Return-Path: Received: from sccrmhc12.comcast.net ([204.127.202.56] verified) by logan.com (CommuniGate Pro SMTP 4.2) with ESMTP id 373574 for flyrotary@lancaironline.net; Sat, 21 Aug 2004 15:54:42 -0400 Received-SPF: none receiver=logan.com; client-ip=204.127.202.56; envelope-from=jesse@jessfarr.com Received: from farrhome (pcp04959909pcs.midval01.tn.comcast.net[68.59.199.44]) by comcast.net (sccrmhc12) with SMTP id <2004082119541001200p4hrse>; Sat, 21 Aug 2004 19:54:11 +0000 Message-ID: <004f01c487b8$89594e00$777ba8c0@farrhome> From: "jesse farr" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: EM-2 MAP readings Date: Sat, 21 Aug 2004 15:53:31 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_004C_01C48797.020C2BA0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 This is a multi-part message in MIME format. ------=_NextPart_000_004C_01C48797.020C2BA0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageNot knowing a darn thing about you fellows calculations, (of = course that has never stopped me from sharing my conclusions and = opinions before - ) I would quickly suggest you need to remember the = 1.3 mazda is really a 2.6 pump; so, double them calcualtions and see if = that doesn't put you more into the plain of reality readings.=20 jesse farr ----- Original Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Saturday, August 21, 2004 3:39 PM Subject: [FlyRotary] Re: EM-2 MAP readings Hmm, Weber was pretty much upfront with the fact that their TB ports were only for balancing idle and shouldn't be relied upon for accurate readings at any sort of power setting. Perhaps the TWM port is placed differently than the Weber TB. I'm still skeptical, but I can't think of any way to prove whether = they're correct or not. =20 IMHO, I think your 42s should do just fine at the revs you're turning. In fact, I think the intake charge velocity created by the 42mm tract may help you. I have info here (not in the attic!) reference intake VNE as well as a link to a calculator for gas velocity in a pipe. The link is http://not2fast.com/gasflow/velocity.shtml - you'll have to do the metric/English conversion thing but the math is sound. I'll post the = gas velocity thing later when I can get to the info. I want to say 600 = f/s but will confirm. Neat calculator, but let's see if I'm using this correctly. =20 I'm looking at one rotor, since each TB bore and intake runner feeds = only one rotor. The displacement of a 13B is 1.3 liters, so one rotor = is .65 liters. My handy converter turns this into .023 cubic feet per = rotor, per revolution. Multiply this by 7000 rpm, and I get 161 cubic = feet per minute. I enter this into the gas flow program, leave the temp = at 100F, and put in the runner ID of 1.625". That gives me a mean = velocity of 186 ft/sec. =20 From the notes at the bottom of the program screen, and your = recollection of 600 fps, my 186 fps figure doesn't appear to be = stressing my intake size at all. The real question is- did I screw = something up in the way I figured this?=20 Feeling better about my intake all the time. Pity the area is covered = with thunderstorms today. I really don't want to test my new XM weather = that bad :-) Thanks, Rusty (replacing home security system destroyed by lightning) ------=_NextPart_000_004C_01C48797.020C2BA0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Not knowing a darn thing about you = fellows=20 calculations, (of course that has never stopped me from sharing my = conclusions=20 and opinions before - <g>) I would quickly suggest you need to = remember=20 the 1.3 mazda is really a 2.6 pump; so, double them calcualtions and see = if that=20 doesn't put you more into the plain of reality readings.
 
jesse farr
----- Original Message -----
From:=20 Russell=20 Duffy
Sent: Saturday, August 21, 2004 = 3:39=20 PM
Subject: [FlyRotary] Re: EM-2 = MAP=20 readings

Hmm, Weber was pretty much upfront with the fact = that their TB=20 ports
were only for balancing idle and shouldn't be relied upon for = accurate
readings at any sort of power setting. Perhaps the TWM = port =20 is placed
differently than the Weber TB.

I'm = still skeptical,=20 but I can't think of any way to prove whether = they're correct or=20 not. 

 IMHO, I think your 42s should do = just
fine=20 at the revs you're turning. In fact, I think the intake = charge
velocity=20 created by the 42mm tract may help you. I have info here (not
in = the=20 attic!) reference intake VNE as well as a link to a calculator
for = gas=20 velocity in a pipe. The link is
http://not2fast.com/g= asflow/velocity.shtml=20 - you'll have to do the
metric/English conversion thing but the = math is=20 sound. I'll post the gas
velocity  thing later when I can get = to the=20 info. I want to say 600 f/s
but will confirm.
 
Neat = calculator, but=20 let's see if I'm using this correctly. 
 
I'm = looking at one=20 rotor, since each TB bore and intake runner feeds only=20 one rotor.  The displacement of a 13B is 1.3 liters, so = one=20 rotor is .65 liters.  My handy converter turns this into = .023 cubic=20 feet per rotor, per revolution.  Multiply this by 7000 rpm,=20 and I get 161 cubic feet per minute.  I enter this into = the gas=20 flow program, leave the temp at 100F, and put in the runner ID of = 1.625".   That gives me a mean velocity of 186 ft/sec.  =   
 
From the notes at the bottom = of=20 the program screen, and your recollection of 600 fps, my 186 fps = figure=20 doesn't appear to be stressing my intake size at all.  = The real=20 question is- did I screw something up in the way I = figured=20 this? 
 
Feeling better about my intake = all the=20 time.  Pity the area is covered with thunderstorms today.  I = really=20 don't want to test my new XM weather that bad :-)
 
Thanks,
Rusty (replacing home security = system=20 destroyed by lightning)
 
 
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