How Bad Are CA Style Hinges?
 

Hi, I'm putting together a 1.40 sized aerobatic plane that's gonna be powered by a 26cc gas engine. Its a Chinese ARF, and the plane comes with those ubitquitous CA style hinges. Right now, I'm debating whether to use them or to install some Robart point hinges like I would on a kit/scratch build.

Yes they're very quick and pretty cheap, and to be fair, I've never had a properly installed CA hinge fail on me. This includes everything from small electrics up to 26cc gassers. Closest was a second hand plane where the hinges on the tail feathers just popped out after 20 flights and it was pretty obvious that the previous owner had not used enough thin CA. Other incidences of failure I've personally seen typically involve the builder using medium or thick CA instead of the prescribed thin variety. I've also seen a 26cc gasser with CA style hinges hit the dirt hard and even after that, all the hinge lines were intact.

I've read some nasty things about these hinges and was just wondering how bad they really are. Afterall, most builders will use CA for various parts of the build. I'm mainly trying to cut weight (and perhaps a little time) off this build. Weight savings would to my mind justify using the CA hinges, but not at the expense of safety.

Any guidance/experience/thoughts would be much appreciated.

RE: How Bad Are CA Style Hinges?
 

I had them on a 54" yak 54 that I crashed severely 3 times going at a good pace. Not once did one single hinge budge. I checked them all ans none have moved. If done right they are going to stay. I am using them on my extra 300S 60 sized plane 63"span with a .91. I trust them enough after that abuse and my steady drill hand ;) to properly finish zee job.

RE: How Bad Are CA Style Hinges?
 

Installed properly, they are fine. I also seal the gap both top and bottom with clear Monocote (if I can't match the color), or the proper color. This protects the hinges from oil residue and adds strength to the joint, as well as improving the effinciency of the control surface.

RE: How Bad Are CA Style Hinges?
 

Ditto - Installed properly they will work fine.

I have a 15 years old plane sitting in my garage that still has the original CA hinges. And that plane gets wrung out on a regular basis.

I have also used them on planes as big as 32cc size with no problems

RE: How Bad Are CA Style Hinges?
 

Do a search here on RCU. I believe there is a tutotial on the "right" way to install them. They work fine in done right.

RE: How Bad Are CA Style Hinges?
 

Thanks everyone for the vote of confidence. Guess that means I can put away the hinge points, drill and drilling jig for this build. Should save plenty of time!

MinnFlyer - Was just a little worried on account of the vibrations, but I guess since you've done it with a 32cc, all should be well.

Ram3500 - it's my practice to seam seal all hinge lines. You make a good point on protecting the hinges from oil; never occured to me. I always did it just to achieve consistent trim plus get a little more responsiveness from the same amount of travel.

Thanks again.

RE: How Bad Are CA Style Hinges?
 

There is nothing inherently wrong with the CA type hinges. Often in the ARF there is not sufficient material for the point style hinge to work well. Be sure to mount the control surface to the stationary surface correctly. I stick a pin through the control surface and the hinge to keep the hinge material located properly, then add the thin CA so that the hinge is adhered to both surfaces at the same time. I have never had a hinge failure using this type of hinge. I do use the blue CA hinges from Radio South, and not what comes with the kit. (I don't assemble ARF'S, but I still use the CA hinges)

Bill, AMA 4720
WACO Brotherhood #1

RE: How Bad Are CA Style Hinges?
 

I have torn several CA hinges that come stock in most ARFs doing extreme 3D. They don't pull out, they rip across the crease. A few years ago I began using the blue CA hinges made for 1/4 scale planes. They have two plys with a thin plastic sheet between them. They may be made by Radio South as mentioned above. I have never had one pull out or rip. They are cheap and can be found in most LHS.

RE: How Bad Are CA Style Hinges?
 

Here's the link to the how to install thread. http://www.rcuniverse.com/magazine/a...?article_id=55

RE: How Bad Are CA Style Hinges?
 

B&B Specialties has some very good CA hinges for less money than most. The large size is rated up to 42% gassers.

RE: How Bad Are CA Style Hinges?
 

In my experience I have only had failure (never in flight) when using CA that was not good quality.

Now I use Zap exclusively for the hinges and I never have a problem with them.

RE: How Bad Are CA Style Hinges?
 

Well, I left my 'properly' statement kinda hanging, so here is my procudure. Assuming the slot is already made and on the center line.

1. Stick pins in the center of the (good quality) hinges
2. Drill a 1/16" hole in the center of each slot (this aids the wicking process)
3. Install all the hinges in the slots and insure that there is free travel with no warping as you move the surface.
4. Move the surface to the maximum deflection you want, and drop 3 or 4 drops of CA on the each hinge. (too much is a bad as not enough)
5. Now pull the pins and repeat step 4 from the other side. (no more than 3 or 4 drops) (if it isn't wicking, you used too much)
6. Seal the gap both sides as noted in other posts

I have never had CA hinges installed in this way fail. I use them in a 50cc gas planes and smaller.

RE: How Bad Are CA Style Hinges?
 

Its probably good practice to toss out the supplied hinges if it is a real cheapo china ARF.I have used Hangar9 Ca hinges for many years.No probs even after full bore crashes.

RE: How Bad Are CA Style Hinges?
 

Thanks guys. The reassurance/ tips/suggestions are very much appreciated.

The stock hinges don't look too bad, so I'll probably just stick them in. Like I said, I've never had any problems with these hinges, was just a little concerned because of some bad reports.