X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-gy0-f180.google.com ([209.85.160.180] verified) by logan.com (CommuniGate Pro SMTP 5.3.5) with ESMTP id 4220626 for flyrotary@lancaironline.net; Tue, 13 Apr 2010 20:33:36 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.160.180; envelope-from=msteitle@gmail.com Received: by gyb13 with SMTP id 13so3856693gyb.25 for ; Tue, 13 Apr 2010 17:33:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:received:message-id:subject:from:to:content-type; bh=ePdTjfVMHbv+QETWTqzr2u5o5JSSzWZFdBvyAXUMflg=; b=pMrXaauK7THf5yzReYLc3AgPlg11mIV+gU9wj1CVJbr3U1PMUVkRSPRjOJ0Kotnw8v 4WKCe3WfEsP5Nz1jjvQckwoLPf+hZ0qZ7BJOmtyyymZVJhSP/L/mK7EhFnwigkYtMzp+ w6bf3YvAsJWnWbFvAJ+ODtc2Hu3akwjJSIFO0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=lNVjtxCIAxdvux2FX1515sm84oWfdeuUY/bzTVifvGJVWJ6+RSg1SxoFmNHqnW/3hV FK4Psn6X+x5SXxBoZEqt9b1jlE4bLXu8qlLvqHXAe3S0mlzNtLgJDyGww4M7p1RbnhE8 fsY0BWHJ2banoh5fhqxcYC8w8mysGmpjVm6wU= MIME-Version: 1.0 Received: by 10.231.183.195 with HTTP; Tue, 13 Apr 2010 17:32:59 -0700 (PDT) In-Reply-To: References: Date: Tue, 13 Apr 2010 19:32:59 -0500 Received: by 10.100.25.38 with SMTP id 38mr11693864any.97.1271205179653; Tue, 13 Apr 2010 17:32:59 -0700 (PDT) Message-ID: Subject: Re: [FlyRotary] Re: Tangential muffler From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0016e6541bd42c7a1c0484278533 --0016e6541bd42c7a1c0484278533 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Bill, I stand corrected. I should have referred to them as expansion chambers. And from my many years of desert racing, I can attest that they are very loud. I always thought the thing hanging on the end was a spark arrestor, as mandated by the National Forest Service. But then maybe Dwane was talking about something different. Mark S. On Tue, Apr 13, 2010 at 4:47 PM, wrote: > Guys, > The conical pipes in 2 cycle engines are NOT MUFFLERS! They are a > specifically designed expansion chamber. The expansion chamber produces > dramatic gains at a narrow range of RPM. > Some chambers have a small silencer grafted on. They are usually VERY LOU= D. > Bill Jepson > > Sent from my Verizon Wireless BlackBerry > ------------------------------ > *From: * Mark Steitle > *Date: *Tue, 13 Apr 2010 13:26:03 -0500 > *To: *Rotary motors in aircraft > *Subject: *[FlyRotary] Re: Tangential muffler > > Dwane, > > Not being an engineer, I usually try to copy something that appears to wo= rk > for others, adding a few modifications of my own in the process. My only > experience with conical mufflers is on 2-stroke engines (go-karts, dirt > bikes, etc.). Might be worth a try for someone with access to a dyno and= a > test stand. > > Mark > > On Mon, Apr 12, 2010 at 3:50 PM, Dwayne Parkinson < > dwayneparkinson@yahoo.com> wrote: > >> Sounds like you've tinkered with mufflers a lot. Have you ever employed= a >> conical tail pipe? >> >> ------------------------------ >> *From:* Mark Steitle >> *To:* Rotary motors in aircraft >> *Sent:* Mon, April 12, 2010 1:43:38 PM >> *Subject:* [FlyRotary] Re: Tangential muffler >> >> Dwane, >> >> OK, you hold your hand over the end while I rev it up. ;-0 >> >> Keep in mind that in an earlier muffler design similar to the Moroso >> Spiralflow, I had an AN-3 bolt holding the baffle in place. After a few >> hours the bolt had gotten so hot that it sagged, resembling a horseshoe. >> The rotary's exhaust has proven to be a force to be reconed with. >> Hopefully, this will be the last muffler I have to build for a while. >> >> Mark >> >> On Mon, Apr 12, 2010 at 1:19 PM, Dwayne Parkinson < >> dwayneparkinson@yahoo.com> wrote: >> >>> This is a very interesting approach. Thanks for posting the pictures. >>> It would be very interesting (at least to me) to measure the exhaust g= as >>> pulses at the tail pipe with this design. I wonder if it will normaliz= e the >>> pulses at all so you have an almost steady stream of exhaust gases comi= ng >>> out of the pipe. >>> >>> >>> >>> ------------------------------ >>> *From:* Al Gietzen >>> *To:* Rotary motors in aircraft >>> *Sent:* Mon, April 12, 2010 10:24:07 AM >>> *Subject:* [FlyRotary] Re: Tangential muffler >>> >>> >>> >>> >>> >>> Ernest; >>> >>> >>> >>> I agree that the geometry of the geometry of the cuts is certainly not >>> ideal; and if it were 321SS or similar; yes, I=92d expect it would it t= o >>> disintegrate in about 50 hrs or less. But inconel is very corrosion >>> resistant and very strong up to 2000+F. There will be some self-anneal= ing >>> of the stresses at 1700F. It would be interesting to know what temp it >>> actually gets to because there is some expansion cooling of the gases i= n the >>> muffler. >>> >>> >>> >>> Also it is very tough stuff =96 trying to drill or file inconel will ju= st >>> wear out the tools. Holes have to be punched, cut with water jet, or s= ome >>> other technique. >>> >>> >>> >>> It will be interesting to see how it stands up; but I think it has a go= od >>> chance to prove to be quite durable. >>> >>> >>> >>> Al >>> >>> >>> >>> A grinder will leave two fairly severe 90 degree corners on every edge >>> >>> of the cut slot. Compounding this is the fact that the side grinder >>> >>> cuts a circle. The end of each slot will be left with a knife edge >>> >>> profile pointing back toward the slot. This will create some mean >>> >>> stress risers. The expectation is that this tube is to live in an >>> >>> environment that has to be the closest thing to hell on Earth we could >>> >>> imagine (extreme heat and constant sonic blasts). >>> >>> >>> >>> I would have suggested drilling 3/16" holes and connecting them with th= e >>> >>> grinder. Unless the inside tube is fabricated different than what I >>> >>> understand, I can't help but to think that it will have a very short >>> >>> life. Cracks will start in the corners of each slot, and the tube will >>> >>> disintegrate. Can it be easily pulled apart so that you could run a >>> >>> round needle file down both sides of all the slots to round them out? >>> >>> >>> >>> -- >>> >>> Homepage: http://www.flyrotary.com/ >>> >>> Archive and UnSub: >>> http://mail.lancaironline.net:81/lists/flyrotary/List.html >>> >>> >> >> > --0016e6541bd42c7a1c0484278533 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Bill,=A0

I stand corrected. =A0I should have referred to= them as expansion chambers. =A0And from my many years of desert racing, I = can attest that they are very loud. =A0I always thought the thing hanging o= n the end was a spark arrestor, as mandated by the National Forest Service.= =A0But then maybe Dwane was talking about something different. =A0

Mark S.

On Tue, Apr 1= 3, 2010 at 4:47 PM, <wrjjrs@aol.com> wrote:
Guys,
The conical pipes in 2 cycle engines are NOT MUFFLERS! They are= a specifically designed expansion chamber. The expansion chamber produces = dramatic gains at a narrow range of RPM.
Some chambers have a small sile= ncer grafted on. They are usually VERY LOUD.
Bill Jepson

Sent from my Verizon Wireless BlackBerry

From:= Mark Steitle <msteitle@gmail.com>
Date: Tue, 13 Apr 2010 13:26:03 -0500
To: Rotary motors in aircraft<flyrotary@lancaironline.net>
Subje= ct: [FlyRotary] Re: Tangential muffler

Dwane,

Not being an engineer, I usually t= ry to copy something that appears to work for others, adding a few modifica= tions of my own in the process. =A0My only experience with conical mufflers= is on 2-stroke engines (go-karts, dirt bikes, etc.). =A0Might be worth a t= ry for someone with access to a dyno and a test stand.

Mark =A0

On Mon, Apr = 12, 2010 at 3:50 PM, Dwayne Parkinson <dwayneparkinson@yahoo.com> wrote:
Sounds like you've tinkered with m= ufflers a lot. =A0Have you ever employed a conical tail pipe?

From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraf= t <flyr= otary@lancaironline.net>
Sent= : Mon, April 12, 2010 1:43:38 PM
Subject: [FlyRotary] Re: Tan= gential muffler

Dwane,
=A0
OK, you hold your hand over the end while I rev it up.=A0 ;-0=A0
=A0
Keep in mind that in an earlier muffler design similar to the Moroso S= piralflow, I had an AN-3 bolt holding the baffle in place.=A0 After a few h= ours the bolt had gotten so hot that it sagged, resembling a horseshoe.=A0 = The rotary's exhaust has proven to be a force to be reconed with.=A0 Ho= pefully, this will be the last muffler I have to build for a while.
=A0
Mark

On Mon, Apr 12, 2010 at 1:19 PM, Dwayne Parkinso= n <dwayneparkinson@yahoo.com> wrote= :
This is a very interesting approach. =A0Thanks for posting the picture= s. =A0It would be very interesting (at least to me) to measure the exhaust = gas pulses at the tail pipe with this design. =A0I wonder if it will normal= ize the pulses at all so you have an almost steady stream of exhaust gases = coming out of the pipe.



From: Al Gietzen <ALVentur= es@cox.net>
To: Ro= tary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, April 12, 2010 10= :24:07 AM
Subject: [FlyRo= tary] Re: Tangential muffler

=A0

=A0

Ernest;<= /span>

=A0

I agree that the geometry of the geometry of the cuts is certa= inly not ideal; and if it were 321SS or similar; yes, I=92d expect it would= it to disintegrate in about 50 hrs or less.=A0 But inconel is very corrosi= on resistant and very strong up to 2000+F.=A0 There will be some self-annea= ling of the stresses at 1700F.=A0 It would be interesting to know what temp= it actually gets to because there is some expansion cooling of the gases i= n the muffler.

=A0

Also it is very tough stuff =96 trying to drill or file incone= l will just wear out the tools.=A0 Holes have to be punched, cut with water= jet, or some other technique.

=A0

It will be interesting to see how it stands up; but I think it= has a good chance to prove to be quite durable.

=A0

Al

=A0

A grinde= r will leave two fairly severe 90 degree corners on every edge

of the c= ut slot.=A0 Compounding this is the fact that the side grinder

cuts a c= ircle.=A0 The end of each slot will be left with a knife edge

profile = pointing back toward the slot.=A0 This will create some mean =

stress r= isers.=A0 The expectation is that this tube is to live in an =

environm= ent that has to be the closest thing to hell on Earth we could

imagine = (extreme heat and constant sonic blasts).

=A0

I would = have suggested drilling 3/16" holes and connecting them with the

grinder.= =A0 Unless the inside tube is fabricated different than what I

understa= nd, I can't help but to think that it will have a very short

life.=A0= Cracks will start in the corners of each slot, and the tube will

disinteg= rate. Can it be easily pulled apart so that you could run a <= /p>

round ne= edle file down both sides of all the slots to round them out?=






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