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Pull Test - AMA rules are unclear

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Pull Test - AMA rules are unclear

Old 08-03-2008, 11:01 PM
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Default Pull Test - AMA rules are unclear

So I open up the 2007-2008 Control Line General Rules from the AMA site in an attempt to learn about pull tests.
Yipes. About as clear as mud![:@]

On their page CLG-2 (attached here), there's a chart that lists some categories ranging from 32G to 64G. It's the only reference in the rules I can find that provides anything resembling a "calculation".

So my first question is, What's a "G"? Gravitational constant? And what does each category represent - engine displacement? If so, where's the list for engines less than 32?

And then...
When doing the multiplication, using the plane's weight in ounces, does the result stay in ounces? So my half-a Baby Ringmaster at 6 oz might need a pull test of, what - 12 oz? 24 oz? I dunno what "G" my Baby Ringmaster would be....





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Old 08-04-2008, 03:45 AM
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Default RE: Pull Test - AMA rules are unclear

Pull tests are based on the size of the engine that is on the model.

Two rules affect how many pounds you will pull for your pull test. One is the required G's for your engine size. One is the required line size for your engine size.

You really haven't found the rules that apply, only one of the charts used by those rules. The chart isn't the rule, it's a tool used by the pull test rules
Old 08-04-2008, 04:00 AM
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Default RE: Pull Test - AMA rules are unclear

"G" is the abbreviation for "gravitational pull". When you are standing on earth, the gravitational pull exerted on you by earth is on the order of "one gravitational pull". You feel one G of pull. And if you weigh 127lbs, then earth is pulling 127lbs with it's one G. If the pull test was for 3 G's, the pull test would be for 3X127=381 lbs.

When the AMA rules require a pull test, they use G and a chart to help you figure how many pounds to look for on the pull scale you're going to use when you pull test. They want to have each different model pull an appropriate amount. Since they don't know what your model weighs, they wrote the rules to cover any weight model that would show up.

Look through the rules for your engine size. Then look for the required line size for your engine size. Your lines are required to be that size. And you should know ahead of time what your model weighs. Then look for the required G for your engine size. That rule will tell what G to apply to the weight of your model to figure the amount you'll need to see on the pull scales.

All that said, I haven't run a C/L contest in years. So I haven't read the rules in years. But I do know that chart was of use years ago. It wasn't the rules, back then, and won't be now. It was used by the rules. You need to find them. The use of the chart will become clearer then.
Old 08-04-2008, 04:23 AM
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Default RE: Pull Test - AMA rules are unclear

I've just jumped over to the AMA website and looked up the pull test rules.

Each event lists the pull test requirements for that event. I looked into the Precision Aerobatics rules to see what they say. They have a chart on page CLA-2 that lists line sizes and pull test amounts required for each engine size.

I placed an arrow beside the line I would be interested in if I were flying a model with a .50 size engine.

The rules say I would have to fly with lines 25-70' long. I'd be using two lines of braided cable, so it would have to be .018" diameter. And that pull amount is listed in pounds (not G's) so I'd simply have to pull 45 lbs.

Look into the rules of the event you'd be flying with your model to see what the requirements are.
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Old 08-04-2008, 11:49 AM
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Default RE: Pull Test - AMA rules are unclear

Somewhere, maybe the safety code, there is a "recommendation" that you use the precision aerobatic's pull tests and line sizes for general sport flying.
Old 08-06-2008, 01:41 PM
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Default RE: Pull Test - AMA rules are unclear

Gents,

The written pull test rules are changing as of January 2009, for CLPA, anyway. You can find the approved rules change wording on the AMA Site.

Yes, the AMA Safety Code is where it says to use CLPA pull test specs for models that don't fit any of the contest event rules specifications... I.e., general, modest performance sport CL models.

To simplify this year's rules: If you're using an 0.049, 0.061 or 0.074 engine on the Baby Ringmaster, you are between 0.000 cu in and 0.0800 cu in, and pull test is 5 lbs. If you're using more than one engine, the total displacement is counted - two 0.049s total to 0.098 cu in, so per the current chart, pull is 15 lbs.

Yes, 1 g is the weight of the model, and 2 g is twice the weight of the model. CLPA pull test rules, until January, go by the engine displacement, instead. As of January, the pull test is to be 10 g, i.e., 10 times the weight of the model. Next year, your 6 oz Baby Ringm will pull 60 oz, which is 3.75 lbs. ( That 0.098 cu in twin engine model, if it weighed 12 oz, would pull 120 oz. or 7.5 lbs.)

Line diameter and material specs will be the same as in the current rule book, in the Electric Powered Models chart:

0.014" diameter solid wire if using only one line, *

and 0.008" diameter either solid or stranded wire, if using two lines (or more if you have a throttled engine...).

Actually, in the "middle sizes" - say 0.15 cu in to about 0.40 cu in, with sport-type engines, the pull test schemes are fairly similar. Safety is "assured" with either. As the half-A and 0.09 example shows, the 10 g scheme may be more realistic for small, light models, and at the other end of the scale, for hefty 4-cycle 0.91 powered stunt models, too.

* - Some in here may not know we can fly CL on a single line - Monoline. The flying line is twisted at the 'handle' to deliver motion to a special control unit that converts the twist into "elevator" control movement. Diagrams of Monoline controllers (handles) and control units (in the model), and how to make line attachments for them, are in the CL General section of AMA Rules. Learning to fly Monoline is quite different from U-Control. For one thing, the controls don't have much self-return force; they tend to stay where your last command put them. You have to intentionally undo a control input to get back to straight flight.

Monoline, today, is pretty much only used in CL speed. One line has less drag than two... Heavier, solid line is necessary to transmit the twist; braided lines don't do that very well.
Old 08-06-2008, 10:51 PM
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Default RE: Pull Test - AMA rules are unclear

Thanks da Rock and Lou Crane. VERY helpful! I really do appreciate folks who actually read and answer the question in a post!
Well Done!
Old 08-07-2008, 12:19 PM
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Default RE: Pull Test - AMA rules are unclear

Keefer,

Glad to help.

BTW, if you DO use two 0.049s, total displacement goes over 0.0800 cu in. Until January, the pull test for that displacement is 15 lbs, and the line requirements change this way:

Single line, same at 0.014" diameter (solid),
Two lines: , 0.010" diameter (solid); 0.012" diameter (braided).

From then on, it is 10 g, and the line specs change at model weight of 24 oz to 0.014, 0.010, 0.012 as in current rules for above 0.0800 cu in total displacement. There are additonal line spec changes at 40, 64, 75 and over 75 oz model weight. Max allowed weight is 123 oz (- WOW!)

Didn't mention this in the longer post, and just wanted to make it clear.
Old 08-10-2008, 07:54 PM
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Default RE: Pull Test - AMA rules are unclear

Lou my d speed model uses .033 wire and the pull test is around 150 lbs. flying one of these monsters is not for the small guys . most weekends here in vegas we sport fly ringmasters and such my flying buddies often harass me about driving hundreds of miles to a speed contest only to put in about 40 sec. of flying time. they do have a point but for 10 sec. at a time you are one of the busiest persons on the planet.
Old 08-11-2008, 12:38 AM
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Default RE: Pull Test - AMA rules are unclear

Joey,

I fully appreciate the difference!

The issue is covered two ways, here.

First, the idea of pull test specs for non-contest fliers is important to the extent that they might hurt somebody, and expect AMA to help make things right for the victim(s). In such a case, it would be good to offer evidence that the existing safety standards were met.

Second, of course, is that those of us who fly by national rules, as published by AMA (or FAI for those nations, or national standards for those), have a double requirement: the safety thing - if anyone gets hurt, and compliance with appropriate regs in case a record performance is submitted for recognition, or a contest placement is acceptable for being completely kosher with the event rules.

The idea of using CLPA pull standards for non-contest, moderate performance sport models appeared in the second rule cycle back, if I recall. At least a reasonable standard is offered. For specialty events, like Proto and Speed, more suitable standards, based on actual conditions, MUST be used for safety and standardization.

Each CL event has some peculiar condition. Speed and Proto. Racing. Combat. Scale. Carrier. Stunt. Combat. Even Balloon Bust... Takes very little thought to realize the unique conditions among these... If there were no standards, we'd still have guys tying knots to join broken .018 braids together, and thinking they were safe...

Been there, done that, it doesn't work for s**t!

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