Return-Path: Sender: (Marvin Kaye) To: flyrotary Date: Thu, 22 May 2003 09:51:55 -0400 Message-ID: X-Original-Return-Path: Received: from ms-smtp-02.southeast.rr.com ([24.93.67.83] verified) by logan.com (CommuniGate Pro SMTP 4.1b6) with ESMTP id 2358343 for flyrotary@lancaironline.net; Wed, 21 May 2003 20:39:47 -0400 Received: from o7y6b5 (clt25-90-099.carolina.rr.com [24.25.90.99]) by ms-smtp-02.southeast.rr.com (8.12.5/8.12.2) with SMTP id h4M0bHNL022551 for ; Wed, 21 May 2003 20:37:19 -0400 (EDT) X-Original-Message-ID: <002f01c31ff9$e29773c0$1702a8c0@WorkGroup> From: "Ed Anderson" X-Original-To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Tuned induction X-Original-Date: Wed, 21 May 2003 20:34:19 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002A_01C31FD8.5AC59100" 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_002A_01C31FD8.5AC59100 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Wednesday, May 21, 2003 7:13 PM Subject: [FlyRotary] Tuned induction Further to my recent response to Tracy's posting, I wanted to clarify = that I was not disagreeing that there benefits to be gained from tuned = induction. Clearly there are. SNIP So, I don't know. We need some data. Tracy is guessing that his = engine puts out 180hp. Could be; but I'm guessing we don't know what it = is, and it could just as likely be 165. Al Al, I don't know much about induction systems and they appear to be as = much "Magic" as science. However, there is little question that Tracy's = engine puts out closer to 180 HP than 165. While its not been on a = dyno, he has flow with 180HP O360 RVs and bested them. In fact, during = the Sun & Fun 100 airrace, he not only beat all 0320 (supposedly 165HP) = entries in his class but also half of the entries in the 180HP class. = Also, fuel flow is a fair indicator of HP being produce and he and I = have both seen 19-20 gph fuel flow (on cold dense air mornings). But = utimately, I think its the performance of his RV-4 which is not a = particularly aerodynamically clean airframe (compared to some), with a = top speed of over 214 MPH and his average of 209 MPH over the Sun & Fun = race 100 mile course from a standing start with a fixed pitch prop (and = a draggy muffler hanging in the slip stream) that clearly gives you a = strong indication that he is producing at least 180 HP.=20 Not Proof?, nope, don't claim it is, but the preponderance of data = strongly indicates Tracy's engine is producing at least 180HP. My own = personal story is that when I had a Weber throttle body with two 2" dia = throats with a relative short length induction (about 1/2 my current = length), my static rpm was 5000 rpm, my top speed was 182 MPH TAS and = rate of climb was around 900 fpm. When I created an intake using = smaller (1 5/8 and 1 3/8" dia tubes) of the length that theoretically = are tuned to provide the "dynamic charging effect" at 5900 rpm, my = static went up to 5300 rpm, my ROC went up to 1200 fpm and my top speed = to 196 MPH TAS. So while I can't prove that my current induction = system is better "tuned" to my operating regime and rpm - I sure like = the improved results much better.=20 Too bad we don't have a wealthy member of the list who would fund a = little R&D with dyno time and different induction system approaches on = the rotary engines. But, as you know that takes time and money and both = are limited for most - if not all of us. Ed Anderson ------=_NextPart_000_002A_01C31FD8.5AC59100 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
----- Original Message -----
From:=20 Al=20 Gietzen
Sent: Wednesday, May 21, 2003 = 7:13=20 PM
Subject: [FlyRotary] Tuned=20 induction

Further to my recent = response to=20 Tracy=92s=20 posting, I wanted to clarify that I was not disagreeing that there = benefits to=20 be gained from tuned induction. Clearly there are.   =20 SNIP

 

So, I = don=92t=20 know.  We need some data.  Tracy is=20 guessing that his engine puts out 180hp. Could be; but I=92m guessing = we don=92t=20 know what it is, and it could just as likely be 165.

 

Al

 

Al, I don't know much = about=20 induction systems and they appear to be as much "Magic" as = science. =20 However, there is little question that Tracy's engine puts out closer = to 180=20 HP than 165.  While its not been on a dyno, he has flow with = 180HP O360=20 RVs and bested them.  In fact, during the Sun & Fun 100 = airrace, he=20 not only beat all 0320 (supposedly 165HP) entries in his = class but=20 also  half of the entries in the 180HP class.  Also, fuel = flow is a=20 fair indicator of HP being produce and he and I have both seen 19-20 = gph fuel=20 flow (on cold dense air mornings).  But utimately, I think its = the=20 performance of his RV-4 which is not a particularly aerodynamically = clean=20 airframe (compared to some), with a top speed of over 214 MPH and his = average=20 of 209 MPH over the Sun & Fun race 100 mile course =  from a=20 standing start with a fixed pitch prop (and a draggy muffler hanging = in the=20 slip stream)  that clearly gives you a strong indication that he = is=20 producing at least 180 HP.

 

Not Proof?, nope, = don't claim it=20 is, but the preponderance of data strongly indicates Tracy's engine is = producing at least 180HP.  My own personal  story is that = when I had=20 a Weber throttle body with two 2" dia throats with a relative short = length=20 induction (about 1/2 my current length), my static rpm was 5000 rpm, = my top=20 speed was 182 MPH TAS and rate of climb was around 900 fpm.  When = I=20 created an intake using smaller (1 5/8 and 1 3/8" dia tubes) of = the=20 length that theoretically are tuned to provide the "dynamic charging = effect"=20 at 5900 rpm, my static went up to 5300 rpm, my ROC went up to 1200 fpm = and my=20 top speed to 196 MPH TAS.   So while I can't prove that my = current=20 induction system is better "tuned" to my operating regime and rpm - I = sure=20 like the improved results much better.

 

 Too bad we don't = have a=20 wealthy member of the list who would fund a little R&D with dyno = time and=20 different induction system approaches on the rotary engines.  = But, as you=20 know that takes time and money and both are limited for most - if = not all=20 of us.

 

Ed=20 Anderson

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