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Old Sep 11, 2012, 10:26 AM
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Herk
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Virginia USA
Joined Jun 2007
1,738 Posts
Quote:
Originally Posted by Stupot46 View Post
The resulting graph.Allowing for measuring discrepancies and that I rounded the decimals,there would appear to be a slight curve developing.
Stuart

I'm going to recheck those last few measurements,no logical reason why it should rise like that.
Hi Stuart,

Your construction is looking more and more flight capable.

I'm still having a bit of a problem grasping exactly what your CofG concern is, and what you are doing about getting a grasp on it.

That said, I have another little offering that you can play with if you wish. To use the spread sheet you will need Excel or Open Office. I included a picture of the result just in case those programs aren't available to you.

The fundamental (simple) assumptions are that you have a constant chord wing layout like Gulliver. Each panel is ten inches wide and fifty inches long. The weight of each panel is ten ounces. The spanwise CG of each panel is half way out. The chordwise CG of each panel is at the 25% point. (just to simplify things) As the panels sweep, the CG of the panels moves aft and the effective chords of the panels increase. Likewise so does the length of the nose moment increase. So the question this attempts to answer ---

Ready for this!! --- In order to keep a longitudinal static stability margin of ten percent, how much weight must be placed at the nose point centerline to balance the model to that criteria at each station as the wing sweep changes in increments from 0 degrees to 60 degrees?????

Disclaimer. I have not done a lot of error checking. If there are errors I will apologize in advance. I wanted to check more by head is beginning to hurt.
EDIT
I did some error checking and found some small ones. If you want the spreadsheet, I'll make it available but here is the corrected result. Not greatly different.
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Last edited by HerkS; Sep 12, 2012 at 03:24 PM. Reason: Did some error checking - found some errors
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