Return-Path: Received: from [24.25.9.103] (HELO ms-smtp-04-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2.8) with ESMTP id 617313 for flyrotary@lancaironline.net; Sat, 22 Jan 2005 09:08:37 -0500 Received-SPF: none receiver=logan.com; client-ip=24.25.9.103; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-185-127.carolina.rr.com [24.74.185.127]) by ms-smtp-04-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j0ME84Ci011569 for ; Sat, 22 Jan 2005 09:08:05 -0500 (EST) Message-ID: <000a01c5008c$18364b40$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Fuel Injector Sizing Date: Sat, 22 Jan 2005 09:10:14 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0007_01C50062.2F2954C0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0007_01C50062.2F2954C0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageYou certainly could be right about that, Rusty. My understanding = was to expect the fuel pressure to vary to compensate for the different = manifold pressure. But, there is no indication on my gauge and this is = the second pressure regulator (but, of the same make Hmmm) that I have = had. It does regulate (else my fuel pressure would be much higher) but = apparently does not compensate for manifold pressure based on what I am = hearing. But, as you indicated, If there is any operational problem associated = with it, I have not encountered it (or recognized it as such). It is = one of the smaller ones and it could be that it is dumping all the fuel = it can at 40-43 psi and there is not sufficient return flow capacity to = compensate for the variations in manifold pressure. I suspect that if I = had a turbo where the manifold pressure varied considerably that the = lack of such compensation might be more detrimental to engine = performance (and life). Just speculation of course. Ed A ----- Original Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Saturday, January 22, 2005 8:50 AM Subject: [FlyRotary] Re: Fuel Injector Sizing Actually, I have a manifold referenced pressure regulator (which if I = understand the concept) attempts to keep the pressure differential = between the fuel side and manifold side of the injector constant. = However, Varying engine manifold pressure (varying throttle opening) = does not appear to have any affect on my fuel pressure. It sits rock = steady at 40 psi with one pump and goes up to 43 psi with both running = regardless of throttle position. =20 Hi Ed,=20 Sounds like your regulator isn't working like it's supposed to, though = I guess it isn't causing you any problems. A simple test would be to = run the pump with the engine off and note the fuel pressure, then check = it again at idle. If you really want to get fancy, and have one of = those Mity-Vac pumps, you can just vary the pressure signal to the = regulator with the engine off. My pressure definitely changes. =20 Cheers, Rusty (wonder if Tommy got his new regulator working yet) ------=_NextPart_000_0007_01C50062.2F2954C0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
You certainly could be right about = that,=20 Rusty.  My understanding was to expect the fuel pressure to vary to = compensate for the different manifold pressure.  But, there is no=20 indication on my gauge and this is the second pressure regulator (but, = of the=20 same make Hmmm) that I have had.  It does regulate (else my fuel = pressure=20 would be much higher) but apparently does not compensate for manifold = pressure=20 based on what I am hearing.
 
  But, as you indicated, If there = is any=20 operational problem associated with it, I have not encountered it = (or=20 recognized it as such).  It is one of the smaller ones and it could = be that=20 it is dumping all the fuel it can at 40-43 psi and there is not = sufficient=20 return flow capacity to compensate for the variations in manifold=20 pressure.  I suspect that if I had a turbo where the manifold = pressure=20 varied considerably that the lack of such compensation might be more = detrimental=20 to engine performance (and life).   Just speculation of=20 course.
 
Ed A
----- Original Message -----
From:=20 Russell=20 Duffy
Sent: Saturday, January 22, = 2005 8:50=20 AM
Subject: [FlyRotary] Re: Fuel = Injector=20 Sizing

Actually, I have a manifold = referenced=20 pressure regulator (which if I understand the concept) attempts = to keep=20 the pressure differential between the fuel side and manifold side of = the=20 injector constant. However, Varying engine manifold pressure = (varying=20 throttle opening) does not appear to have any affect on my fuel=20 pressure.  It sits rock steady at 40 psi with one pump and goes = up to 43=20 psi with both running regardless of throttle = position.   
 
Hi = Ed, 
 
Sounds like your regulator isn't working like = it's=20 supposed to, though I guess it isn't causing you any problems.  A = simple=20 test would be to run the pump with the engine off and note the fuel = pressure,=20 then check it again at idle.  If you really want to get fancy, = and have=20 one of those Mity-Vac pumps, you can just vary the pressure signal to = the=20 regulator with the engine off.  My pressure definitely=20 changes.  
 
Cheers,
Rusty (wonder if Tommy got his new regulator = working=20 = yet) 
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