X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fmailhost04.isp.att.net ([207.115.11.54] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3882574 for flyrotary@lancaironline.net; Sun, 11 Oct 2009 17:07:42 -0400 Received-SPF: none receiver=logan.com; client-ip=207.115.11.54; envelope-from=keltro@att.net DKIM-Signature: v=1; q=dns/txt; d=att.net; s=dkim01; i=keltro@att.net; a=rsa-sha256; c=relaxed/relaxed; t=1255295263; h=Content-Type: MIME-Version:In-Reply-To:Message-Id:Date:Subject:To:From; bh=Zk2Yp2 8tSVdJGd7/aX3a7dD9p2lZ1sWQjVD7sFTuYqE=; b=MDKEYgNXebYvg8RZlSJCxMs1e eGLpzwq+m2qzWDh6r1YQbIM+WClwRx75LzTJVMI5e3OHdiNA9zXPqFPwjvorA== Received: from fwebmail06.isp.att.net ([204.127.218.106]) by isp.att.net (frfwmhc04) with SMTP id <20091011210707H0400g4tboe>; Sun, 11 Oct 2009 21:07:07 +0000 X-Originating-IP: [204.127.218.106] Received: from [208.114.34.45] by fwebmail06.isp.att.net; Sun, 11 Oct 2009 21:07:06 +0000 From: "Kelly Troyer" To: "Rotary motors in aircraft" Subject: where's the missing power? Date: Sun, 11 Oct 2009 21:07:06 +0000 Message-Id: <101120092107.8410.4AD248FA000C00B4000020DA22230682329B0A02D29B9B0EBF019D9B040A05@att.net> In-Reply-To: X-Mailer: AT&T Message Center Version 1 (Mar 2 2009) X-Authenticated-Sender: a2VsdHJvQGF0dC5uZXQ= MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_8410_1255295226_0" --NextPart_Webmail_9m3u9jl4l_8410_1255295226_0 Content-Type: text/plain Content-Transfer-Encoding: 8bit -------------- Original message from Lynn Hanover : -------------- Lynn, I realize that the Drummond dyno exhaust system is sized to get maximum power at much higher rpm (9000+) than we use but can you give us approximate tubing diameters and lengths of both the primaries and collector of the Drummond system then pulling from your many years of "Real World Experience" recommend tubing diameters and lengths sized for our aircraft systems (perhaps one for the 2.17 re-drive that spends most of the time at 5000 to 5500 rpm then one for the 2.85 re-drive typically used at 6000 to 6500 rpm).............. Thanks, -- Kelly Troyer "Dyke Delta"_13B ROTARY Engine "RWS"_RD1C/EC2/EM2 "Mistral"_Backplate/Oil Manifold The goal will be the scavenge effect and not actually pumping up torque at lower RPM. So any system that does not screw up the scavenge effect should be a huge improvement. So one system design should work fine for either reduction ratio. This all conjecture since I no longer have a dyno. But, I would use 1/7/8" ID primaries of 18" to 22" into a long collector maybe 8" ending at 2 1/4". Then a smooth transition to a flex pipe (to allow for engine moving in the mounts) then to the end of a fixed down tube of 2 3/4" clamped to an engine mount tube with Dutch clamps. A streamlining cuff over the down tube with air holes for cooling. Then into a Bomb style muffler with the cooling tube through the center as seen here on the news group. I would use crossed fish tails so as to look like ordnance. With air along the outside and through the centerline, plus the distance from the engine, muffler failures would be reduced. Plus there would be less heat inside the cowl. No dripping liquids would be set alight. More room for other items to fit. If it does fall apart the worst that could happen is that it falls off, never to be seen again. Just don't put your tail number on it. I would have the cooling center tube turned through the centerline to disconnect the cooling tube from the exhaust note. The important part of the build is to get the primary pipes exactly the same length to the collector. I can do drawings if you like. Lynn E. Hanover Lynn, I would like to see a drawing and I am sure others of the group would also !!.............I know this is splitting hairs but I am planning on splitting my exhaust after the collector to two mufflers (no good reason other than the Dyke Delta bottom skin has a "Keel" shape (V) and I want to keep the bottom symmetrical with a muffler (recessed with cooling air) on each side of the "V" ) and I wonder what size you would use from the 2.75" to branch off to the mufflers ??......... Again Thanks, Kelly Troyer "Dyke Delta"_13B ROTARY Engine "RWS"_RD1C/EC2/EM2 "Mistral"_Backplate/Oil Manifold --NextPart_Webmail_9m3u9jl4l_8410_1255295226_0 Content-Type: multipart/related; boundary="NextPart_Webmail_9m3u9jl4l_8410_1255295226_1" --NextPart_Webmail_9m3u9jl4l_8410_1255295226_1 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable




 
 
-------------- Original message from Lynn Hanover <lehano= ver@gmail.com>: --------------

Lynn,
   I realize that the Drummond dyno exhaust system is sized = to get maximum power at much
higher rpm (9000+) than we use but can you give us approximate tubing = diameters and lengths
of both the primaries and collector of the Drummond system then pullin= g from your many years
of "Real World Experience" recommend  tubing diameters and length= s sized for our aircraft
systems (perhaps one for the 2.17 re-drive that spends most of the tim= e at 5000 to 5500 rpm
then one for the 2.85 re-drive typically used at 6000 to 6500 rpm)....= ..........
 
Thanks,
--
Kelly Troyer
"Dyke Delta"_1= 3B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifol= d
 
The goal will be the scavenge effect and not actuall= y pumping up torque at lower RPM. So any system that does not screw up the = scavenge effect should be a huge improvement. So one system design should w= ork fine for either reduction ratio.
 
This all conjecture since I no longer have a dyno. B= ut, I would use 1/7/8" ID primaries of 18" to 22"  into a long collect= or maybe 8" ending at 2 1/4". Then a smooth transition to a flex pipe (to a= llow for engine moving in the mounts) then to the end of a fixed down tube = of 2 3/4" clamped to an engine mount tube with Dutch clamps. 
 
A streamlining cuff over the down tube with air hole= s for cooling. Then into a Bomb style muffler with the cooling tube through= the center as seen here on the news group. I would use crossed fish tails = so as to look like ordnance. With air along the outside and through the cen= terline, plus the distance from the engine, muffler failures would be reduc= ed. Plus there would be less heat inside the cowl. No dripping liquids woul= d be set alight. More room for other items to fit. 
 
If it does fall apart the worst that could happen is= that it falls off, never to be seen again. Just don't put your tail number= on it. I would have the cooling center tube turned through the centerline = to disconnect the cooling tube from the exhaust note.  
 
The important part of the build is to get the primar= y pipes exactly the same length to the collector.
 
I can do drawings if you like.
 
Lynn E. Hanover
 
 
Lynn,
   I would like to see a drawing and I am = sure others of the group would also !!.............I
know this is splitting hairs but I am planning on sp= litting my exhaust after the collector to two
mufflers (no good reason other than the Dyke Delta b= ottom skin has a "Keel" shape (V)
and I want to keep the bottom symmetrical with a muf= fler (recessed with cooling air) on each
side of the "V" ) and I wonder what size you would u= se from the 2.75" to branch off to the mufflers ??......... 
 
Again Thanks,
 
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
= "RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold
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