Leadout ends - eyelet or loop

[Dennis Toth]

Doing up some cable leadouts tonight and have been trying to see how people have been doing them. I have done the eyelet with then closed it over the cable. This works but I plan on crimping the end rather than wrapping (just lazy). I'm wondering if using a small length of 1/32" brass tubing to form a teardrop loop at the end and then do the crimp would be a better approach?

Best,          DennisT

[Avaiojet]

Dennis,

I'm not sure what you're saying, but without that loop you may be looking for trouble. IMHO.

I started looping in the late 50's with my first JR. Flite Streak , that's how I was taught.

Still loop today, I remembered. 

[John Rist]

Lately I have used large Brodak eyelets.  I do wrap the end.  I am not sure sleeveing it with brass tubing would be easy to do.  Might work but sounds like a pain.

[Avaiojet]

Lately I have used large Brodak eyelets.  I do wrap the end.  I am not sure sleeveing it with brass tubing would be easy to do.  Might work but sounds like a pain.

I use small eyelets and a tube, through the tube then one loop.

Larger eyelets sound inviting.

[Geoff Goodworth]

Be careful with eyelets. The eyelets that I bought from Brodak—approx 1/8" ID—close to ten years ago remain unused because they are about 1/8" wide. I use Hawiian Snaps as line connectors and they simply do not open far enough to fit over the wide eyelets. The eyelets from Mel Shoup on the other hand, are about 1/16" wide and work fine. The wider eyelets should be fine with Sullivan style line clips.

That said, I also use 1/16" OD copper tube in a tear drop shape on leadouts. They have worked well on models up to 58 oz—and probably greater, but that's the heaviest I've flown.

[Jim Kraft]

I have been using the 1/32" brass tubing for years on leadouts, and it works great. Much easier than using eyelets. It also makes a nice bushing on the bellcrank end. It also makes it easy to get the right length because as you bend the tube with the wire inside it locks it where you put it for wrapping.

[Steve Helmick]

"I have been using the 1/32" brass tubing for years on leadouts, and it works great. Much easier than using eyelets. It also makes a nice bushing on the bellcrank end. It also makes it easy to get the right length because as you bend the tube with the wire inside it locks it where you put it for wrapping."

"That said, I also use 1/16" OD copper tube in a tear drop shape on leadouts. They have worked well on models up to 58 oz—and probably greater, but that's the heaviest I've flown."

Ding Ding Ding! WINNERS!!! This method is better than eyelets, IMO, because they seem to be much less likely to do that "twist & lock" crap that can and will make you soil yourself if you aren't really fussy about checking all the clips just before launch. Better yet if you do the same on the lines also.   Steve

[Phil Krankowski]

I have been using the 1/32" brass tubing for years on leadouts, and it works great. Much easier than using eyelets. It also makes a nice bushing on the bellcrank end. It also makes it easy to get the right length because as you bend the tube with the wire inside it locks it where you put it for wrapping.

I made up a set with 1/16 OD tubing (I think that is the 1/32 ID, but I didn't buy it labeled as such) with stranded wire a couple weeks ago.  Very easy.    Wrapping only took a few minutes per end.  If I got my fly tying stuff out it might have been much faster.    I set the wraps in epoxy.  I considered hot glue and shrink tubing to set the wraps, but didn't have suitable shrink tubing.

Using the bent tubing with a properly installed crimp should be perfectly acceptable.

Phil

[Randy Cuberly]

I have used Sullivan, SIG, and more recently Brodak, eyelets for about 35 years for leadout terminations.  I use .5 inch long thick wall copper tubing available from Sullivan brodak and SIG (not sure about SIG now).  Crimp in the manner shown in the AMA Rule book with two crimps on each tube.  I have never had a failure.

I use this method because after making 10 (ten) wires of eyelets with crimped terminations and 10 wires with wrapped terminations and pulling them all to failure, all of the wrapped terminations failed at significantly lower force of pull than the crimped terminations.  In all cases with the crimped terminations the failure was wire breakage around the eyelet.  Most of the wrapped terminations failed in slippage.  Only two failed in cable breakage.

I used to have photos and a list of the actual forces involved but lost them in a computer crash a number of years ago (lightening strike close by).  I did the testing in the metalurgy lab at Raytheon using a dynomometer and a fixture to hold the  wire and eyelets.

The tests were very conclusive and showed the eyelets with crimped terminations to be superior.

Actually this is really no suprise because all heavy cabeling used on cranes etc. use crimped or bolted shackles for terminations.

All of these methods basically use friction to hold the cable and properly crimped tubing simply provides much higher unit loading at the friction points than wrapping.

It is important that the end of the cable is bent back on itself at the end of the tube.

Sullivan provides .031 cable kits with the proper type of tubing for leadouts.

The bellcrank terminations obviously cannot use eyelets and should have tubing formed around a loop and then terminated in the same manner as above!

Another obvious reason for using eyelets is that they greatly reduce stretch in the termination.

Randy Cuberly

[john e. holliday]

I use the 1/16 OD tubing to make the loop.   Use 3/32 for the swage to hold every thing.   Slide the 3/32 on the line.  Then the 1/16 on and position it, then bend.   Slide the 3/32 over the cable.  Take the loose end and slide back through the 3/32, may be a little tight on lead outs, but can be done.  Then swage,  don't crimp.  On flying lines I cut a piece of scrap to double up going through the tube that gets bent.   I can do a set of lines in the time it takes to wrap one end.

Don't know if he still makes them, but swaging pliers came from Carl Shoop.

[Paul Smith]

I'm also big on using the small brass tubing at both ends.  I anneal it with a blow torch first so it's easy to bend.

I put in on straight and bend the horseshoe shape with the cable inside.  The tubing crushes onto the cable and provides enough friction to absorb some or maybe all of the stress, thereby relieving the load on the wrapping. Win-win as they say.

[Igor Burger]

down on this page are my leadout ends

http://www.rcmania.cz/viewtopic.php?f=123&t=49546

[Ward Van Duzer]

OR,

W.

[Tim Wescott]

I use this method because after making 10 (ten) wires of eyelets with crimped terminations and 10 wires with wrapped terminations and pulling them all to failure, all of the wrapped terminations failed at significantly lower force of pull than the crimped terminations.  In all cases with the crimped terminations the failure was wire breakage around the eyelet.  Most of the wrapped terminations failed in slippage.  Only two failed in cable breakage.

Hey Randy:  A question and a comment:

The question: were the wraps the 2-layer wrap shown in the handbook?  I could see these yielding a bit from slipping, but only until the bend around the second layer of wrapping was cinched up tight.

The comment: Mark Hanson, here in PDX, told me that he once did similar tests on a bunch of used lines.  He got the opposite results, with most of the cables breaking at the crimp.

Given the distinct lack of news reports of Impact impacts, I think either way must be adequate.

[Tim Wescott]

down on this page are my leadout ends

http://www.rcmania.cz/viewtopic.php?f=123&t=49546

That's a nifty build thread.  I'm glad that there's pictures, because I can't make heads or tails of the language, nor even identify it.

[Phil Krankowski]

https://translate.google.com/translate?hl=en&sl=cs&tl=en&u=http%3A%2F%2Fwww.rcmania.cz%2Fviewtopic.php%3Ff%3D123%26t%3D49546

[Randy Cuberly]

Hey Randy:  A question and a comment:

The question: were the wraps the 2-layer wrap shown in the handbook?  I could see these yielding a bit from slipping, but only until the bend around the second layer of wrapping was cinched up tight.

The comment: Mark Hanson, here in PDX, told me that he once did similar tests on a bunch of used lines.  He got the opposite results, with most of the cables breaking at the crimp.

Given the distinct lack of news reports of Impact impacts, I think either way must be adequate.

Hi Tim.  Yes the wraps were as recommended in the AMA rule book with double wrapping of the cables bent back on themselves.  During the pulls on the dynamometer, which was done relatively slowly, as the slippaage began it unraveled the wrapping wire and actuall broke many strands of that wire as the bent portion of the cable was pulled through the wrapping.

I obviously can't comment on why your friends failed at the crimps.  I would state that I used a crimping tool that puts two dimpled crimps in the tubing.  I also, as stated, use thick walled copper tubing.  This allows the copper to actually flow under pressure, within the strands of cable.  The crimping tool I use is made from one of the standard crimping tools made for electrical terminations.  The Jaws are ground to allow slightly more closure than the stock tool.

I also made and pulled 5 pieces of the cable to insure that it was uniform in tensile strength.  The cable was .031 Stainless aircraft control cable (MS Part number).

Randy Cuberly

[Igor Burger]

That's a nifty build thread.  I'm glad that there's pictures, because I can't make heads or tails of the language, nor even identify it.

Well I knew there are few peple still not speaking Slovak in stunt comunity, so I posted all in "picture language" 

[Tim Wescott]

Well I knew there are few peple still not speaking Slovak in stunt comunity, so I posted all in "picture language" 

If we learn Slovak will we fly as good as you?  The domain was .cz, which threw me off, at the same time it just made me more impressed with how many languages you must speak.

[Igor Burger]

We usually speak and write "our" slavic language, but we understand also others, means czech, slovak, russian, ukrainian, polish. So if I speak to czech or polish guy, I speak slovak and they speak czech or polish. It is because we have many slavic languages used in small nations, Slovakia has only 5 milons people, so our language is "small" we simply must learn other languages.

We also mostly understand german, but germans do not understand slavic languages. So I speak english with germans and other west european nations.

So that forum is written mixed in slovak and czech language, and noone cares about it. So do not be confused if you try to translate it and translator fails :- ))) ... may be you try to convert wrong language :-))) ... but picture is universal and it tells it all, so I do not see problem.

[NED-088]

Sounds pretty much like our Dutch (only spoken by ~25 mil. people)
We're also forced to learn foreign languages if we want to communicate with the rest of the world.

But another thing, since Henk and I had to leave early, we didn't attend the finals. So here it is after all: CONGRATULATIONS!

By the way, seeing your pictorial, what size is the canopy you used and where did you get it?

[Igor Burger]

Thanks :- ))


Good question, I simply had such canopy and it looked just like I need, but since I have all 3d modelled I do them myself on CNCed templeat, so that it exactly fits to the fuselage :-))
 

may be it should be in separate building thread, but I will post some pictures :- ))

[Randy Cuberly]

down on this page are my leadout ends

http://www.rcmania.cz/viewtopic.php?f=123&t=49546

Hi Igor,
Your leadout ends  are done very much as mine are and as the ones I spoke about above that I tested a number of years ago.  I, of course used the round commercial eyelets which are not nearly as pretty as yours but very much the same in function.  It's a very good indication of the round dimples I referred to rather than flat crimps.

Very interesting build thread.  Thanks for posting it.  It's nice for us "stay at homes" that do not get to travel to Europe (or anywhere else for that matter) to see the functional beauty of your work.

Thanks again,
Randy Cuberly

[Scott Richlen]

Whatever the language, Igor: you do good work!!

And yes, I hit "translate" but it still only got about half the words into English.

Scott

[Lauri Malila]

Hi.

Well, this is more about line ends than lead-out ends, but anyway:

Static pull tests are interesting, but at least as important in my opinion is the capability of line-end to stand dynamic stress witout weakening. I mean stress from vibration and handling. For that reason I don't like crimped or copper wire-wrapped endings. Those often introduce a big stress riser in end of crimp/binding. It is ok if you are carefull, but every year I see more and more people with not so skilled fingers to work with.
For this reason I use very thin Kevlar thread (from free flight suppliers) and cyano for binding my lines. I use eyelets and must admit that the last ones from Brodak were quite crap, but they still work ok for me. I allways fill the eyelet groove with slow epoxy after binding.

Lauri

[Ward Van Duzer]

Seems to me that CA and epoxys are harder, and more brittle than solder. And we all know solder is a no-no...

w.

[Randy Cuberly]

Seems to me that CA and epoxys are harder, and more brittle than solder. And we all know solder is a no-no...

w.

Yes and not only are they brittle but they degrade a lot with UV light over time!  If they work for you fine, but this would not be my recommendation.  In fact you mentioned vibration and CA is not very resistant to stress from vibration because of its brittleness.

Randy Cuberly

[Lauri Malila]

There are flexible cyano's available but so far (about 25 years of doing so) there has been zero problems with any kind of CA's. I have also used all kinds of threads like thin button thread or silk thread without problems but I still feel Kevlar is better as you can wrap it tighter.
The brittleness of glue has no effect whatsoever to the strenght of cable. Every now and then people claim such things but I would really appreciate some reliable proof of that. And about UV-light, of course there is a risk but let's not over-engineer. If you want, you can put some paint over bindings to protect, I just put a piece of heat-shrink tube over the eyelet. Not really to protect but to prevent kinking with line clip.
I use only carbon steel lines and fly a lot alone, so the lines get quite a lot of abuse. Lines are abandoned only because of wear of brass coating and sometimes kinks but never-ever because of problems with line-ends.
It is also a common practise to make ends by soldering, practically everyone in eastern Europe does so. If the soldering is well done and you know how to handle them, zero problems. I solder only the lead-out cable ends.
Anyway, I will show soon some photos how I do it. L

[Phil Krankowski]

While I would like to see testing, I have read a number of people state that soldering traps the flux in the cable where it cannot be removed, and alters the temper of the cable, which both reduce the strength. 

That said I have soldered lines and lead outs with no problems.  Honestly soldering is a bother.

I like the sound of using GSUMP for whipping.  I'll have to try that sometime.

Phil

[Lauri Malila]

Yes, there are risks in soldering. If the cable type requires use of aggresive flux, then:

 -use soda water to neutralize the acidity. Good industrial (for cleaning) soda is much better than baking soda.
 -clean off the soda in boiling water. Repeat a few times.
 -then remove water in methanol bath and dry well.
 -when still hot, oil with good penetrating oil. I use turbine oil.

 So far no problems. But my models are take-apart so it is easy to check both ends and replace if necessary. But maybe I would not use solder in one-piece model. L

 

[Tim Wescott]

My current ride has at least 250 flights on it; I just wound the leadouts dry with copper wire -- no glue, solder, or heat sink.  It's shown no signs of unraveling or fatigue.

[Igor Burger]

It is also a common practise to make ends by soldering, practically everyone in eastern Europe does so.

We are here probably middle europeans, because you will not see soldered lines here around me :- ))))

[Igor Burger]

and alters the temper of the cable, which both reduce the strength. 

exactly

[Igor Burger]

My current ride has at least 250 flights on it; I just wound the leadouts dry with copper wire -- no glue, solder, or heat sink.  It's shown no signs of unraveling or fatigue.

this is also not good idea, copper on stell makes electrochemical voltage and it can cause corrosion in first rain

[Igor Burger]

Seems to me that CA and epoxys are harder, and more brittle than solder.

The strength of glue on that place is not an issue, it is only to fill gaps and unload the stress where metals touch to wider area. The eye must be strong enough also without glue, the glue. That is reason why I crimp it dry and only then I soak it with thin CA.

Another task of the glue is to cover edges, so that lines will not lock in maneuvers and so that they can be much closer together in LO guide.

[Tim Wescott]

this is also not good idea (wrapping steel cable with copper wire -- TaW), copper on steel makes electrochemical voltage and it can cause corrosion in first rain

I have some big spools of insulated magnet wire, from a pile of electronic parts that I inherited from an uncle.  That's what I use.

[Eric Viglione]

Also, the temper of Epoxy can be changed by what you thin it with. I thin it with denatured alcohol when I apply some on my leadout wraps right up to the thimble, and it gives it a much more flexible cure and limits any stress riser issues...  I still cover with heat shrink to make them pretty (my wraps are utilitarian) My planes get litterally thousands of flights (each!) with this method of wrap.

I use acetone or similar to thin epoxy when I want it to dry more brittle for other applications.

Never solder! Might get away with it on small sport planes that don't get a lot of air time and don't weight much, but I still wouldn't chance it. I put way too much work into a plane to chance it on something like that.

EricV

The strength of glue on that place is not an issue, it is only to fill gaps and unload the stress where metals touch to wider area. The eye must be strong enough also without glue, the glue. That is reason why I crimp it dry and only then I soak it with thin CA.

Another task of the glue is to cover edges, so that lines will not lock in maneuvers and so that they can be much closer together in LO guide.

[Randy Cuberly]

I guess we've all proven it can be done a lot of different ways successfully!  Then again, over the many years I've been doing this, I've seen more than a half dozen airplanes lost due to broken leadout cables, at the termination.   Two of those were at the bellcrank end and were bushed with brass tubing, and the rest were broken at the line connection end.  I have seen one solid leadout broken, but it was obvious that the wire had been bent too sharply at the termination.  I did see one soldered connection that broke but had no opportunity to examine it.  I'm personally always interested in these things as a materials and structual engineer!  Personally I have used several different methods over the years and never had a failure.  Of course my earlier years don't count because I was primarily a combat flier and airplanes don't last long enough to worry about leadout failures. 

Randy Cuberly

[Lauri Malila]

Hi.

Ok, it seems that you can do it with whatever method and there is allways something wrong:)
Anyway, here is some pictures of how I do it with Kevlar thread. Close-up photos look allways horrible.

L

[Lauri Malila]

..then..

[Lauri Malila]

..and..

[Lauri Malila]

..and like this. Point is that the very end of line goes past the sharp 180 degr. bend about 1/2" to make transition smoother. I also wrap kevlar inside the eyelet and in the end fill it with epoxy.
This example is 19 strand stainless line which in my opinion is not as good in use as the Russian carbon steel line.

Lauri

[Lauri Malila]

One more picture; result of pull test. The line broke in halfway between wrapped ends. I don't know the break strenght of 19-strand 0.015" cable, I'll guess it is less than 20kp.

Also, I think you exaggerate the effect that soldering has to temper of cable. Even the most sensitive tool steels are relieved to spring temper at about 300C, I doubt that any cable used in our toys is left that hard. Bigger risks are the remains of acid flux and possible stress risers.

L

[Randy Cuberly]

One more picture; result of pull test. The line broke in halfway between wrapped ends. I don't know the break strenght of 19-strand 0.015" cable, I'll guess it is less than 20kp.

Also, I think you exaggerate the effect that soldering has to temper of cable. Even the most sensitive tool steels are relieved to spring temper at about 300C, I doubt that any cable used in our toys is left that hard. Bigger risks are the remains of acid flux and possible stress risers.

L

Lauri,
I agree that a normal soldering operation shouldn't get hot enough to seriously anneal stainless cable.  Our cable is typically 300 series stainless and it doesn't really harden except work hardening during the wire draw and spooling process.
I agree that the biggest threst is from the flux that can be trapped inside the cable under the solder that cannot be neutralized or removed.  It then corrodes the wire and seriously weakens it.
I do not agree with soldering steel cables used in stressed conditions.

I think your method with kevlar thread is likely to be quite secure.  It does seem to require a lot of work as compared to simple dimpling of a copper tube however.

I assume you cover the thread with CA and opaque shrink tubing to reduce the effect of UV light.

Randy Cuberly

[Lauri Malila]

Yas Randy, I put a short piece of heat shrink but just over the eyelet. But it is mainly to prevent the line clip from kinking. So far the UV light has not been a problem but sun rarely shines over here.

L

[Igor Burger]

well ... as I wrote, I never combine copper with steel on such place which often get wet, and I try to keep lines without kinks (like they apear on round eyelets - try to use math and calculate load of wire on such place you will be surprised, plus periaodically loaded in kink ... must break one day) ... they should be only little bend, like on real "drop" shaped steel rope ends, and after all it is much smaller and makes less drag on place where we not need it ... here is how I do it

https://www.facebook.com/igor.burger/posts/859277157422944?notif_t=like

and yes, glue is in metal tube so no troubles with UV as well :- ))

[John Stiles]

well ... as I wrote, I never combine copper with steel on such place which often get wet, and I try to keep lines without kinks (like they apear on round eyelets - try to use math and calculate load of wire on such place you will be surprised, plus periaodically loaded in kink ... must break one day) ... they should be only little bend, like on real "drop" shaped steel rope ends, and after all it is much smaller and makes less drag on place where we not need it ... here is how I do it

https://www.facebook.com/igor.burger/posts/859277157422944?notif_t=like

and yes, glue is in metal tube so no troubles with UV as well :- ))

Really cool stuff right there Igor, thanks for the slide show!