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General control line discussion => Open Forum => Topic started by: Peter in Fairfax, VA on March 01, 2019, 05:44:05 PM
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How do stunt pilots refer to line length? Eyelet to eyelet, as I just saw in another thread, or handle to prop nut center? In combat, it is handle to prop center.
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most stunters prefer eyelet to eyelet
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As I'm trimming out a new airplane and trying to settle on a proper line length, I go by handle to fuselage center line. Once I'm there in the ball park, I measure the lines eye to eye and note that on the reel. That way, if I need to replace them I know what the length is, or if I decide I need to make a change form some odd reason, I know which way I need to go, longer or shorter than the original. Some guys in the old days went to a different length line for windy weather and such. I make up a set of lines and handle for each model I have ready to fly and sometimes use the length of one as a reference for what lines to use on a new to me model. Line length is one way to speed up or slow down your airplane with out changing anything on the engine.
Type at you later,
Dan McEntee
PS to add: The AMA maximum is 70 feet handle to fuselage center. It's good to have that in mind as a reference so you know you stay legal. I have seen many models in my time that had the out board wing sheared off by a light pole because the owner didn't check the length against what was printed on the package!
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How do stunt pilots refer to line length? Eyelet to eyelet, as I just saw in another thread, or handle to prop nut center? In combat, it is handle to prop center.
Almost always eyelet-to-eyelet. That's because the airplanes vary a lot, and I know that David's 64' lines are the same as my 64' lines and Ted's 64' lines. As long as you don't go over the max, the handle-to-centerline measurement is irrelevant (unlike a lot of the other events). In any case, most people aren't that close to 70 and going over is a non-issue. It doesn't really matter as long as you specify the measurement type you use when talking to other people.
As noted, *beware* pre-made lines, and be sure and measure them. Poorly made end "crimps" are very common, and I have seen Sullivan/Pylon "60 foot" lines that were supposed to be 58' (which always seemed like a poor way to do it, since they have no idea what airplane it might be going on), but were instead 54 feet or 64 feet, or 74 feet.
At some WAM contest a long time ago, someone took off with their brand-new Sullivan ".015x60" lines, we set up our chairs dutifully outside the circle upwind. He takes off, and after about a quarter of a lap and it is obvious that the airplane is sort of coming at us. A little while longer, and hey, this doesn't look right, a little while longer and "HIT THE DECK!". That airplane probably went 15 feet *behind our heads* with us diving onto the ground. Afterwards, we had the lines checked and there were something like 85'. Both the pilot, and the judges, were a little less than pleased with Sullivan that day, the pilot because they had caused him to get a 0/DQ on a flight, and the judges, who take things like almost getting decapitated rather personally.
I am not sure how they do the measurement in production - probably something like count the turns of the reel required to get the necessary length. Which is a little different from OCD stunt guys out there pre-stretching them to set the breaid, and letting the lines sit on the blacktop for 1/2 hour so they will warm up, so they can get it within 1/64" including thermal expansion.
Brett
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Sounds like a great thread to start on the Handle section on how to do a really good set of lines.
Sources of wire, best ends, wrapping or crimping, shrink tube color coding, or topics of which I am not aware, but would like to be. Never heard of stretching and sun warming, for instance.
This would be very valuable for safety in addition to performance. H^^
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A bunch of local Experts use one line about 5" longer than the other, so we'd need to refer to the longer line, or maybe an average length. Or somethin'. I believe Howard and Mike fly their F2B planes at near the 70' center/center limit. Not sure about Paul, Chris and Alan. I typically fly on 64' i2i, but my SV-11 pulls too hard, so I'm gonna make up a set of 66' i2i or maybe go nuts and actually measure it out to be close to 70'. It looks like fun to be close to the judges. ;) Steve
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There is already threads on doing lines. lead outs and handle terminations. A search will give a lot of reading will waiting for epoxy to cure or paint to dry, especially this time of year. D>K