Return-Path: Sender: (Marvin Kaye) To: flyrotary Date: Wed, 21 May 2003 19:13:56 -0400 Message-ID: X-Original-Return-Path: Received: from BAY0-SMTP08.adinternal.hotmail.com ([65.54.241.115] verified) by logan.com (CommuniGate Pro SMTP 4.1b6) with ESMTP id 2357792 for flyrotary@lancaironline.net; Wed, 21 May 2003 11:54:23 -0400 X-Originating-IP: [68.7.218.110] X-Originating-Email: [alventures@msn.com] Received: from BigAl ([68.7.218.110]) by BAY0-SMTP08.adinternal.hotmail.com with Microsoft SMTPSVC(5.0.2195.5600); Wed, 21 May 2003 08:54:21 -0700 Reply-To: From: "Al Gietzen" X-Original-To: "Rotary motors in aircraft" Subject: Tuned induction X-Original-Date: Wed, 21 May 2003 08:54:24 -0700 Organization: ALVentures X-Original-Message-ID: <000001c31fb1$435dd080$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C31F76.96FEF880" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4024 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Original-Return-Path: alventures@email.msn.com X-OriginalArrivalTime: 21 May 2003 15:54:21.0958 (UTC) FILETIME=[3EC9A260:01C31FB1] This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C31F76.96FEF880 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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. I would just like to see some hard data to support that the way it is being done with the "wrap-over" tubes is really giving significant benefits. Is anybody really getting more than about 85 hp/rotor at 6000 rpm in their NA engine. I question it based of theory; not on fact. There is a reason why pipe organ pipes are straight, and why Mazda used straight-in tubes on their 4-rotor that won at Lemans. In that manner there is the least amount of spreading of the pulse generated by the sudden closing of the intake port. The pressure wave front travels at the same speed at all points in the cross-section of the tube. Of course there is some mixing, and wall friction distorting and flattening (extending) the pulse. When the tube makes 180 degree turn, the different distances traveled by the different parts of the pulse spread and flatten it further. Do this a couple of times, out and back, with the mixing and wall friction, and how much pressure increase is left? It may still help - a couple of hp? I've seen the argument about various automotive tuned induction systems being curved. True; but looking closely at those that are curved more than about 90 degrees show that there are some added features to make some compensation - reverse curves, dual reflected waves traveling in different directions and reinforcing or whatever. 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 ------=_NextPart_000_0001_01C31F76.96FEF880 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

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.  I would just = like to see some hard data to support that the way it is being done with the = “wrap-over” tubes is really giving significant benefits.  Is anybody really = getting more than about 85 hp/rotor at 6000 rpm in their NA engine.

 

I question it based of theory; not on fact.  = There is a reason why pipe organ pipes are straight, and why Mazda used = straight-in tubes on their 4-rotor that won at Lemans.  In that manner there is = the least amount of spreading of the pulse generated by the sudden closing = of the intake port. The pressure wave front travels at the same speed at all = points in the cross-section of the tube.  Of course there is some mixing, and = wall friction distorting and flattening (extending) the pulse.  When the = tube makes 180 degree turn, the different distances traveled by the different = parts of the pulse spread and flatten it further. Do this a couple of times, = out and back, with the mixing and wall friction, and how much pressure increase = is left?  It may still help -  a couple of hp?

 

I’ve seen the argument about various = automotive tuned induction systems being curved.  True; but looking closely at = those that are curved more than about 90 degrees show that there are some = added features to make some compensation – reverse curves, dual = reflected waves traveling in different directions and reinforcing or whatever.  =

 

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

 

 

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