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General control line discussion => Open Forum => Topic started by: John Witt on December 01, 2009, 12:40:31 PM
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Can anyone comment for sure on how the AMA measures line length. There is a 70 foot maximum. Is that a radius that includes the flier's arm and the distance to the centerline of the airplane, or is it to the outer tip, or just the actual lines?
Thanks,
John W
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Well, traditionally, it's measured from the center of the plane to the center of the handle.
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Yeah, what Randy said!
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Thanks, folks. Gonna cut lines for the Jenny project this week.
John W
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From CL General rulebook:
5.2. The length of the control line(s) is
measured from the center point of the grip part of
the control handle (device) to the fore and aft
center line of the model. All speed computations
are to be based on the lengths specified for the
event, and no allowance is to be made where
lines used exceed those lengths.
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If this is the scale model you are working on, go check the scale rules. But, as Randy says most events have a max of 70 feet center of plane to center of handle. Racing, combat, speed and carrier have their limitations.
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http://www.modelaircraft.org/files/events/rulebooks/Scale.pdf (http://www.modelaircraft.org/files/events/rulebooks/Scale.pdf)
http://www.modelaircraft.org/files/events/rulebooks/CLGeneral.pdf (http://www.modelaircraft.org/files/events/rulebooks/CLGeneral.pdf)
The links above will give you all the info you need to know, if you can only find it...bring it on down to TMF for the first flight? y1 Steve
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John,
I have to wonder why you are asking about full-length lines. As I recall, your Jenny project is based upon a Proctor kit. Quite a lot of model, tons of drag--I would be staying away from the longer lines until developing a feel for the line length a model like this seems to want.
Test flight when?
Dan
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OK, I'm up for advice. Here's the parameters:
Wingspan 84 inches, 1400 sq inches area, probable weight 10-12 lbs
1800 Watt motor with 16-6 prop ( 2.4 HP), Clancy's throttle control.
If it flies at 30 mph, line pull at 10lbs will be about 8.5 lbs, and about 10 sec laps at 70 ft radius. Line pull at 12 lbs flying wt will be about 10 lbs. This data from Line III
The RC versions are flying with about this power.
I was considering that 10 lbs continuous pull is a lot, but perhaps not for wind. Don't plan on flying it in much wind.
The May NW Regionals shows scale on the agenda, so that's a goal. Should fly sometime before then, but there's still a lot to do and that's only 4 months away. For sport scale it doesn't have to have all the cockpit detail finished, but it does need at least most of the outside surface detail.
I have a 70 ft set of insulated lines from Brodak, but only need one insulated line per pair, so I could make up a short set without losing the ability to go out to 70 feet. My thought was that the plane is large and heavy enough to fly OK on max length lines.
John W