soaking up CA and causing cracking and breaking later. I have not had one of these CA hinges break since I started doing this. I use a crayon that somewhat matches the covering color, so they don't show as white hinges when done.

The slot in the hinge performs the same function as drilling the hole. That is to say, it allows the CA to wick further down into the slot and then wick sideways. So if you have slotted hinges, the hole is not necessary.

Im gonna get in trouble for this, but, IMO, the hinges will serve you better if you place them in the garbage can and get some Dubro hinges or something else.
I just put a new 4* in last weekend due to ca hinge failure, the ones which came with the kit. The hinges, 5 of them broke into on the elevator.
I wouldnt listen to anyone regarding ca hinge failure prior to the crash, I thought if anything went wrong it was due to improper installation.
If and when you completely disregard this advice, you must inspect the hinges prior to EVERY flight, dont do as I did and become complacent because theyre ok every time you check, sure as you do, youll miss the one chance you get, maybe, to save your plane.
I installed ca's on 5 other planes with no problems, now, I find out another club member just had the same problem.

Anything can fail!!!!

You hit the nail on the head regardless of the equipment used in any plane A Preflight check of the aircraft should be performed before each flight and an inspection on the bench should also be performed from time to time. All things can and do wear with usage and age!!!

BTW I saw a plane with pinned hinges loose an elevator in flight.
so rather then blame this type of crash on faulty equipment use it to institute a more detailed inspection of your aircraft before and after flying. Even then there will be no garrantees that you won't loose a plane due to a mechanical failure in flight. You will however know that you did everything possible to discover it prior to flying. Then it becomes a matter between you and Murphy

Yes, anything can fail, however, considering the TLC I put into those hinges while installing them, Id feel better about them had they lasted more than maybe 15 flights and 2 mos..
I consider this accident my fault and take all responsibility for the loss, however, this is a beginner forum and used correctly, can be a great tool.
If, however, beginners arent exposed to all the possibilities, the threads they start cant be as helpfull,...can they?
Ive learned a great deal since I found RCU last Sept or so, but, I learned from taking ALL the info provided and making my own decision as to how to use it.
Just my thoughts.

No offense was intended!

And as you point out being expossed to all possibilities is a good thing. that was the point of my comment when something like this happens it can serve to highlight places were we are a little lax like a good preflight.

I'm guilty of this also. I can't tell you how many times I've just refeuled and gone rather then preflight inbetween sometimes I've had it bite me.

Like I said for every guy that mistrusts a certain type of component another will swear by it.

3rd failure I've heard about concerning Sig CA hinges.
My new pack is going in the garbage. Will continue using other brands until I have a reason not to.

flap, Please tell me exactly how you installed the hinges, how large or small your gap was, if you filled the gap or not, and how the controls were set up (ie as per the plans, or radical for 3-D) Also, how the hinges failed, that is, whether they broke, pulled out, or whatever.

MinnFlyer,
I used a hobbyknife to make "slits" for hinge slots, they were pefectly centered and cut prior to beveling the elevator.
I did not, however, drill a hole through the center to allow better "seepage" of ca.
I did a few simple tests and conviced myself that the hinges wick rather well without a hole and figured, theres more more material there for the hinge to "bite" into without an extra hole.
I used the thin ca as recommended.
The gap was unsealed and just large enough to allow the controll surface to deflect more than I knew was necessarry without any resistance.
Probably should have sealed the gap, this is the one thing I can think of that could have made the difference.

Hinge adhesion was not the problem though, the hinges are still, and will always be embeded inside the stabilizer and elevator and I cannot pull them out without tearing out balsa.


I dont think I understand what you mean about "filling" them?

I had dual rates set up on the radio, clicked them over a couple times to see the response, other than that, I only flew on low rates, as I was during the crash, less than the kit manual recommended. I was still getting used to the plane.

The hinges all broke in a somewhat jagged manor in the hinge gap.

Too everyone else,
What happened,Ill say again, was my fault due to the fact I failed to perform a preflight inspection sufficient to see there was a problem as I dont imagine all those hinges failed at once, though they all did fail within a short amount of time because, I have checked them before and the plane was almost new.

Heres an after, top left and before, top right pic of the 4*.
http://wtrcf.tripod.com/01_11_03.html

Flap, it's not necessary to take the blame. I don't think anyone here is trying to do anything but figure out what happened.

I just took a random CA hinge out of my parts box, and tried to tear it apart. No way. So I picked up two pairs of plyers, and tried again. No way could I tear that hinge. It stretched a little, but it wouldn't tear, and I'm a lot stronger than a servo. Try it yourself. So, if they didn't pull out of the wood, something catastrophic happened that 5 hinges would tear at the hinge line.

Since you were building a 4*, we can probably assume they were Sig hinges. Did they have a score on them, such as Don Davis was talking about when he started this thread? I haven't used SIG hinges in a while, but it sounds like they now have a slit on them that wicks CA into the wood. Is it possible you installed them with the slit parallel to the trailing edge?

Another possibility is that something (nitro or CA or ?) attacked the hinge and weakened it. I'm going to soak my test hinge in thin CA, let it dry, and then repeat the test.

I think we're better off if we apply some science, and figure this out rather than blindly scare folks away from CA hinges. I've used other hinges, and CA hinges are about 100 times easier to install on small airplanes.

Hi Pinball,
I believe the ca got into the center layers of the material and became brittle where the hinge bends, causing them to break like anything stiff thats folded back and forth over and over again.

Im sure the hinges were Sig, they came with the kit.
The hinges had no score on them, they were rectangular in shape and if installed accoding to the plan, no way to get it wrong.
If I understand correctly, the "score" is there to provide a wicking chanell to aid in proper distribution of ca throughout the surface of the hinge?
If Im right here, having the scores wouldnt have helped because the hinges are still very secure in their slots.

Agree, ca hinges are at least 100 times easier to instsall,.........the 1st time

Dont want to scare anyone, just would like to think something good came from this.

I've discovered that with a little trial and error, I stumbled on a technique where I can actually tear a CA hinge in half, almost as easily as if it were paper. This is a brand new hinge that never saw a drop of CA. Basically, it's a bit resistant to tearing, but once it starts to tear, it tears without any effort.

So... What to do? I'm currently building a .40-sized profile fun-fly that (like most) has big control surfaces. Anybody got any good ideas on easy to install hinges?

Hey pinball, now you've got me very worried. All my three planes are on ca hinges !! I used the ones from GP exclusively. Which one did you test, SIG, GP, or Radio South ? Maybe not all ca hinges are created equal ?

First, I have to say, I have planes with CA hinges that never gave me any problems, but they had smaller control surfaces and much less control throw than the plane I'm building now. Right now, I'm flying SPADs, so it's not an issue except the plane on the building board.

I can't say what brand the hinges are, they probably came with a kit, but I have no idea.

Obviously, there's a zillion planes out there flying on CA hinges of various brands. I'm not sure what I'll do.

Mabey you guys have some input on something I did with my CA hinges that now has me worried.

I installed the hinges on the ailerons and wicked them in. While I was doing this I noticed the CA climb the uninstalled side of the hinge like water on tissue paper. Obviously it dried and I am wondering if it has lost its ability to soak up the CA once I try to wick them into the wing. What do you guys think, did I make a grave error that needs to be undone before I install the ailerons to the wing ?

Thanks for the input.
Ron

YES! if you didnt have the hinge in the wing AND the aileron, you have screwed up.
try to remove the hinge with pliers, if it doesnt give up, cut it off flush and cut a new hinge slot beside the old one and do it right this time.
If you just gotta use those things, CHECK THEM OFTEN.....Please.

Flap,
What would be a viable alternative to CA hinges ? I have seen the plastice ones that resemble a series of cones for grip I am sure. Are they any good ? Years ago I heard of using monocote in an over and under pattern but since nobody seems to discuss that application during my lapse from the hobby they must have proved unreliable. Any suggestions ?
Thanks
Ron

This is the reason you should use a crayon or wax candle to rub on the hinge line of the CA hinges before installing. It will keep them from hardening in this area and breaking.

Pinball, I found many different sizes of pinned Dubro hinges available at our LHS after my crash.
The ones I chose are relativly small and looks like its going to be a pretty simple install.
I read a thread advising to cut a bit larger slot than necessary to get the hinge in and use a straw to draw some epoxy, squeeze the end flat and stick it into the slot then squeeze some in.
After that, Im going to drill in some dowels (toothpicks) from the bottom side so as not to penetrate the top covering and glue those in also.

I've used Sig CA hinges for years and never had one pull out or break. I've also never drilled a hole.

I've been putting off using the CA hinges with the slit, as I didn't know how they'd hold up. I watched one of the most aggressive flyers in our club throw around a Pizazz with this style hinge. If they work on his plane, then I figure they'll work on almost anything.

Come to think of it, I don't really see much of a time savings with CA hinges. It always seems like one or two gives you fits. Also, the CA seems to run everywhere and turn the covering white. I'm trying odorless CA this time, but at $10 a bottle, I think I might go back to the pinned hinges. I never glued the pinned hinges, but used toothpicks instead. The straw idea with epoxy does work great though.

Robb