[NSRCA-discussion] Odyssey CG

[Tom Simes]

On Tue, 1 May 2007 10:40:01 -0800
Tom Simes <simestd at netexpress.com> wrote:

> On Tue, 1 May 2007 14:13:54 -0400
> "Ken Velez" <kvelez at comcast.net> wrote:
> 
> > Anthony I think the 3 inches will not work for you that is not 30%.
> > That holds true if it was a straight wing like in a trainer. In a
> > taper wing you have to figure out the center of the wing compensated
> > for the taper and them measure and figure out your 30%. There is a
> > few different ways to do this but I think the easiest is to add the
> > root length to the tip and the tip length to the root. Any way I
> > attached the figure so you can see it, If you have any questions
> > just ask. Hope it helps.\\
> 
> I agree with Ken, I believe the good Dr. is referring to 30% aft of
> the leading edge on the Mean Aerodynamic Chord (or MAC) as opposed to
> 30% aft of the LE on the root chord. Here is a good explanation of the
> the method Ken was referring to:
> 
> http://www.lferc.com/Tips/mean_aerodynamic_chord.php

Just for the archives, here are a couple more good links on deriving a
resonable CG range for a model by finding the Mean Aerodynamic Chord (or
MAC):

http://www.airfieldmodels.com/information_source/math_and_science_of_model_aircraft/formulas/mean_aerodynamic_chord.htm

Here's a good drawing explaining the various measurements as well as a
web based tool to figure it all out for you:

http://www.geistware.com/rcmodeling/cg_calc.htm

(just enter data in the top 5 boxes and hit the calculate CG button)
Tom
 
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Tom Simes                                       simestd at netexpress.com 
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