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Building Tips and technical articles. => Building techniques => Topic started by: joe renfro on December 22, 2007, 04:46:51 PM
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OK..this should be simple, ..Is there a generally accepted rule of thumb for line size and length for a given size engine..or does it depend on the size of the plane....Does anyone still,ever,. use one of those Jim Walker Reely things...were they worth a hoot?...just curious...I hear of folks using 50'..60'..70' and everything in between for the .35 size planes...just curious...Be curious to hear what the jury has to say....Thanks in advance
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Most people think (or thought) that U-Reely's were nothing but trouble, for a lot of reasons. Weight, bulk, no adjustment, lines getting buggered up inside. Very few were seen in actual use.
.015" x 60 is a good starting point for 35-size planes. The .015" (minimum) is a rule. The length (up to 70') is matter of trial and error.
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Paul,
When refering to "Ureely" you said "Very few were seen in actual use."
Actually when I started most had a Ureelys. I learned on one. The massive size made it very easy for the instructor to hold on or let go while the student had his had in the handle portion.
Many in the old Stunt Masters club from Long island used the Ureely.
Artie Meyers, from Long Island,won Sr Stunt at the 1960 NATS, beating Bill Werwage, using a Ureely.
And yes, it had all the disvantages mentioned, including a tendency for the brake to let loose if the safety lock was not engaged. In fact, Artie lost his Nats winning airplane at the first GSCB contest in E. Paterson NJ (before the famous GSCB field) when the he forgot the safety lock, and the lines pulled out of the handle.
Most of were using the EZ-Just handle by then.
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I guess somebody, somewhere, might have used 'em, but they were darn scarse in these-here parts.
The elders of Control Line advised against them in my formative years, and I pass on the advice.
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Basically what you want is line length which is long enough to give slow enough lap time that you can fly the airplane comfortably; and short enough that you have good line tension. As a rough rule of thumb, on @ 60 ft lines a change of one foot gives a change of 0.1 sec. in lap time. So if you are flying 4.8 sec laps and would like 5.0, you make up a set of line @ 2 ft. longer. Of course all kinds of other things enter in like airplane trim, engine setting, prop, etc. etc.
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It has not been stated that 70' center of plane to center of handle is max length for competition. For different engine size groups requires different lengths and diameter. Check the rule book on the AMA site. MERRY CHRISTMAS, DOC Holliday
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I used a U-Reely when I first started flying CL planes with .15 & up engines, but for the simple reason that we sometimes needed to vacate the "flying field" one step ahead of the cops. I would never suggest using one these days, and personally favor "hard point" handles. If you're flying a .25LA, 58' to 60' eye to eye in .012" braid works. For a Fox .35 Stunt, most like 58' e2e .015's. A Magnum .36 can haul 62' lines, and the .46LA does well with 62'-64', depending on plane weight, trim, etc.
The safest thing you can do is dedicate a handle and set of lines for each model. CHEAP insurance! If you take the handle off the lines, put the handle and lines together in a quart sized Ziplock freezer bag, and ID them as to what plane they are for. Leave a clip on the lines and a clip on the handle, a clip on the plane, and one on the other end of the lines. Then hook them up as you took them off, i.e., always unhook the lines from the plane first, and handle last, then re-attach the handle first, plane last. Or leave the handle attached to the lines, which I do. I may change, tho. H^^ Steve
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I found the U- Reely handy when flying off a frozen pond. I didn't run the lines out until the engine was started. That way there was no chance of someone running over the lines with ice skates or having the lines freeze to the ice. I've had both happen.
Perry Rose
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I have flown CL on the same exact spot (in summer) that I've gone ice skateing (in winter)...but I've never flown CL off a frozen pond, and don't think I will be doing so, anytime soon. But if I do, I'll be sure and use a U-Reely! Personally, I think that's just plane sick (pun intended!). y1 Steve
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AMA rules dictate line size based on engine size. Prop pitch for aircraft speed and line length for lap times. This is of course assuming the plane is trimmed. In CLPA and only CLPA, the line size/engine sizes are as follws: .0000 to .0510.=.008. .0511 to .1525=.012. .1526 to .4028=.015. .4029 to.4600=.018. .4601 to.6500= .018. This is for multi strand lines. Single strands are smaller in diameter. See the AMA rule book. Speed, racing, carrier, scale, etc have different line size rules. H^^
I think they changed the rules so you can use .12 lines on 25 size now. We used .12 on 35 sized planes in the sixty's.
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Joe, line length is a trimming tool, just like adding weight to the nose, tail, or wing tip, or moving the leadout position. Every plane/motor combination has an ideal line length. Too long and you will have problems with line tension, especially up high, and the plane will get whipped around by the weight of the lines swinging around in maneuvers. Too short limits the amount of maneuvering room, and of course you may end up turning around faster than you find comfortable.
Once you've got the plane trimmed so it is straight and flys OK on stock lines(60 ft for 35-40's, 65 for bigger motors, 50ish for 25's) make up a set of lines about 5 ft longer and see how the plane flies and re-trim it. Cut off a foot at a time and re-trim until you stop seeing any improvement. With some planes, especially the smaller lighter ones, as little as six inches can make a noticeable difference in flying.
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I have a Top Flite Nobler ARF with an LA40 engine (and I think the prop is master airscrew 11-4), flying on 60' lines, but haven't measured the lap time. What lap time would be preferred for that model? I first tried it on 70' lines, and it had no tension up high. At 60', the tension is fine. I'm trying to learn to fly the stunt pattern, but don't have a feel for what is needed to be optimized.
Dave
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I have a Top Flite Nobler ARF with an LA40 engine (and I think the prop is master airscrew 11-4), flying on 60' lines, but haven't measured the lap time. What lap time would be preferred for that model? I first tried it on 70' lines, and it had no tension up high. At 60', the tension is fine. I'm trying to learn to fly the stunt pattern, but don't have a feel for what is needed to be optimized.
Dave
Hi Dave,
No one can give a hard set rule for the optimum lap time. The optimum for each plane is a little different usually, and dependent on several factors. *Most* people start around 5.0 with a Nobler sized plane using 58'-60' eye to eye lines. It's tough when the company mis labels the line length on premade lines, ain't it!
Aaron's Ares had to fly at 4.8-4.9 on 60' E-E when the OS 32F was in it. When we switched to the Magnum 36XLSII, the plane was VERY comfortable at 5.3-5.4 on the same lines. Nothing but an engine/prop change.
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Thanks Bill. I'm pretty busy with work right now, but I'd like to fly with you again sometime this spring.
Dave
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Thanks Bill. I'm pretty busy with work right now, but I'd like to fly with you again sometime this spring.
Dave
We'll get together this Spring, all you want.
IMHO (after many years of stealing the best ideas from the best pilots!), Lap times are very overrated. It is the airplane's airspeed that is important. Each model will have a speed it needs to fly at to be optimum. Prop pitch sets that, and line length sets the rotational speed you are comfortable with. I am not alone in believing that far too many people fly on lines that are too long. I time the plane AFTER I get it flying the way it feels good. Simply a reference point for trimming in that case.
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Ok. Thanks.
Dave
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Aaron's Ares had to fly at 4.8-4.9 on 60' E-E when the OS 32F was in it. When we switched to the Magnum 36XLSII, the plane was VERY comfortable at 5.3-5.4 on the same lines. Nothing but an engine/prop change.
Another point of interest - when Ted and I ballasted his Tucker Special from ~40 oz to ~48 oz, with no other changes, the airplane could be flown much more slowly. I think it pretty much had to be in the 4.5-4.6 sec range at 40 oz (and still wasn't anything to write home about), and could easily be flown at 5.2-5.3 at 48 oz.
Brett