X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from qmta09.emeryville.ca.mail.comcast.net ([76.96.30.96] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with ESMTP id 4610271 for flyrotary@lancaironline.net; Fri, 03 Dec 2010 10:58:02 -0500 Received-SPF: pass receiver=logan.com; client-ip=76.96.30.96; envelope-from=wschertz@comcast.net Received: from omta07.emeryville.ca.mail.comcast.net ([76.96.30.59]) by qmta09.emeryville.ca.mail.comcast.net with comcast id ebPM1f0061GXsucA9baK4z; Fri, 03 Dec 2010 11:34:19 +0000 Received: from WschertzPC ([71.57.77.95]) by omta07.emeryville.ca.mail.comcast.net with comcast id ebaG1f00B23NHuF8UbaH3e; Fri, 03 Dec 2010 11:34:18 +0000 Message-ID: From: "Bill Schertz" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Re: Reactive Muffler Design for PP Date: Fri, 3 Dec 2010 05:34:16 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_007F_01CB92AB.B9DD44A0" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 15.4.3502.922 X-MimeOLE: Produced By Microsoft MimeOLE V15.4.3502.922 This is a multi-part message in MIME format. ------=_NextPart_000_007F_01CB92AB.B9DD44A0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable I know I weighed things way back when. Whether I can find the notes is = another question. I will look the next time I am at the hanger. HOWEVER, I would not rate my system as =E2=80=98well muffled=E2=80=99 . = It is loud =E2=80=93 everyone at the airport knows when I go flying. Bill Schertz KIS Cruiser #4045 N343BS Phase I testing From: Kelly Troyer=20 Sent: Thursday, December 02, 2010 10:24 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: Reactive Muffler Design for PP Bill, Do you know approx weight of your total exhaust system including the = Spintech ?? I ask wondering how it would compare to my proposed turbo system to get = a ballpark weight figure to see what weight penalty I may have............ Thanks, Kelly Troyer "DYKE DELTA JD2" (Eventually) "13B ROTARY"_ Engine "RWS"_RD1C/EC2/EM2 "MISTRAL"_Backplate/Oil Manifold "TURBONETICS"_TO4E50 Turbo -------------------------------------------------------------------------= ------- From: Bill Schertz To: Rotary motors in aircraft Sent: Thu, December 2, 2010 7:18:44 PM Subject: [FlyRotary] Re: Reactive Muffler Design for PP was [FlyRotary] = Re: Modified header Calculations No, the Spintech held up, Tracy had earlier used another automotive = muffler that failed quickly. I have a spintech on my plane, 39.8 hours in the air and still holding = up. Bill Schertz KIS Cruiser #4045 N343BS Phase I testing From: bktrub@aol.com=20 Sent: Thursday, December 02, 2010 1:14 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: Reactive Muffler Design for PP was [FlyRotary] = Re: Modified header Calculations 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 =20 -----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). =20 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=20 Sent: Thursday, December 02, 2010 12:23 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: Reactive Muffler Design for PP was = [FlyRotary] Re: Modified header Calculations Ed, =20 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=20 Sent: Thursday, December 02, 2010 10:45 AM To: Rotary motors in aircraft=20 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:=20 Mark,=20 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.=20 Two things occurred -=20 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 ------=_NextPart_000_007F_01CB92AB.B9DD44A0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I know I weighed things way back when. Whether I can find the notes = is=20 another question. I will look the next time I am at the hanger.
 
HOWEVER, I would not rate my system as =E2=80=98well = muffled=E2=80=99 . It is loud =E2=80=93=20 everyone at the airport knows when I go flying.
 
Bill=20 Schertz
KIS Cruiser #4045
N343BS
Phase I testing
 
Sent: Thursday, December 02, 2010 10:24 PM
Subject: [FlyRotary] Re: Reactive Muffler Design for=20 PP
 
Bill,
   Do you know approx weight of your total exhaust system = including the Spintech ??
 
I ask wondering how it would compare to my proposed turbo system to = get a=20 ballpark
weight figure to see what weight penalty I may = have............
 
Thanks,
 

Kelly Troyer
"DYKE DELTA JD2" (Eventually)

"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil = Manifold

"TURBONETICS"_TO4E50 Turbo

 
 
From: Bill Schertz=20 <wschertz@comcast.net>
To: Rotary motors in aircraft=20 <flyrotary@lancaironline.net>
Sent: Thu, December 2, 2010 = 7:18:44=20 PM
Subject: = [FlyRotary] Re:=20 Reactive Muffler Design for PP was [FlyRotary] Re: Modified header=20 Calculations

No, the Spintech held up, Tracy had earlier used another automotive = muffler=20 that failed quickly.
 
I have a spintech on my plane, 39.8 hours in the air and still = holding=20 up.
 
 
Bill=20 Schertz
KIS Cruiser #4045
N343BS
Phase I testing
 
From: bktrub@aol.com=20
Sent: Thursday, December 02, 2010 1:14 PM
Subject: [FlyRotary] Re: Reactive Muffler Design for PP was=20 [FlyRotary] Re: Modified header Calculations
 
Tracy used one and it blew out like a cheap tire, IIRC. It's got = sharp=20 corners, which don't hold up to heat and stress very well.
 
Brian Trubee
 


 


-----Original=20 Message-----
From: Mark Steitle <msteitle@gmail.com>
To: = Rotary=20 motors in aircraft <flyrotary@lancaironline.net>
Sent: Thu, Dec = 2, 2010=20 11:00 am
Subject: [FlyRotary] Re: Reactive Muffler Design for PP was=20 [FlyRotary] Re: Modified header Calculations

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

On Thu, Dec 2, 2010 at 11:40 AM, Ed Anderson = <eanderson@carolina.rr.com>=20 wrote:
All I can really tell you it combined the most = sound=20 deading with the least restriction of any of the muffler designs I = tried -=20 which really doesn't necessarily prove anything.  I guess what = you could=20 do is calculate the open area of the disc and compare it to the area = of the=20 Exhaust port - if as large/larger in area then not necessarily a lot = of=20 restriction to gas flow.
 
SpinTech was the first reactive muffler Tracy=20 used.
 
Ed
 
Sent: Thursday, December 02, 2010 12:23 PM
Subject: [FlyRotary] Re: Reactive Muffler Design for PP = was=20 [FlyRotary] Re: Modified header = Calculations
 
Ed, =20
 
It sounds like it might work, but also appears to be very=20 restrictive.  Did you make any measurements regarding flow=20 restriction?  Maybe a larger diameter main body would alleviate = the back=20 pressure to an acceptable level, maybe not.  I would want to run = some=20 tests first.
 
What do you make of this site? =20 = http://en.wikibooks.org/wiki/Acoustics/Filter_Design_and_Implementation
I think we can pretty much rule out "absorptive" type mufflers = for our=20 purposes.  Wasn't Tracy's early muffler a "reactive" type=20 (Hushpower)?  As 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>=20 wrote:
I agree, Finn.  It probably would  = not take=20 much, but I just got to the point I was tired of messing with it and = put on=20 the HushPower II.  I always felt I was just one more step away = from=20 making it successful - but did not take it.  Just too leery of = learning=20 to weld with only one good eye ball left {:>)
 
The 5/8" SS threaded shaft ran through the = middle of=20 the tube/discs with a jam nut on each side of each disc.  The = shaft/rod=20 was not anchored otherwise.  However, I did have a squished = "Fishtail"=20 end so that the last disc could not back out of the = tube.
 
Ed
 
Sent: Thursday, December 02, 2010 10:45 AM
To: Rotary motors in = aircraft=20
Subject: [FlyRotary] Re: Reactive Muffler Design for PP = was=20 [FlyRotary] Re: Modified header Calculations
 
Hi Ed,

Not that I'm going to jump on this = right=20 away, but it seems that it would be relatively easy to rosette weld = the tips=20 of the discs. Drill 1/8" (or slightly bigger) holes through the tube = at the=20 center of each disc tip.

But, how did you secure the 5/8" = shaft=20 itself?

Finn

On 12/1/2010 5:45 PM, Ed Anderson wrote:=20
Mark,
 
Since you have not gotten to the muffler = part of=20 your design, here are some thoughts (Yes, I did do 6 muffler = experiments -=20 don't ask me why)
 
The one design that was "almost" totally = successful=20 in achieving my goals is attached.  Hard to make out the = details, but=20 enough to give you the general ideal.
 
My objective was trying to decided how to = muffler=20 the shock wave (which creates most of the ear problems) but let = the=20 exhaust gas flow freely.  My conclusion was that reactive = design=20 muffler was the only acceptable choice given our = constraints.
 
What I came up with was the idea of = stuffing=20 (I  put five but I think three would make a considerable = difference)=20 disc with outer parts cut into blades and bent at a 45 deg angle = into a=20 tube.  Looked a bit like an old farm windmill.
 
  The idea behind this approach was = if you=20 looked head on at the fan-disc - you see basically a solid metal=20 front.  That is what the shock wave would see and most (a = lot?) of=20 the energy would be reflected back toward the engine (actually to = the next=20 disc in the tube).  The bent blades on the other hand would = permit=20 exhaust gas to flow with minimum restriction.
 
It really did deaden the sound where folks = could=20 stand by the wing tip with no problem hearing someone else talk. I = was=20 thrilled.  It also met  my minimum restriction as I = could still=20 get my 6000 rpm static.
 
Ok, what went wrong - well, not being a = welder I=20 resorted to other methods - which ultimately failed.
 
Two things occurred -
 
one if the disc broke loose of the small = 5/8" thread=20 SS shaft from the Jam nuts on each side holding the disc, well, = the disc=20 could (and did) begin to spin inside the tube like the turbine = wheel of a=20 jet engine. This windmilling effect acted just like a windmilling = prop on=20 the exhaust gas and definitely impeded gas flow.  So can not = permit=20 the disc to spin (the tips polished the inside of the tube where = the=20 spun)
 
Second because I donot weld, I did not = secure the=20 tips of the blades of the disc to the sides of the tube.  = Well the=20 shock wave naturally causes those blades to flex and eventually = break=20 off.
 
The SS disc were 2" in diam 1/8 thick and = fit really=20 nice inside the 2 1/4" tubes.  I cut slots in the outer part = of the=20 SS disc and then used pliers to bend the tabs to an approx 45 deg = angle=20 (see attached Jep).
 
So none of this was difficult to fabricate = (tedious=20 perhaps but not difficult).
 
I gave up on it because without welding = skills I=20 could not figure out away to secure the tips of the blades to the = tube to=20 give them better support.  Perhaps better than disc would = have been=20 cones but couldn't find any {:>).
 
So since I couldn't see any way around my = lack of=20 welding (and too cheap to hire someone), I went  the = hushpower II=20 route.
 
Just thought I would throw some fuel on = your fire=20 {:>)
 
FWIW
 
Ed
 
=
 

 
 
<= /DIV>
------=_NextPart_000_007F_01CB92AB.B9DD44A0--