Hey guys. I am currently working on my next project and had a real quick question. Having never used CA hinges on my previous apps, the instructions say to push a t-pin through the center of the hinge, insert it into the wing half, and then attach the aileron to the other side of the hinge before using CA? Does the hinge wick up all the CA and disperse it to the sides that are inside the wing and aileron?

Sorry for the stupid question, but on all my other planes, I used plastic hinges and epoxy rather than CA hinges.

Thanks and Merry Christmas to everyone.

Derek

Derek, CA Hinges are great but they MUST be installed properly.

Here's a handy little "How To" for installing them.

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

And for a quick answer to your question, Yes, you have the aileron hinged to the wing BEFORE applying any CA

Read the "How To" and you'll see why

Hi!
Using CA hinges is easy. Just push half the hinge inside and drop on some thin CA (I use Flash). Then do the same with all the other hinges...when the glue has dried ...attach the rudder /elevator /aileron and observe how it fits...if everything looks OK drop on some CA onto all the hinges and hold still and push hard against the wing/stab/fin so the gap becomes more or less non existent. When everything has dried ...wick the control surface side to side /up and down to control that it is moving freely
Using a pin to hold hinge is not necessary and I don't recommend using one either.

Regards!
Jan K
Sweden

NO!!!

That is one way to get CA hinges to fail!!!!

The hinge MUST be inserted into BOTH sides (Wing AND Aileron - or - Stab AND Elevator) BEFORE applying ANY CA!!!

The reason for this is that THIN CA (And when working with CA Hinges, THIN is the ONLY kind that should be used) works on a capillary principle. That means it needs a POROUS surface to wick into.

If you insert half of the hinge into the aileron and apply CA, the CA will wick into the pores of the entire hinge sealing any pores in the exposed side. Now when you put that side into the wing, the CA doesn't have a good surface to grab on to.

Thanks for posting that link, MinnFlyer. That pushpin idea is great to keep the hinge centered while inserting the control surface.

MinnFlyer's advise is great as always!! And as he said a BIG no NO on C A'ing
half of the hinge!! Install both sides and wick the C A while flexing the surface...
I've used the crayon method and I'm also unsure of the need for it.. Seems to
me the C A wicks so I'm unsure how much would be "un-C A'ed"???
The other thing I wanted to say was a few also drill a small centered hole in the
middle of the hinge slot to "assist" the wicking action in spreading through out,
I have never done this, as my C A hinges has never pulled out.. But I have had
a few break.. The gap was good... But I may have used too much C A.. But they
were on high mileage 3D planes also, So I'm not sure what or why?

Hey derek! What plane are you working one? The Cap or the Laser?


The CA hinges are really cool. Listen to Minnflyer, you want the hinge installed on both sides and then add the glue. You can see the thin CA wick very quickly into the wood.

Neither Septic, it's a H9 Twist. I was told by you know who, that on low rates, it'll fly as slow and floaty as a trainer but it's ready for 3d when I am. I figured since I already have a sport flyer in the Cap, I would get something a little different this time. It'll be powered by an Evo 46 that you know who (again) recommended to me. I am hoping to have it done by New Years for the fun fly but we'll see. I thought I didn't have any servos and was going to have to purchase some more, but I was able to scavenge my old stuff laying around. I have three S3003's, an old Hitec 303 and a newer 3004 (off my Mach I, the only surviving servo). Basically, it's a hodge podge of servos but they all work and the Twist is so light (b/w 5-6lbs), they'll do just fine.

twist? I've heard it's alot like the SSE, but more 3D capable. Heard great things about it. You will enjoy it!

As allways, Minn's advice here is true & sound! I have used the drilling of a small hole method & it worked extremely well. The CA hinges I was using had a small slot cut into the middle of them anyway, & the drilling a hole was a tip in the instructions that I chose to take the time to use. It also had me using the pin to center & create an equal gap along the entire hinge line. I simply put the hinges & control surfaces in place with the pins in the small slot of the hinges, then using a pen marked a small dot at the center of the hinge slot on both sides of the surfaces to be hinged ie. wing & aileron. Then I took it back apart & using a very small drill bit I just hand drilled the tiny holes about 3/8" to 1/2" deep into each side of each hinge spot. Then put it all back together using the pins for gap alignment, and as Minn said, used no CA untill it was allready to be glued at once. I used very thin Zap CA & squirting it into the tiny holes I had made that matched the slots in the hinges, it just flowed right into the wing & aileron, then flipped it over & repeated myself on that side too. All of it wicked together at the same time, and it was very evident to me that I was getting a sunstantial amount more of the CA down into the hinge wing & aileron than I ever had before without the tiny holes. In just a matter of a few seconds I litterally could not budge that aileron. Because of the pins I had a perfectly even tiny gap the distance of the control surface. I'm sold on this method & it is the only way I will install CA hinges from now on. I this info helps.

Merry Christmas!!


Mark

Actually, I think the "pin in the center" is for a couple of reasons. One of the most important is to keep the hinge from being shoved down into one side when you put the surface onto all the hinges. You really do want all the hinges to be equally into the slots on both sides of the hinge line. And it's also nice to have them square.

The most recent ARFs I've stuck together came with the hinges in and the surfaces in place but not CA'ed. One instruction booklet even suggested that saved me time. NO! Not even.... Bad idea! Heck, one of the hinges on that ARF was stuffed almost completely into the wing.

You really should make sure the hinges are not stuffed into one side. I always take the surface "off" and check. Truth is, what I'm doing is checking each hinge and placing it into the side where the slot is tightest. I don't bother with the "pin through the center" but that's because I am so careful. I draw a very light pencil line along the centerline and watch all those lines as I'm putting the surface back on. Some hinges wind up in one surface, and some in the other. That actually makes it easier sometimes to get the two sides back together, sometimes it makes it harder. But even when it's harder, it ain't no big deal.

One thing I have noticed that seems worth mentioning in this thread.... It seems to be a good idea to me to put more than one drop on into "the joint". One never seems to be a safe amount. A second drop after a second, and maybe a third. And then go to the other side of THAT hinge. I want to CA the other side before the CA kicks. The first side application might wick around and seal off the the very center of the other side and I'd have a one sided seal.

Another thing I'd like to mention. I've found it very sensible to run the UltraCote iron over the hinge lines before I hinge 'em up. A bunch of ARFs have had the covering in those gaps just there, along for the ride, not actually stuck to balsa. The CA wicks off everywhere under that stuff. Seal it down and very little wicks off to NAIL DOWN that covering that ought to have been sticking to the wood already.

And yet another.... I watch the CA wick into the slots very carefully. I always try for zero hinge gaps, and even when they're not touching tightly that CA can wick down along the line. I certainly seals the hinge line then, but the first ARF I made wound up with a rather stiff rudder, and the stiff came from the entire hinge line being sealed by CA. CA doesn't want to "hinge" very gently. I've since learned when to stop with the CA, but have noticed that often it's even the first drop that goes everywhere.

It's almost all technique. Every detail. But better technique is what makes your airplane better.

Good points darock!


Mark

GUYS:

All are excellent ideas except for the CA'ing one side then the other. They must be done at one time. Here is one other thing I do as I lost a plane to CA hinges. As I watched my beloved LT40 go 90 degrees nose down into the ground I could see the elevator flapping in the breeze. Needless to say my biggest piece was the engine. Anyways since then I see where some poeple would insert a small piece of wood thru the hinge from top to bottom. They would do this after the covering was on. I took this one further. Once im ready to install my hinges I make sure everything is where I want it cut the slots for the hinges and install them. I make sure it moves freely and no gaps are present. Then I remove them instead of glueing them. I get my covering and I cut it to fit over the training edge of the wing and iron it on, I do this on the same for the leading of the control surface. I then get the hinges install them and align it so it fits the way I want it, and then CA it as normal. ( all I have done is install covering in the gap on the leading edge and trailing edge). next I drill a small hole about a 1/16" thru the wood that is holding the hinge and thru the hinge from top to bottom of the wing. I then install a small balsa stick into the hole thru the hinge, and sand flush. The sanding takes a little time. When all the hinges have been installed with the stick and glued and sanded I get the iron back out and iron the covering down. I usually iron it up to the edge when the ribs end at the trailing edge so when I go to finish coveing the wing you wont see a seam. The covering I usually take right to the trailing edge this make a nice neat covering job. Also you cant pull the hinges out. I now have extreme trust in my hinge job. The other reason I do this is that I usually can see the hinge as it is in the wood so Im not totall convienced that the glue did its job. This is just an added piece of insurance on my hinges.

If you guys want I could do photo essay on how I do them.
Alan

This is actually a bad idea, and a leading cause of hinge failure.

Since I can't show you, you'll have to try to imagine this...

Ok, you have an Elevator hinged to a Stab - but not glued.

You press the elevator against the stab so there is no gap.

Now, flex the Elevator both up and down about 45 degrees, then bring it back to level.

Do you see how now there will be a slight gap? (If you don't think it will happen, try it with a few pieces of scrap)

This gap is essential!!!

Flexing the Elevator up and down caused the hinge to pull out slightly. The hinge was PRIED out of its slots by the LE of the Elevator pushing against the TE of the Stab.

Now, if you do not allow for this gap, every time the elevator moves, it will pull on the hinge thereby stressing it. This can VERY LIKELY lead to an eventual hinge failure.

SO LEAVE THAT GAP!!!

This is why, if you read my "How To" you will see that it says to "Flex the hinge MORE than it will move in flight" and with the hinge in THAT FLEXED POSITION, add a few drops of CA - That way, when it returns to center, the gap will be set by the motion of the control surface.

Just one more thing to add to MinnFlyer's great response.
You may want to seal the gap with tape or clear monocote to get better reponse and help eliminate flutter.
When sealing the gap, be sure to follow the contour of the fixed surface and the control surface edges and not just go straight across the joint. If you seal the gap straight across, you will restrict the movement of the control surface.
Maybe MinnFlyer could add one of his great drawings to this to clear up what I'm trying to say.

Already have one JR

BTW, I used to always seal hinge gaps, but more recently I have stopped. I will do it if I find a plane needs more control response, or I would do it if I heard Flutter, but sealing a gap does not mean you won't get flutter, nor will it necessarily prevent it - but that's another topic of discussion.

What exactly are you guys using when you seal your hinge gaps? Do they sell the covering in a pinstripe type form?? Thanks in advance.


Mark

I just use celophane tape. Some guys cut monocote in 1/2-3/4" strips and iron that on.

Jr is correct, just about anything will work.

I've used both covering and Tape - Tape is easier (no ironing) but covering lasts longer.

Cool Thanks guys, I'm off to the not so LHS, as the Dragon Lady has just arrived, woo-hoo!


Mark

Sweet!

Enjoy!

Hi!
Strange MinnFlier??!!.... On all my airplanes, F3D pylonracers, Q-500 racers,scale, twin engined, sport, combat, aerobatic airplanes, since Ca hinges came along... I have use the same metode...glued in all the hinges one side first and then let it cure. Then test fit the aileron/rudder/elevator and glue the other side in, pressing it in rather/fairly hard so that the gap is nonexistent or there about... and I never have had any hinges coming lose...I have even used kicker to have the thin Ca (Flash) cure faster without any hinges ever coming loose.
Come on guys...![>:]

Since on the subject MinnFlyer
You said you stopped on BTW, "I used to always seal hinge gaps, but more recently I have stopped. I will do it if I find a plane needs more control response, or I would do it if I heard Flutter, but sealing a gap does not mean you won't get flutter, nor will it necessarily prevent it - but that's another topic of discussion. "

How do you test this or listen to it ? Many times I hear this an don't understand the whisle or swooooo sound. When does it become destructive an then to put tape on hinge to stop.
A repley on your test method or concern of level of sound I would read an learn from thanks in advance
Rich

I'm sorry, but trying for a zero gap works likes gangbusters.

Do I ever get one? Have you ever? Has anyone? Sorry to have caused you concern, but I should have typed a lot more words and described what I do in detail. I actually try for as close a gap as inhumanly possible and almost always get it. I also will use nylon mechanical hinges as my preference because they will have almost zero resistance to the surface movement yet are almost bulletproof in strength and wear. And whenever I can, I also use wire in metal tubing along with those hinges. If I have a steering tail wheel that's driven by the rudder or if I have torque tube driven ailerons, there will be wire that does the driving and with some design effort, I can run the wire through a tight fitting tube. The tube will then be attached to one side, and the wire to the other. It gives a massively strong hinge that is awesomely free of resistance. The sucker always happens to be quite a different dimension compared to the nylon hinges and takes some craftsmanship to have the different thicknesses built into the two surfaces so that they have a common hinge line. And that works like gangbusters also.

As for zero hinge lines actually opening up or whatever it was they were supposed to be doing wrong. I just came back from the flying field where just a couple of hours ago I was holding up my Hots against the setting sun so the guys could see that in fact, you could see light along the hinge line. It happens to have wire/tube hinge, nylon hinges and "alternating crossed fabric" hinges all on each of the ailerons. And it was built in 1980something and is into it's 3rd engine. I tried for zero gap on that airplane and darn near got it. And it flies just awesome. And after a lot of real hard use, you still have to hold that baby up to the light to see through the hinge line.

BTW, almost all nylon hinges and any one made with "hard" materials will have some tolerance that allows them to allow the hinge line to open up. That is, if they are installed very nearly "square" to the hinge line. So I don't. I alternate them being about a degree out of line. And that way I can get the movable surface to stay almost zero distance away from the surface it's hinged to. In theory that's not a good practice. In practice it's an excellent practice.

BTW, my practice of putting a couple of drops of CA on one side of a hinge and then hitting the other side of the same hinge quickly with a couple of drops also is an excellent practice for me. I guess I don't understand what could be wrong with it. It certainly has insured that I wasn't forgetting to glue both sides of any hinge, and it's insured that both sides have a chance to wick before the CA applied to the first side kicks and seals just a small area of the other side to future wicking when you try to apply CA later.

You know, I have noticed that for any building task, there is almost always way more than just one technique that works well.

jaka,
I've done just what you said and had exactly the same results. Great results. But I think the horror at that technique is that it MIGHT inhibit the wicking that happens later when we have slid on the surface and start to CA the other half of the hinges. In practice, it worked for you and me. There is a chance we might be doing something different that others don't do, or aren't doing something that others do. Or it might be that one brand of hinges reacts badly with your technique and you haven't used them. (I doubt it, all the brands of hinges I've seen look like they would wick ok)

Some of the theory of hinging with CA hinges does sound like it'd be the reason for the statement, In theory, practice and theory are equal. In practice they are not.