flying line ends

OK, when I started flying control line again several years ago everything I read said don't soder the ends of wires. The first set of lines I got from SIG came with crimps, which I used. These lines broke just beyond the crimp, and I lost a good plane. Next I heard, wrap the ends with copper wire, just like we used to do, but seal with epoxy. OK, I did that.

This weekend I was flying my old Shoestring on a set of Sig 0.015 wires only used about a dozen times, made using the wrap/epoxy method. The up wire broke at exactly the place when the epoxy wrap stopped on the end. Thanks to incredibly good piloting, or luck, or maybe a combination of both, I got the plane down with only a broken tail.

Now the question, what am I doing wrong! Is Sig line no good? I'd appreciate some help here guys, I'm sick of losing planes to stupid accidents!

This will be one of many replies, so here goes.

What you are trying to AVOID is to make a sudden change in the flexibility of the control lines. In the case of crimping, the last instruction sheet I saw suggested to use round nose pliers to make the crimp. This prevents putting a sharp edge that the control lines would bend against. There are certainly other crimping techniques that work, although some will swear at them and some will swear for them.

The copper wire technique works well because the copper prevents a hard edge--unless you soak the end with epoxy (or solder). If you just lightly put some epoxy on the copper coils to prevent their coming unwound, that would be fine. Just don't get the epoxy on the point where the single cable comes in. The same is true for soldering too, since as long as it is just on the copper, and not at the very end, it would be ok. The sole purpose is of epoxy or soldering is to keep the copper from unwinding. You don't need it for strength.

Hope this helps. Alan

When you wrap the ends with copper wire use no glue or solder, allow the bind to flex. The lines that Tom Morris sells are done this way and his lines look perfect. I do the same thing at the bellcrank. If your worried about the binding coming loose you could use a piece of shrink wrap.

Couldn't agree more Circle Burner.

I normally fly with a group that include several top 20 fliers have never seen any of them use crimped lines or any epoxy or solder on the wrapping. I have never seen any of their lines break or come loose. With shrink wrap use different colors to identify up and down lines.

I bind and epoxy mine and have not had a failure with lines up to 3 years old. Are you sure you're not bending and straightening the ends at the end of the binding? If they're not kinked and straightened alot they should last just as long as the rest of the cable.

>I bind and epoxy mine and have not had a failure with lines
>up to 3 years old. Are you sure you're not bending and
>straightening the ends at the end of the binding? If they're
>not kinked and straightened a lot they should last just as
>long as the rest of the cable.
>

Randy,

Just a thought: the results obtained could be very vibration dependent. If your engines run smoothly, then there would be little stress caused by vibration flexure at the epoxy/cable interface. But if you've got a lot of shakin' goin' on, then the vibration could cause a lot of flexure cycles at the interface and premature failures. Given how carefully you set up your engines, I'll bet they are running smoothly with little vibration. Others may get very different wear lifetimes, depending on the vibration levels. My take is to avoid a stiff stress riser and go with only enough cement or solder to prevent the copper wire wrapping from unwinding. Shrink wrap sounds like a good choice--nice and flexible.

JMHO, and FWIW,

OK, I will jump in here also and agree with those who say to use NO epoxy or solder. None needed.

Crimps work if you use round crimps and pull straight with no flexing whatsoever. (Did you ever see lines that didn't flex somewhere? Me neither.) If the lines flex against a hard point, that is exactly where they will break. So, if you crimp and pull them straight you can show how strong they are. Crimp and fly with them a while and they will break. I have had Sulivans do the same thing.

And if you epoxy or solder, you have done the same thing just using different methods. If you wrap the lines according to the rule book method they won't unwind. We have used lines and gotten several thousand flights on them using the above methods. (Matt's present set of lines have about 1000 flights on them as I write this. We will make up a new set of lines for the new plane, but these will stay with this plane.) I would never suggest using epoxy or solder. Just wrap and go.

(Matt's present set of lines have
>about 1000 flights on them as I write this. We will make up
>a new set of lines for the new plane, but these will stay
>with this plane.) I would never suggest using epoxy or
>solder. Just wrap and go.

Got him beat... I have a set of lines with over 1500 flights and the ends are crimped...go figure

It's nice to tell some one on how it's done BUT to see it done right is a differant story. Get the rule book or go to the AMA web sight and find the section on line wraping.

Scott(pictures are good)Riese

Richard,
People have had successes and failures with all kinds of terminations. I believe the key point is to allow some flexibility at both ends of the connection to prevent stress points. The crimps, solder and epoxy all work if done properly.
As someone pointed out, if you solder or epoxy only the center part, it shouldn't cause a problem...same with crimping with round nose pliers.
A very important point is to use them carefully and minimize any unnecessary flexing at the connections.
Also avoid kinks !!

Good luck,
George

>OK, I will jump in here also and agree with those who say to
>use NO epoxy or solder. None needed.
>And if you epoxy or solder, you have done the same thing
>just using different methods. If you wrap the lines
>according to the rule book method they won't unwind. We
>have used lines and gotten several thousand flights on them
>using the above methods. (Matt's present set of lines have
>about 1000 flights on them as I write this. We will make up
>a new set of lines for the new plane, but these will stay
>with this plane.) I would never suggest using epoxy or
>solder. Just wrap and go.

Just to point it out, the AMA rule book drawiing
(http://modelaircraft.org/templates/ama/PDF-files/Rulebook/cline.pdf)showing wrapped lines has the following little note tucked at the bottom: "Coat wrapping with epoxy or solder to secure". So technically, solder or epoxy are *required* if you use wrapped lines. Based on this discussion, a thin coating of epoxy, just to secure the wrapping, is in order. The idea is to keep epoxy away from the interface between the line and the wrapped portion, to prevent a stress riser.

While we're on the topic, what is a good supply of eyelets, and what is the correct diameter copper wire to use for wrapping? McMaster Carr can provide the copper wire, but all their eyelets have to be crimped. Where can I find eyelets that are ready to use? I suppose the use of tubing instead of eyelets might be the best alternative(http://clstunt.com/htdocs/dcforum/DCForumID1/4544.html)

Just found some responses to an old thread that are also helpful (24 gauge wire suggested for wrapping)
(http://clstunt.com/htdocs/dcforum/DCForumID1/5265.html).

Thanks,

I'm surprised that anyone had trouble with epoxy, which is fairly good at absorbing vibration. However, all that is needed is to prevent the copper wire from unwrapping, and I just use a dab of thin CA on the coil..

The intelligent idea is to add shrink tubing over it, and you can color code your lines to boot.

[photo not recovered: 3e69bb3870f12ad5.jpg]

"Experience is that marvelous thing that enables you to recognize a mistake when you make it again." -F. P. Jones

Thanks for the help, the problem is almost certainly vibration. All my old engines, both Foxes, and McCoys shake badly. As I remember these engines always did on anything but a full built up plane. I suspect the solution is to just use one set of wires for the old stuff and go with a new set for the newer smoother engines.

I have a 40 year old set of 70 feet 0.018 lines cut down to 60 feet where I used shrink tubing to seal the wrap, and these have worked just fine for the last 2 years.

Thanks again for the thoughts. Happy skies to you all.

Andy Tomasch wrote:

>While we're on the topic, what is a good supply of eyelets,
>and what is the correct diameter copper wire to use for
>wrapping? McMaster Carr can provide the copper wire, but
>all their eyelets have to be crimped. Where can I find
>eyelets that are ready to use? I suppose the use of tubing
>instead of eyelets might be the best
>alternative(http://clstunt.com/htdocs/dcforum/DCForumID1/4544.html)

I know SIG sells them. A lot of people used to salvage them from the packages of Perfect parts (they hold the little card labels and plastic bags together) and hoard them, but I can't imagine anyone being able to get together very many. SIG simply puts a whole bunch of eyelets on pieces of scrap cardboard using their package eyelet-sealer machine and sells the cards for a buck or two. A lot of Combat fliers don't even use eyelets (I don't) - I've never had lines or connectors break or wear through at the loop, but that doesn't mean it won't happen with the stump-pulling line tension you get with a full blown Stunt ship, over the course of hundreds of flights. So if you want to get eyelets by the hundred, cheap, the way would be to buy the unmashed ones (I'll bet companies that sell packaging sell them in huge bags real cheap) and a handheld eyelet mashing tool (I think they sell them at sewing supply stores).

>Just found some responses to an old thread that are also
>helpful (24 gauge wire suggested for wrapping)
>(http://clstunt.com/htdocs/dcforum/DCForumID1/5265.html).

I wonder if insulated wire (such as the stuff they use for wire wrap connections on old-style computer breadboards, or small diameter bell wire, or old telephone cable wire) would work. I've seen a lot of wire for sale cheap at hamfests.

http://clstunt.com/htdocs/dcforum/DCForumID1/5265.html).
>
>I wonder if insulated wire (such as the stuff they use for
>wire wrap connections on old-style computer breadboards, or
>small diameter bell wire, or old telephone cable wire) would
>work. I've seen a lot of wire for sale cheap at hamfests.
>
>
Enameled insulated wire works fine. YOu can get it at any motor rewind shop. I have used it for years.

On the eyelets, Brodak also carries them in several sizes. They are packaged in quantities of 12 to a package (he calls them thimbles, by the way) but we can also get them in bulk in larger quantities in case you are getting like 1000 feet of wire.

I got some eyelets from RSM, and some from Brodak. The RSM eyelets are quite a bit larger diameter, and would probably cause even more trouble with connectors getting "twisted". I am going to change to use the brass tubing method of Mr. Dirt, with 28 gauge copper wire binding, not crimps, and cover the bindings with heat shrink tubing. The wire is said to be available at the craft stores. Steve

I wonder if the teflon thimbles they sell for deep sea fishing would work:

http://www.captharry.com/hooks-offshore.html

I have used some really small stainless thimbles but took them off because of the difficulty in getting a clip over them. The abuse that the whole termination took when connecting was worse than no thimble. This was of course on the leadout wires which are nylon coated 7x19.

I like the brass tubing set up for this end of things and use the standard small eyelets that Tom Morris sells for the lines.

FWIW

>I am going to change to use the brass tubing method of Mr.
>Dirt, with 28 gauge copper wire binding, not crimps, and
>cover the bindings with heat shrink tubing. The wire is said
>to be available at the craft stores.

This apeals to me also. And McMaster Carr sells spools of bare copper wire in any size you like for typically $3.00.

... I wonder if insulated wire (such as the stuff they use for wire wrap connections on old-style computer breadboards...

Wire for SLT wrap would probably work if you strip the insulation. SMS wire would be too coarse. Don't know about other types.
IMHO any small solid copper wire would work. Lamp cord will work if you strip off the insulation and use one strand at a time

and a handheld eyelet mashing tool (I
>think they sell them at sewing supply stores).

Yep, and they sell the unmashed eyelets too, pretty cheap. They are, however, a little on the large side. Picked some up recently.

I have used carbon/kevlar fishing line to wrap line ends and coated with "liquid insulation tape" then heat shrink for a strong and flexible termination. on lines and lead outs. lines for 15 size and smaller crimping seems to work fine.

>I have used carbon/kevlar fishing line to wrap line ends and
>coated with "liquid insulation tape" then heat shrink for a
>strong and flexible termination. on lines and lead outs.
>lines for 15 size and smaller crimping seems to work fine.

The problem I would see in using the carbon/kevlar line to wrap line ends is it will not form well to the wire. Copper wire wrapped around the joint binds itself tight and stays. The other stuff will tend to come unwound and won't nearly hold as tightly. since copper wire of the appropriate size is readily available, I don't see the need to use anything else.

That reminds me. In my personal control line prehistory (high school, when lines were hard to come by and information was even more scarce) the first set of lines I made were wrapped with sewing thread and epoxied. Thereafter, I used solder, which worked because these were Laystrate lines.

Gotta find myself a huge spool of that Euro carbon steel wire.

Radio Shack sells some "wire wrap" wire that has red, blue, white, or yellow insulation. Don't strip the insulation use it for coding.
This is without a doubt the very best stuff to use for wrapping lines.
It's about 30 guage I think, The size is good enough to make a safe wrap but not so small that you can't make a neet looking job. It's very easy to work with this wire. After wrapping, twist the loose ends together and snip off at 3/8 inch and fold down next to wrap. No need to epoxy. No shrink wrap needed.
Frank Williams