Mailing List lml@lancaironline.net Message #20774
From: Larry Henney <LHenney@attg.net>
Sender: Marvin Kaye <marv@lancaironline.net>
Subject: CG Neutra Point
Date: Mon, 29 Sep 2003 20:29:35 -0400
To: <lml@lancaironline.net>
Message
Eric,  Jerry, Ron,
 
My neighbor Don Saint spent some time banging me in the head with a 2x4 last night.  He explained my errant thinking regarding the interrelationship of the CG and my horizontal stab incidence.
 
His comments clarified that as we push the CG aft toward the neutral point (CG collocated with center of pressure) control forces with decrease.  Additionally, speed with increase.
 
The unique fact that my elevator is sitting a touch tail low at high speed is roughly unchanging as the CG is moved aft.  This bit of drag could be reduced also in a separate discussion.  That is, the H.S. could be chopped out and reinstalled with a slightly higher leading edge.
 
He described some very interesting neutral point analysis.  It seems the neutral point can be easily extrapoloated  with minor CG shift studies (spring scale and a couple 25 lb shot bags).
 
I am looking forward to at least doing this analyis with Don and perhaps considering a CG adjusting system.  Of course this system while appoaching the neutral point will NOT exceed the aft design CG of the airframe.  My CG is now very far forward.  Don routinely races 1" forward of his neutral point.
 
I hope my confused thinking originally about this whole topic hasn't mislead anyone.
 
Larry Henney
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