<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; "><DIV><SPAN></SPAN></DIV><DIV><BR><BLOCKQUOTE type="cite"><DIV> <DIV> </DIV> <DIV>In a message dated 5/29/2006 8:03:41 PM Eastern Standard Time, <A href="mailto:vanputte@cox.net">vanputte@cox.net</A> writes:</DIV> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"> <DIV>In my calculations I do include the area occupied by the fuselage. I assume the calculation by Nat does as well, but I don't speak for him.</DIV> <DIV><BR class="khtml-block-placeholder"></DIV> <DIV>Ron Van Putte<BR> <BLOCKQUOTE type="cite"> <DIV><SPAN class="240415422-29052006"><FONT face="Arial" color="#0000ff" size="2"></FONT></SPAN></DIV> <BLOCKQUOTE dir="ltr" style="MARGIN-RIGHT: 0px"> <DIV class="OutlookMessageHeader" dir="ltr" align="left"><FONT face="Tahoma" size="2">-----Original Message-----<BR><B>From:</B> <A href="mailto:nsrca-discussion-bounces@lists.nsrca.org">nsrca-discussion-bounces@lists.nsrca.org</A> [<A title="mailto:nsrca-discussion-bounces@lists.nsrca.org" href="mailto:nsrca-discussion-bounces@lists.nsrca.org">mailto:nsrca-discussion-bounces@lists.nsrca.org</A>]<B>On Behalf Of </B>Ron Van Putte<BR><B>Sent:</B> Monday, May 29, 2006 6:07 PM<BR><B>To:</B> NSRCA Mailing List<BR><B>Subject:</B> Re: [NSRCA-discussion] CG<BR><BR></FONT></DIV><BR> <DIV> <DIV>On May 29, 2006, at 4:40 PM, Nat Penton wrote:</DIV><BR class="Apple-interchange-newline"> <BLOCKQUOTE type="cite"> <DIV><FONT face="Arial" size="2">The following formula was presented by noted British modeller Gordon Whitehead in How To Make Scale Models Fly ( 1980 ??). I have been using it over 20 years and find it dead on for pattern:</FONT></DIV> <DIV><FONT face="Arial" size="2"></FONT></DIV> <DIV><FONT face="Arial" size="2">CG (from LE MAC) = MAC/6 + 0.25x As/Aw M</FONT></DIV> <DIV><FONT face="Arial" size="2">As - area stab Aw - area wing</FONT></DIV> <DIV><FONT face="Arial" size="2">M - moment arm, ac to ac</FONT></DIV> <DIV><FONT face="Arial" size="2"></FONT></DIV> <DIV><FONT face="Arial" size="2">It is easy to use the graphic method to find the wing MAC. You can guess at the stab MAC and be close enough.</FONT></DIV> <DIV><FONT face="Arial" size="2"></FONT></DIV> <DIV><FONT face="Arial" size="2">The formula works on anything from a tailess to a Quickie.</FONT></DIV></BLOCKQUOTE><BR></DIV> <DIV>Nat - I haven't compared the formula with the one I developed more than 40 years ago, but I think yours would be better understood if you use some parentheses:</DIV> <DIV><FONT face="Arial" color="#0000ff" size="2"></FONT><BR class="khtml-block-placeholder"></DIV> <DIV><SPAN class="Apple-tab-span" style="WHITE-SPACE: pre"></SPAN>CG (from LE MAC) = MAC/6 + 0.25x (As/Aw) M</DIV> <DIV><FONT face="Arial" color="#0000ff" size="2"></FONT><BR class="khtml-block-placeholder"></DIV> <DIV>Also, the wing and stab area should include the ailerons and elevators, respectively.</DIV> <DIV><BR class="khtml-block-placeholder"></DIV> <DIV><BR class="khtml-block-placeholder"></DIV> <DIV>Ron Van Putte</DIV></BLOCKQUOTE></BLOCKQUOTE></DIV></BLOCKQUOTE></DIV> <DIV></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">_______________________________________________</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">NSRCA-discussion mailing list</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><A href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</A></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><A href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</A></DIV> </BLOCKQUOTE></DIV><BR></BODY></HTML>