X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with ESMTP id 4598630 for flyrotary@lancaironline.net; Wed, 01 Dec 2010 12:37:29 -0500 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.120; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=pepdxKapwHuwCZNFD5uob2wvham6E+RljB0uXw08FdQ= c=1 sm=0 a=ku24OJKnaaoA:10 a=rPkcCx1H5rrOSfN0dPC7kw==:17 a=ayC55rCoAAAA:8 a=arxwEM4EAAAA:8 a=r1ClD_H3AAAA:8 a=7g1VtSJxAAAA:8 a=Ia-xEzejAAAA:8 a=ZbQg5mX3-jiwI44ni8QA:9 a=DGWLhPKeFzvRVKzS8I8A:7 a=BvEr_mDubndXMw4nNm_VlaWK1egA:4 a=wPNLvfGTeEIA:10 a=Qa1je4BO31QA:10 a=zDRSQxe67vSaBFuh:21 a=n0uwzT8efu1YwSVR:21 a=pGLkceISAAAA:8 a=E93lBu2AAAAA:8 a=TzBhHN-CPuOjMXvRxzQA:9 a=uZH6llz1dp8UkH3uDosA:7 a=WCO4eefEgsmpnvrYrjjOSmH96aMA:4 a=MSl-tDqOz04A:10 a=EzXvWhQp4_cA:10 a=MpuOTR30KwMA:10 a=x6VBWS02HY8A:10 a=d1n8sfsg-lQA:10 a=NWVoK91CQyQA:10 a=rPkcCx1H5rrOSfN0dPC7kw==:117 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.167.5 Received: from [174.110.167.5] ([174.110.167.5:64448] helo=EdPC) by cdptpa-oedge03.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id 5E/F7-19545-7B786FC4; Wed, 01 Dec 2010 17:36:55 +0000 Message-ID: <1E6F8C919A3744F18AF62E2D80F07E23@EdPC> From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Re: Modified header Calculations Date: Wed, 1 Dec 2010 12:36:48 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0025_01CB9154.6C459150" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 This is a multi-part message in MIME format. ------=_NextPart_000_0025_01CB9154.6C459150 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Mark, Yeah, I thought you might find some interesting and potentially useful = data in there. Not many books commonly available on the Rotary engine = even mention PP. This one also has some useful analysis (as you pointed = out) on the PP. I agree, its money well spent if you are going to buy a book on the = rotary. Ed From: Mark Steitle=20 Sent: Wednesday, December 01, 2010 11:36 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: Modified header Calculations Ed,=20 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.) =20 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. =20 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. =20 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.=20 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! =20 =20 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". =20 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 ------=_NextPart_000_0025_01CB9154.6C459150 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Mark,
 
Yeah, I thought you might find some interesting = and=20 potentially useful data in there.  Not many books commonly = available on the=20 Rotary engine even mention PP.  This one also has some useful = analysis (as=20 you pointed out) on the PP.
 
I agree, its money well spent if you are going = to buy a=20 book on the rotary.
 
Ed
 
 

Sent: Wednesday, December 01, 2010 11:36 AM
Subject: [FlyRotary] Re: Modified header=20 Calculations

Ed,
 
It took a while, but my copy of Street Rotary - How = to Build=20 Maximum Horsepower & Reliability into Mazda's 12A, 13B & Renesis = Engines finally arrived yesterday.  Thanks for the=20 recommendation.  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 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=20 found a paragraph that is right on target relating to what we've been = discussing=20 (exhaust system restriction).  They compare a 2-rotor wankel to a 2 = cylinder 4-stroke where both cylinders share the same = exhaust=20 port. 
 
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 = served by=20 a single exhaust port.  If cylinder #1 was in overlap period, and = the=20 exhaust valve of the #2 cylinder then opened, high pressure gas would = flow from=20 the #2 to #1 cylinders.  A highly restrictive exhaust system would=20 aggravate the situation.  This, the authors point out, is the major = reason=20 why a free-flowing exhaust system is so important in a rotary = engine." =20 This explains why I saw such an improvement when switching exhaust=20 systems. 
 
There is also much discussion on primary header length.  = Disregarding=20 the "long" header system as we don't have the room, the "short" header = length=20 shown for a p-port engine is between 10 and 18 inches.  So, your=20 calculations for header length seem to be right in the ballpark.  = Now I=20 have to figure how to get the three very short primary tubes of 11 3/4" = to=20 meet on the same tangent at the collector. 
 
Finally, I liked their comment regarding the peripheral ported = engines.  It reads, "Traditionally relegated to = speciality=20 race cars, occasionally a peripherally ported engine finds its way onto = the=20 street in some high-performance vehicle. These engines are not, however, = for the=20 faint of heart."  LOL  Not to worry, my heart is=20 strong! 
  
Mark

On Sun, Nov 21, 2010 at 7:53 AM, Ed Anderson = <eanderson@carolina.rr.com&g= t;=20 wrote:
Mark,
 
I did some additional reading in the rotary = book I=20 recommended to you and a bit more head scratching on exhaust=20 systems.
 
I modified the tube length formula = I used=20 earlier to compensate for the fact the rotary puts out two exhaust = pulses per=20 port per 720 deg cycle compared to 1 for the piston engine.  This = in=20 effect halved the length of tube needed to get the same scavenging=20 effect.
 
Also using the recommended rotary  book = values for=20 area of a rotary exhaust tube , I calculated the tube diameter = which came=20 out to 1.8". 
 
In any case, I have attached the spreadsheet = with those=20 modifications
 
Ed
 
 
Edward L. Anderson
Anderson Electronic = Enterprises=20 LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com

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


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