Sewn Hinges - How-To

Here is another great Charlie Fite article!

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By Charlie Fite

Sewn hinges have been around for a long, long time. It is said that that they originated in the late 1930’s with the introduction of control line airplanes and were basically the only choice for hinging the control surfaces. Nylon pinned hinges weren’t introduced until the 1960’s, when plastics became more available, and Dewey Broberg formed Du-Bro. Since then, all types of pinned, wafer, post, and even CA hinges have become popular. I’ve used them all until I built a 1917 Eastbourne as close to scale as I could manage. I went back to my early days of building and flying control line airplanes, and the first method I used to hinge the control surfaces.

Since then, every balsa aircraft I’ve built (close to 50) has had sewn hinges on the ailerons, flaps, elevator, and rudder. With a little practice, they’re not that hard to do, they are self-aligning, self-centering, almost frictionless with 180⁰ of throw, require no special tools, and they are really, really inexpensive. There is also almost no gap at the hinge line, which all but eliminates the possibility of flutter. I’ve tried all kinds of thread (Nylon, Rayon, cotton, and silk to name just a few), all with varying degrees of success. Then I discovered Spider-Wire, a braided, flat wound Dyneema fishing line with Flouropolymer coated fibers. It is the strongest “thread” for its diameter, it lies flat, and a 125 yd spool of 6 lb test will last forever.

For the purposes of this article, I used a heavy rayon thread so that you could see the “braid”.

The first thing I do is locate and mark where the hinges will be.

Then I drill a 3/64” hole, at least 1/4” back from each edge.

Next, I’ll tape the tag end of the thread to one of the surfaces near the hole. Then push the needle down through the hole….

And come back up in the gap between the surfaces, then down through the adjacent hole…and back up through the gap……

Down through the first hole, and back up through the gap….forming a figure 8.

I keep repeating this process until I have at least (6) “figure 8 laces”….pulling each lace tight.

A drop of CA at each hole secures the ends, eliminating the need for a knot. Then I trim the tag ends flush.

Repeat the process for each pair of holes, and each control surface.

I’ve added one step. I’ll take a triangular shaped file and cut in a shallow notch at each hinge point so that the thread is flush with the surface. It takes a bit longer, but the hinge won’t show beneath the covering. You also end up with zero gap.

That’s all there is to it…..

Y’all keep your nose up in the turns!

NOTE FROM RCG - Any negative posts or posts that are an attack against the intelligence, character will be redacted.

Last edited by Jim T. Graham; Jul 27, 2021 at 09:14 AM..
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Jul 27, 2021, 09:12 AM
AndyKunz's Avatar
Good article, Charlie. Hopefully this will help more guys see the light!

Andy
Jul 27, 2021, 10:48 AM
Sagitta Fanboy
Nice, I've got a couple 'restorations' in the queue that would really benefit from sewn hinges. I was pretty sure I new how to do them, but this is exactly the info I needed.
Jul 27, 2021, 12:29 PM
Ad eos qui nesciunt crepitus
Old_Pilot's Avatar
Quote:
Originally Posted by AndyKunz
Good article, Charlie. Hopefully this will help more guys see the light!

Andy
Thank you Andy, coming from you, it's quite a compliment....

Cheers
Latest blog entry: Alternate covering
Jul 27, 2021, 01:04 PM
B for Bruce
BMatthews's Avatar
I really like your method with the closer grouping.

I've used sewn hinges in a lot of my own models but went for a little more spacing so they come out looking a bit more like a line of WWW. Your closer spacing looks more crisp visually.
Jul 27, 2021, 01:04 PM
AndyKunz's Avatar
I hope that doesn't mean I'm a negative person! I sure try not to be.

And I still like the lines of that plane.

Andy
Jul 27, 2021, 05:06 PM
I fly, therefore, I crash!!!
SteveT.'s Avatar
These type of hinges were literally the first type of hinges I learned to do/use and am quite happy to see somebody posting an article showing how to do them! Bravo!

SteveT.
Latest blog entry: My shop....
Jul 27, 2021, 05:35 PM
Ad eos qui nesciunt crepitus
Old_Pilot's Avatar
Quote:
Originally Posted by AndyKunz
I hope that doesn't mean I'm a negative person! I sure try not to be.

And I still like the lines of that plane.

Andy
No, No, NO....you're not negative at all....you've been building these things longer than I have.....it was meant as a compliment.....I was honored.

guess that's the danger of the typewritten word....can't hear the inflection on one's voice
Latest blog entry: Alternate covering
Jul 27, 2021, 07:28 PM
B for Bruce
BMatthews's Avatar
Good grief Andy... .if there is ONE SOUL here on RCG that is always ready with a positive word (when not being directly attacked at least) it is you. I very much took OP's post as being the "Thankyou " that was intended.

I didn't mention it above but darn that Altegeera is smart looking. I don't see a cylinder and I also see too many hinge lines... So... .Electric RC? As a short coupled control line design how is it for flying as an RC model?
Jul 27, 2021, 09:01 PM
Ad eos qui nesciunt crepitus
Old_Pilot's Avatar
Quote:
Originally Posted by BMatthews
I didn't mention it above but darn that Altegeera is smart looking. I don't see a cylinder and I also see too many hinge lines... So... .Electric RC? As a short coupled control line design how is it for flying as an RC model?
She was pretty docile at slow speeds, and very agile..Yes she was electric......5 channels

Here's a video of her sister:
Altagerra Maiden (3 min 35 sec)
Latest blog entry: Alternate covering
Jul 27, 2021, 09:24 PM
Registered User
thanks for sharing....ive always wondered how it was done..pretty nifty
Jul 27, 2021, 09:31 PM
Flying in OZ.
iflylilplanes's Avatar
I've never seen that way of sewn hinges, mine have always been the zig zag version.

I have a vintage Aeroflyte control line trainer in restoration, will try your way Jim.

Great show and tell.

Dave
Jul 27, 2021, 09:37 PM
Flying in OZ.
iflylilplanes's Avatar
Jim, how do you cover the hinges/gap?, (what there is of it), do you cover before or after you produce the hinges?
Jul 28, 2021, 01:46 AM
B for Bruce
BMatthews's Avatar
Now that's a proper flying sport aerobatic model!

I'm not surprised that it doesn't want to knife edge. There's simply way too little side area to develop any lift. But darn if it doesn't do just about everything else really nicely. And of course given it's roots obviously the looping maneuvers are going to be the strong point.
Jul 28, 2021, 05:40 AM
Ad eos qui nesciunt crepitus
Old_Pilot's Avatar

Covering the hinge gap


Quote:
Originally Posted by iflylilplanes
Jim, how do you cover the hinges/gap?, (what there is of it), do you cover before or after you produce the hinges?
I cover all my planes with heat shrink plastic film (MonoKote, UltraKote, etc) after I sew the hinges. Because the control surfaces will rotate through 180 degrees, I can pretty much "wrap" the hinge line of each surface, both top and bottom.....lemme see if I have a picture.

You can see the hinge bump in this photo because it was before I started notching the the wood at each hinge location...it was also before I discovered Spider-Wire.

Once I started using spider-wire and notching the wood, the hinge all but disappears

Hope this helps

Charlie
Latest blog entry: Alternate covering


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