Lead Out Wire

I had three 1/2A class C/L models that needed crimp-tubes installed on their .015" stranded SS lead-outs. The "bell-crank" ends had been done previously. It's a tedious task.. and I need to be in a certain frame of mind to get into it. Since I quit smoking cigarettes 18 months ago.. I don't have near the patience that I used to.

I use .062" (O.D.) brass tubing for my crimp-tubes. I cut them to approx. .625" length. The .015" stranded SS cable will pass-thru this size tube X3 times, which locks the line securely once crimped. It's important to "dress" (open-up) both sides of the tube, to remove any burrs from cutting it to length. I made a tool from a safety-pin.




The 1st model to be done was my tiny "Flying Blind"..




The 2nd model.. my Lockheed P-38-J..




The 3rd model.. my "Fulcrum Flyer".. (it got a lot easier by this time..)






I decided to use the music-wire pushrod.. rather than the CF pushrod that I had fabricated.



One step closer to getting to the flying field.

Oldenginerod wrote:Roddy.
Do you just thread the wire through the tube, loop it and thread it back?  I was under the impression that the wire should do one full loop around the outside of the crimp tube, as in, through the tube, loop, back through the tube, around the outside and then back through the tube before crimping.  Am I overdoing it?

I enjoyed Dave's video.. and yes; he loops his cable around the outside of the crimp-tube and back through. That's a better way to do it. My crimp-tubes were small enough that I could barely fit the line through a third time. When cinching-up tight; the inside loop gets smaller.. until it "binds" against itself at the tube opening.

I usually stagger the terminations.. to avoid the possibility of them snagging on each other. My airplanes are small/lightweight.. so I feel that these crimps will be fine.

dirk gently wrote:Just throwing out a wild idea here - how about using the eyelets found on guitar strings?


Or even simply using guitar strings for leadouts?

I like the "eyelet".. but I didn't have any. The guitar string eyelets would work.. but I believe that they're thicker than the purpose-made eyelets for our application.

The "eyes" formed in the .015" diameter SS stranded-cable lead-outs shown in my examples, will be inspected at pre-determined intervals.. but at the least; seasonally.

The model that would raise the most concern with my lead-out construction-technique would be my P-38-J. It will be pulling harder on the lines than a single reed-valve engine airplane. I still feel that my lead-out lines; their crimps/eyes will be more than strong enough. My concerns are more with the landing-gear.. (wheels.. in particular)

944_Jim wrote:Roddie,
Given that you are using what appears to be 7-steand stainless, I have a question for you.

Do you think your lead-outs would saw through WD-40 straws slowly, or quickly? I ask because my mini Mossie needs some really small lead-out tubes, and I also plan on using 7-strand. My wingtips are fairly thin, and the lines need to come out the wingtips. If the straw can't hack braided lines,  then I may go solid lead-outs.

Thanks in advance! Oh, your wheels may wind up in the Speed Dolly!

I'd be more concerned with anchoring those plastic guide-tubes. (don't use those...) I don't know what I'd use to keep WD-40 straws from pulling-out. I'd opt instead; for equal-size "alloy-tubes" for guides. I would have included a pair of alloy tubes with the wheels if I had known about this sooner. Some food for thought Jim; Portable air-conditioners (window-units) often utilize coils of small-diameter copper tubing for refrigerant. Your local landfill might have an area for recycling "dead" air-conditioners. Bring cutters with you.. and snip-off the coil if you can find one that looks to be the right size. You can straighten the tubing later-on at home. Cut your tubes to length and rough them up with coarse abrasive-paper. You can also use a blade to scratch the surface to aid in glue-retention. The "plastic-tube" would work.. but why worry about the abrasion-factor?

I don't know how your Mossie's wing-tips are constructed.. but if the tip is "framed" conventionally.. with a flat-plate for the guides to lay-on; you could "tack" the tubes in-place with CA.. followed by mixing-up some epoxy to brush-on over the tubes to permanently secure them. "Candle-Wax" could be melted/dripped onto the stranded-cable where it will pass-through the guides, as an anti-abrasion measure.. if you're concerned about that. Any "sawing-action" on a models' lead-out guides is a "right-of-passage"... as far as I'm concerned. Many models don't last long-enough to earn that privilege..

rsv1cox wrote:It's been bugging me, so it's a good time to ask the question - Whats the case for using stranded lead-outs over solid wire and visa versa?  

I switched from stranded to solid quite a few builds ago for .09 and less engines.  



Pretty pedestrian compared with what you guys come up with but it works for me.  

Your lead-outs look GREAT Robert. I would say that it's a matter of preference.. when it comes to a sport/scale-model. The people who fly C/L combat are concerned with razor-sharp control-input. Solid lead-outs may not deliver the "feed-back".. especially with the "fast-combat" models. Ken Cook would be the man to comment about that.

That said; I do prefer solid lead-outs. My latest models are using the 7-strand braided-stainless because I wanted to try making bell-crank-buttons. I also have a few old-spools of .015"/.018" 7-strand S.S. line X 60+ feet.. which have been languishing on the wall in my workshop. Why not try to utilize them? I'd never trust that line for actual C/L flying wire.. but for 1/2A-sport lead-out cable, I think it will work just fine. I'd sourced those spools over 30 years ago.. with some model-parts buys.