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General control line discussion => Open Forum => Topic started by: Andrew Borgogna on November 27, 2010, 04:21:51 PM
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You know I have been flying model airplanes for nearly 60 years and I thought I had seen it all, that is, until this morning. Larry Renger and I went flying today and when I was setting up the Madman the control lines did the strangest thing I have ever seen. I unrolled a fairly new set of .015x60 lines and as normal when they were rolled out I ran them out to remove any twists. As usual I then tried to wiggle the elevator up and down, but the controls acted as if something was bound up in the plane. No movement at all! I went to the plane and the controls were smooth as silk, again I ran the lines out (no twist this time) and again the control system acted as if something was jammed solid in the plane.
I called Stan Tyler over and he ran the lines out and held them apart and the controls were smooth as glass, but as soon as he let the line touch each other, they bound up like a knot. They looked and acted like they were twisted together, but they were not! So thinking there was something coating the lines that was the source of the problem I took a paper towel and drenched it in alcohol and wiped the lines down, no help at all. As long as the lines were kept separate everything worked as expected, but let the lines come in contact with each other they acted as if they were twisted tight. We took each line and ran them back from the handle to the plane to see if they were twisted, but they were not. At this point I replaced the lines and everything was fine. After giving this some thought I think I might know what the problem is. The lines may have been sitting on starter in my box and became magnetized. I thought that stainless steel could not be magnetized, but Stan Tyler seemed to think that some can. I really have no other explanation. Larry Renger has a device that demagnetizes old real-to-real audio tapes; we are going to give it a try. Has anybody ever seen this problem before?
Andy Borgogna
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The term "stainless steel" covers a whole lot of territory. Some stainless will magnetize, some won't. If it doesn't get attracted to a magnet, it won't magnetize.
I just checked my lines (Sig and Sullivan), and they're barely attracted to a really strong magnet.
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Low grades of stainless steel are slightly magnetic. When the lines are stretched out, the contact area may be enough to create the lockup.
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Magnetized lines!! Andy.... you're just trying too hard. I feel so unworthy........
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Dave
I got an email from "Big Art" and the only Big Art I know is your father. When I tried to send him a reply Stunthanger could not find the name, but the name is the first in the members list. Anyway if was your dad tell him thanks and I will try his recommendation ASAP and report back. Big Art said to reverse one of the lines because they are too closely matched in twists, he said he has seen the problem before. Anyway it makes sense and worth a try.
Andy
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The term "stainless steel" covers a whole lot of territory. Some stainless will magnetize, some won't. If it doesn't get attracted to a magnet, it won't magnetize.
I just checked my lines (Sig and Sullivan), and they're barely attracted to a really strong magnet.
Agree - depends what alloy of Stainless those lines are. Coiled tightly, sitting on a magnet - yup.
On a Commercial Airliner we use a DeGauss ring big enough for the fuse. (fwd) to pass through. Kills all those little avionics "bugs".
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Not to high-jack the thread, but Douglas' post reminded me of our aircrewmen carrying little magnets in the pockets of their flight suits to slip onto the side of the forward radar scope in the S2F's so certain pilots who were a pain would think the scope was bad. The old sweep would go bonkers on that side of the scope but when the pilot squawked the APS 38 it seems the aircrewman always could fix it as soon as they got back! LL~ LL~
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Well I went out to the garage and took the reel and put it next to a magnet and is showed slight magnetic attraction. That would indicate the lines can be magnetized, and possibly the problem. But until I try Big Art's test I can't say for sure. I will try to do that tomorrow.
Andy
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Brodak lines are attracted to a magnet too - I found that out the hard way
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Interesting.
I have noticed in returning to C/L that new lines seem to get stiff on the controls with just a few twist compared to older lines that would still slide freely with many many twist.
When time allows will get out some old sets and see if any difference.