X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3884101 for flyrotary@lancaironline.net; Tue, 13 Oct 2009 02:11:18 -0400 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (sv1-1.per.aanet.com.au [203.24.100.68]) by poplet2.per.eftel.com (Postfix) with ESMTP id B4DD81738F8 for ; Tue, 13 Oct 2009 14:10:36 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id ACFCEBEC01F for ; Tue, 13 Oct 2009 14:09:48 +0800 (WST) Message-ID: <774F1C61E43F4DD6B132C5B77B7BB735@ownerf1fc517b8> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Your muffler Date: Tue, 13 Oct 2009 16:09:48 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0007_01CA4C1F.968890F0" 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 X-Antivirus: avast! (VPS 091012-0, 10/12/2009), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_0007_01CA4C1F.968890F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Dean,=20 Did you get the details of the muffler? George ( down under) Mike, etal Mid June, 1968, I was employed by the U S Army Aviation Systems Cmd in = St Louis as a Dept of Army Civilian Aeronautical Engineer and assigned = to the Fixed Wing Project Engineering Office. Shortly thereafter, I was = tasked with evaluating several Engineering Change Proposals on the YO-3A = aircraft. Early flight testing had uncovered some structural weakness = in the new retractable main landing gear installation in the wings that = were now repositioned as low wings, and other areas of the aircraft. = This may be common knowledge to most if not all of you but the eleven = YO-3A production all flew with Continental IO-360 210 hp engines and = never with rotary engines. There was a 12 V- belt reduction driving a 6 = blade fixed pitch wooden propeller, later replaced with 3 blade constant = speed wooden propellers. The earlier quiet development aircraft, the = QT-2, the two QT-2 Prize Crew aircraft that did Operational Evaluation = in Vietnam, and the Lockheed Q Star propeller eval aircraft all had = Continental O-200 100hp engines with reduction drives, high -mounted = behind the cockpit, with a long drive shaft and pylon on the nose = supporting the propeller end. The two QT-2 Prize Crew aircraft had a = seat for the observer behind the pilot. The Q Star had a conventional = main landing gear similar to a Cessna 180 and was the only one to also = test the Curtiss-Wright FC2-60 Wankel rotary engine. The Info came from = Google "YO-3A Aircraft" . The header " Quiet Aircraft Association" was = on the first page of Google. The first page of QAA lists both test = engines for the Q Star and a photo collage of all 4 aircraft is about = mid -article. I gave up searching for any further data on the = Curtiss-Wright installation. Dean Van Winkle Slo Build RV-9A '89 -13B, RD-1B, EC2, EM2, Mistral = Intake ----- Original Message -----=20 From: Mike Wills=20 To: Rotary motors in aircraft=20 Sent: Friday, October 09, 2009 9:26 PM Subject: [FlyRotary] Re: Your muffler 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_0007_01CA4C1F.968890F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
Dean,
Did you get the details of the = muffler?
George ( down under)
 
Mike, etal
 
Mid June, 1968, I was employed by the = U S Army=20 Aviation Systems Cmd in St Louis as a Dept of Army Civilian = Aeronautical=20 Engineer and assigned to the Fixed Wing Project Engineering Office. = Shortly=20 thereafter, I was tasked with evaluating several Engineering Change = Proposals=20 on the YO-3A  aircraft. Early flight testing had uncovered some=20 structural weakness in the new retractable main landing gear = installation=20 in the wings that were now repositioned as low wings, and other areas = of the=20 aircraft. This may be common knowledge to most if not all of you but = the=20 eleven YO-3A production all flew with Continental IO-360 210 hp = engines and=20 never with rotary engines. There was a 12 V- belt reduction driving a = 6 blade=20 fixed pitch wooden propeller, later replaced with 3 blade constant speed wooden propellers. The earlier = quiet=20 development aircraft, the QT-2, the two QT-2 Prize Crew aircraft = that did=20 Operational Evaluation in Vietnam, and the Lockheed Q Star propeller = eval=20 aircraft all had Continental O-200 100hp engines with reduction=20 drives, high -mounted behind the cockpit, with a long drive = shaft =20 and pylon on the nose supporting the propeller end. The two QT-2 Prize = Crew=20 aircraft had a seat for the observer behind the pilot. The Q Star had = a=20 conventional main landing gear similar to a Cessna 180 and was the = only one=20 to also test the Curtiss-Wright FC2-60 Wankel rotary=20 engine. The Info came from Google "YO-3A Aircraft" . The = header "=20 Quiet Aircraft Association" was on the first page of Google. The first = page of=20 QAA lists both test engines for the Q Star and a photo collage of all = 4=20 aircraft is about mid -article. I gave up searching for any further = data on=20 the Curtiss-Wright installation.
 
Dean Van Winkle   Slo Build = RV-9A =20 '89 -13B, RD-1B, EC2, EM2, Mistral Intake
----- Original Message -----
From:=20 Mike = Wills=20
To: Rotary motors in = aircraft=20
Sent: Friday, October 09, = 2009 9:26=20 PM
Subject: [FlyRotary] Re: Your = muffler

George, I agree with you on getting = the muffler=20 out of the cowl. But I know there are those that would like to keep = it under=20 cowl, and of course the canard guys probably dont have a choice. For = a=20 canard this 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=20 the exhaust system unfaired. I'd like to know what if anything is in = that=20 muffler at the front. Behind that muffler is what the guy refers to = as a=20 "piccolo tube" which is also enclosed in the fairing. The fairing = and the=20 fuselage side are lined with absorbant material held in place with a = metal=20 screen.
 
http://www.youtube.= com/watch?v=3DrIhK8PWRMbI
 
Mike Wills
RV-4 N144MW
----- Original Message ----- =
From:=20 George=20 Lendich
To: Rotary motors in = aircraft=20
Sent: Friday, October 09, = 2009 2:12=20 PM
Subject: [FlyRotary] Re: = Your=20 muffler

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

Al,
Not tested yet, but have one = almost=20 complete 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=20 waves will be going all over the place within the exhaust and = I tried=20 to replicate that with the zig zaggy lines.
 
There is no restriction as = the area=20 around 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=20 this will interrupt the swirl motion, I suspect it might. The=20 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=20 concern with the tangential muffler is something called = =91swirl flow=20 choking=92 =96 discovered in connection with a similar = attempt with gas=20 turbine exhaust.  High circumferential velocity tends = to keep=20 the flow from moving out the end, and consequent pressure = buildup.=20  I don=92t know whether it applies to the pulsed flow, = but it=20 might, and your conical restriction toward the outlet could = make it=20 worse.

 

To avoid=20 that possibility in my tangential muffler I added internal = vanes at=20 a 45 degree angle opposite the ports, and extended the = header pipes=20 into muffler to a squared end. Disrupts the circumferential = flow and=20 helps 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 = Message-----
From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net]=20 On Behalf Of = George=20 Lendich
Sent:=20 Thursday, October 08, 2009 1:14 PM
To: Rotary motors in=20 aircraft
Subject:=20 [FlyRotary] Re: Your muffler

 

Kelly

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

George (=20 down under)

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

From: Kelly Troyer=20

To: Rotary motors = in=20 aircraft

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

Subject: [FlyRotary] = Your=20 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 the=20 past but do not know where to find=20 it......

 

 

Thanks,

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


 

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


> Ed,
> Cones are the GO.
> =
> Any bare edge will take a battering from the = heat and=20 shock waves. Cones
> formed back to back = eliminate any=20 edges.
>
> There must be supporting = structure for=20 the cones, I've used 1/4" solid
> round bar = welded into=20 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
------=_NextPart_000_0007_01CA4C1F.968890F0--