X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao102.cox.net ([68.230.241.44] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3878533 for flyrotary@lancaironline.net; Thu, 08 Oct 2009 00:07:43 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.44; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao102.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20091008040708.UDNN12000.fed1rmmtao102.cox.net@fed1rmimpo03.cox.net> for ; Thu, 8 Oct 2009 00:07:08 -0400 Received: from wills ([68.105.87.66]) by fed1rmimpo03.cox.net with bizsmtp id q4741c00N1RstZw04477Yd; Thu, 08 Oct 2009 00:07:07 -0400 X-VR-Score: -100.00 X-Authority-Analysis: v=1.0 c=1 a=-NbklyyyDmcA:10 a=kviXuzpPAAAA:8 a=HF0xf31GfTw4SN5NTpgA:9 a=8miTZf95tADdtTqtBLAA:7 a=GGpLREg8BgLg3mobUbN7Tl258FcA:4 a=4vB-4DCPJfMA:10 a=Fj6kjvhSXlkF4VQu:21 a=x0MgG_8fQaayq70h:21 a=HZJGGiqLAAAA:8 a=Ia-xEzejAAAA:8 a=ayC55rCoAAAA:8 a=froXjQtZz-iuYpAfn7wA:9 a=Gd4aNr05je8zllphxI0A:7 a=sQ4FB5s5EEuxeMwewCr7NQSxutkA:4 a=HeoGohOdMD0A:10 a=EzXvWhQp4_cA:10 a=vQzC4QW6GfV6bqTS:21 a=YqFJqd278LEfQRqz:21 X-CM-Score: 0.00 Message-ID: <3F68FE9F6170479FA406408E0D7EAD17@wills> From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Absorbtion muffler Date: Wed, 7 Oct 2009 21:07:05 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0088_01CA4792.1FCA2820" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0088_01CA4792.1FCA2820 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Not yet. Hoping to get some more info/details on what is going on in = there. Mike ----- Original Message -----=20 From: Kelly Troyer=20 To: Rotary motors in aircraft=20 Sent: Wednesday, October 07, 2009 5:01 AM Subject: [FlyRotary] Re: Absorbtion muffler=20 Mike, Were you able to determine the approx diameter and length of the = expansion chamber=20 ahead of the perforated tube ??................. -- Kelly Troyer=20 "Dyke Delta"_13B ROTARY Engine=20 "RWS"_RD1C/EC2/EM2=20 "Mistral"_Backplate/Oil Manifold=20 -------------- Original message from "Mike Wills" = : --------------=20 Ed, I assume all of your attempts were built along the lines of a = typical glasspak or "Swiss muffler" with packing either wrapped or = stuffed around some sort of perf tube? The type of muffler I'm considering is the one I mentioned having = seen over the weekend. The reasons I think it might work and live behind = the rotary are: 1) Lots of internal volume. The muffler I saw was at least 8 feet = long. 2) The perforated tube down the center ran the full length of the = muffler providing lots of perforations to dissipate the exhaust energy. 3) The muffler introduces fresh air into the muffler to cool the = exhaust. I have no idea if it will really work and I'm not rushing into = anything. But I went out to Miramar and watched the airplane depart on = sunday. It was virtually silent. Mike ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Tuesday, October 06, 2009 3:29 AM Subject: [FlyRotary] Absorbtion muffler [FlyRotary] Re: engine = runup video Good luck, Mike, on the absorption muffler with a rotary. I have = tried a number of different approaches including mufflers with ceramic = packing that can withstand 2000F+. The heat is no problem, the problem = is the exhaust shock wave pulverizes the ceramic/fiberglass/stainless = steel/etc into small pieces in a relative short time. Its true they = were good in suppressing sound while they lasted, but two weeks = =E2=80=93 1 month was about the limit. =20 I still dream of doing a remake of a muffler design I came up with = which had 3=E2=80=9D 1/8=E2=80=9D stainless steel discs (about 4-5) in a = 36=E2=80=9D tube. The disc were slotted and =E2=80=9Cblades=E2=80=9D = bent until the disc looked a bit like a fan. The blades were bent at an = approx 45 deg angle. If you looked down the tube with the disc in it = all you saw was solid metal =E2=80=93 however the blades provide room = for exhaust gas to flow around them. The theory was the shock wave = would see basically a solid disc and reflect some/most of its energy = back and forth between discs, whereas the gas could more or less freely = flow around and through the blades. =20 The concept worked well in that my hangar neighbors were all = remarking how quite the engine sounded and I could still get a static = rpm of 6000.=20 =20 The problem was I am not a welder and while I had the disc clamped = with Jam nuts to a SS thread rod through their center =E2=80=93 it was = not sufficient to keep the exhaust from loosening the nuts and causing = the discs to spin like a turbine wheel. IF I could have welded the tips = of the blades to the tube then it may have been viable. But, not a = welder and got tire of messing with exhaust so I hung two Hushpower = mufflers and went flying. =20 Ed =20 Ed Anderson Rv-6A N494BW Rotary Powered ------=_NextPart_000_0088_01CA4792.1FCA2820 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
Not yet. Hoping to get some more = info/details on=20 what is going on in there.
 
Mike
----- Original Message -----
From:=20 Kelly = Troyer
Sent: Wednesday, October 07, = 2009 5:01=20 AM
Subject: [FlyRotary] Re: = Absorbtion=20 muffler

Mike,
  Were you able to determine the approx diameter and length = of the=20 expansion chamber
ahead of the perforated tube ??.................
--
Kelly Troyer
"Dyke = Delta"_13B=20 ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil = Manifold=20
--------------=20 Original message from "Mike Wills" <rv-4mike@cox.net>: = --------------=20

Ed,
 
 I assume all of your attempts = were built=20 along the lines of a typical glasspak or "Swiss muffler" with = packing either=20 wrapped or stuffed around some sort of perf tube?
 
 The type of muffler I'm = considering is=20 the one I mentioned having seen over the weekend. The reasons I = think it=20 might work and live behind the rotary are:
1) Lots of internal volume. The = muffler I saw=20 was at least 8 feet long.
2) The perforated tube down the = center ran the=20 full length of the muffler providing lots of perforations to = dissipate the=20 exhaust energy.
3) The muffler introduces fresh air = into the=20 muffler to cool the exhaust.
 
I have no idea if it will really = work and I'm=20 not rushing into anything. But I went out to Miramar and watched the = airplane depart on sunday. It was virtually silent.
 
Mike
----- Original Message ----- =
From:=20 Ed Anderson
To: Rotary motors in = aircraft=20
Sent: Tuesday, October 06, = 2009 3:29=20 AM
Subject: [FlyRotary] = Absorbtion=20 muffler [FlyRotary] Re: engine runup video

Good = luck, Mike,=20 on the absorption muffler with a rotary.  I have tried a = number of=20 different approaches including mufflers with ceramic packing that = can=20 withstand 2000F+.  The heat is no problem, the problem is the = exhaust=20 shock wave pulverizes the ceramic/fiberglass/stainless steel/etc = into=20 small pieces in a relative short time.  Its true they were = good in=20 suppressing sound while they lasted, but two weeks =E2=80=93 1 = month was about the=20 limit.

 

I still = dream of=20 doing a remake of a muffler design I came up with which had = 3=E2=80=9D 1/8=E2=80=9D=20 stainless steel discs (about 4-5) in a 36=E2=80=9D tube.  The = disc were=20 slotted and =E2=80=9Cblades=E2=80=9D bent until the disc looked a = bit like a fan. =20 The blades were bent at an approx 45 deg angle.  If you = looked down=20 the tube with the disc in it all you saw was solid metal =E2=80=93 = however the=20 blades provide room for exhaust gas to flow around them.  The = theory=20 was the shock wave would see basically a solid disc and reflect = some/most=20 of its energy back and forth between discs,  whereas the gas = could=20 more or less freely flow around and through the=20 blades.

 

The = concept=20 worked well in that my hangar neighbors were all remarking how = quite the=20 engine sounded and I could still get a  static rpm of 6000.=20

 

The = problem was I=20 am not a welder and while I had the disc clamped with Jam nuts to = a SS=20 thread rod through their center =E2=80=93 it was not sufficient to = keep the=20 exhaust from loosening the nuts and causing the discs to spin like = a=20 turbine wheel.  IF I could have welded the tips of the blades = to the=20 tube then it may have been viable.  But, not a welder and got = tire of=20 messing with exhaust so I hung two Hushpower mufflers and went=20 flying.

 

Ed

 

Ed=20 Anderson

Rv-6A = N494BW=20 Rotary=20 = Powered

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