X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-ew0-f52.google.com ([209.85.215.52] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with ESMTP id 4599205 for flyrotary@lancaironline.net; Wed, 01 Dec 2010 20:38:35 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.215.52; envelope-from=msteitle@gmail.com Received: by ewy23 with SMTP id 23so4882658ewy.25 for ; Wed, 01 Dec 2010 17:37:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=JRk3ZnalrZVbp6N9KI7UQ/BxBfewSxJuf8ENYkZ1hUE=; b=es+uPmODyOyQg0LPrTNXebM66gAnlOrPLTLoMvno8kAoCIHgVjSlWiAXohW/mGDUP1 vJdkOZtBSmYq1SJQpvWyQPt+Vrt5Cr+n1a/z6d3HtEx8JeLkTOWDNcZYBbr/R2nUaUnH VDhehkP7hRoAQIs+6/+/iDKtkNSCQYvEt6R6U= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=tGvGyG9KsquZxxjHc61e6E6PquEhNel3yiz0sqpOSMcLsCwMa4vUH5O22NVkFMd9Qw VGu3Crkj1ArtYJKJNkS6DAs9Z815oegzQEl03x6wFTdcSaFRNYKhNsCJaa5Czef35NBY HP+XCwVS+Xjw+COgMLkDQuydZdRiZIxT/TqI0= MIME-Version: 1.0 Received: by 10.213.114.5 with SMTP id c5mr183185ebq.39.1291253878531; Wed, 01 Dec 2010 17:37:58 -0800 (PST) Received: by 10.213.34.212 with HTTP; Wed, 1 Dec 2010 17:37:58 -0800 (PST) In-Reply-To: References: Date: Wed, 1 Dec 2010 19:37:58 -0600 Message-ID: Subject: Re: [FlyRotary] Re: Modified header Calculations From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0015174c3894bea65404966378bd --0015174c3894bea65404966378bd Content-Type: text/plain; charset=ISO-8859-1 Bill, The DNA muffler that I'm currently running seems to do a so-so job of scrubbing off the worst of the exhaust noise, but it would be nice if it was as quiet as the tangential muffler without the loss of power. And therein lies the dilemma. Mark On Wed, Dec 1, 2010 at 7:14 PM, wrote: > Mark, > More of a comment than a question. The exhaust system on P-port rotarys is > simple, as little obstruction as possible. I crewed for a RX-2 racing sedan > that had the Mazda factory racing exhaust. That system was a truly expanding > system from the exhaust port to the exit. The header length was 18" then it > went into a 2 into 1 collector and gently tapered to a 4" diameter megaphone > exiting under the passenger side door. It was the pre-muffler era, but that > car probably started the requirements for mufflers. I have been around AA/FD > dragsters that were quieter! For best performance the least back pressure > you can have while being quiet enough will be the way to go. > Bill > > > > -----Original Message----- > From: Mark Steitle > To: Rotary motors in aircraft > Sent: Wed, Dec 1, 2010 9:52 am > Subject: [FlyRotary] Re: Modified header Calculations > > > Bill, > > Not sure what you're asking. My p-port will idle down to below 1000 rpm, > although not as smoothly as my side port 20B did, or like my LS1 Chevy V-8. > This thread was addressing WOT issues caused by an overly restrictive > exhaust system. Changing to my previous "tangential" exhaust made a HUGH > improvement in WOT power (exactly as the chart that Ed posted earlier > showed). I am now in the process of building an equal-length header/exhaust > to maximize power at around 6500 rpm. The runners on my current exhasut are > not all the same length and are made from 2.0 DIA .140" 304SS. The > new exhasut will be made of 625 inconel. > > I hope to get it right this time. > > Mark > > > On Wed, Dec 1, 2010 at 11:23 AM, wrote: > > Mark, and group, > If p-ports are so difficult why was the first car with a rotary equiped > with them? P ports can be fairly tame if you put the throttle plate, > (butterfly or slide), close to the port, or in the port. The original > powersport guys put together an in-port butterfly that idled very well. In > fact Steve Beckham told me that when using their pendrolous damper they > could idle their p-port engine at 1000 RPM! Their p-ports were 1-5/8 > diameter. > Bill Jepson > > > > Finally, I liked their comment regarding the peripheral ported engines. It > reads, "Traditionally relegated to speciality race cars, occasionally a > peripherally ported engine finds its way onto the street in some > high-performance vehicle. These engines are not, however, for the faint of > heart." LOL Not to worry, my heart is strong! > > Mark > > > > > > > > -----Original Message----- > From: Mark Steitle > To: Rotary motors in aircraft > Sent: Wed, Dec 1, 2010 8:37 am > Subject: [FlyRotary] Re: Modified header Calculations > > > Ed, > > It took a while, but my copy of Street Rotary - How to Build Maximum > Horsepower & Reliability into Mazda's 12A, 13B & Renesis Engines finally > arrived yesterday. Thanks for the recommendation. Lots of good info, > everyone on the list ought to order a copy and read it from cover to cover, > except for Lynn H. - he ought to write his own book on rotary engines. (I'd > buy the first copy.) > > As you suggested, I've been reading the chapter on exhaust systems. I > found a paragraph that is right on target relating to what we've been > discussing (exhaust system restriction). They compare a 2-rotor wankel to a > 2 cylinder 4-stroke where both cylinders share the same exhaust port. > > Quote, "...the exhaust system on a 12A or 13B rotary engine is roughly > analogous to a two-cylinder piston engine in which both cylinders are served > by a single exhaust port. If cylinder #1 was in overlap period, and the > exhaust valve of the #2 cylinder then opened, high pressure gas would flow > from the #2 to #1 cylinders. A highly restrictive exhaust system would > aggravate the situation. This, the authors point out, is the major reason > why a free-flowing exhaust system is so important in a rotary engine." This > explains why I saw such an improvement when switching exhaust systems. > > There is also much discussion on primary header length. Disregarding the > "long" header system as we don't have the room, the "short" header length > shown for a p-port engine is between 10 and 18 inches. So, your > calculations for header length seem to be right in the ballpark. Now I have > to figure how to get the three very short primary tubes of 11 3/4" to > meet on the same tangent at the collector. > > Finally, I liked their comment regarding the peripheral ported engines. It > reads, "Traditionally relegated to speciality race cars, occasionally a > peripherally ported engine finds its way onto the street in some > high-performance vehicle. These engines are not, however, for the faint of > heart." LOL Not to worry, my heart is strong! > > Mark > > > On Sun, Nov 21, 2010 at 7:53 AM, Ed Anderson > wrote: > > > Mark, > > I did some additional reading in the rotary book I recommended to you and a > bit more head scratching on exhaust systems. > > I modified the tube length formula I used earlier to compensate for the > fact the rotary puts out two exhaust pulses per port per 720 deg cycle > compared to 1 for the piston engine. This in effect halved the length of > tube needed to get the same scavenging effect. > > Also using the recommended rotary book values for area of a rotary exhaust > tube , I calculated the tube diameter which came out to 1.8". > > In any case, I have attached the spreadsheet with those modifications > > Ed > > > Edward L. Anderson > Anderson Electronic Enterprises LLC > 305 Reefton Road > Weddington, NC 28104 > http://www.andersonee.com > http://www.eicommander.com > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > > > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > > > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > --0015174c3894bea65404966378bd Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Bill,=A0

The DNA muffler that I'm currently running = seems to do a so-so job of scrubbing off the worst of the exhaust noise, bu= t it would be nice if it was as quiet as the tangential muffler without the= loss of power. =A0And therein lies the dilemma.=A0

Mark

On Wed, Dec 1, 2= 010 at 7:14 PM, <wr= jjrs@aol.com> wrote:
Mark,
More of a comment than a question. The exhaust system on P-port rotarys is = simple, as little obstruction as possible. I crewed for a RX-2 racing sedan= that had the Mazda factory racing exhaust. That system was a truly expandi= ng system from the exhaust port to the exit. The header length was 18"= then it went into a 2 into 1 collector and gently tapered to a 4" dia= meter megaphone exiting under the passenger side door. It was the pre-muffl= er era, but that car probably started the requirements for mufflers. I have= been around AA/FD dragsters that were quieter! For best performance the le= ast back pressure you can have while being quiet enough will be the way to = go.
Bill



-----Original Message-----
From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Wed, Dec 1, 2010 9:52 am
Subject: [FlyRotary] Re: Modified header Calculations


Bill,
=A0
Not sure what you're asking.=A0 My p-port will idle down to below 1000 = rpm, although not as smoothly as my side port 20B did, or like my LS1 Chevy= V-8.=A0 This thread was=A0addressing WOT issues caused by an overly=A0rest= rictive exhaust system.=A0 Changing to my previous "tangential"= =A0exhaust made a HUGH improvement in WOT power (exactly as=A0the chart tha= t Ed posted earlier showed).=A0 I am now in the process of building an equa= l-length=A0header/exhaust to maximize power at around 6500 rpm.=A0 The runn= ers on my current=A0exhasut are not all=A0the same=A0length and are=A0made = from 2.0 DIA .140" 304SS.=A0 The new=A0exhasut will be made of 625 inc= onel.
=A0
I hope to get it right this time.=A0=A0
=A0
Mark=A0=A0


On Wed, Dec 1, 2010 at 11:23 AM, <wrjjrs@aol.com> wrote:

Mark, and group,
If p-ports are so difficult why was the first car with a rotary equiped wit= h them? P ports can be fairly tame if you put the throttle plate, (butterfl= y or slide), close to the port, or in the port. The original powersport guy= s put together an in-port butterfly that idled very well. In fact Steve Bec= kham told me that when using their pendrolous damper they could idle their = p-port engine at 1000 RPM! Their p-ports were 1-5/8 diameter.
Bill Jepson



Finally, I liked their comment=A0regarding the peripheral ported engines.= =A0 It reads,=A0"Traditionally relegated to speciality race cars, occa= sionally a peripherally ported engine finds its way onto the street in some= high-performance vehicle. These engines are not, however, for the faint of= heart."=A0 LOL=A0 Not to worry, my heart is strong!=A0
=A0=A0
Mark







-----Original Message-----
From: Mark Steitle <msteitle@gmail.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Wed, Dec 1, 2010 8:37 am
Subject: [FlyRotary] Re: Modified header Calculations


Ed,
=A0
It took a while, but my copy of=A0Street Rotary - How to=A0Build Maximum Ho= rsepower & Reliability into Mazda's 12A, 13B & Renesis Engines= =A0finally arrived yesterday.=A0 Thanks for the recommendation.=A0 Lots of = good info, everyone on the list ought to order a copy and read it from cove= r to cover, except for Lynn H. - he ought to write=A0his own=A0book on rota= ry engines.=A0 (I'd buy the first copy.)=A0
=A0
As you suggested, I've been reading the chapter on exhaust systems.=A0 = I found a paragraph that is right on target relating to what we've been= discussing (exhaust system restriction).=A0 They compare a 2-rotor wankel = to a 2 cylinder 4-stroke=A0where both cylinders share the same exhaust port= .=A0
=A0
Quote, "...the exhaust system on a 12A or 13B rotary engine is roughly= analogous to a two-cylinder piston engine in which both cylinders are serv= ed by a single exhaust port.=A0 If cylinder #1 was in overlap period, and t= he exhaust valve of the #2 cylinder then opened, high pressure gas would fl= ow from the #2 to #1 cylinders.=A0 A highly restrictive exhaust system woul= d aggravate the situation.=A0 This, the authors point out, is the major rea= son why a free-flowing exhaust system is so important in a rotary engine.&q= uot;=A0 This explains why I saw such an improvement when switching exhaust = systems.=A0
=A0
There is also much discussion on primary header length.=A0 Disregarding the= "long" header system as we don't have the room, the "sh= ort" header length shown for a p-port engine is between 10 and 18 inch= es.=A0 So, your calculations for header length seem to be right in the ball= park.=A0 Now I have to figure how to get the three very short primary tubes= of 11 3/4" to meet=A0on the same tangent at the collector.=A0
=A0
Finally, I liked their comment=A0regarding the peripheral ported engines.= =A0 It reads,=A0"Traditionally relegated to speciality race cars, occa= sionally a peripherally ported engine finds its way onto the street in some= high-performance vehicle. These engines are not, however, for the faint of= heart."=A0 LOL=A0 Not to worry, my heart is strong!=A0
=A0=A0
Mark


On Sun, Nov 21, 2010 at 7:53 AM, Ed Anderson <eanderson@carolina.rr.com> wrot= e:


Mark,
=A0
I did some additional reading in the rotary book I recommended to you and a= bit more head scratching on exhaust systems.
=A0
I modified the tube length=A0formula I=A0used earlier to compensate for the= fact the rotary puts out two exhaust pulses per port per 720 deg cycle com= pared to 1 for the piston engine.=A0 This in effect halved the length of tu= be needed to get the same scavenging effect.
=A0
Also using the recommended rotary =A0book values for area of a rotary exhau= st tube=A0, I calculated the tube diameter which came out to 1.8".=A0<= br> =A0
In any case, I have attached the spreadsheet with those modifications
=A0
Ed
=A0
=A0
Edward L. Anderson
Anderson Electronic Enterprises LLC
305 Reefton Road
Weddington, NC 28104
http://www.anderson= ee.com
http://www.eicomma= nder.com


--
Homepage: =A0http:/= /www.flyrotary.com/
Archive and UnSub: =A0 http://mail.lancaironline.net:81/lists= /flyrotary/List.html






--
Homepage: =A0http:/= /www.flyrotary.com/
Archive and UnSub: =A0 http://mail.lancaironline.net:81/lists= /flyrotary/List.html






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Homepage: =A0http:/= /www.flyrotary.com/
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