Return-Path: Received: from [65.54.169.126] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.2b2) with ESMTP id 3183582 for flyrotary@lancaironline.net; Wed, 21 Apr 2004 22:31:33 -0400 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Wed, 21 Apr 2004 19:31:33 -0700 Received: from 4.171.174.120 by BAY3-DAV96.phx.gbl with DAV; Thu, 22 Apr 2004 02:31:32 +0000 X-Originating-IP: [4.171.174.120] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: intake ideas? Date: Wed, 21 Apr 2004 22:31:29 -0400 MIME-Version: 1.0 X-Mailer: MSN Explorer 7.02.0011.2700 Content-Type: multipart/alternative; boundary="----=_NextPart_001_0006_01C427F0.63C42610" Message-ID: X-OriginalArrivalTime: 22 Apr 2004 02:31:33.0311 (UTC) FILETIME=[ED3F24F0:01C42811] ------=_NextPart_001_0006_01C427F0.63C42610 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable At one time I did measure the MAP at the far end of the small (primary) r= unners and found a .8" Hg drop at WOT compared to dynamic chamber reading= =20 At what RPM? This is really what I was after; a feel for the pressure dro= p due to flow losses, and trying to understand the nearly 4=E2=80=9D Hg d= rop from atmospheric that I measured at 6000 rpm. I am pulling both port= s through a 1.75=E2=80=9D dia, 5=E2=80=9D long TB barrel, and maybe a bit= of loss in the inlet plenum; but not likely that could account for such = a large loss. As you suggested, it must have something to do with the pl= acement of the measurement port. I may call the guy at TWM and see what = his thoughts are. =20 I expected this drop. For reasons of not wanting to enter a prolonged a= nd fruitless discussion on rotary engine manifold design, I will not expl= ain why this drop is desirable : ) Oh; come on =E2=80=93 gives us the 25 words or less version =E2=80=93 wel= l; maybe 50 words. We promise no prolonged and fruitless discussion. Al Damn, I'm such a sucker for that line. Most gear heads already understand that successful intake tuning is the a= rt and science of maximizing and managing the energy represented by the m= oving mass of air in the manifold as it accelerates and decelerates. But= , there are some less obvious subtleties at work in the Mazda rotary mani= fold. =20 I believe Mazda's intent on the 2nd gen NA rotary was to intentionally re= strict the flow on the primary ports so as to increase the velocity in th= e larger secondaries. This goal is also aided by opening the secondaries= a bit sooner than the primaries (gets the train moving early). Note tha= t porting (enlarging) the primaries or making the primary runners larger = may be counterproductive here so the time honored tradition of "bigger is= better" will lead you the wrong way. The resultant higher velocity in t= he secondary runners is then used to increase VE with the later closing s= econdary port. So why not close up the primaries completely and get even= higher velocity in the secondary? It's all about finding the point of = diminishing returns. Tracy (way past 50 word limit) ------=_NextPart_001_0006_01C427F0.63C42610 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable

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At one time I did measure the MAP at the far&= nbsp;end of the small (primary) runners and found a .8" Hg drop at WOT co= mpared to dynamic chamber reading.

At what RPM? This is= really what I was after; a feel for the pressure drop due to flow losses= , and trying to understand the nearly 4=E2=80=9D Hg drop from atmospheric= that I measured at 6000 rpm. I am pulling both ports through a 1.7= 5=E2=80=9D dia, 5=E2=80=9D long TB barrel, and maybe a bit of loss in the= inlet plenum; but not likely that could account for such a large loss.&n= bsp; As you suggested, it must have something to do with the placement of= the measurement port. I may call the guy at TWM and see what his t= houghts are.



I expected this drop.  For reasons = of not wanting to enter a prolonged and fruitless discussion on rotary en= gine manifold design, I will not explain why this drop is desirable : )

Al

Damn= , I'm such a sucker for that line.

Most gear heads already understand that s= uccessful intake tuning is the art and sc= ience of maximizing and managing the energy represented by the moving mas= s of air in the manifold as it accelerates and decelerates. But, th= ere are some less obvious subtleties at work in the Mazda rotar= y manifold.

I believe Mazda's intent on the 2nd gen NA rotary = was to intentionally restrict the flow on the primary ports so as to incr= ease the velocity in the larger secondaries. This goal is also aide= d by opening the secondaries a bit sooner than the primaries (gets the tr= ain moving early). Note that porting (enlarging) the primaries or m= aking the primary runners larger may be counterproductive here = so the time honored tradition of "bigger is better" will lead you the wro= ng way. The resultant higher velocity in the secondary ru= nners is then used to increase VE with the later closing secondary p= ort. So why not close up the primaries completely and get even high= er velocity in the secondary?   It's all about finding the poin= t of diminishing returns.

Tracy (way past 50 word limit)
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