X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao101.cox.net ([68.230.241.45] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3881261 for flyrotary@lancaironline.net; Fri, 09 Oct 2009 22:27:14 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.45; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao101.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20091010022637.KRSX16492.fed1rmmtao101.cox.net@fed1rmimpo01.cox.net> for ; Fri, 9 Oct 2009 22:26:37 -0400 Received: from wills ([68.105.87.66]) by fed1rmimpo01.cox.net with bizsmtp id qqSb1c00A1RstZw03qSdEo; Fri, 09 Oct 2009 22:26:37 -0400 X-VR-Score: -200.00 X-Authority-Analysis: v=1.0 c=1 a=vnREMb7VAAAA:8 a=Ia-xEzejAAAA:8 a=Hl1Gy0H5AAAA:8 a=7g1VtSJxAAAA:8 a=HbWMDa2i_iW2fOGt3aYA:9 a=1yleTXPjFrt29sDghggA:7 a=-Taw-BgBnBQUuMBY09rYt8rzDywA:4 a=EzXvWhQp4_cA:10 a=_cLQy3aD8e9q4IWv:21 a=_yg93vL5VWes9_Es:21 a=HZJGGiqLAAAA:8 a=Jht0puWbvbovUfWukI8A:9 a=HKbF8R3j2enZn4VkteYA:7 a=wMpr7hiAHkOevFP0c6KmxDlm0NMA:4 a=HeoGohOdMD0A:10 a=-zlxhkmCKQm5fPfq:21 a=3FtAWo1gN4UlDGgG:21 X-CM-Score: 0.00 Message-ID: <5C567633969B476ABEA5ACAAC1CA64D9@wills> From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Your muffler Date: Fri, 9 Oct 2009 19:26:35 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0021_01CA4916.6A28D710" 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_0021_01CA4916.6A28D710 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable George, I agree with you on getting the muffler out of the cowl. But I = know there are those that would like to keep it under cowl, and of = course the canard guys probably dont have a choice. For a canard this = could be a good way to go. There's a youtube video from a guy restoring a YO-3A up in the LA area. = It's pretty dry but a minute in there is a shot of the exhaust system = unfaired. I'd like to know what if anything is in that muffler at the = front. Behind that muffler is what the guy refers to as a "piccolo tube" = which is also enclosed in the fairing. The fairing and the fuselage side = are lined with absorbant material held in place with a metal screen. http://www.youtube.com/watch?v=3DrIhK8PWRMbI Mike Wills RV-4 N144MW ----- Original Message -----=20 From: George Lendich=20 To: Rotary motors in aircraft=20 Sent: Friday, October 09, 2009 2:12 PM Subject: [FlyRotary] Re: Your muffler Thanks Mike, For your kind comments, but I must emphasize that this design is = designed primarily for outside cowl use. I understand that this, to some = people, might give rise to concerns of extra drag - but to my mind = anything to get the heat out of the cowl. For my own design I envisage the muffler sitting within a half = circle recess formed in the cowl, but there no reason that it can't sit = behind the cowl under the fuselage. If your talking about the long under fuselage design which forms = part of the fuselage, I must admit I like that design as well. The = longer the better in my opinion, you could string a number of light = weight mufflers along a line, each feeing into the next with cooling air = mixing in, as well as cooling the OD. That would be super quiet. I = notice the best muffling ( to date) is done with more than one muffler = i.e. a primary and a secondary. I'm not trying to convince anyone this is the best design, merely = putting it up for possible solution to the problem. As you and others = have said, off-the-shelf types aren't lasting anywhere near long enough. = Bill Jepson and I laboured over this design for some time, before we = came to the final design, I have been unable to finish my single so = haven't been able to test it yet - but it sure looks good. George ( down under) 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_0021_01CA4916.6A28D710 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
George, I agree with you on getting the = muffler out=20 of the cowl. But I know there are those that would like to keep it under = cowl,=20 and of course the canard guys probably dont have a choice. For a canard = this=20 could be a good way to go.
 
There's a youtube video from a guy = restoring a=20 YO-3A up in the LA area. It's pretty dry but a minute in there is a shot = of the=20 exhaust system unfaired. I'd like to know what if anything is in that = muffler at=20 the front. Behind that muffler is what the guy refers to as a "piccolo = tube"=20 which is also enclosed in the fairing. The fairing and the fuselage side = are=20 lined with absorbant material held in place with a metal = screen.
 
http://www.youtube.= com/watch?v=3DrIhK8PWRMbI
 
Mike Wills
RV-4 N144MW
----- Original Message -----
From:=20 George=20 Lendich
Sent: Friday, October 09, 2009 = 2:12=20 PM
Subject: [FlyRotary] Re: Your=20 muffler

 
Thanks Mike,
For your kind comments, but I must = emphasize=20 that this design is  designed primarily for outside cowl use. I = understand that this, to some people, might give rise to concerns of = extra=20 drag - but to my mind anything to get the heat out of the = cowl.
 
For my own design I envisage the = muffler=20 sitting within a half circle recess formed in the cowl, but there no = reason=20 that it can't sit behind the cowl under the fuselage.
 
If your talking about the long under = fuselage=20 design which forms part of the fuselage, I must admit I like that = design as=20 well. The longer the better in my opinion, you could string a number = of=20 light weight mufflers along a line, each feeing into the next with = cooling=20 air mixing in,  as well as cooling the OD. That would be super = quiet. I=20 notice the best muffling ( to date) is done with more than one = muffler i.e.=20 a primary and a secondary.
 
I'm not trying to convince anyone = this is the=20 best design, merely putting it up for possible solution to the=20 problem.  As you and others have said, off-the-shelf = types=20 aren't lasting anywhere near long enough. Bill Jepson and I laboured = over=20 this design for some time, before we came to the final design, I = have been=20 unable to finish my single so haven't been able to test it yet - but = it sure=20 looks good.
 
George ( down under)
 
OK George, my memory is now jogged = having seen=20 your drawing. I liked the design when I saw it the first time but = discounted=20 it for my application because I couldnt see a good way to make = any=20 muffler with a tangential entry fit my airframe. This is the same = reason I=20 passed on Al's proven muffler design.
 
I think the use of cooling airflow = introduced=20 into the muffler makes a lot of sense and this is something your = design has=20 in common with the YO-3A muffler I've been talking about. I believe = the=20 YO-3A design would prove superior by virtue of the greatly increased = volume=20 of the muffler and the use of absorptive materials.
 
Of course until someone builds one = and tries it=20 who knows if it will hold up to the abusive exhaust output of a = rotary. But=20 the YO-3A design does have the advantage of being flight proven in a = pretty=20 tough environment - low altitude recon in Vietnam.
 
Your muffler design (or Al's) = is a winner=20 if the goal is to keep the muffler within the confines of the cowl. = My cowl=20 is already too tight without a muffler in it.
 
Mike Wills
RV-4 N144MW 
----- Original Message ----- =
From:=20 George=20 Lendich
To: Rotary motors in = aircraft=20
Sent: Thursday, October 08, = 2009 9:18=20 PM
Subject: [FlyRotary] Re: = Your=20 muffler

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

George;

 

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

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

 

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

 

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

 

Al=20 G

 

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

 

Kelly

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

George ( down=20 under)

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

From:=20 Kelly = Troyer=20

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

Subject:=20 [FlyRotary] Your muffler

 

 =20 George,

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

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

 

 

Thanks,

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


 

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


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