X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from exhub003-1.exch003intermedia.net ([207.5.74.28] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTPS id 3876242 for flyrotary@lancaironline.net; Tue, 06 Oct 2009 08:23:34 -0400 Received-SPF: none receiver=logan.com; client-ip=207.5.74.28; envelope-from=jwhaley@datacast.com Received: from EXVMBX003-5.exch003intermedia.net ([207.5.74.45]) by exhub003-1.exch003intermedia.net ([207.5.74.28]) with mapi; Tue, 6 Oct 2009 05:22:57 -0700 From: Jeff Whaley To: Rotary motors in aircraft Date: Tue, 6 Oct 2009 05:23:47 -0700 Subject: RE: [FlyRotary] Absorbtion muffler [FlyRotary] Re: engine runup video Thread-Topic: [FlyRotary] Absorbtion muffler [FlyRotary] Re: engine runup video Thread-Index: AcpGbqwIti94/O6VTG+taNxjDvttBwAEQdOg Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_C03ABB0A7362B84BB53D544B3C305E0E0153652EA00CEXVMBX0035e_" MIME-Version: 1.0 --_000_C03ABB0A7362B84BB53D544B3C305E0E0153652EA00CEXVMBX0035e_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hey Ed, can you make a sketch? ... I can't quite picture your concept just= from text. Jeff From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Ed Anderson Sent: Tuesday, October 06, 2009 6:30 AM To: Rotary motors in aircraft Subject: [FlyRotary] Absorbtion muffler [FlyRotary] Re: engine runup video Good luck, Mike, on the absorption muffler with a rotary. I have tried a n= umber of different approaches including mufflers with ceramic packing that = can withstand 2000F+. The heat is no problem, the problem is the exhaust s= hock wave pulverizes the ceramic/fiberglass/stainless steel/etc into small = pieces in a relative short time. Its true they were good in suppressing so= und while they lasted, but two weeks - 1 month was about the limit. I still dream of doing a remake of a muffler design I came up with which ha= d 3" 1/8" stainless steel discs (about 4-5) in a 36" tube. The disc were s= lotted and "blades" bent until the disc looked a bit like a fan. The blade= s were bent at an approx 45 deg angle. If you looked down the tube with th= e disc in it all you saw was solid metal - however the blades provide room = for exhaust gas to flow around them. The theory was the shock wave would s= ee basically a solid disc and reflect some/most of its energy back and fort= h between discs, whereas the gas could more or less freely flow around and= through the blades. 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. 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 - it was not sufficient to ke= ep 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 wi= th exhaust so I hung two Hushpower mufflers and went flying. Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm ________________________________ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Mike Wills Sent: Tuesday, October 06, 2009 12:58 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: engine runup video George, Thanks. Read through it yesterday. Nothing too earth shattering here. What = the article really didnt discuss and what I think is the major problem we f= ace in aircraft which is less of a problem in a car is the need to get suff= icient muffler volume. Finding space for a muffler that actually has suffic= ient volume to do any good on an airplane is problematic. Havent yet seen the muffler that relies on "reflective" (aka passive cancel= lation) that really works. Tried a variety of them on various cars over the= years, and of course the homebrewed "spiral flow" muffler on my airplane c= urrently. Still waiting for someone to come up with one that actually works= and will fit on my airplane. Meanwhile I am intrigued by the absorptive design which I posted here the o= ther day. Its the only thing I've seen that actually provides plenty of vol= ume, appears to be capable of both muffling and lasting, and wont look too = terrible. I'm thinking about trying to throw together something cheap and e= asy to try out before committing a bunch of time and effort. Mike ----- Original Message ----- From: George Lendich To: Rotary motors in aircraft Sent: Sunday, October 04, 2009 11:38 PM Subject: [FlyRotary] Re: engine runup video Mike, The address is right, but it didn't work when I tried it also. What I did was use up to Miscellaneous on the address and clicked on exhaus= t etc on the LHS of the screen - OK. George ( down under) ----- Original Message ----- From: Mike Wills To: Rotary motors in aircraft Sent: Monday, October 05, 2009 11:45 AM Subject: [FlyRotary] Re: engine runup video That link didnt work for me George. Mike ----- Original Message ----- From: George Lendich To: Rotary motors in aircraft Sent: Sunday, October 04, 2009 3:45 PM Subject: [FlyRotary] Re: engine runup video Mike, Here's a good site for general info on mufflers, mine and Bill Jepson desig= n is around deflection. www.nsxprime.com/FAQ/Miscellaneous/exhausttheory.html George ( down under) ----- Original Message ----- From: Mike Wills To: Rotary motors in aircraft Sent: Monday, October 05, 2009 2:34 AM Subject: [FlyRotary] engine runup video For anyone who hasnt had that first engine run and is looking for some moti= vation. A buddy visited the hangar a few weeks ago and shot some video of a= n engine runup. He posted it to his website and you can find it here: http://www.stinsonvoyager.com/images/MikeWills13bEngineRun.wmv This was shot right after I re-installed my original muffler after the abor= ted DNA muffler test. Noticeable in the video is the big staging bog. I had= this tuned out about 15 minutes after he shot the video. Mike Wills RV-4 N144MW --_000_C03ABB0A7362B84BB53D544B3C305E0E0153652EA00CEXVMBX0035e_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Hey Ed, can you make a sketch?  … I can’t q= uite picture your concept just from text.

Jeff

 

From: Rotary motors= in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anders= on
Sent: Tuesday, October 06, 2009 6:30 AM
To: Rotary motors in aircraft
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 proble= m is the exhaust shock wave pulverizes the ceramic/fiberglass/stainless steel/et= c into small pieces in a relative short time.  Its true they were good i= n suppressing sound while they lasted, but two weeks – 1 month was abou= t the limit.

 

I still dream of doing a remake of a muffler design I came up w= ith which had 3” 1/8” stainless steel discs (about 4-5) in a 36R= 21; tube.  The disc were slotted and “blades” bent until the disc looked a bit= like a fan.  The blades were bent at an approx 45 deg angle.  If you loo= ked down the tube with the disc in it all you saw was solid metal – howev= er the blades provide room for exhaust gas to flow around them.  The theory w= as the shock wave would see basically a solid disc and reflect some/most of it= s energy back and forth between discs,  whereas the gas could more or le= ss freely flow around and through the blades.

 

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.

 

The problem was I am not a welder and while I had the disc clam= ped with Jam nuts to a SS thread rod through their center – it was not su= fficient to keep the exhaust from loosening the nuts and causing the discs to spin l= ike 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.=

 

Ed

 

From: Rotary motors= in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Will= s
Sent: Tuesday, October 06, 2009 12:58 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: engine runup video

 

George,

 

Thanks. Read through it yesterday. Nothing too earth shattering here. What the arti= cle really didnt discuss and what I think is the major problem we face in aircraft which is less of a problem in a car is the need to get sufficient muffler volume. Finding space for a muffler that actually has sufficient vo= lume to do any good on an airplane is problematic.

 

Havent yet seen the muffler that relies on "reflective" (aka passive cancellation) that really works. Tried a variety of them on various cars ov= er the years, and of course the homebrewed "spiral flow" muffler on = my airplane currently. Still waiting for someone to come up with one that actu= ally works and will fit on my airplane.

 

Meanwhile I am intrigued by the absorptive design which I posted here the other day. = Its the only thing I've seen that actually provides plenty of volume, appears t= o be capable of both muffling and lasting, and wont look too terrible. I'm think= ing about trying to throw together something cheap and easy to try out before committing a bunch of time and effort.

 

Mike

 

 

----- Original Message -----

Sent: Sunday, Octobe= r 04, 2009 11:38 PM

Subject: [FlyRotary] Re= : engine runup video

 

Mike,

The address is right, but it didn't work when I tried it also.

What I did was use up to Miscellaneous on the address and clicked on exhaust etc= on the LHS of the screen - OK.

George ( down under)

----- Original Message -----

From: Mike Wills

Sent: Monday, Octobe= r 05, 2009 11:45 AM

Subject: [FlyRotary] Re= : engine runup video

 

That link didnt work for me George.

 

Mike

----- Original Message -----

Sent: Sunday, Octobe= r 04, 2009 3:45 PM

Subject: [FlyRotary] Re= : engine runup video

 

Mike,

Here's a good site for general info on mufflers, mine and Bill Jepson design is ar= ound deflection.

George ( down under)

----- Original Message -----

From: Mike Wills

Sent: Monday, Octobe= r 05, 2009 2:34 AM

Subject: [FlyRotary] en= gine runup video

 

For anyone who hasnt had that first engine run and is looking for some motivati= on. A buddy visited the hangar a few weeks ago and shot some video of an engine runup. He posted it to his website and you can find it here:

 

 

This was shot right after I re-installed my original muffler after the aborted D= NA muffler test. Noticeable in the video is the big staging bog. I had this tu= ned out about 15 minutes after he shot the video.

 

Mike Wills

RV-4 N144MW

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