H5487

Hi All...

I'm just returning to R/C after a 35 year absence and a lot has changed in those 35 years! One area of changes is in control surface hinges.

I've just started building a GP Slow Poke kit (the .15-.25 one, not the Sport 40) and I'm at the point where I need to hinge the tailfeathers. The kit comes with CA hinge material but I seem to prefer the pinned-type of hinges like those from Du-Bro and others. (At least that's what I was familiar with 35 years ago.) What do y'all suggest? CA, pinned, or ?

The trailing edges of the stab and fin, and the leading edges of the elevators and rudder is 3/16" balsa. And I have a brand new GP Slot Machine.

Thanks,

Harvey

aerowoof

a lot of r/c'ers swear by the ca hinges.I first tried them in 1975 and have gone back to using dubro pinned hinges or for scale robart pinned hinges.I also used klett hinges but they sre no longer availabe.I have planes dating back to 1970 in flyable condition with the pinned type hinge installed with epoxy and not onme has failed or loosened in all these years.

H5487

And the pinned hinges in my Falcon 56 (also from 1970) are still in great shape!

Thanks for your reply,

Harvey

DavidAgar

My Feedback: (108)

If the CA hinges are installed correctly, they work great. Make sure that your hinging tool has the CA hinge cutting blades in it and that you use a good grade of thin CA glue. I use them on all my smaller planes, but on the bigger ones, I still use the hinge pin hinges. Good Luck, Dave

H5487

Thanks, Dave, for your reply. Just out of curiosity, why do you default to pinned hinges for your bigger planes? Is it a strength issue?

I am also curious about how hinges affect control surface flutter. All other factors being equal, does the semi-stiffness of a CA hinge help dampen a surface's tendency to flutter whereas the free action of a pinned hinge allow a surface to flutter easier? (This is for my education only - I realize that the Slow Poke doesn't normally fly fast enough for flutter to become an issue.)

Harvey

DavidAgar

My Feedback: (108)

I use the hinge pins hinges on my bigger planes as the flying surfaces are just bigger and under more strain in flight so I figure a tougher hinge is needed. I have not had any flutter problems with the CA hinges at all, however I always make sure that my moving surfaces are as close to the mating surface as possible. I typically sand my moving surfaces into a V shape after I have the hinge slots cut, which allows you to get the moving surface butted up tight on the mating surface. One thing that is also important with CA hinges is to make sure that you have an even ammount of hinge in each surface. I will install a pin in the center of the hinges and install them into one of the surfaces and then install the other surface. Once I have the 2 pieces where I want them, I remove the pins and glue them with the thin CA, both on the top and bottom sides of the hinges. With the surfaces being so close together, flutter is almost impossible. Good Luck, Dave

ChuckW

The CA hinge material in the GP kits is very high quality. For a .40 sized sport plane they'll usually do fine. Just follow the tips for installing them in the manual.

Krener

I use pinned hinges and Robart hinges whenever I can.

I also pin my hinges after installing them, for peace of mind
There is nothing worng with correctly installed CA hinges, but I simply don't trust em, it's a 'me' thing.

Cheers

FlyingPilgrim

My Feedback: (26)

Harvey,
Welcome back to the hobby after your time away. You are right, much has changed, most of it good. Advancements in batteries, radios, engines, composite materials...

As for your question, on small (up to .60 size planes) I usually prefer CA hinges. You will love the slot machine for cutting the slots, but practice on some scrap before you cut your slots in the plane. It takes some practice to get them straight. Also, make sure you use the correct thickness of blades, as GP offers a few different ones. I would not use CA hinges on anything with a gas engine, as the added vibration may cause them to fatigue and break.

I like Robart hinge points in different diameters for larger planes as long as you build in enough material for them to adhere to. Many kits designed for either CA or pinned hinges do not have much "meat" to glue the long hinge points into, but it is simple enough to add more before it is covered.

There are other kits that a standard hinged pin is best for, and they are available in different sizes for each application. I have used Dubro and Great Planes with equal success.

Hope this helps.

MinnFlyer

My Feedback: (4)

Harvey, I too started in this hobby back in the "Silk and Dope" days, and I am a big fan of CA hinges. They are so easy to install and they work great BUT they must be installed correctly. You don't glue them in one side first and then the other, and they must have a slight gap so they can flex.

For a good, simple, detailed explaination on their installation, please read this:

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

SST

My Feedback: (2)

I use the GP pinned hinges, and I install with polyurethane glue and a cross pin. Those installations are forever.

Mode One

I agree with every thing stated so far. CA hinges are very easy to install and work well. I think a pinned hinge is a good idea for large scale or racing airplanes just due to the increased stresses involved. There is no reason not to use tooth picks to pin in CA hinges like we used to do with the Klett or others of those type hinges and I have done this on several occasions. I did this on my .40 sized Funtana, becuse the control surfaces are so huge! You will notice one of the changes now is that kits are getting to be fewer and fewer. I think this is sad as the building part is what I like best about the hobby. I'm hoping this trend will reverse! Welcome back Harvey!

H5487

Thanks, everyone, for your inputs! I started practicing with my new Slot Machine right after my first post and WOW what a handy toy! This is one of those little workshop helpers that makes a tedious job so easy and quick.

After reading your replies, I decided to go ahead with the CA hinges included in the kit, chose the proper blades for the machine (I got the "gift set" that included the alignment jig, center locator & blades for CA and two sizes of pinned hinges), and got all 9 tail hinge slots cut in under 30 minutes!

I LOVE tools! (Insert Tim "The Tool Man" Taylor grunting sounds here.)

Harvey

Dr1Driver

I've sworn by CA hinges for almost 25 years. Properly installed, they can't be beat!

CA Hinge Installation

There are several rules to follow for an easy, correct CA hinge installation. These rules are good for hinges from different manufacturers, including Great Planes and Radio South. I’ve used them on many planes from pylon racers to Unlimited class Fun Fly planes to even a giant scale Stinger (the 1/4 scale size hinges). I have never seen an in-flight failure using this procedure.

I have seen only two in-flight hinge failures. One failure was from catastrophic flutter, which also destroyed the wing panel. The other was due to doubled hinges and the use of thick CA.

Here we go:

Use a #11 blade to cut the slots.
Cut only once per side/per hinge.
Use only thin CA.
Do not double the hinges.
Do not use “kicker”.
Install after covering.

1. Slot the wood pieces, install the hinges, and mount the control surface. Gently push the pieces together.
2. Flex the control surface both ways for the maximum amount of travel you expect to use. This will automatically create the proper hinge line gap.
3. Slowly drop 2-3 drops of CA on each hinge at the hinge line on one side only. If any CA puddles in the hinge line, blot it with a paper towel.
4. When that is dry, apply 2-3 drops of CA to the other side of each hinge.
5. When both sides are dry, flex the control surface both ways.

That’s it! The wood will pull out before the hinge will let go. The surface will tend to stay centered and will not flop around. Both will help prevent flutter.

Dr.1

H5487

Thanks Dr1.

Harvey