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 4599232 for flyrotary@lancaironline.net; Wed, 01 Dec 2010 21:19:06 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.215.52; envelope-from=msteitle@gmail.com Received: by ewy23 with SMTP id 23so4900337ewy.25 for ; Wed, 01 Dec 2010 18:18:30 -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=wn03Oipkz5r3q/HvYIMmq9V9S5Kz0HYBRrJMgRQAgyE=; b=hW/o0Pzal/by8igEL7sAcke2zvY2F0syEzqLGLglxPpVY5fHaCVEyuxr2PiRfDZHbe bI6lFBufjIFNuh92/Cd9U1pXH+12ZpuNnqSJfmBuTB8MmFLFjB8MKZ6MTAwRmS7fZChu ONHSizi+bH2V/InKJeMMHr25glDiclz3aqUhA= 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=xtmGO7RdFavk+M4GxyHtmaXLpQm8by+Mm9iGHvoKACB/vZlzJl3TQfMtvYIEh0/1z/ 84reIR/PyU0jSaE0OHs69QRoWJ40FRTuhC/VPG6sH6kn7Np8H84BEZdGelwUrNtbsTbx f75/gBfUZTE9tIWAzeY7mg7YnuDUANyGLEXWw= MIME-Version: 1.0 Received: by 10.213.114.5 with SMTP id c5mr209060ebq.39.1291256309082; Wed, 01 Dec 2010 18:18:29 -0800 (PST) Received: by 10.213.34.212 with HTTP; Wed, 1 Dec 2010 18:18:29 -0800 (PST) In-Reply-To: References: Date: Wed, 1 Dec 2010 20:18:29 -0600 Message-ID: Subject: Re: [FlyRotary] Re: Modified header Calculations From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0015174c38949de92804966409ea --0015174c38949de92804966409ea Content-Type: text/plain; charset=ISO-8859-1 Joe, Sorry, while the author goes into great detail about the other intake designs, it barely touches on the p-port intake. There is a chart that shows the length of the 787B LeMans engine. As you may know, Mazda used a variable length intake. There's a graph that shows that runner length was +175mm at 6000 rpm, and +125mm at 7000 rpm. However, it doesn't state the overall length, or the length of the fixed intake tube. (Maybe someone knows that number) So, if you know the fixed length, you can add either 175mm for optimization at 6k rpm, 150mm for 6500 rpm, or 125mm for 7k rpm. Using calipers, I measured the width of the rotor housing in the drawing and extrapolated to get the length of the fixed intake tube on the 787B motor. My measurement gives approx. 16" (rotor housing to end of bellmouth at its shortest setting). Adding 150mm (5.9") to that (tuning for 6500 rpm), and 1.5" (rotor face to outside rotor housing), I came up with a total intake runner length of 22.4" (bellmouth to rotor face). Or, subtract 1" for a max torque at 7000 rpm. While just a SWAG, this is close to what I've read previously. Mark On Wed, Dec 1, 2010 at 4:10 PM, josrph berki wrote: > What does it say about intake runner lenght for a P Port? What happens > if the exhaust header length is longer? Can it be tuned. 10 to 11 inches > is pretty short although a collector could make the transition and get the > hot stuff out of the cowl. > > Joe Berki > Limo EZ > > ----- Original Message ----- > *From:* Mark Steitle > *To:* Rotary motors in aircraft > *Sent:* Wednesday, December 01, 2010 11:36 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 >> >> > --0015174c38949de92804966409ea Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Joe,=A0

Sorry, while the author goes into great detail a= bout the other intake designs, it barely touches on the p-port intake. =A0T= here is a chart that shows the length of the 787B LeMans engine. =A0As you = may know, Mazda used a variable length intake. =A0There's a graph that = shows that runner length was +175mm at 6000 rpm, and +125mm at 7000 rpm. = =A0However, it doesn't state the overall length, or the length of the f= ixed intake tube. =A0(Maybe someone knows that number) =A0So, if you know t= he fixed length, you can add either 175mm for optimization at 6k rpm, 150mm= for 6500 rpm, or 125mm for 7k rpm. =A0

Using calipers, I measured the width of the rotor housi= ng in the drawing and extrapolated to get the length of the fixed intake tu= be on the 787B motor. My measurement gives approx. 16" (rotor housing = to end of bellmouth at its shortest setting). Adding 150mm (5.9") to t= hat (tuning for 6500 rpm), and 1.5" (rotor face to outside rotor housi= ng), I came up with a total intake runner length of 22.4" (bellmouth t= o rotor face). =A0Or, subtract 1" for a max torque at 7000 rpm. =A0Whi= le just a SWAG, this is close to what I've read previously. =A0=A0=A0

Mark


On We= d, Dec 1, 2010 at 4:10 PM, josrph berki <jskmberki@windstream.net> wrot= e:
What does it say about intake runner l= enght for a P=20 Port?=A0 What happens if the exhaust header length is longer?=A0 Can it be= =20 tuned.=A0 10 to 11 inches is pretty short although a collector could make t= he=20 transition and get the hot stuff out of the cowl.
=A0
Joe Berki
Limo EZ
----- Original Message -----
From:=20 Mark Steitle=20
Sent: Wednesday, December 01, 2010 = 11:36=20 AM
Subject: [FlyRotary] Re: Modified h= eader=20 Calculations

Ed,
=A0
It took a while, but my copy of=A0Street Rotary - How to=A0Build= =20 Maximum Horsepower & Reliability into Mazda's 12A, 13B & Rene= sis=20 Engines=A0finally arrived yesterday.=A0 Thanks for the=20 recommendation.=A0 Lots of good info, everyone on the list ought to order= a=20 copy and read it from cover to cover, except for Lynn H. - he ought to=20 write=A0his own=A0book on rotary engines.=A0 (I'd buy the first=20 copy.)=A0
=A0
As you suggested, I've been reading the chapter on exhaust syste= ms.=A0=20 I found a paragraph that is right on target relating to what we've be= en=20 discussing (exhaust system restriction).=A0 They compare a 2-rotor wankel= =20 to a 2 cylinder 4-stroke=A0where both cylinders share the same=20 exhaust port.=A0
=A0
Quote, "...the exhaust system on a 12A or 13B rotary engine is = roughly=20 analogous to a two-cylinder piston engine in which both cylinders are ser= ved=20 by a single exhaust port.=A0 If cylinder #1 was in overlap period, and th= e=20 exhaust valve of the #2 cylinder then opened, high pressure gas would flo= w=20 from the #2 to #1 cylinders.=A0 A highly restrictive exhaust system would= =20 aggravate the situation.=A0 This, the authors point out, is the major=20 reason why a free-flowing exhaust system is so important in a rotary=20 engine."=A0 This explains why I saw such an improvement when switchi= ng=20 exhaust systems.=A0
=A0
There is also much discussion on primary header length.=A0=20 Disregarding the "long" header system as we don't have the = room, the "short"=20 header length shown for a p-port engine is between 10 and 18 inches.=A0 S= o,=20 your calculations for header length seem to be right in the ballpark.=A0= =20 Now I have to figure how to get the three very short primary tubes of 11 = 3/4"=20 to meet=A0on the same tangent at the collector.=A0
=A0
Finally, I liked their comment=A0regarding the peripheral ported=20 engines.=A0 It reads,=A0"Traditionally relegated to speciali= ty=20 race cars, occasionally a peripherally ported engine finds its way onto t= he=20 street in some high-performance vehicle. These engines are not, however, = for=20 the faint of heart."=A0 LOL=A0 Not to worry, my heart is=20 strong!=A0
=A0=A0
Mark

On Sun, Nov 21, 2010 at 7:53 AM, Ed Anderson <= span dir=3D"ltr"><eanderson@carolina.rr.com>=20 wrote:
Mark,
=A0
I did some additional reading in the rotary b= ook I=20 recommended to you and a bit more head scratching on exhaust=20 systems.
=A0
I modified the tube length=A0formula I=A0used= =20 earlier to compensate for the fact the rotary puts out two exhaust puls= es=20 per port per 720 deg cycle compared to 1 for the piston engine.=A0 This= =20 in effect halved the length of tube needed to get the same scavenging= =20 effect.
=A0
Also using the recommended rotary =A0book val= ues=20 for area of a rotary exhaust tube=A0, I calculated the tube diameter=20 which came out to 1.8".=A0
=A0
In any case, I have attached the spreadsheet = with=20 those modifications
=A0
Ed
=A0
=A0
Edward L. Anderson
Anderson Electronic Ent= erprises=20 LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com

--
Hom= epage:=20 =A0http://www.f= lyrotary.com/
Archive and UnSub: =A0 http://mail.lanca= ironline.net:81/lists/flyrotary/List.html



--0015174c38949de92804966409ea--