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determining CG

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Old 04-21-2008, 02:06 PM
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rheauljj
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Default determining CG

I have an old .40 size Stix that I've completely rebuilt the tail section (oil soaked) and extended both the width and length of the ailerons. I have no manual/plans for this plane, and with my modifications, I'm not sure of where the CG should be. Are there some "basics" I can use to calculate the CG point?

Advice?
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Old 04-21-2008, 02:21 PM
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da Rock
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Default RE: determining CG

Yeah, get out a yardstick and take 9 measurements. Plug them into the giestware application and put 10% for safety margin. Click the button and then look down the page for the CG location. You got how far back the CG can go for some people. Now put in 20% and click the button. You now have as far forward at the CG can go. Got the CG range.

http://www.geistware.com/rcmodeling/cg_super_calc.htm
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Old 04-21-2008, 03:08 PM
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Default RE: determining CG

perfect. Thanks.
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Old 04-21-2008, 05:48 PM
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Default RE: determining CG

Determined the CG at 3.25 inched from the leading edge. Now do I add weight to the plane to balance with a full tank of fuel?
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Old 04-21-2008, 05:58 PM
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Nathan King
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Default RE: determining CG


ORIGINAL: rheauljj

Determined the CG at 3.25 inched from the leading edge. Now do I add weight to the plane to balance with a full tank of fuel?
Always set the center of gravity with your fuel tank empty. Instead of adding ballast try moving your battery around first.
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Old 04-21-2008, 06:18 PM
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Default RE: determining CG

Actually, it depends whether the tank is in front OR behind the CG. Basically you want to balance the plane in the most tail-heavy condition, so that any other condition will add more weight to the nose.
Remember, a nose-heavy plane may fly poorly but a tail-heavy plane will only fly once! (If at all)
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