For all of us, CA hinges have been the mainstay for a long time. It's only natural to use them in the second airplane that is usually another 40 or 60 sized airplane. Many of the more experienced pilots have learned the lessons regarding the weaknesses in using these hinges in 1/4 scale and larger airplanes with gas engines. I have read many threads on this subject and always felt there must have been something wrong with the way the CA hinges had been installed. Rational? I had never had a hinge fail and many of the much more experienced pilots I fly with have said the same. These guys have 20 and 30 years experience flying pattern, aerobatic scale and large-scale multi engine airplanes. Many of these airplanes are using glow engines up to roughly the 160 range. Airplanes in the 1/4 scale and up with 50cc and up gas engines have slowly been making their way, or making a come back at our field. I am on my second Pitts project with a DA-50 mounted on the nose. I had a Fuji 50 in the first model. Used CA hinges in both airplanes. This past weekend two of the three CA hinges failed in the rudder. Cut clean like I had taken a knife to them and I wasn't doing anything wild and crazy. Just flying around to get stick and engine time for break-in. Fortunately I was able to get the airplane down without a mishap. Since then I have read more thread comments of CA hinges failing with more disastrous results in gassers. Some were lucky, like me, and didn't have any damage. Others were not so fortunate. Here are a few of the threads proving such.

http://www.rcuniverse.com/forum/Grea...1315484/tm.htm See post by Smaze 17

http://www.rcuniverse.com/forum/Grea...1315484/tm.htm See the post by Flyster63
and R/C Dragonfly-RCU

http://www.rcuniverse.com/forum/Grea...1315484/tm.htm See post by RC Falcon

These are just a few of the responses I could find quickly. My interest in posting this thread is to pass the information along to others who possibly have not read these thread comments, or have, and didn't consider an option important. I for one will never use CA hinges again in a gasser of any size. Some of you are just getting into gassers. I just did myself this past year. I lost my first model due to my own stupidity that had nothing to do with CA hinges. I could have lost my second model by not listening to the sound advice provided by many others with much more experience in this area of the hobby. Research this for yourself, but by all means pay attention to the knowledge gained by doing so. When you think about how much money one of these airplanes cost and consider the cost of CA hinges vs. a quality option this becomes a 'no brain-er'. Da, then why did I almost have to learn the hard way? Go figure.

rwf1953,
I've been keeping up w/ your posts regarding the CA hinges, and appreciate the knowledge gained by other's experience. I still have my GP Pitts in the box, and until your posts, I was planning on using the CA hinges. I now will use a pinned hinge. This will be my first gasser.

I suspect the failures are due to the gassers vibrating more than smaller single cylinder glow engines. I was just talking with one of our club members today that refused to try gas because of (among other things) the violent shaking of the engines and abuse it can cause the airframe and radio equipment. He likes the huge multi-cylinder glows.

I am still putting the Fuji 50 in my Pitts, but for sure will use better hinges.
Thanks for all the knowledge you have shared regarding yours!!

Pilgrim

Hey roger, I'm really glad you didn't loose your plane with the hinge failure. I also read wher smaze had hinge failure to. I think this has to be a bad batch of hinges because I had about 50 flights on mine with the G-62 & no failures, by the way I just sold the pitts. I am now flying a hanger 9 edge with a fox 3.2 & it is awesome. I am building up a stock of 5945 hitec servo's & some other gear to outfit a 35-40% size plane. Glad to hear your bird survived.
Later
Gil

My buddy Shane had the CA hinges fail two seperate times on his GP Pitts. The first time it was all of the hinges on the top left aileron. He replaced them with Pin hinges. The second time it was the bottom right aileron. Needless to say, he replaced all of the CA's with pins. No need in carelessly losing a beautiful plane like that along with a G-62. After two incidents like that, I'd have to change them out too. It's funny because I know of a lot of guys flying 1/4 scale and larger planes with CA's in them and they swear by them. It really sounds like a batch of bad hinges, or the ones that were sent with that particular model simply aren't strong enough.

Question..... Do they make a larger, thicker, more duarable CA hinge, or is one CA hinge the same as all others? Surely for larger scale planes you would be provided with a larger sized hinge. I mean think about it, would you put the same hinge that comes with a Lancair in a 35% Edge? I really don't know, that's why I'm asking.

I think the problem is also the brand of the hinge material. I used to use the Radio South hinges 10-15 yrs ago on my pattern airplanes and never had a problem. The "newer" hinges from GP, H9 etc are different in that they seem to just be the white "material", whereas the old Radio South hinges were heavy plastic that were bonded to the white CA "material" on both sides. I had 2 H9 CA hinges fail on my .40 size trainer that I use for radio testing. I have a GP Pitts and a Wagstaff, and both use this "cheaper" CA hinge material. I threw out this stuff and used Robart hinge points. FWIW

Has anyone determined how thick the balsa is on the trailing edge of the wings of the GP Pitts(ie: are they deep enough to use Robat hinge points)? I was thinking about using the Du-Bro 1/4 scale pin hinges if the Robarts will not have enough "meat" to hang on. I don't want to cut into the covering.

Pilgrim

I have a DP extra 330 and have a Zenoah G-45 mounted to it (helps the plane balance out!). I have not yet flown or even started up the G-45. I used Robart hinge points for the ailerons and rudder, but had to stick with CA hinges for the elevators. I ditched the CA hinges that came with the kit, and bought Bennet 1/4 scale CA hinges. These have the heavy plastic material in the middle of the white CA material sandwiched together. They seem to be exceptionally strong and pretty thick. Anyway, on the DP extra there was not much room to fit the robart points, as the stab tube gets in the way. This is why I went CA in that area. Im pretty sure it will hold, but will keep my eye open for problems.

FlyingPilgrim - You hit on my concern as well. Just not enough wood without placing a hard point behind where you want to mount the Hinge Point. Like you, I don't want to cut into the covering if I can avoid. Basinbum has made a suggestion on a different thread that I am trying to get more info on. Check this out. Maybe onto a solution.

http://www.rcuniverse.com/forum/Grea...1315484/tm.htm

ual767 - what did you do about this concern when you mounted the hinge points in your Pitts? from what I can tell if you just drill through the wood there just isn't enough wood there to bite into to make me confident this will hold. Likewise, won't the glue just be pushed out the back end of the hole? Take a look at this thread above and let me know what you think. Gorilla Glue that expands thus creating a plug effect.

I am pretty well sold on the hinge points for the elevator and ailerons. I used the Kletts Flexpoint hinges in the rudder. Used six of them and didn't go through the wood. Used think Zap CA. Not sure this is the right hinge for the elevator and ailerons though.

Gentlemen

I have read your posts with great interest concerning the failure of CA hinges. Are the failed hinges referred to the furry types? I ask because another forum has raised this issue and stated that the furry type of CA hinges are 100% safe provided that they are inserted correctly, that the slots are not too wide and that the furry hinges are wicked whilst in place on all surfaces and thus will not need to be pinned.
I have my doubts as to the safety issue of not pinning myler or CA hinges.

Your comments would be appreciated.

Macx
I believe what the above are talking about is not the hinges pulling out, but actually breaking. Have also seen this in the gassers at my field and for some reasons worse on the ailerons.
Good Luck,
Twinman
PS If you are crazy enough to do twins and over power them, you really use strong hinges and pin them!!

Thanks for that info!

I am presently assembling the Jamara Spitfire 60 ( ASP .91 4/stroke) and this kit features CA furry hinges which need to be CA'd into place on wings, ailerons, rudder and elevator. Are these the type of CA hinges that you refer to that are failing? They are circullar in shape with a brushed surface that makes them appear furry!

I am not sure which hinges are failing. In this post I have seen and heard more of different types of CA hinges than I knew existed.
The most recent failure was on a large gasser bipe at our field. Will try to find out more.
Twinman

FWIW I cut out the Monkote from the bottoms on the stab and added a 1/4" piece of balsa before I added the hinge points. Yes, small "patch" in the Monokote, but it's on the bottom. Also, the most important part about these CA hinges is that you MUST seal the hinge gap w/ Monokote etc. This takes some of the stress from the hinges, improves control surface effectiveness, and most importantly, keeps the control surface attached should a hinge fail.

Twinman,

I would very interested to find out which CA hinges are failing. Thanks for your assistance.

The ones that come with the GP Pitts are the first ones that I have heard of, and seen, that just break at the hing point. I have heard of hinges pulling out of the slots, but this is the first time I have ever heard of a CA hinge splitting in half, or breaking.

The CA hinges referenced in the above examples are those you get in most kits and that you buy at the local hobby store. They usually come in sheets. Cutting to shape each hinge is required. The problem I experienced, and what apparently most others have experienced is that with a larger gas model airplane the hinges break in two at the flex point as though cut with a knife. In my case, this was not the result of 3-D flying or aggressive throw set-up. Several fellow pilots with years of experience using CA hinges in various models were stumped as to why mine failed. There is a history about this subject that many of us had heard about, but just didn't take seriously enough to realize just how easily this can happen. That said, I'm not sure any CA hinge would be a solution after what I have read and now personally experienced. Here are a couple sites provided in a post on another thread that Basinbum passed along. These sites explain how to install hinge points.

The problem many of us are having is that there isn't enough wood to bite into for the hinge point to be secured in the movable surface. The obvious solution is to cut away the covering and add a hard point block to add additional wood for mounting. What appears to be a reasonable solution is to drill through the wood, use Gorilla glue, which expands and hardens when making contact with a small amount of water. This then forms a plug behind the hinge point. The glue also expands around the ribs on the hinge point helping to add strength.

I am going to test before applying this application today. Once I'm confident how to do this and that it will work I will then apply to the elevators on my Pitts and let you guys know how it went. If I can do it anyone can.

http://www.rcuniverse.com/forum/m_13...tm.htm#1331665

http://www.fly-imaa.org/imaa/hfartic.../v11-2-40.html

http://www.airfieldmodels.com/inform...ints/index.htm

RFW1953,

Are the hinge sheets that you refer to and need cutting to shape the smooth plastic Mylar hinge type?

If yes I understand that the surface of this smooth material is best roughened first with glass paper or a file then smeared with epoxy and mated to the hinge slots forming a secure base about the surrounding wood. CA is then eased across the hinge surface to wick around the epoxy to form a secure housing. When set the hinges are drilled and pinned with cocktail sticks.

The newer furry or hairy type hinge material has a pre-roughened surface similar to hairs and are positioned onto both surfaces then simultaneously CA'd which wicks through the hairs to form a very secure fitting. I would be interested to find out if these latter CA hinges are also failing as some modellers appear to believe that they are without fault.

I'm no expert but I would like to clarify this grey area before fitting these CA hairy type hinges to my latest Spitfire.

Thanks!

I think Pilgrim has it right on this one, I have not flown with gas yet as the ones I see at our field (20 t0 50 CC) vibrate an order of magnitude worse than the big bore glo engines. With most of them if you watch closely as the owner runs his engine up and down the RPM range you can see points where one or more of the control surfaces go absolutely nuts turning into blur that you can hardly see. When a gas flyer says his engine is really smooth, he is not talking about smooth compared to a good glo engine, he is talking about smooth compared to other gas engines. Just as I see it. [8D][8D]

RJ

I have experienced hinge cracking and I believe it was due to over saturation of thin CA. One drop on each side, and no zip kicker seems to work best. I pin the hinges with cocktail tooth picks, and trim the excess flush with a pair of dykes. Grind the back side of the dykes down so that the cutting edge is a single bevel and you will get a perfectly flush cut everytime.

yard-dart said,,,

"The ones that come with the GP Pitts are the first ones that I have heard of, and seen, that just break at the hing point. I have heard of hinges pulling out of the slots, but this is the first time I have ever heard of a CA hinge splitting in half, or breaking. "

Talked to my buddy at the field and this is exactly the plane that it happened on and the exact break point, and it was only his third flight. Maybe someone else can say what hinges come in this thing. My buddy reviewed this post and has grounded his plane as he had not changed the rest of the hinges......until now.
Twinman

Macx,
The CA hinges refered to are a Mylar plastic core, bonded on both sides with a thin fabric (the fuzzy part you refer to). All brands I have seen are very similar in appearance and construction. The fabric bonding gives the wood something to grip when it is glued in place, and helps the CA "wick" to all areas of the surface. You should never use anything except CA on these type hinges (you refered to epoxy). Some people will draw a line with wax down the bend line of the hinge to prevent the CA from adhering where it bends. I have not tried this (yet), so I don't know if it makes a difference.

CombatPigg,
If you only put one drop per side, I think you are asking for trouble!!
Great Planes instructs to drill a 3/32" hole straight in the slotted wood to allow the CA to wick deep into the slot, then they tell you to use six drops of thin CAper side to make sure you get good adhesion. I use one of the little plastic pipettes (Dave Brown Products sells them by the 12 pk) to drop the thin CA in place. This gives much better control than the bottle nozzle. If the CA stops soaking in, it is saturated already, and won't accept any more drops.

Pilgrim

Interesting reading. I got burned past extra crispy early last year when I posted a thread on this topic. I was relating a warning from the IMAA's High Flight magazine as to failure reports of the Ca hinges. In general, the text mentioned that fabric hinges hardened by Ca then exposed to UV rays tended to tear or break more often than should be expected. Since 2002, the plastic sandwich type has been introduced. If this will help, I'm not sure -- but has to be an improvement. None of my 1/4 and 1/3 planes are ARF's and are not using the Ca's. One person replied in divine wisdom by saying "If that was the case, why would we build the rest of the plane using Ca if it would fall apart".
It's bad enough when a 6 or 7 pound plane starts shedding parts; but, a 15 to 20 pounder is much more deadly and expensive.

Robart Hinges are installed in all my planes, it's a little more work but worth it. Just last week a guy at our field lost 4 of the 5 CA hinges in his UCAN-DO, was no apparent flutter issue. I'm not sure what is causing it but seeing that and all these replies is enough reason for me not to install them.

I quit using ca hinges years ago when I had two failures in a row on two successive airplanes.I now use pinned hinges and robert hinge points[ The steel pined ones]exclusivly. The ca hinges are just the lazy way to do it[cheaper too] and most get away with it for a while.Most of the time the models[trainers] don't last long enough to wear the hinges out. For permanent hinges[long time use] nothing beats pinned or hinge points.

Mine did use the hinges provided in the kit by G.P. I also drilled the hole to allow wicking and did apply a good dose of CA. I may have applied too much causing mine to harden and snap in the cold weather. This is a new airplane with only three flights on it. I doubt UV had anything to do with the failure seeing that the airplane had not been exposed to the sun maybe more than a few hours.

I went to my LHS and looked at the robart hinge points and concerned they are too big. The length really concerned me as well. I just can't see how these are going to work in the Pitts elevators because the wood is so thin. So, I purchased the Dubros pinned nylon hinges. I went hone and tried to test fit and the blade on my hinge sloy maker is too small and the hobby store is now closed. Going to have to wait until Monday to get the larger cutting blades. I think this may do the trick if I can get four of these in each elevator. I will have to cut beside the old hinge slots due to how hard the wood is after the CA cured. I picked up Gorilla glue. Anyone use this glue with Dubros pinned hinges or would you use epoxy?