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Old 03-31-2013 | 05:52 PM
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Rob2160
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Default RE: OK gujys, I need help on CG

ORIGINAL: goirish

Finishing my G-Shark with a dle-55. The instructions say 5 1/4" back from the leading edge at the middle of the wing. Does that mean from root to tip on one side of the fuselage go halfway and that is the CG. At that point the wing is only approx 7". Of of this because I didn't finish the 3rd. grade.[&o][]
CG is also defining lateral CG, and therefore it will be in the middle of the fuselage, not halfway down a wing span or at the tip..

Based on the root chord dimension you specified, the 5 1/4 position is about 30% back from the leading edge at the wing root.. sounds about right.. Adjusting the CG forward will make the aircraft more stable, adjusting it rearward (only to a point) will make the aircraft more manoeuvrable in pitch IE it will loop better..

Don't get bogged down with terms like MAC (mean aerodynamic chord) this is usually a formula to calculate the chord of a swept and tapered wing for an equal sized rectangular wing.. In these situations CG is given as a percentage of MAC... http://aviationglossary.com/mean-aerodynamic-chord

5/14 inches will work great..
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