PROBLEM
When I control the motion of the elevator on my Mini Telemaster it twists the stabilizer, causing not only the obvious twist of wood but a buzzing in the servo. The stabilizer is of stick construction and all the control mechanisms are installed and otherwise running smoothly with no obstruction of the pushrods.

QUESTION
Is this happening because I used too much glue in the CA hinges, causing a tight flex?

SOLUTION???
I do NOT want to cut out the hinges and redo.
Instead, can I attach balsa supports (much like wing struts) from the fin tip to the stabilizer tips to add strength to the stabilizer? Would this be better done AS EXPLAINED or perhaps UNDERNEATH the stabilizer from both tips on either side to the bottom of the fuselage?

Do you think stabilizer struts would work in preventing the twist when I control the elevator?

Please help ASAP, thank you!!!

did you take the control rod loose and flex the surface back and forth to full deflection MANY times until the surface is moving "smoothly"? If not DO SO before trying any UN NEEDED braces. braces won't fix the problem If this doesn't help, you'll need to redo the surface attachment. hope this helps

edited to change flew to flex

Yes, I flexed them over a dozen times before gluing them to the fuselage. Flexing by hand also twists the stabilizer so its not the pushrods either. I really do not want to cut the hinges off and redo, I want the struts to work for me, common sense tells me they should work because they are preventing the twisting motion.

If you are getting twisting due to an over glued hinge, then no amount of additional struts will be of any help to you. You state that the servo already buzzes when elevator is activated, that is a sure sign that something is binding ,and if you continue to fly like that , the excess drain on the servo will quickly drain all power from the flight pack, and then you wont have control at all. End scenerio, CRASH.
So please find the cause of binding and fix that, don't go adding extra supports to try to overide the problem, FIX IT. Even if it means you have to replace the hinges. A little bit of extra work now is better than a complete wreck because you were too lazy to fix it.
bill, down-under in Australia

This is one of those times when it sure would be nice if someone with experience could see it up close and personal. I agree you should find the cause of the problem instead of adding a patch. Can you take it to someone to see what they think?

td426, First things first. From what I can see by your photos you've done a very good job so far. So don't get discouraged.

There are only a couple of things that will cause the type of problem you describe. One is not having all the hinges mounted on the same line. From the photos this doesn't seem to be the problem so try this. Deflect the elevator as far as you dare away from you so you can easily see the gap at each hinge. Look for excess glue in these spots or perhaps some glue built up behind the covering. It takes very little to cause a problem. Use the point of a #11 blade to remove the excess. You may have to take a little covering with it.

On future hinge installations deflect the control surface about twenty degrees away from the glue, glue that side (being careful not to pull the hinge and increase the gap at the hinge), then flex the surface befor gluing the other side. If you have a problem it will show up right away and you can fix it before gluing the other side. Also, CA hinges don't require a lot of glue. If glue is visible then the hinge has been over-glued.

Maybe it's moving too much?

Can you post a pic of the elevator at its fullest deflection?

I know I used too much glue in the hinges as I could see the glue on the hinge as it was drying.
Could it be that there is not ENOUGH gap between the control surfaces? Maybe I should give a tiny bit more gap between when I redo the hinges [:@] (according to what you members are saying here I have no choice, struts do not fix over-glued hinges).

When I cut these hinges off to replace them, what hinges should I use? I trimmed some off the CA hinges to make them alittle smaller but maybe I should have trimmed more off them cause maybe they are still too wide for such a small model.

If not CA hinges, what ones would be best for this model? Or should I still use CA hinges, just smaller? I only need a couple drops of glue on both sides of the surface, top and bottom OR JUST TOP? 2 drops will be enough?

Removing the hinges will be easy I hope. From what I see, just cut the old ones off, make sure the material is level with the wood, and add new hinges further down. Only 2 drops per side of the control surface top and bottom. OR will only one drop per side be enough?

As you can see from the attached pics, the same is happening to the rudder.

EDIT: I am thinking maybe all I need is 1/2 of a CA hinge for something this small. Will that work? I would only need 1 drop per side. So what you are all saying is I do not need to see the glue in the hinge to have it hold!!!

I'm surprised Minn didn't post a link to his article on installing CA hinges: http://www.rcuniverse.com/magazine/a...?article_id=55

What kind of CA are you using? You should be using the thin kind. If you can see it on the hinge, it sounds like either too much or it's too thick.

Edit: I forgot to ask, what size hinges are you using? They do make small sizes for smaller planes.

It is a little hard to tell by your pictures but it does look like you have the rudder hitting the hinge post on the vertical stablizer. Here's the rub. You want as little gap as possible between your fixxed surfaces and the moveable surfaces. The tighter the gap the better response you get from control inputs and the better your plane flies. However, if the the control surface is not working properly then you've got a problem. The solution is to properly bevel the leading edges of your control surfaces so that the hinge point and the point on the bevel are one and the same.
In your case, you can cut the hinges and install new ones leaving a slight gap to free up the surface. Before doing that you could try slipping a couple of playing cards into hinge gap and try to GENTLY crush a little balsa out of the way. Be careful, but it is worth a try before cutting the hinges. Start with one card then go to two. Don't force it just deflect it a couple of times then remove the card and check it.

I am using thin CA, but I am making the mistake of gluing both the top and bottom of the hinge as well as gluing to the point where I can SEE the glue on the hinge. So I know I am using too much.

The hinges I am using, after trimming some, are still apprx. 1"X1/2" CA hinges, but I am considering trimming the new replacement ones down to apprx. 1/2X1/4. What size would you recommend??

I just checked the ones I used on one of the kits I built last year, a .15 sized pattern plane. They measure 1" x 1/2". I would not cut them shorter than the 1", you need as much possible to allow the glue to adhere to. When I glue in the hinges I put enough CA so I can see that it's wicked into both surfaces, and I do this from both the top and the bottom.

Also, it's not a mistake to put CA on both sides of the hinge. When I am installing CA hinges I will put the hinges into the surface and the control surface, and then position them to where there is as little gap as possible. Then I will deflect the control surface as far in one direction as possible, then apply CA the hinge in the opened up gap. After all hinges have had CA applied to them I will turn the surface over and repeat the same procedure on the other side. Once all is done flex the control surface back and forth a few times to loosen it up.

Ken

I was just looking at your pictures again. It's not clear how bad the problem is. If you haven't already cut the hinges off, try flexing them some more.

i think it's probably that you don't have enough gap between the stab and the control surfaces. it looks like you have almost no gap in there. if you take off the control rods and try to move the surfaces by hand, i assume that it's also very tight and the wood gets in the way. as someone said before, just deflect the control surfaces while you're applying the CA. about 3 drops a side is good but up to 4. just let the CA wick into the hinge.

but beautiful otherwise!

I'm going to take a different slant on the problem : Tiger dude you said in your first post that your servo was buzzing when you activated the controls, that's not a good thing and to me it indicates that you are activating your controls farther then they were designed to go causing the stab to flex. Try readjusting your control linkages so there is No buzzing and No binding .
If you still think you have a hinge problem here's somthing I have done in the past. If you have a small trim iron (I've used a small soldering iron ). Try very carefully running the iron along the hing line to loosen the excess glue, then peal it out with a knife or something. Don't increase the gap, the less the better as long as it doesn't bind. ENJOY !!! RED

If you see a clump of CA interfering with the movement you could also carefully put a drop of debonder on the clump to soften it and then try to pick it out of there. When the debonder evaporates the hinge should be just as secure as before.