X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rn-out-0910.google.com ([64.233.170.189] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTP id 3482307 for flyrotary@lancaironline.net; Sun, 08 Feb 2009 01:52:12 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.233.170.189; envelope-from=lehanover@gmail.com Received: by rn-out-0910.google.com with SMTP id j42so1019559rne.1 for ; Sat, 07 Feb 2009 22:51:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:date:message-id:subject :from:to:content-type; bh=5oLqZMggnneN71c4r6pxd8+5/a038816b/vtNZki+hw=; b=p1yEYkb5fAaB1KwaAC87zrYeB86RBq4Ups746nZSFMPem78suJtUs7zCXT3coON81r SuolhnMH1PsVrr3B1fC1CxFVBfcGRFSU6qigSs5i8gmRdqtDLPsq7+IOKjUZArnwxCtQ ORKA5Yd6jNc2AIpNVd3PKV5NXIoE5IDwLl3FQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=RuInw0P1DXzqe8SQo4+ZM8mzgu9kCKuUqkyr7qcfH5+LLJws3OpsKa94AgpuFYyoDI l7yiR93xO+DMa6qAKTtquL3O+3mTZSdZeLhpz72kV9DKFA3Eq5YTmpVzaR9xltXabCqY xEcKKjP7/g8e1YfgLvqI8vC8kX6Dss6JAQHmA= MIME-Version: 1.0 Received: by 10.90.66.14 with SMTP id o14mr7683aga.106.1234075895687; Sat, 07 Feb 2009 22:51:35 -0800 (PST) Date: Sat, 7 Feb 2009 22:51:35 -0800 Message-ID: <1ab24f410902072251s53baa39aqe39851f6fea4ed20@mail.gmail.com> Subject: Exhaust question. From: Lynn Hanover To: flyrotary@lancaironline.net Content-Type: multipart/alternative; boundary=001636163c5f636878046262afc0 --001636163c5f636878046262afc0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit The 11"-12" 22"-24" 33"-36" is for primary lengths into a collector. 36" is about as much as you can fit into a race car. The next primary length with any data is 102" inches to the collector, and in that case the muffler is under the rear bumper. Any length that will have 2 full exhaust pulses inside before the collector is the one of interest. I have read that the high frequency stuff tends to move along the outer wall of the pipe, so even a steel pack or glass pack muffler can work for a while, with the really annoying part of the sounds. The 90 degree cut off the pipe is the loudest, any angle of cut away from 90 will be quieter. You can see this morphing to a fish tail muffler, which works well. The hammering will disassemble a fish tail unless it has some blades to support the sides but the long angle cut needs no such support. Removing heat also quiets the sound. If the headers have no cooling air supply they will glow orange and heat anything that can "see" the orange part. A thin wall bit of stainless stood off 1/2" or more, from the pipe will break the transmission of heat. Lynn E. Hanover Here are some pics from today. I have to safety some wires, hang the prop, fill the fluids, then I can make some noise. If everything goes well, I can start her up this week. My exhaust questions: You can see in the picture, that I stuck a 150* piece on the end of the muffler. This isn't permanent, I just put it there for the radius. I remember Lynn writing something about the exhaust length should be a multiple of 11 to 12 inches. Is this for 6500 ish rpm? Where do I start measuring? I measured from the front rotor exhaust port to the back of the muffler and got 30". I can run a short bend and let the exhaust exit out the side of the cowling, right where it shows in the picture. But I am worried about the exhaust being too close to the fresh air intake. The other option is to turn it inboard and down, so it passes over the engine mount tube and exits out the bottom of the cowling. What is the appropriate angle for the end of the pipe as it exits the cowl so I don't have any back pressure? Chris --001636163c5f636878046262afc0 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable

The 11"-12"  22"-24" 33&= quot;-36" is for primary lengths into a collector. 36" is about a= s much as you can fit into a race car. The next primary length with any dat= a is 102" inches to the collector, and in that case the muffler is und= er the rear bumper. Any length that will have 2 full exhaust pulses inside = before the collector is the one of interest. I have read that the high freq= uency stuff tends to move along the outer wall of the pipe, so even a steel= pack or glass pack muffler can work for a while, with the really annoying = part of the sounds.

The 90 degree cut off the pipe is the loudest, an= y angle of cut away from 90 will be quieter. You can see this morphing to a= fish tail muffler, which works well. The hammering will disassemble a fish= tail unless it has some blades to support the sides but the long angle cut= needs no such support. Removing heat also quiets the sound. If the he= aders have no cooling air supply they will glow orange and heat anything th= at can "see" the orange part. A thin wall bit of stainless stood = off 1/2" or more, from the pipe will break the transmission of heat.&n= bsp;

Lynn E. Hanover

 

Here are some pics from today.  I have to sa= fety some wires, hang the prop, fill the fluids, then I can make some noise= .  If everything goes well, I can start her up this week.

 My exhaust questions:  You can see in = the picture, that I stuck a 150* piece on the end of the muffler.  Thi= s isn't permanent, I just put it there for the radius.  I remember= Lynn writing something about the exhaust length should be a multiple of 11= to 12 inches.  Is this for 6500 ish rpm?  Where do I start measu= ring?  I measured from the front rotor exhaust port to the back of the= muffler and got 30".

 I can run a short bend and let the exhaust = exit out the side of the cowling, right where it shows in the picture. But = I am worried about the exhaust being too close to the fresh air intake.&nbs= p; The other option is to turn it inboard and down, so it passes over the e= ngine mount tube and exits out the bottom of the cowling.

What is the appropriate angle for the end of the = pipe as it exits the cowl so I don't have any back pressure? 

 Chris

 


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