I am sealing the gaps on the ailerons of my Seagull Yak and was wondering if I need to stop at the CA hinges or just go right over the top of them?? The article in the AMA mag on hinge sealing used robart hinges and I can see that you should work around those but the CA hinges seem to be exactly on the center line and it seems like I can just go right over the top of them without issue. What do you think???

Just go over the top of the CA hinges ! No problem !

jvino,

Yeap, over the top of the hinges. I'll normally cut a few short pieces and over lap them when I seal the gap. Less chance of getting a lot of wrinkles in the covering. Seal on the bottom only.

Do you do that with monacote?

Seal over the hinges as stated, but I diisagree with only doing one side. Do both sides and seal the covering to itself in the gap. This creates one long hinge and prevents oil residue from getting under the covering and into the hinges. Make sure you move the surface all the way to maximum deflection before as you seal the second side. Use clear Monocote if you can't match the colors.

You can seal both sides if you like but it's not nessesary. If your using CA hinges, the CA glue once applied during installation will harden the hinge so if any residue from the exhaust gets to the hinge it will do no damage. If it does then the hinges were not properly installed. Been doing this for over 15 years, never has a problem with sealing the bottom only. All it's for is to keep the air from passing through and causing flutter. It also makes for a more stable flying plane.

While you have your iron set up and other stuff, it is only a few more minutes to to do the other side. This makes a fuel proof, tight, seal, if your careful to seal the covering to itself. Sealing only one side takes care of the any escaping air through the gap, but does nothing to fuel proof or strengthen the hinge line, especially with CA hinges.

PS.........I have been building and flying RC for 38 years. Now this doesn't nessasarily mean anything. I could have been doing things wrong all these years, but in this case, I don't think so. I have never regretted taking the time to do something throughly, especially when it come to aviation.

I totally agree with Zippi. I only seal the bottom. If your getting that much exhaust residue and dirt into the hingeline you need to reposition your exhaust away from the plane / wing. Regarding the dirt, my planes spend most of their time in the air not rolling around on the ground. Try that...

But hey, it's your time, waste it as you see fit.

Mike

What about sealing the gaps in the rudder & elevator hinges? Waste of time?? The gaps are small. Just enough to allow full throws no more. I don't know if flutter is a big issue with the rudder & elevator anyway.

jvino,

The way that I have explained how to seal the hinge gap and the way ram3500-RCU has explained it is correct. There is no wrong way here. It's just a matter of personal prefference. Some guys do not seal the control surfaces and that could turn into trouble down the road. I have never sealed the rudder gap but that's not to say that you can't.

When I use CA hinges, I seal all the gaps, and this includes the tail. And, as stated, with CA type, I seal top and bottom to strengthen the hinge joint. CA hinges usually tear rather than pull out. This shear movement is kept to a minimum by creating one long hinge with covering. I agree that right or wrong isn't the issue here. In 38 years, I have never had a hinge related failure. My procedures lend to this record, IMO, but of course, others may have just as much succsess doing things differently.

As far as oil and 'dirt' goes, I fly gas (very little residue) and 4-stroke (filthy). No exhaust known to man will keep this away from an airframe that is gyrating around in the slip stream of all this exhaust, unless you simply fly strait and level. It goes everywhere. To suggest otherwise is very ludicrist. I also run air filters on my gas engines because I fly off of grass.

It does take me longer to finish an airplane than some, but I take pride in my attension to detail that has won me awards, and results in aircraft that fly as well now, as they did 4 or 5 years ago (with CA hinges, in some cases). Please don't look down on those of us who are willing to go the extra mile for our craft.

Flutter, yes, sealed gaps will help prevent this, But, consider this. I had flutter on a Cermark Pitts one time, when an aileron servo failed. The wings became a blurr like Humming Bird wings till I got things slowed down. It knocked one I strut mount loose and cracked the top wing, but she held together and I landed safely. The plane had CA hinges and all gaps were sealed top and bottom. All four ailerons held. Not sure they would have, had the gaps not been sealed and on both sides.

I have encounterd this three times over the last 38 years. The event above was the most recent (about 4 years ago). Each time the plane was landed safely without losing a hinge.

Ok, let's debunk this myth right now...

Sealing a gap has nothing to do with stopping flutter. In fact. sealing a gap can even CAUSE flutter.

The reason for sealing a gap is to give better control surface response. Nothing else.

Look at a flag waving (A flag waves due to the exact same principles that cause flutter). There is a gap between the flag and the flagpole. If you seal that gap will the flag stop waving? Of course not.

If you want to prevent flutter, use strong servos and avoid having any slop in your linkages.

you guys glue your hinges?

My flag 'waves' because it is made of cloth.

Ram,
When your building it sounds like you take your time and do a great job with a lot of pride. I am the same way when I build. For the most part I was just stirring the pot. Anyway to get the hinge sealed will improve the handling of the ship.

The reason my flag waves is because it flys over a country that is the greatest in the world, and because I waved first!

I'll go over to the AMA thread now and see who wants to argue there.

Mike

Hey Mike, Ya gotta a love this site. I sure do. A real asset to us modelers. I'm sure it has saved me some time and money, while improving my craft. Hope I have helped others in the process. Keep challenging us to engage ourselves. Debate can reveal many points of interest, and be entertaining as well.

I,m still learning to fly and am flying foamies. Does the "CA" hinge trick work with them as well or is there another method for foam?

DO NOT use CA on foam!

It will disolve the foam

*[sm=what_smile.gif]*

I use "foam safe" CA on my foamies all the time. It's one of the recommended adhesives for the foamies I've put together along with various other types of glue.

But yeah, regular CA will do a number on foam...[X(]

Yea, I knew regular CA will melt foam, but I guess the real question is does the foam safe CA come in "thin" and will this process work for foam. I have only built a few of the foamies but when I cut the slot for the hinges I don't feel that the slot is exactly tight on the hinge. Epoxy fills the gap nice but it seems that this trick would be easier.


Denny

Yes it works. You can get thin CA for foam. I build depron jets and use micro CA hinges instead scotch tape for hinges. It looks better and makes a better looking finish after paint. Installation is no different and it is even more important to not use too much.

Thanks Ram3500,

I'll tried it on my GWS Stearman the other night to replce the Pin Hinges I bought (that everyone told me not to) and it worked great. Now if I can just figure out a better way to put those Aileron control wires in the wings on those GWS's better. I have a problem with gluing those little tubes in the slots in the wings. But I'm learning.

North Canton hah, I live in Frenso, OH and go to Areo Tech now and then.

My house is about 5 blocks from Aero Tech. Much too close! I put ailerons on one of my Cox Corsairs. It works great (also have all the gaps sealled ). I used the smallest rod and tube.

I would love to see your Corairs aileron job plus how you sealled them, sounds fun to fly?