Return-Path: Received: from ms-smtp-03.southeast.rr.com ([24.93.67.84] verified) by logan.com (CommuniGate Pro SMTP 4.1.3) with ESMTP id 2579497 for flyrotary@lancaironline.net; Sun, 14 Sep 2003 22:36:14 -0400 Received: from o7y6b5 (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-03.southeast.rr.com (8.12.5/8.12.2) with SMTP id h8F2Y24S004991; Sun, 14 Sep 2003 22:34:02 -0400 (EDT) Message-ID: <006401c37b31$da179b60$1702a8c0@WorkGroup> From: "Ed Anderson" To: "flyrotary" Cc: "Laura Crook" , "Tracy Crook" Subject: Shady Bend Flyin Presentation: Mazda DIE effect and Increased Performance Date: Sun, 14 Sep 2003 22:34:13 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0061_01C37B10.52C2D7E0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 This is a multi-part message in MIME format. ------=_NextPart_000_0061_01C37B10.52C2D7E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Does he really have DIE? - No, its not some new virus or social disease, = it's associated with performance and the rotary engine. In fact a = presentation on DIE will be presented at the Shady Bend Rotary flyin in = October (see outline at end of message) As those of you who may also be on the rotaryengine list know, Paul and = I have gone around a bit about whether or not my 48" (port - port) = intake ever provide the dynamic intake effect (DIE) (self supercharging = of the rotary engine) at a high enough rpm to be of use for aircraft = application. Paul maintains (correctly, I might add) that with 48" intake manifold = (length on the 1988 NA 13B) the Mazda data (rpm/torque/hp curves) = clearly shows that the DIE effect occurs around 3500 rpm for the pre = 1990 NA 13B. That much was clearly evident in the Mazda data. But, I = knew something was causing my engine to go from a static rpm of 5200 = nominal on a 70F + day to 5800 on a cold day. At first I convinced = myself that the lower density altitude due to the cold was causing a = small HP increase enough to put my prop in the "stalled" condition. = But, I finally figured out that was not the case. Paul suggested the = Helmholtz Resonance effect, but after working on that approach for a = while, I decided that did not provide the answer. So I turned back to = the DIE. =20 Paul was kind enough to provide me with some of his SAE Mazda Papers. I = am not certain whether to keep me busy and from pestering him or to = educate me (I chose to think the latter). After we exchanged a few more = e mails, he made it fairly clear, as only Paul can do, that as far as = he was concerned the topic was closed and that I should radically = shorten the planned intake for my 3rd intake (the one with the plastic = plenum). So I knew it was time to drop the debate with Paul. In any case amongst the SAE papers that Paul was a gent to provide, I = finally realized I was looking at the KEY bit of information. In other = words, I found (at long last) the answer after much head scratching, = skull work and spread sheet doodling. =20 The answer is that Paul IS correct IF you have a STOCK NA 13B block - = with the STOCK Intake manifold and operating under stock conditions. = Otherwise, all bets are off where the DIE rpm point may occur at. It turns out, I WAS also correct. I was indeed getting a increase in = power from the DIE in the mid 5000 rpm range with a 48" Length manifold = but did not understand how that was possible at the time. Let me make it clear that when I say a manifold length of 48" that is = the total distance from the intake port of the front rotor through the = intake manifold past the throttle body to the intake port of the rear = rotor. In other words, it includes the 2.5" inches distance into the = block to the port opening as well. So approx 1/2 of that distance = (minus the internal block distance) is my runner length. Anyhow, Once I had completed the analysis a number of things I had = noticed with my engine became clear. My analysis will show how that is = possible - no not possible - ordained (not in the religious sense) that = I would get DIE at a mid 5000 rpm with a 48" length. Paul's advice to = make my intake shorter was incorrect but only because MY engine is NOT = STOCK. And to be fair, neither of use really understood the effect of = the variables involved at that point. So Paul was relying on the Mazda = data he had which ,of course, is for a stock engine. The 3rd manifold ended up too short as I completed it before I = completed my analysis, darn!. However, its short length was not a = result of following Paul's advice. I ran into a physical configuration = constraint with the size of the new plastic plenum that forced me to = make the manifold length around 42". And no, no DIE effect in my = operating rpm range - it turns out the DIE for this manifold is above my = normal RPM operating range for MY ENGINE. It took me over a month of sitting down and working out the real = details (never before revealed {:>)) of the variables involved and the = relationships among them (in other words equations that could be used). RPM and Manifold Length are only two of the variables that I have = identified that have a significant effect at what RPM the DIE effect = occurs. actually there are over twice as many. If any of these = variables are not operating as designed for on a STOCK NA 13B with the = stock intake manifold, then the DIE will not occur at the Mazda designed = RPM point - BUT it can still occur, the question is at what new point. I have a presentation that I am whittling down from its current 60 = VuGraphs (arrggg!) to be presented at the Shady Bend Flyin in late = October. I will not reveal the findings before then, but if your are = interested the outline of the briefing is: Dynamic Intake Effect - The Concept (This is just a few introductory = Vugraphs to reacquaint or introduce the newcomer to the dynamic intake = effect concept that Mazda used) Dynamic Intake Effect - The Analysis and Synthesis (This is guts of the = presentation taking you through the analysis, the identification of the = variables, and their influence on the DIE and showing the relationships = of these variables (no math higher than simple algebra) with a number of = charts and graphs showing this stuff - currently 31 vgs) Dynamic Intake Effect - The Comparison with Ground Truth (The dicey part = {:>) - where I show how well the numbers that my equations come up with = stack up against what hard facts we know about the effect - from Mazda = itself. I create some parametric curves based on the equations derived = that correlate manifold length with RPM for the DIE effect holding the = other terms constant, its really pretty straight forward once you see it = (says I) - currently 29 vgs) I think you will find it interesting (if I don't put you to sleep). Hope to see you there. Check Tracy and Laura's website for details of = the flyin. Please let Laura know if you plan on coming. Best Regards Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com ------=_NextPart_000_0061_01C37B10.52C2D7E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Does he really have DIE? - No, its not = some new=20 virus or social disease, it's associated with performance and the rotary = engine.=20 In fact a presentation on DIE will be presented at the Shady Bend Rotary = flyin=20 in October (see outline at end of message)
 
As those of you who may also be on the = rotaryengine=20 list know, Paul and I have gone around a bit about whether or not my 48" = (port -=20 port) intake ever provide the dynamic intake effect (DIE) (self = supercharging of=20 the rotary engine) at a high enough rpm to be of use for = aircraft=20 application.
 
Paul maintains (correctly, I might add) = that with=20 48" intake manifold (length on the 1988 NA 13B)  the Mazda = data=20 (rpm/torque/hp curves) clearly shows that the DIE effect occurs around = 3500 rpm=20 for the pre 1990 NA 13B.  That much was clearly evident in the = Mazda=20 data.  But, I knew something was causing my engine to go from a = static rpm=20 of 5200 nominal on a 70F + day to 5800 on a cold day.  At first I = convinced=20 myself that the lower density altitude due to the cold was causing a = small HP=20 increase enough to put my prop in the "stalled" condition.  But, I = finally=20 figured out that was not the case.  Paul suggested the Helmholtz = Resonance=20 effect, but after working on that approach for a while, I decided that = did not=20 provide the answer.  So I turned back to the DIE.  =
 
Paul was kind enough to provide me with = some of his=20 SAE Mazda Papers.  I am not certain whether to keep me busy and = from=20 pestering him or to educate me (I chose to think the latter). After = we=20 exchanged a few more e mails,  he made it fairly clear, = as=20 only Paul can do, that as far as he was concerned the topic was = closed and=20 that I should radically shorten the planned intake for my 3rd = intake (the=20 one with the plastic plenum).  So I knew it=20 was time to drop the debate with Paul.
 
 In any case amongst the SAE = papers that=20 Paul was a gent to provide,  I finally realized I was looking = at the=20 KEY bit of information.  In other words,  I found (at long = last) the=20 answer after much head scratching, skull work and spread sheet=20 doodling. 
 
The answer is = that Paul IS=20 correct IF you have a STOCK NA 13B block - with the STOCK Intake manifold and operating under = stock=20 conditions. Otherwise, all bets are off where the DIE rpm point = may occur=20 at.
 
It turns out, =  I WAS=20 also correct.  I was indeed getting a increase in power from = the DIE=20 in the mid 5000 rpm range with a 48" Length = manifold but did not understand how that was possible at the=20 time.
 
Let me make it clear that when I say a = manifold=20 length of 48" that is the total distance from the intake port of the = front rotor=20 through the intake manifold past the throttle body to the intake port of = the=20 rear rotor.  In other words, it includes the 2.5" inches distance = into the=20 block to the port opening as well.  So approx 1/2 of that distance = (minus=20 the internal block distance) is my runner length.
 
Anyhow, Once I had completed the = analysis a number=20 of things I had noticed with my engine became clear.  My analysis = will show=20 how that is possible - no not possible - ordained (not in the religious = sense)=20 that I would get DIE at a mid 5000 rpm with a 48" length.   = Paul's=20 advice to make my intake shorter was = incorrect=20 but only because MY engine  is NOT=20 STOCK. And to be fair, neither of use really understood the = effect=20 of the variables involved at that point.  So Paul was relying on = the Mazda=20 data he had which ,of course, is for a stock engine.
 
The 3rd manifold  ended up too = short as I=20 completed it  before I completed my analysis, darn!.  However, = its=20 short length was not a result of following Paul's advice.  =  I ran=20 into a physical configuration constraint with the size of the = new plastic=20 plenum that forced me to make the manifold length around = 42". =20 And no, no DIE effect in my operating rpm range - it turns out the DIE = for this=20 manifold is above my normal RPM = operating range=20 for MY ENGINE.
 
It  took me over a month of = sitting down=20 and working out the real details (never before revealed {:>)) of the=20 variables involved and the relationships among them (in other words = equations=20 that could be used).
 
RPM and Manifold = Length are=20 only two of the variables that I have identified  that = have a=20 significant effect at what RPM the DIE effect occurs. actually there are = over=20 twice as many.  If any of these variables are not operating as = designed for=20 on a STOCK NA 13B with the stock intake manifold, then the DIE will not = occur at=20 the Mazda designed RPM point - BUT it can still occur, the question = is at=20 what new point.
 
I have a presentation that I am = whittling down from=20 its current 60 VuGraphs (arrggg!) to be presented at the Shady Bend = Flyin in=20 late October.  I will not reveal the findings before then, but if = your are=20 interested the outline of the briefing is:
 
Dynamic = Intake Effect -=20 The Concept (This is just a few introductory Vugraphs to = reacquaint or introduce the newcomer to the dynamic intake effect = concept that=20 Mazda used)
 
Dynamic = Intake Effect -=20 The Analysis and Synthesis (This is guts of the = presentation=20 taking you through the analysis, the identification of the variables, = and their=20 influence on the DIE and showing the relationships of these variables = (no math=20 higher than simple algebra) with a number of charts and graphs showing = this=20 stuff - currently 31 vgs)
 
Dynamic = Intake Effect -=20 The Comparison with Ground Truth (The dicey part {:>) = - where=20 I show how well the numbers that my equations come up with stack up = against what=20 hard facts we know about the effect - from Mazda itself.  I create = some=20 parametric curves based on the equations derived that = correlate manifold=20 length with RPM for the DIE effect holding the other terms = constant, its=20 really pretty straight forward once you see it (says I) - currently = 29=20 vgs)
 
I think you will find it interesting = (if I don't=20 put you to sleep).
 
Hope to see you there. Check Tracy and = Laura's=20 website for details of the flyin. Please let Laura know if you plan on=20 coming.
 
Best Regards
 
 
Ed Anderson
RV-6A N494BW Rotary=20 Powered
Matthews, NC
eanderson@carolina.rr.com
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