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Building Tips and technical articles. => Building techniques => Topic started by: Shawn Kuntz on January 29, 2008, 08:51:02 PM
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Guys-
I have seen nylon/cloth elevator hinges on models with iron on coverings. How do I do it? I want to completely cover my new CL model with ultrakote. I want to try using the cloth hinges with ultrakote covering on the elevator. I've seen it done and I would like to learn how. Any tips or tricks out there?
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I've never had any luck putting iron on covering over cloth hinges. For starters, it's difficult to cut the the covering around the hinges that have already been installed. Also the covering doesn't want to stick to the cloth very well. It's sooooo much easier to cover the stab and elevators seperately then hinge them together with a pinned hinge.
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YEARS AGO back in the late 70s i used to fly RC gliders, I used monokote for hinges. cut tabs about 1 inch by two inchs , flip them adhesive to adhesive, overlaping about the same thickness as your surface you are hinging. using an iron just hot enough to bond the adhesive, tack the two strips together. Make up enough of those to hinge the surface,, install them just like cloth hinges over the monokote surface. You will have all the usual issues with monokote over monokote , bubbles ect. Now having used Ultracote for the first time, I would think this technique would work even better since the adhesive temp is much lower than the shrink temp.
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Monokote hinges. I'm using them on the flaps on my Pathfinder twin.
Mark's partly right on his description, but here's a neater way of doing the job.
You prepare the strips exactly as Mark described, but before you cover the wing, or stab surfaces, install the hinges in the following manner.
First cover the trailing edge,of the static surface, and the leading edge of the movable surface, with a strip of Monokote, or other plastic covering, that extends about 1/8" onto the top and bottom surfaces.
Now, install the prepared hinge strips, in the familiar over under manner we use for cloth hinges. I fit them tight, next to each other, so when I'm finished, I have a sealed hingeline. Use an iron and make the hinges tight. The hinges will extend onto the balsa surfaces, and the area between inter weaves will now be covered and protected from fuel and oil.
Now, install your covering onto the rest of the surfaces, ending at the straight line at the hinge line, in the case of the static surface, or the joining of the 45 degree line on the movable surface.
Most of you will likely not use this method for fear of failure of the plastic hinges.
I've never had a problem though. H^^
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John,
I have used exactly that technique with Ultra Cote and Mono Cote hinges on RC and Cl planes. Hinges usually out last the rest of the plane.
Jim
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Jim, especially if you fly like some of us!
John, thats a "why didnt I think of that" if ever there was one,, sheesh, perfect
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John & Mark:
If I read that right you need about 1/4" overlap on the sticky side where the material comes together?
John: how far back on the wood do you have to go with the hinge? Indeed with the finish covering coming over the top I'm not sure if that would not be enough to hold things togeter since it is looked down on the hinge strips...
I have also used the continuous hinge method with Monocote where you cover through the hingeline from each side and let it touch on the sticky side - tough to do well though...
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From what I recall, I used the thickness of the surface being hinged as a guide for the overlap. IOW if the elevator is 3/8 you can overlap 3/8. this allows the adhesive, (heat activated of course) to bond to the surface of the elevator, flap wing whatever without bonding into the hinge area. Also allows the maximum bonded surface per hinge "leaf" as for how far onto the surface, do what feels good, I think I used to go about an inch onto the surface, I didnt do it like John though, I put hinges on after surfaces were covered, I like his way better, even more secure than mine
John,, your turn,,,,,
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John,
That's another one we should have discussed, like so many other things, while eating at the Barbeque place.
I'll try it, next plane, thanks!
Roger
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Dennis, Mark, Roger, et al,
I like Marks method of figuring overlap at the transition point. it makes sense and may provide a stronger bond at the hinge point. Having said that, I normally use a 1/8" overlap, and no problems. I will try Marks idea on the next one.
As far as how long the tab should be, I'll admit to being lazy and not testing this out to find the minimum double safe legnth to use. I normally use about an inch of tab. The overcovering of "Kote" softens the tab outlines similar to what a good dope finish does, and looks right to these eyes for a classic ship. I would suspect that one could get by with as little as 1/4" tabs up on the flat surfaces. Small pieces set between the tabs, and then overcovering would look sweet. I'll have to give that idea a try.
Roger, we had a great modeling "Bull session" at the diner. I'll treasure the memory of it. Brought back a lot of memorys of past sessions from the golden era. Hope to do it again, and often in the future.
Dennis, you are so right about using the continuous method to create a hinge. It is extremely difficult to do well. Most that I've seen done that way leave a little to be desired, though it seems durable enough. I believe the continuous method is a bit stiffer than I like. Over-under hinging seems very smooth and has the low resistence to movment that I like. Remember the Old Days, when the weight of the surfaces, deployed the controls at rest? I like that kind of low resistance. D>K H^^