X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao107.cox.net ([68.230.241.39] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3880522 for flyrotary@lancaironline.net; Fri, 09 Oct 2009 13:06:37 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.39; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao107.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20091009170601.MJSE21470.fed1rmmtao107.cox.net@fed1rmimpo03.cox.net> for ; Fri, 9 Oct 2009 13:06:01 -0400 Received: from wills ([68.105.87.66]) by fed1rmimpo03.cox.net with bizsmtp id qh5x1c00V1RstZw04h5zzN; Fri, 09 Oct 2009 13:06:00 -0400 X-VR-Score: -150.00 X-Authority-Analysis: v=1.0 c=1 a=Ia-xEzejAAAA:8 a=Hl1Gy0H5AAAA:8 a=7g1VtSJxAAAA:8 a=dgVy8Qnve_LwdC2R8p4A:9 a=tyceSnPfyIzKpoeSkKMA:7 a=JE_X0l5k6aKWuK24E8hu6eLYzdIA:4 a=EzXvWhQp4_cA:10 a=HZJGGiqLAAAA:8 a=hPhO7XNhJtNeGnsHno0A:9 a=My5UcmiVRV5cd8fvc2QA:7 a=xaBO9fVnwxxZcS_Spe07R9s5bAwA:4 a=HeoGohOdMD0A:10 X-CM-Score: 0.00 Message-ID: From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Your muffler Date: Fri, 9 Oct 2009 10:05:58 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0035_01CA48C8.1900C3A0" 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_0035_01CA48C8.1900C3A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable OK George, my memory is now jogged having seen your drawing. I liked the = design when I saw it the first time but discounted it for my application = because I couldnt see a good way to make any muffler with a tangential = entry fit my airframe. This is the same reason I passed on Al's proven = muffler design. I think the use of cooling airflow introduced into the muffler makes a = lot of sense and this is something your design has in common with the = YO-3A muffler I've been talking about. I believe the YO-3A design would = prove superior by virtue of the greatly increased volume of the muffler = and the use of absorptive materials. Of course until someone builds one and tries it who knows if it will = hold up to the abusive exhaust output of a rotary. But the YO-3A design = does have the advantage of being flight proven in a pretty tough = environment - low altitude recon in Vietnam. Your muffler design (or Al's) is a winner if the goal is to keep the = muffler within the confines of the cowl. My cowl is already too tight = without a muffler in it. Mike Wills RV-4 N144MW=20 ----- Original Message -----=20 From: George Lendich=20 To: Rotary motors in aircraft=20 Sent: Thursday, October 08, 2009 9:18 PM Subject: [FlyRotary] Re: Your muffler Al, Not tested yet, but have one almost complete for the single. The cones are there to stop the sound waves having a direct line of = sight out the rear end, the sound waves will be going all over the place = within the exhaust and I tried to replicate that with the zig zaggy = lines. There is no restriction as the area around the back to back cones, is = equal to the area of the 2" exhaust manifold area. However I do take your point on swirl restriction, but I don't see a = problem as it will swirl out the end, whereas sound waves travel in a = straight line ( I think). Bill did have me put in a reflector plate = opposite the incoming exhaust, but I don't know if this will interrupt = the swirl motion, I suspect it might. The reflector plate is on the LHS = of the parts count - photo attached. George ( down under) George; Nice design. Has anyone run one of these yet. My concern with the tangential muffler is something called 'swirl = flow choking' - discovered in connection with a similar attempt with gas = turbine exhaust. High circumferential velocity tends to keep the flow = from moving out the end, and consequent pressure buildup. I don't know = whether it applies to the pulsed flow, but it might, and your conical = restriction toward the outlet could make it worse.=20 To avoid that possibility in my tangential muffler I added internal = vanes at a 45 degree angle opposite the ports, and extended the header = pipes into muffler to a squared end. Disrupts the circumferential flow = and helps direct the exhaust toward the exit. Your depiction of the idealized sounds waves going axially; ah-h, = well; maybe/maybe notJ. Al G -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of George Lendich Sent: Thursday, October 08, 2009 1:14 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Your muffler Kelly There you go matey. All off the shelf SS cones and tube. George ( down under) ----- Original Message -----=20 From: Kelly Troyer=20 To: Rotary motors in aircraft=20 Sent: Thursday, October 08, 2009 9:32 PM Subject: [FlyRotary] Your muffler George, Do you have a photo or drawing available of your muffler = design..........I seem to remember seeing some design info in the past but do not know where = to find it...... Thanks, -- Kelly Troyer=20 "Dyke Delta"_13B ROTARY Engine=20 "RWS"_RD1C/EC2/EM2=20 "Mistral"_Backplate/Oil Manifold=20 =20 -------------- Original message from "George Lendich" = : --------------=20 > Ed,=20 > Cones are the GO.=20 >=20 > Any bare edge will take a battering from the heat and shock = waves. Cones=20 > formed back to back eliminate any edges.=20 >=20 > There must be supporting structure for the cones, I've used = 1/4" solid=20 > round bar welded into the exhaust skin.=20 > George (down under)=20 -------------------------------------------------------------------------= ----- -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_0035_01CA48C8.1900C3A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
OK George, my memory is now jogged = having seen your=20 drawing. I liked the design when I saw it the first time but discounted = it for=20 my application because I couldnt see a good way to make any muffler = with a=20 tangential entry fit my airframe. This is the same reason I passed on = Al's=20 proven muffler design.
 
I think the use of cooling airflow = introduced into=20 the muffler makes a lot of sense and this is something your design has = in common=20 with the YO-3A muffler I've been talking about. I believe the YO-3A = design would=20 prove superior by virtue of the greatly increased volume of the muffler = and the=20 use of absorptive materials.
 
Of course until someone builds one and = tries it who=20 knows if it will hold up to the abusive exhaust output of a rotary. But = the=20 YO-3A design does have the advantage of being flight proven in a pretty = tough=20 environment - low altitude recon in Vietnam.
 
Your muffler design (or Al's) is a = winner if=20 the goal is to keep the muffler within the confines of the cowl. My cowl = is=20 already too tight without a muffler in it.
 
Mike Wills
RV-4 N144MW 
----- Original Message -----
From:=20 George=20 Lendich
Sent: Thursday, October 08, = 2009 9:18=20 PM
Subject: [FlyRotary] Re: Your=20 muffler

Al,
Not tested yet, but have one almost = complete for=20 the single.
 
The cones are there to stop the sound = waves having a direct line of sight out the rear end, the sound = waves=20 will be going all over the place within the exhaust and I tried to = replicate=20 that with the zig zaggy lines.
 
There is no restriction as the area = around the=20 back to back cones, is equal to the area of the 2" exhaust=20 manifold area.
 
However I do take your point on swirl = restriction, but I don't see a problem as it will swirl out the end, = whereas=20 sound waves travel in a straight line ( I think).  Bill did have me put in a reflector plate opposite the = incoming=20 exhaust, but I don't know if this will interrupt the swirl motion, I = suspect=20 it might. The reflector plate is on the LHS of the parts count = - photo=20 attached.
 
George ( down under)

George;

 

Nice=20 design.  Has anyone run one of these yet.

My = concern with=20 the tangential muffler is something called =91swirl flow choking=92 = =96 discovered=20 in connection with a similar attempt with gas turbine exhaust. =  High=20 circumferential velocity tends to keep the flow from moving out the = end, and=20 consequent pressure buildup.  I don=92t know whether it applies = to the=20 pulsed flow, but it might, and your conical restriction toward the = outlet=20 could make it worse.

 

To = avoid that=20 possibility in my tangential muffler I added internal vanes at a 45 = degree=20 angle opposite the ports, and extended the header pipes into muffler = to a=20 squared end. Disrupts the circumferential flow and helps direct the = exhaust=20 toward the exit.

 

Your = depiction of=20 the idealized sounds waves going axially; ah-h, well; maybe/maybe=20 notJ.

 

Al=20 G

 

-----Original=20 Message-----
From: Rotary=20 motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of George = Lendich
Sent: Thursday, October 08, = 2009 1:14=20 PM
To: Rotary = motors in=20 aircraft
Subject: = [FlyRotary] Re: Your muffler

 

Kelly

There you go matey. = All off the=20 shelf SS cones and tube.

George ( down=20 under)

----- = Original=20 Message -----

From: Kelly = Troyer=20

To: Rotary motors in = aircraft=20

Sent:=20 Thursday, October 08, 2009 9:32 PM

Subject:=20 [FlyRotary] Your muffler

 

 =20 George,

   Do you have = a photo or=20 drawing available of your muffler design..........I seem=20 to

remember seeing some = design info in=20 the past but do not know where to find = it......

 

 

Thanks,

--
Kelly=20 Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2=20
"Mistral"_Backplate/Oil Manifold =


 

-------------- Original message from = "George=20 Lendich" <lendich@aanet.com.au>: -------------- =


>=20 Ed,
> Cones are the GO.
>
> Any bare edge = will take=20 a battering from the heat and shock waves. Cones
> formed = back to=20 back eliminate any edges.
>
> There must be = supporting=20 structure for the cones, I've used 1/4" solid
> round bar = welded=20 into the exhaust skin.
> George (down under)=20 =

--
Homepage:  http://www.flyrotary.com/
Archive and=20 UnSub:  =20 = http://mail.lancaironline.net:81/lists/flyrotary/List.html
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