X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from m15.nyc.untd.com ([64.136.22.78] verified) by logan.com (CommuniGate Pro SMTP 5.0.8) with SMTP id 981950 for flyrotary@lancaironline.net; Sun, 12 Feb 2006 14:47:14 -0500 Received-SPF: none receiver=logan.com; client-ip=64.136.22.78; envelope-from=jbker@juno.com Received: from m15.nyc.untd.com (localhost [127.0.0.1]) by m15.nyc.untd.com with SMTP id AABB89EESAZEJ2BJ for (sender ); Sun, 12 Feb 2006 11:46:24 -0800 (PST) Received: (from jbker@juno.com) by m15.nyc.untd.com (jqueuemail) id LG2KTZTS; Sun, 12 Feb 2006 11:45:59 PST To: flyrotary@lancaironline.net Date: Sun, 12 Feb 2006 14:41:50 -0500 Subject: Re: [FlyRotary] How to attach a muffler Message-ID: <20060212.144150.2216.2.JBKER@juno.com> X-Mailer: Juno 5.0.33 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary=--__JNP_000_14bf.34de.1334 X-Juno-Line-Breaks: 8-6,7-8,10,13-14,18-19,22-23,26,29-42,48-49,56-57,61-62,68-78,83-86,87-32767 From: WALTER B KERR X-ContentStamp: 32:16:2528609380 X-MAIL-INFO:0ba5a564449595951090e1e5902020e430bd05f5e425d9a181a1254d3dd93dd51060bd8105cd90d00d64cd31ade02084592970706de5c0912075dd49c06149e1f150e4b159f9498065993150d4c96da9311d656d74fdf4dd84c441215415d438385445dde4cd9064e0a165d021257171b90db959598d612474a1603dd9f5f94da195 X-UNTD-OriginStamp: Y+Mfppm2QyGfnY/dq+iW1f5cJZCcTSamTzF/RZyAoaA= X-UNTD-Peer-Info: 127.0.0.1|localhost|m15.nyc.untd.com|jbker@juno.com This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ----__JNP_000_14bf.34de.1334 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit On Sun, 12 Feb 2006 12:20:29 -0600 "M Roberts" writes: So I am trying to plan my muffler installation. I just bought a hushmaster II to hang under the cabin. I want the exhaust the exit where it currently does mid cowl. The question is how to make the connection. It seems that if I make rigid connections then I will get fatigue cracks in the exhaust, even if I support the weight of the muffler. Do the pipes themselves just absorb the vibration of the engine? I need to use either a slip fit or a v-band clamp to remove the pipe to get the cowl off. Will either of these provide enough play in the system. Flowmaster also sells a ball-and-socket type of joint. http://www.flowmastermufflers.com/products/index.phpmain_page=product_inf o&products_id=2317 That seems better in terms of flexibility, but is more costly and will probably let more heat into the cowl, and will need a larger cowl opening (would prefer the slip or v-band joint). Am I worried about nothing? -- Dave Leonard Turbo Rotary RV-6 N4VY David, You are most definitely not "worried about nothing". When I worked with rocket engines, there was a tremendous amount of effort placed in making sure that there was no stress imposed on the piping due to temperature changes and vibration. Granted rockets see much larger extremes in temp due to cryogenic temps and very high stoiciometric combustion right next to it. But the principles are the same. In the ideal world you would use very thin inconel and place a slip joint at each length between any fixed object (turbo, engine block, muffler). Any bend would also have a slip joint before and after it so that both torsion and expansion is eliminated. Each slip joint gets a metal bellows to seal it and allow relative motion. Then you have to look very closely at how you mount and constrain each piece of plumbing. Your exhaust would cost $5K In the real world, most of what we use is heavy enough that you don't have to go to such lengths. In auto use the pipe is so heavy and the stresses low enough that these are usually not a concern. We are closer to the Auto than the rocket. I would mount the muffler so that it can move a bit using silicone or wire rope isolators. Then I would use a stainless or inconel metal bellows with the wire mesh constraint (front wheel drive auto) to let the engine move around also. I really like V-band clamps for joints. How the mounts are placed and muffler oriented really determines the detail design here. Post some pics and drawings. Sorry about your engine woes. Monty ================================ Hi David, I kinda copied Tracy Hush II installation. Come off the exhaust stack with a peice of SS flex tube about 12 inches long into the muffler. Hang the I hung the muffler from two places with battery/ ground strapping material and then attempted to isolate it when I fastened it at the beefed up floor. Can send some pictures if you are interested. Bernie ----__JNP_000_14bf.34de.1334 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: quoted-printable
 
 
On Sun, 12 Feb 2006 12:20:29 -0600 "M Roberts" <montyr2157@alltel.net> writes:=
So I am trying to plan = my muffler=20 installation.  I just bought a hushmaster II to hang under the=20 cabin.  I want the exhaust the exit where it currently does mid=20 cowl.
 
The question is how to = make the=20 connection.  It seems that if I make rigid connections then I will = get=20 fatigue cracks in the exhaust, even if I support the weight of the=20 muffler.  Do the pipes themselves just absorb the vibration of the=20 engine? 
 
I need to use either a = slip fit or=20 a v-band clamp to remove the pipe to get the cowl off.  Will either = of=20 these provide enough play in the system.
 
Flowmaster also sells a= =20 ball-and-socket type of joint. http://www.flowmastermufflers.com/products/index.phpmain_page=3D= product_info&products_id=3D2317=20
That seems better in = terms of=20 flexibility, but is more costly and will probably let more heat into the = cowl,=20 and will need a larger cowl opening (would prefer the slip or v-band=20 joint).
 
Am I worried about=20 nothing?
--
Dave Leonard
= Turbo Rotary=20 RV-6 N4VY
 
 
 
 
 
David,
 
You are most definitely not "worried = about=20 nothing". When I worked with rocket engines, there was a tremendous = amount of=20 effort placed in making sure that there was no stress imposed on the = piping=20 due to temperature changes and vibration. Granted rockets see much larger= =20 extremes in temp due to  cryogenic temps and very high stoiciometric= =20 combustion right next to it. But the principles are the same.
 
In the ideal world you would use very = thin=20 inconel and place a slip joint at each length between any fixed= =20 object (turbo, engine block, muffler). Any bend would also have a slip = joint=20 before and after it so that both torsion and expansion is eliminated. = Each=20 slip joint gets a metal bellows to seal it and allow relative motion. = Then you=20 have to look very closely at how you mount and constrain each piece of=20 plumbing. Your exhaust would cost $5K
 
In the real world, most of what we use = is heavy=20 enough that you don't have to go to such lengths. In auto use the pipe is= so=20 heavy and the stresses low enough that these are usually  not a= =20 concern. We are closer to the Auto than the rocket.
 
I would mount the muffler so that it can= move a=20 bit using silicone or wire rope isolators. Then I would use a stainless = or=20 inconel metal bellows with the wire mesh constraint (front wheel = drive=20 auto) to let the engine move around also. I really like V-band clamps for= =20 joints. How the mounts are placed and muffler oriented really determines = the=20 detail design here.
 
Post some pics and drawings.
 
Sorry about your engine woes.
 
Monty
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
 
Hi David,
 
I kinda copied Tracy Hush II = installation. Come=20 off the exhaust stack with a peice of SS flex tube about 12 inches long = into=20 the muffler. Hang the I hung the muffler from two places with battery/ = ground=20 strapping material and then attempted to isolate it when I fastened it at= the=20 beefed up floor.
 
Can send some pictures if you are=20 interested.
 
Bernie
 
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