X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from nm25.bullet.mail.ac4.yahoo.com ([98.139.52.222] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with SMTP id 4586714 for flyrotary@lancaironline.net; Sat, 20 Nov 2010 20:41:02 -0500 Received-SPF: none receiver=logan.com; client-ip=98.139.52.222; envelope-from=ceengland@bellsouth.net Received: from [98.139.52.194] by nm25.bullet.mail.ac4.yahoo.com with NNFMP; 21 Nov 2010 01:40:27 -0000 Received: from [98.139.52.183] by tm7.bullet.mail.ac4.yahoo.com with NNFMP; 21 Nov 2010 01:40:27 -0000 Received: from [127.0.0.1] by omp1066.mail.ac4.yahoo.com with NNFMP; 21 Nov 2010 01:40:27 -0000 X-Yahoo-Newman-Id: 771284.71571.bm@omp1066.mail.ac4.yahoo.com Received: (qmail 61897 invoked from network); 21 Nov 2010 01:40:27 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bellsouth.net; s=s1024; t=1290303627; bh=vQgp975MzsMdmzKb68CePNiDr0eN/OBHGS/jkNTvgYk=; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:Date:From:User-Agent:MIME-Version:To:Subject:References:In-Reply-To:Content-Type; b=wJrH/MT4ojlfat+iuyNaJ30XaKhRU3eCt2O6gTYqLJbHim2TdV0P6AmgqSCLipXYV3J/FlFu2i5MGycSoRwzQfFd7lIfXdxRD+q+htjHm34X7+KEzY6pcd36g9XXnG8kkMNbIz+AW0QvLwOXkWa47j4PktdHdakP75WqX/9D8mU= Received: from [192.168.10.5] (ceengland@98.95.187.93 with plain) by smtp103.sbc.mail.ac4.yahoo.com with SMTP; 20 Nov 2010 17:40:27 -0800 PST X-Yahoo-SMTP: uXJ_6LOswBCr8InijhYErvjWlJuRkoKPGNeiuu7PA.5wcGoy X-YMail-OSG: CKYLORoVM1l6Tv5IQgEvQkvX_UAuChp9WrTdY0wsfn7ALXi 0QvIAY6DyC4u_d89udBig3BakTNo3UzThGoS8DLWRlKlXwoZ2JVktmVAGwFp 4WyPr6csD3lmv4JAt9XsOKcBPgZ1zZCUWJbNGAYFUOj7tTja3SCoN8.xOclw gUuhfuPM98x3GpiHezW42EFbt1iazV2uCKaCTnGGso_gZ14bRUK5TfITCaRA OVrTUhgjIKhIspgphaG2ZxGslH5.fZ44zavWBPt6.QxhPDJRmGsqli04.09A S0nG0OAIgUbjs X-Yahoo-Newman-Property: ymail-3 Message-ID: <4CE878DE.7030804@bellsouth.net> Date: Sat, 20 Nov 2010 19:41:50 -0600 From: Charlie England User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.12) Gecko/20101027 Thunderbird/3.1.6 MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Exhaust Calcuations References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------000708060507090709010702" This is a multi-part message in MIME format. --------------000708060507090709010702 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit My thought is to take a somewhat different approach to tuning. My desire would be to tune for intended cruise rpm. My reasoning is that just about all homebuilt designs that will run a rotary will have excess power anyway, so why not tune for max efficiency at the rpm where the the engine will spend 95%+ of its time? Even more applicable if a controllable prop is available. Can anyone see any problem with that logic? Charlie On 11/20/2010 10:18 AM, Mark Steitle wrote: > Ed, > > OK, that answers my question. By going with 1-7/8" OD pipe (.049 > wall), it would be tuned for about 7800 rpm. Obviously, this is too > high for our purposes. I'll go with 1-5/8 (.063 wall) to shoot for > 6700 rpm peak power. This is typically the rpm I see on ground roll > and early climb before I start adjusting the prop down to a lower rpm > to transition to cruise climb. > > Have you used the header designer tool available from Burns Stainless? > You need to know all the timing numbers, rpm, etc. I may give it a > try and see what I come up with. I have a test p-port housing that I > made up to see if the tube could be welded to the inner liner. So, I > can use that with a spare rotor to verify the EVO and EVC numbers. > Mark > > > On Sat, Nov 20, 2010 at 9:55 AM, Ed Anderson > > wrote: > > Mark, > Here is the corrected spreadsheet - I've colored the changeable > cells blue - you can plug in any rpm and EVO. The rest of the > cells are protected to keep from accidently overwriting them. > Ed > Edward L. Anderson > Anderson Electronic Enterprises LLC > 305 Reefton Road > Weddington, NC 28104 > http://www.andersonee.com > http://www.eicommander.com > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > --------------000708060507090709010702 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit My thought is to take a somewhat different approach to tuning. My desire would be  to tune for intended cruise rpm. My reasoning is that just about all homebuilt designs that will run a rotary will have excess power anyway, so why not tune for max efficiency at the rpm where the the engine will spend 95%+ of its time? Even more applicable if a controllable prop is available.

Can anyone see any problem with that logic?

Charlie

On 11/20/2010 10:18 AM, Mark Steitle wrote:
Ed,

OK, that answers my question.  By going with 1-7/8" OD pipe (.049 wall), it would be tuned for about 7800 rpm.  Obviously, this is too high for our purposes.  I'll go with 1-5/8 (.063 wall) to shoot for 6700 rpm peak power.  This is typically the rpm I see on ground roll and early climb before I start adjusting the prop down to a lower rpm to transition to cruise climb.

Have you used the header designer tool available from Burns Stainless?  You need to know all the timing numbers, rpm, etc.  I may give it a try and see what I come up with.  I have a test p-port housing that I made up to see if the tube could be welded to the inner liner.  So, I can use that with a spare rotor to verify the EVO and EVC numbers.  
 
Mark


On Sat, Nov 20, 2010 at 9:55 AM, Ed Anderson <eanderson@carolina.rr.com> wrote:
Mark,
 
Here is the corrected spreadsheet - I've colored the changeable cells blue - you can plug in any rpm and EVO.  The rest of the cells are protected to keep from accidently overwriting them.
 
Ed
 
Edward L. Anderson
Anderson Electronic Enterprises LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com

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