X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-ew0-f52.google.com ([209.85.215.52] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with ESMTP id 4600229 for flyrotary@lancaironline.net; Thu, 02 Dec 2010 15:03:07 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.215.52; envelope-from=msteitle@gmail.com Received: by ewy23 with SMTP id 23so5581750ewy.25 for ; Thu, 02 Dec 2010 12:02:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=zoXACBf7KsYv8EZctu0hdpYURgqLn5VduOpll7YaTPk=; b=GlbRo6v0RWBR6E6u21f2O21xEnUb88UO/ljD4en8CqHzDagR4OGwUNz9llzKBiF/Ri r4Tdd2RpRE80ncYigdme2ET+lFxsGq9W3Wie2CsZNCzMsqBUlumOCS3T9s4+rhhE+KkH FEhCXFebHcwzDXRt8P2KpeZLF9fu9EmLLUbZI= 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=SJJxs8y8hAaxPmZgXz8HsIlxJVT3bDxjcjYlGdtsPjmhoLqw0W7CEqz9UQrYBrHwYF rHFfzvQQHiF0PEa1CDhOi5CutfB/LtKDpFrUEVwyiik1OlUOxAB9xrvFQrLzR83e1Jp9 ijHHROMhpw/RZbWEvHCLLlvouXZNtfwh9NWxw= MIME-Version: 1.0 Received: by 10.213.114.5 with SMTP id c5mr1595565ebq.39.1291320148983; Thu, 02 Dec 2010 12:02:28 -0800 (PST) Received: by 10.213.34.212 with HTTP; Thu, 2 Dec 2010 12:02:28 -0800 (PST) In-Reply-To: References: Date: Thu, 2 Dec 2010 14:02:28 -0600 Message-ID: Subject: Re: [FlyRotary] Re: Reactive Muffler Design for PP was [FlyRotary] Re: Modified header Calculations From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0015174c3894c58163049672e600 --0015174c3894c58163049672e600 Content-Type: text/plain; charset=ISO-8859-1 Ditto Mark On Thu, Dec 2, 2010 at 1:28 PM, wrote: > I might have spoken too soon. I recall that he had an eldlebrock muffler > that split open. Then he went to a spintech. I thought he then went to a > Hushpower. I haven't looked into my Hushpower with a bore scope, but it > rattles like all the innards are coming loose. The outter case looks Ok. It > would be nice if I could have some degree of confidence in my exahust > system. It's the most worrisome part on my airplane. > > Brian Trubee > > > > -----Original Message----- > From: Mark Steitle > To: Rotary motors in aircraft > Sent: Thu, Dec 2, 2010 11:21 am > Subject: [FlyRotary] Re: Reactive Muffler Design for PP was [FlyRotary] Re: > Modified header Calculations > > Brian, > > That's very surprising to hear. Do you know which model he tried? They > make a bunch of different types, some made specifically for racing > applications. I find it hard to believe that their racing mufflers would > "blow out like a cheap tire". (Maybe Tracy can enlighten us on this?) > > Mark > > On Thu, Dec 2, 2010 at 1:14 PM, wrote: > >> Tracy used one and it blew out like a cheap tire, IIRC. It's got sharp >> corners, which don't hold up to heat and stress very well. >> >> Brian Trubee >> >> >> >> >> >> >> -----Original Message----- >> From: Mark Steitle >> To: Rotary motors in aircraft >> Sent: Thu, Dec 2, 2010 11:00 am >> Subject: [FlyRotary] Re: Reactive Muffler Design for PP was [FlyRotary] >> Re: Modified header Calculations >> >> I looked at the Spin Tech site and those look to be a very robust >> design... used by many serious racing types. I may try one (some day in the >> future). >> >> Mark >> >> On Thu, Dec 2, 2010 at 11:40 AM, Ed Anderson wrote: >> >>> All I can really tell you it combined the most sound deading with the >>> least restriction of any of the muffler designs I tried - which really >>> doesn't necessarily prove anything. I guess what you could do is calculate >>> the open area of the disc and compare it to the area of the Exhaust port - >>> if as large/larger in area then not necessarily a lot of restriction to gas >>> flow. >>> >>> SpinTech was the first reactive muffler Tracy used. >>> >>> Ed >>> >>> *From:* Mark Steitle >>> *Sent:* Thursday, December 02, 2010 12:23 PM >>> *To:* Rotary motors in aircraft >>> *Subject:* [FlyRotary] Re: Reactive Muffler Design for PP was >>> [FlyRotary] Re: Modified header Calculations >>> >>> Ed, >>> >>> It sounds like it might work, but also appears to be very restrictive. >>> Did you make any measurements regarding flow restriction? Maybe a larger >>> diameter main body would alleviate the back pressure to an acceptable level, >>> maybe not. I would want to run some tests first. >>> >>> What do you make of this site? >>> http://en.wikibooks.org/wiki/Acoustics/Filter_Design_and_Implementation >>> I think we can pretty much rule out "absorptive" type mufflers for our >>> purposes. Wasn't Tracy's early muffler a "reactive" type (Hushpower)? As I >>> recall it was heavy, but it worked very well. >>> >>> Mark >>> >>> >>> On Thu, Dec 2, 2010 at 10:30 AM, Ed Anderson wrote: >>> >>>> I agree, Finn. It probably would not take much, but I just got to >>>> the point I was tired of messing with it and put on the HushPower II. I >>>> always felt I was just one more step away from making it successful - but >>>> did not take it. Just too leery of learning to weld with only one good eye >>>> ball left {:>) >>>> >>>> The 5/8" SS threaded shaft ran through the middle of the tube/discs with >>>> a jam nut on each side of each disc. The shaft/rod was not anchored >>>> otherwise. However, I did have a squished "Fishtail" end so that the last >>>> disc could not back out of the tube. >>>> >>>> Ed >>>> >>>> *From:* Finn Lassen >>>> *Sent:* Thursday, December 02, 2010 10:45 AM >>>> *To:* Rotary motors in aircraft >>>> *Subject:* [FlyRotary] Re: Reactive Muffler Design for PP was >>>> [FlyRotary] Re: Modified header Calculations >>>> >>>> Hi Ed, >>>> >>>> Not that I'm going to jump on this right away, but it seems that it >>>> would be relatively easy to rosette weld the tips of the discs. Drill 1/8" >>>> (or slightly bigger) holes through the tube at the center of each disc tip. >>>> >>>> But, how did you secure the 5/8" shaft itself? >>>> >>>> Finn >>>> >>>> On 12/1/2010 5:45 PM, Ed Anderson wrote: >>>> >>>> Mark, >>>> >>>> Since you have not gotten to the muffler part of your design, here are >>>> some thoughts (Yes, I did do 6 muffler experiments - don't ask me why) >>>> >>>> The one design that was "almost" totally successful in achieving my >>>> goals is attached. Hard to make out the details, but enough to give you the >>>> general ideal. >>>> >>>> My objective was trying to decided how to muffler the shock wave (which >>>> creates most of the ear problems) but let the exhaust gas flow freely. My >>>> conclusion was that reactive design muffler was the only acceptable choice >>>> given our constraints. >>>> >>>> What I came up with was the idea of stuffing (I put five but I think >>>> three would make a considerable difference) disc with outer parts cut into >>>> blades and bent at a 45 deg angle into a tube. Looked a bit like an old >>>> farm windmill. >>>> >>>> The idea behind this approach was if you looked head on at the >>>> fan-disc - you see basically a solid metal front. That is what the shock >>>> wave would see and most (a lot?) of the energy would be reflected back >>>> toward the engine (actually to the next disc in the tube). The bent blades >>>> on the other hand would permit exhaust gas to flow with minimum restriction. >>>> >>>> It really did deaden the sound where folks could stand by the wing tip >>>> with no problem hearing someone else talk. I was thrilled. It also met my >>>> minimum restriction as I could still get my 6000 rpm static. >>>> >>>> Ok, what went wrong - well, not being a welder I resorted to other >>>> methods - which ultimately failed. >>>> >>>> Two things occurred - >>>> >>>> one if the disc broke loose of the small 5/8" thread SS shaft from the >>>> Jam nuts on each side holding the disc, well, the disc could (and did) begin >>>> to spin inside the tube like the turbine wheel of a jet engine. This >>>> windmilling effect acted just like a windmilling prop on the exhaust gas and >>>> definitely impeded gas flow. So can not permit the disc to spin (the tips >>>> polished the inside of the tube where the spun) >>>> >>>> Second because I donot weld, I did not secure the tips of the blades of >>>> the disc to the sides of the tube. Well the shock wave naturally causes >>>> those blades to flex and eventually break off. >>>> >>>> The SS disc were 2" in diam 1/8 thick and fit really nice inside the 2 >>>> 1/4" tubes. I cut slots in the outer part of the SS disc and then used >>>> pliers to bend the tabs to an approx 45 deg angle (see attached Jep). >>>> >>>> So none of this was difficult to fabricate (tedious perhaps but not >>>> difficult). >>>> >>>> I gave up on it because without welding skills I could not figure out >>>> away to secure the tips of the blades to the tube to give them better >>>> support. Perhaps better than disc would have been cones but couldn't find >>>> any {:>). >>>> >>>> So since I couldn't see any way around my lack of welding (and too cheap >>>> to hire someone), I went the hushpower II route. >>>> >>>> Just thought I would throw some fuel on your fire {:>) >>>> >>>> FWIW >>>> >>>> Ed >>>> >>>> >>>> >>>> >>> >> > --0015174c3894c58163049672e600 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Ditto

Mark

On Thu, Dec= 2, 2010 at 1:28 PM, <bktrub@aol.com> wrote:
I might have spoken too so= on. I recall that he had an eldlebrock muffler that split open. Then he wen= t to a spintech. I thought he then went to a Hushpower. I haven't looke= d into my Hushpower with a bore scope, but it rattles like all the innards = are coming loose. The outter case looks Ok. It would be nice if I could hav= e some degree of confidence in my exahust system. It's the most worriso= me part on my airplane.
=A0
Brian Trubee



-----= Original Message-----
From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Thu, Dec 2, 2010 11:21 am
Subject: [FlyRotary] Re: Reactive Muffler Design for PP was [FlyRotary] Re:= Modified header Calculations

Brian,=A0

That's very surprising to hear. =A0Do you know which model he trie= d? =A0They make a bunch of different types, some made specifically for raci= ng applications. =A0I find it hard to believe that their racing mufflers wo= uld "blow out like a cheap tire". =A0(Maybe Tracy can enlighten u= s on this?)

Mark =A0

On Thu, Dec 2, 2010 at 1:14 PM, <bktrub@aol.com> wrote:
Tracy used one and it blew out like a cheap tire, IIRC. It's got s= harp corners, which don't hold up to heat and stress very well.
=A0
Brian Trubee
=A0


=A0


-----= Original Message-----
From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Thu, Dec 2, 2010 11:00 am
Subject: [FlyRotary] Re: Reactive Muffler Design for PP was [FlyRotary] Re:= Modified header Calculations

I looked at the Spin Tech site and those look to be a very robust desi= gn... used by many serious racing types. =A0I may try one (some day in the = future). =A0=20

Mark

On Thu, Dec 2, 2010 at 11:40 AM, Ed Anderson <eanderson@carolina.rr.com> wrote:
All I can really tell you it combined the most so= und deading with the least restriction of any of the muffler designs I trie= d - which really doesn't necessarily prove anything.=A0 I guess what yo= u could do is calculate the open area of the disc and compare it to the are= a of the Exhaust port - if as large/larger in area then not necessarily a l= ot of restriction to gas flow.
=A0
SpinTech was the first reactive muffler Tracy use= d.
=A0
Ed

Sent: Thursday, December 02, 2010 12:23 PM
To: Rotary motors in aircraft <= /div>
Subject: [FlyRotary] Re: Reactive Muffler Design for PP was [Fl= yRotary] Re: Modified header Calculations

Ed,=A0=20

It sounds like it might work, but also appears to be very restrictive.= =A0Did you make any measurements regarding flow restriction? =A0Maybe a la= rger diameter main body would alleviate the back pressure to an acceptable = level, maybe not. =A0I would want to run some tests first.

I think we can pretty much rule out "absorptive" type muffle= rs for our purposes. =A0Wasn't Tracy's early muffler a "reacti= ve" type (Hushpower)? =A0As I recall it was heavy, but it worked very = well.

Mark


On Thu, Dec 2, 2010 at 10:30 AM, Ed Anderson <eanderson@carolina.rr.com> wrote:
I agree, Finn.=A0 It probably would=A0 not take m= uch, but I just got to the point I was tired of messing with it and put on = the HushPower II.=A0 I always felt I was just one more step away from makin= g it successful - but did not take it.=A0 Just too leery of learning to wel= d with only one good eye ball left {:>)
=A0
The 5/8" SS threaded shaft ran through the m= iddle of the tube/discs with a jam nut on each side of each disc.=A0 The sh= aft/rod was not anchored otherwise.=A0 However, I did have a squished "= ;Fishtail" end so that the last disc could not back out of the tube.
=A0
Ed

Sent: Thursday, December 02, 2010 10:45 AM
Subject: [FlyRotary] Re: Reactive Muffler Design for PP was [Fl= yRotary] Re: Modified header Calculations

Hi Ed,

Not that I'm going to jump on this right away, but it seems that it wou= ld be relatively easy to rosette weld the tips of the discs. Drill 1/8"= ; (or slightly bigger) holes through the tube at the center of each disc ti= p.

But, how did you secure the 5/8" shaft itself?

Finn

On 12/1/2010 5:45 PM, Ed Anderson wrote:=20
Mark,
=A0
Since you have not gotten to the muffler part of = your design, here are some thoughts (Yes, I did do 6 muffler experiments - = don't ask me why)
=A0
The one design=A0that was "almost" tota= lly successful in achieving my goals is attached.=A0 Hard to make out the d= etails, but enough to give you the general ideal.
=A0
My objective was trying to decided how to muffler= the shock wave (which creates most of the ear problems) but let the exhaus= t gas flow freely.=A0 My conclusion was that reactive design muffler was th= e only acceptable choice given our constraints.
=A0
What I came up with was the idea of stuffing (I= =A0 put five but I think three would make a considerable difference) disc w= ith outer parts cut into blades and bent at a 45 deg angle into a tube.=A0 = Looked a bit like an old farm windmill.
=A0
=A0 The idea behind this approach was if you look= ed head on at the fan-disc - you see basically a solid metal front.=A0 That= is what the shock wave would see and most (a lot?) of the energy would be = reflected back toward the engine (actually to the next disc in the tube).= =A0 The bent blades on the other hand would permit exhaust gas to flow with= minimum restriction.
=A0
It really did deaden the sound where folks could = stand by the wing tip with no problem hearing someone else talk.=A0I was th= rilled.=A0 It also met=A0 my minimum restriction as I could still get my 60= 00 rpm static.
=A0
Ok, what went wrong - well, not being a welder I = resorted to other methods - which ultimately failed.=A0
=A0
=A0Two things occurred -
=A0
one if the disc broke loose of the small 5/8"= ; thread SS shaft from the Jam nuts on each side holding the disc, well, th= e disc could (and did) begin to spin inside the tube like the turbine wheel= of a jet engine.=A0This windmilling effect acted just like a windmilling p= rop on the exhaust gas and definitely impeded gas flow.=A0 So can not permi= t the disc to spin (the tips polished the inside of the tube where the spun= )
=A0
=A0Second because I donot weld, I did not secure = the tips of the blades of the disc to the sides of the tube.=A0 Well the sh= ock wave naturally causes those blades to flex and eventually break off.
=A0
The SS disc were 2" in diam 1/8 thick=A0and = fit really nice inside the 2 1/4" tubes.=A0 I cut slots in the outer p= art of the SS=A0disc and then used pliers to bend the tabs to an approx 45 = deg angle (see attached Jep).
=A0
So none of this was difficult to fabricate (tedio= us perhaps but not difficult).
=A0
I gave up on it because without welding skills I = could not figure out away to secure the tips of the blades to the tube to g= ive them better support.=A0 Perhaps better than disc would have been cones = but couldn't find any {:>).
=A0
So since I couldn't see any way around my lac= k of welding (and too cheap to hire someone), I went=A0 the hushpower II ro= ute.
=A0
Just thought I would throw some fuel on your fire= {:>)
=A0
FWIW
=A0
Ed







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