Return-Path: <13brv3@bellsouth.net> Received: from imf21aec.mail.bellsouth.net ([205.152.59.69] verified) by logan.com (CommuniGate Pro SMTP 4.2b2) with ESMTP id 3208051 for flyrotary@lancaironline.net; Wed, 05 May 2004 22:26:39 -0400 Received: from rad ([65.0.146.202]) by imf21aec.mail.bellsouth.net (InterMail vM.5.01.06.08 201-253-122-130-108-20031117) with ESMTP id <20040506022639.RJRG24544.imf21aec.mail.bellsouth.net@rad> for ; Wed, 5 May 2004 22:26:39 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: surging / rough idle Date: Wed, 5 May 2004 21:24:37 -0500 Message-ID: <020501c43311$48e1ba70$6001a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0206_01C432E7.600BB270" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 Importance: Normal In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_0206_01C432E7.600BB270 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable The reason is this - the open time of the injectors (and therefore the amount of fuel released per injection ) IS NOT dependent on the RPM but = the loading of the engine (manifold pressure or air flow rate is normally = used to determine this). All the rpm does is determine how many times the injectors fire per unit time (and over simplification but essentially correct). The injectors will of course fire more often at higher rpms = (but will not necessarily stay open longer-depends on manifold pressure) =20 =20 That was the key point that I was missing. HP is a TIME based = measurement, so you don't have to deliver the full load of fuel in just one intake = cycle. Makes perfect sense now. =20 Thanks, Rusty (finding out how my engine compares to Tracy's on Sat) =20 =20 =20 ------=_NextPart_000_0206_01C432E7.600BB270 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message
The reason is this - the open time of = the injectors=20 (and therefore the amount of fuel released per = injection ) IS NOT=20 dependent on the RPM but the loading of the engine (manifold pressure or = air=20 flow rate is normally used to determine this).  All the rpm does is = determine how many times the injectors fire per unit time (and over=20 simplification but essentially correct).  The injectors will of = course fire=20 more often at higher rpms (but will not necessarily stay open = longer-depends on=20 manifold pressure)
 
 
That was=20 the key point that I was missing.  HP is a TIME based=20 measurement, so you don't have to deliver the full load of fuel in = just one=20 intake cycle.  Makes perfect sense now.
 
Thanks,
Rusty=20 (finding out how my engine compares to Tracy's on=20 Sat)  
 
 
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