More Hinge Questions...Please Help!
 

Okay, so I've been told by two people to replace the CA hinges on my LT-40 all together (one of them failed last weekend). I'm looking at the Robart Hinge Points, as well as some Dubro nylon hinges. Can anyone tell me how those dubro nylon hinges are installed? I'm at a loss as to how they are fixed to the airplane. I'm assuming some sort of pin runs through them and secures on the other side, but please, someone clarify here. Also, regarding the Robart hinge points, so they are drilled into the horizontal stab and elevator itself, okay. But, I'm worried with all the slotting that's gone on for the two sets of CA hinges I've done will weaken the horizontal stab to the point where the Robarts might pull out or split the surface. Also, for a Kadet, should I use 1/8" or 3/16" width? I don't think that new CA's are going to work because there will already be two sets in there, and it's pretty tough to find the space between them to put new ones. Plus, I just run the risk of them failing again! So, I'm convinced to go with a tougher hinge, just please help me understand the installation process! Thanks so much! - Spool

RE: More Hinge Questions...Please Help!
 

the nylon hinges are inserted the same way as the ca hinges. they are jsut wider. ca hinges are still good. you can get some better ones at hoby shops. the advantages of ca hinges is that if they aren't perfectly aligned, they still work fine

RE: More Hinge Questions...Please Help!
 

Never had a CA hinge fail! Don't go overboard with the glue, that can make them stiff, otherwise, no worries!

RE: More Hinge Questions...Please Help!
 

If your hinges are already failing, you need to replace them. A simple solution would be to make a "Covering Hinge" like this:

RE: More Hinge Questions...Please Help!
 

if you decide to use hinge points, then the right size is 1/8". They're good up to .90 size models.

RE: More Hinge Questions...Please Help!
 

Have had no problems with CA hinges can't figure out what people are doing to loose these hinges. My LT40 is 4 years old and the only thing that has not broke is the hinges.

RE: More Hinge Questions...Please Help!
 

RC Outlaw,

To answer your question about why the hinges are failing then I would have to say its most of the time user error. You must have enough glue but not too much, enough gap between the surface but not too much and you really need to seal the gap between the surface. I think a lot of times it comes back to the fact that the hinge is binding b/c the gap is too small or too much CA has gotten on the part where the hinge pivots and this can make the hinge brittle.

RE: More Hinge Questions...Please Help!
 

Well said S-T9

RE: More Hinge Questions...Please Help!
 

All good points, but i need to know as well as mahoney 45 on the dubro hinge you cut the slot, insert hinge, and the put ca in slot, or drill holes, and pin the thing or just exactly what?

RE: More Hinge Questions...Please Help!
 

Thats a great idea for my Douglas 4 rudder! Thanks! The insrtuctions say to use hinge tape, which I can't find at any LHS. The reason, I think, that I can't use CA, or other hinges, is the fact that the back is, has to be, sealed with epoxy. Sorry to get off your subject wheelpant ;)
Joe

RE: More Hinge Questions...Please Help!
 

If you use flat hinges, then glue the hinges into the control surface first. Let them dry and then attach the control surfaces. I always use toothpicks to pin the hinges in place. Drill a 5/64" hole and push in the toothpick. Trim it flush with the surface and then put a drop of thin CA on it. You can cover it with little circles of covering made using a hole punch (put covering between two pieces of paper to make it punch better) or you can color over it with a marker.

You do all this AFTER the airframe is covered. Did this answer your question? If not, what else do you still need to know?

RE: More Hinge Questions...Please Help!
 

I've always used epoxy to install the dubro or other brand pinned (ie, non-ca) hinges. I'm not sure that CA sticks well enough to that kind of plastic. (But I've never bothered to test CA on them, so it might work. If other guys say it does, then it probibly does).

Anyway, I cut all the slots in both sides, and dry-fit the surface in place. This is to make sure it's smooth, and that there is no binding in the surface movement due to a hinge being out of alignment. You should be able to flip the plane over, and the surface should flop around by itself. If it doesn't, check the hinge alignments until it does.

Then I take the hinges, and apply a little Vasilene to the moving parts of the hinge to keep the epoxy from freezing the hinges. Then, I mix up some 30min epoxy and work it in to the slot on either the control surface or the wing/stab. I usually epoxy in all the hinges on one side first, eyeballing the alignments as I go. Once that dries, check each hinge to make sure they all still move freely.

Now, mix up some more epoxy and work it in to the other slots, and slide the hinges in place. It often helps to tape the surface in place so it doesn't pull out as the epoxy sets.

It's a pain, but you get control surfaces that move much more freely than CA hinges.

However, it's worth noting that on most of my planes, I don't bother with this type of hinge. Either use CA hinges, or I tape a hinge, kind of like what Minn posted, but using bi-directional packing tape instead of covering material. I happen to really like tape hinges, they are fast, durable, easy to repair, gap free, and can create a very freely moving surface with lots and lots of deflection.

RE: More Hinge Questions...Please Help!
 

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RE: More Hinge Questions...Please Help!
 

I am re-covering a GP Spacewalker ARF. I am using Robart 1/8" hinge points. I put them on the ailerons about a year ago after the Walker took a dirt nap!! :eek: I used a Dremmel cutting disk and cut them off ..... ground them out slightly, and filled in the depression. I drilled new holes right in the middle of the ORIGINAL CA hinges that were simply cut off when the ailerons were repaired. Whatever you do..... get a Robart drill guide. It costs about $5 from Tower.
http://www2.towerhobbies.com/cgi-bin...?&I=LXET65&P=7
If drilling new wood or through old, hardened CA hinges and balsa, this thing will help keep the drill going where it is supposed to. Even with this thing........ you have to REALLY be careful because the drill wants to slide off the old hinge. (which is in center). I helped start the spot for the drill, forming a small hole with my #11 blade. I also modified the "wings" on the jig by grinding out a viewing "notch" so I could see the bottom of the drill bushing at the wood surface. I made a test with one hinge point using Hinge Point Glue. It looks like plain yellow glue to me. Anyway..... after 24 hours, I tried to pull the hinge out with a big pair of pliers. I ended up twisting and pulling and FINALLY it come out. It was at the point where I was about to break my wing. This was good enough for me!!! Several of my planes have Robat points and I really like them. I can get a REAL nice, tight gap, notching the control surface like this. I do a LOT of trial fitting etc, but the finished hinge job is worth every minute. [8D]
.....lownslo......