My Knife and I had our 3rd or 4th date today. To the amazement of me and everyone else I performed a really sweet waterfall. I did it for while and continued to fly. I noticed she was handling funny. Sort of ballooning but I couldn't peg it. When I got to the ground I saw that one of my ele wires had pulled loose. I was so lucky it was the the bottom wire. If it had been the top wire I would have had no up ele and probably wouldn't have figurerd out why until I was going through the wreckage! Even if I had known what was up int flight I would have had to land inverted. I'm least that potential threat is in my memory banks now. -- No up? Any down? Yes? LAND INVERTED!
Man that was close!

Glad to hear you made it back!

Billy - that is why I like the 'weave' method outlined by Dubro on their Pull-Pull packs. The weave approach prevents what happen to you all together.
Glad to hear that you still got your aircraft. Your Knife is know considered to be a Free Plane to you, because it should be BALSA SEED!!!

I tried the "weave" approach on the pull-pull wires on the rudder of my GP 60 size Extra. Right at the part that the clevis is on, the wire snaps. It's done this twice in the air. Good thing they aren't on the elevator!

You might want to check for burrs around the drilled hole in the coupler.

Good thinking. I think the crimp just let go. I went back and CAed the wires in.

the best way I have found for pull pull is this:
this came from Don the designer of the Wasp.
he told me to go to the fishing store or K-Mart and get some 30lb test nylon coated fishing wire for 2 bucks. now you run it where you want and to close it you simply twist it after the loop and heat the twist with a lighter. the nylon melts to itls self and bonds like nothing I have ever seen I have tested it over and over off the plane be making a loop on each end of a piece then incerting a screwdriver in each end and pulling apart. the loops never give before the wire. now on a small plane 30lb test is much more than you are gioing to need. I have even crashed and after the crash the servo horns break off the servo before the wire breaks....
simple, fast, and cheep....
try it.

Best thing to do is put the wire through one end, loop it around and go back through it again. Then slightly crimp it, add a couple drops of CA to each end, then to finalize things add plastic shrink wrap over the crimps. They won't come out then...

I just started covering my Knife tonight... Can't wait to fly it!

I just crimped with pliers and added a drop of thin CA. Fine after approx 70 flights.

That makes me feel better.

What about putting it thru the crimp, make a tiny knot and add some CA ? SHould work fine. At least it works on my Top Cap.
Just my $0.02

I've been using a chunk of aluminum tubing about 1/16" id. Just cut off a peice about 3/16". Run the wire thru the crimp, then thru the servo horn or clevis rigger, then back thru the crimp then loop around and one more time thru the crimp..... Then crimp it on both ends.... Really strong....

I've also used the "twist and melt" method from Don Incolls.... I liked it, but it takes more room to do the connection.

How about some pics?

How's this:



I can take a real pic later if this isn't clear.

Do you back the aluminum tube up to the coupler or leave it a little in front of the coupler? And thanks.

I backed it up to the coupler with a little room... and pulled the the loop tight before I crimped it.

What Paul has kindly illustrated is what I referred earlier to the 'Weave Method'. I've been using it for years without failure. I now purchase plastic coated steel leader from a fishing supply store. I buy the A3 couplers from the fihsing supply store for 2-56 cabling systems as my crimpers, and A4s for my 4-40 systems. I use to cut my own tubing to use as crimpers, though I can buy the A3 & A4 crimps for making up steel leaders that its not worth my time anymore to make the crimpers manually. Then I purchase rigging couplers only from the LHS to make up my Pull-Pull cabling systems.

I have a Knife and I did my pull-pull like Paul's diagram shows. I had to debur the inside of the aluminum pieces. Mine had a slight bur, so make sure you check this to avoid cutting into the wire when crimping. I have a tiny round file that has a tapered point that I used for this, worked like a charm. I crimped the assembly snugly, then put CA on it. It has been bulletproof so far and I have no fear of it ever failing.

Wade