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General control line discussion => Open Forum => Topic started by: Motorman on September 29, 2012, 12:37:31 PM
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There is a recent thread here from Phil Cartier who said he used .018 Spectra lines at the NATS in combat, IIRC. Strength was rated at 100# but his knots dropped that to 65#.
BIG Bear
RNMM/AMM
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Well Motorman, I see that you have already been there several days ago!! http://stunthanger.com/smf/index.php?topic=28401.0 n1
Course you have to buy 300 yards at $44.99 plus shipping - not too bad considering you can make a bunch of line sets and they should last about forever!! LL~
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I use spectra (spider wire) in 1/2a, but I don't consider the diameter. I weight the plane multiply by 10 (10g pull test) then add in 100% for safety. Spectra does lose some strength when making the loops at the ends. At least that's what the experts say, anyway this has worked good for me. Larry Renger has quite a bit of experience with spectra maybe he will pipe in with his thoughts.
Andy
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Can the loops on the spectra lines be doubled up when making them. I used to do that for the loops on the F2C and Goodyear lines that used monoline button bellcranks?
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Andy got it right. H^^
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I use spectra (spider wire) in 1/2a, but I don't consider the diameter. I weight the plane multiply by 10 (10g pull test) then add in 100% for safety. Spectra does lose some strength when making the loops at the ends. At least that's what the experts say, anyway this has worked good for me. Larry Renger has quite a bit of experience with spectra maybe he will pipe in with his thoughts.
Andy
I have not researched the subject too much but as an avid fisherman, the Palomar knot is regarded as the #1 knot for terminal tackle specially braided lines. Use it 100% of the time for anything I tie on my lines. It keeps almost all the line strength and has no slippage once it is tied properly. Also very simple to use on stainless welded loops with line clips. I am really interested if it becomes legal in stunt... H^^
D>K
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Yes, and maybe. :)
The AMA CL General rules state:
2. General. A Control Line model is flown on one or more steel or GSUMP, commonly
referred to as Spectra or Dyneema, lines' steel wire line(s) or metal line(s) of
equivalent strength, attached to the model in a manner providing aerodynamic
control of the model’s elevation through manipulation of the control surfaces during flight. ...
and then later they add
5.3.5.1 Spectra Lines.
Lines made of Spectra fiber, made of gel spun ultra high molecular weight polyethylene are
permitted for sport flying and demonstration purposes. Spectra lines are not permitted in competition
unless the specific rules for the event flown expressly permit such use. The use of high visibility yellow ...
(My bolding for emphasis.)
So, yes, for sport flying, and the only event where they are currently allowed is combat.
That being said, if a CD wishes to allow Spectra lines in a contest, he can add that as a "Deviation" when submitting the sanction application. If the AMA Technical Director deems the "Deviation" as safe, the sanction will be issued and the "Deviation" allowed at that contest.
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The general rules cover Spectra lines for sport flying. 24 oz., .09. 20 lb. test, .010 diameter, 40oz. .25. 40lb. .013, 64oz. .40 60lb. .016 in., 75 oz. .75. 100lb. .018 in. diam. To reiterate, even a simple overhand knot(folded over and tied in a loop) will give 50% of the rated strength- about equal to stainless cable. Any knot that gets a higher rating will be much stronger than standard lines. Not to mention no fatigue failure, no kinks, and very slippery and tough.
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And less tip weight and much lighter lines. 6-10 feet longer than normal- no problem...
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Graph provided for reference only.
--Stephen
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Well Melvin showed me how he tied his Spectra lines. He states so far no slippage on the 1/2A combat ships. He said the knot was he old reliable granny knot.
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I tried the Palomar knot that is listed on back of the 10 LB. Spiderwire box. This was the easiest knot for me. I had a hard time making the lines the same length with the other superior knots. I was only off by 3/8” at the end of 52 ½’ lines. The adjustable handle can make up the difference. I did notice while flying the lines did bow more than steel lines. I tried the lines today in the rain. The Spiderwire did not stick together even after a few loops. This was just a quick try to see what would happen. Good stuff so far on an OS .10 powered Ringmaster Jr.
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Motorman,
You are correct about the 10 LB line is only .006 diameter.
The Ringmaster Jr. only weighs 12 oz. The AMA Spectra line chart shows 24 oz uses 20 LB line.