X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.123] verified) by logan.com (CommuniGate Pro SMTP 5.2.11) with ESMTP id 3413938 for flyrotary@lancaironline.net; Tue, 06 Jan 2009 21:17:52 -0500 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.123; envelope-from=echristley@nc.rr.com Received: from [192.168.0.19] (really [66.57.38.121]) by cdptpa-omta06.mail.rr.com with ESMTP id <20090107021715.PDYF2036.cdptpa-omta06.mail.rr.com@[192.168.0.19]> for ; Wed, 7 Jan 2009 02:17:15 +0000 Message-ID: <49641124.3040604@nc.rr.com> Date: Tue, 06 Jan 2009 21:19:16 -0500 From: Ernest Christley User-Agent: Thunderbird 2.0.0.16 (X11/20080724) MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Muffler design (was 20B isssues . . ) References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Ernest Christley wrote: > Al Gietzen wrote: >> ---------------------- >> Unless I did the math wrong; the maximum filling fraction you can get >> with these rods is about .8. So I think there would be a problem >> there. >> >> Al G >> > I'll have to do the math, but I think it can be quite a bit more with > a hexagonal packing. > http://en.wikipedia.org/wiki/Sphere_packing The math was to much for me, so I turned to Wikipedia. The maximum filling fraction of close packed circles is about 0.9069. Close enough to 0.907. 8*) I would say that even though it would provide the best signal attenuation, I don't think a 0.907 filling fraction would provide a very useful muffler. -- http://www.ernest.isa-geek.org