X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from wproxy.gmail.com ([64.233.184.225] verified) by logan.com (CommuniGate Pro SMTP 5.0.9) with ESMTP id 1056837 for flyrotary@lancaironline.net; Mon, 03 Apr 2006 12:02:07 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.233.184.225; envelope-from=russell.duffy@gmail.com Received: by wproxy.gmail.com with SMTP id i30so1182251wra for ; Mon, 03 Apr 2006 09:01:22 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:from:to:subject:date:message-id:mime-version:content-type:x-priority:x-msmail-priority:x-mailer:importance:in-reply-to:x-mimeole; b=RGnzJCbWsn3Y+X0D6OVJ1sZOKZUQBE2c9elSZDmhU0452uKI/b7uoSLtu6Z2fTwPUgtSzrZ+BbVgtSQ1cE2Mfbb4oSl8UaY4gNq018iCvX7Yif7kAj56Gru0J0/1x6/Zrvvo9mABujlxrxlPSJayqXZZJKFGoWXhk5Tw14W6yNw= Received: by 10.54.72.4 with SMTP id u4mr80818wra; Mon, 03 Apr 2006 09:01:21 -0700 (PDT) Return-Path: Received: from rd ( [65.6.194.9]) by mx.gmail.com with ESMTP id 64sm57186wra.2006.04.03.09.01.21; Mon, 03 Apr 2006 09:01:21 -0700 (PDT) From: "Russell Duffy" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Erratic mixture Date: Mon, 3 Apr 2006 11:01:21 -0500 Message-ID: <000001c65737$da1cdbe0$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C6570D.F146D3E0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2670 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C6570D.F146D3E0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Is it that there isn't enough adjustment range using injector pulse timing to accomodate both an idle opening time and max boost opening time? Hi Ernest, =20 Sounds like you understand it all. I do believe this lack of timing = range is the problem, and correct again that it's much less of a problem with = a NA engine. =20 =20 For any fixed fuel pressure, you can certainly get injectors large = enough to deliver the fuel you need at max boost. The problem is that they will = now need to open for the smallest possible time at idle to deliver the tiny = bit of fuel that's required. All injectors have a certain amount of time = they need to physically open and close. During the time they're in = transition, some fuel is still being transferred, so that factors into the timing as well. It's pretty easy to get to the point where the pulse width is too short to work reliably, which causes inconsistent fuel metering, and = keeps you from having a smooth idle. =20 =20 Staged injectors help this considerably, and I believe Tracy has the = ability now to use different size primary and secondary injectors. You might = could use a smaller primary, and a large secondary if you got desperate. = BTW, the FD does in fact use 550 primaries, and 850 secondaries. Anyone know what the Renesis uses? =20 I'm attempting to implement a returnless system that will be referenced to atmospheric pressure. =20 The big question is, "Will there be enough timing adjustment range in the EC2 to allow the injector pressure to remain constant?" That's what test stands are for. Amen :-) Rusty (teaching Wendell a cheap lesson about believing everything you = read ) ------=_NextPart_000_0001_01C6570D.F146D3E0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

Is it that
there isn't enough adjustment range = using injector=20 pulse timing to
accomodate both an idle opening time and max boost = opening=20 time?

Hi=20 Ernest,
 
Sounds = like you=20 understand it all.  I do believe this lack of timing range is the = problem,=20 and correct again that it's much less of a problem with a NA=20 engine.  
 
For any = fixed fuel=20 pressure, you can certainly get injectors large enough=20 to deliver the fuel you need at max boost.  The problem = is that=20 they will now need to open for the smallest possible time at idle = to=20 deliver the tiny bit of fuel that's required.  All injectors = have a=20 certain amount of time they need to physically open and=20 close.  During the time they're in transition, some fuel = is still=20 being transferred, so that factors into the timing as well.  It's = pretty=20 easy to get to the point where the pulse width is too short to work = reliably, which causes inconsistent fuel metering, and keeps you = from=20 having a smooth idle.    
 
Staged = injectors help=20 this considerably, and I believe Tracy has the ability now to = use different=20 size primary and secondary injectors.  You might could use a=20 smaller primary, and a large secondary if you got = desperate.  =20 BTW, the FD does in fact use 550 primaries, and 850 secondaries.  = Anyone=20 know what the Renesis uses?     

I'm attempting to implement a returnless system that will be = referenced
to=20 atmospheric pressure.  

 The big question
is, "Will there be enough timing adjustment = range=20 in the EC2 to allow
the injector pressure to remain = constant?"

That's=20 what test stands are for.

Amen :-)

Rusty (teaching Wendell a = cheap lesson=20 about believing everything you read = <g>)

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