Return-Path: Received: from smtp106.mail.sc5.yahoo.com ([66.163.169.226] verified) by logan.com (CommuniGate Pro SMTP 4.2.8) with SMTP id 618305 for flyrotary@lancaironline.net; Sun, 23 Jan 2005 11:21:47 -0500 Received-SPF: none receiver=logan.com; client-ip=66.163.169.226; envelope-from=prvt_pilot@yahoo.com Received: from unknown (HELO stevehome) (prvt?pilot@24.136.242.117 with login) by smtp106.mail.sc5.yahoo.com with SMTP; 23 Jan 2005 16:21:16 -0000 Reply-To: From: "Steve Brooks" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] 12:1 vs 1:1 Pressure Regulation Date: Sun, 23 Jan 2005 11:22:16 -0500 Message-ID: <00c101c50167$b4fcc1d0$6401a8c0@workgroup.com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00C2_01C5013D.CC26B9D0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook CWS, Build 9.0.6604 (9.0.2911.0) In-Reply-To: Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 This is a multi-part message in MIME format. ------=_NextPart_000_00C2_01C5013D.CC26B9D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Ed, Assuming that most turbo users are limiting boost to 8-10 lbs maximum, that would be a pretty high fuel pressure. Assuming 8 lbs of boost @ 12 psi fuel pressure increase per lb of boost, that would be an increase of 96 lbs (8*12), on top of a static (0) fuel pressure of 38 lbs, that would be a whopping 134 lbs of fuel pressure if I understand your message correctly. That seems pretty high, and I don't know that the injector seal would hold up to that. I'm using the Aeromotive regulator, since I had trouble with the Mallory. It, as you stated is a 1:1 ratio of adjustment. I don't have a panel mounted fuel pressure gauge, but I do have a sender installed which I can attach an analog gauge to for testing, and also for the day I put in an EM-2. With a 38 lb static fuel pressure, the fuel pressure at an idle was down to about 20 lbs. It did go up with boost, but being on the ground, it was hard to get an exact reading on the gauge. It responds kind of slow, and I was also watching where I was going, more so than watching the gauge. It did look like about 40 something lbs at a 5 lb boost setting. I'm still running rich at low RPM's, but in flight, the mixtures are good. Steve Brooks -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]On Behalf Of Ed Anderson Sent: Sunday, January 23, 2005 10:32 AM To: Rotary motors in aircraft Subject: [FlyRotary] 12:1 vs 1:1 Pressure Regulation Here is some food for thought for you turbo folks. Most of the pressure referenced fuel regulators regulate the fuel rail pressure on a 1:1 ratio with the manifold pressure change. In other words if the manifold pressure changes 1psi (2" HG) the fuel pressure changes 1 psi. This increase does of course increase the rate at which the fuel will flow through the injector. However, the flow rate changes on the order of the square root of the pressure increase (as best I recall). This means if you double your fuel pressure you Do NOT double your fuel flow. With higher boost pressures the preferred regulation ratio is like 12:1 or 12 psi for each psi of manifold pressure. Not certain that for the lower boost levels being used in aircraft whether this is really significant - but, just though I would pass this on in case anyone wants to investigate it further or comment. BLOX FMUs The Blox fuel management unit is designed to increase the fuel pressure as the pressure in the intake manifold increases. The Blox FMU is a universally design product with a 12:1 fixed ratio. The FMU is used on fuel injected vehicles, either supercharged or turbocharged, using the factory electronic engine management system. Blox FMU's are available in blue, red, gold and gun metal Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com ------=_NextPart_000_00C2_01C5013D.CC26B9D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Ed,
Assuming that most turbo users are limiting boost to 8-10 lbs = maximum,=20 that would be a pretty high fuel pressure.
 
Assuming 8 lbs of boost @ 12 psi fuel pressure increase per lb = of boost,=20 that would be an increase of 96 lbs (8*12), on top of a static (0) fuel = pressure=20 of 38 lbs, that would be a whopping 134 lbs of fuel pressure  if I=20 understand your message correctly.  That seems pretty high, = and I=20 don't know that the injector seal would hold up to = that.
 
I'm=20 using the Aeromotive regulator, since I had trouble with the = Mallory.  It,=20 as you stated is a 1:1 ratio of adjustment.  I don't have a panel = mounted=20 fuel pressure gauge, but I do have a sender installed which I can attach = an=20 analog gauge to for testing, and also for the day I put in an = EM-2.  With a=20 38 lb static fuel pressure, the fuel pressure at an idle was down to = about 20=20 lbs.  It did go up with boost, but being on the ground, it was hard = to get=20 an exact reading on the gauge.  It responds kind of slow, and I was = also=20 watching where I was going, more so than watching the gauge.  It = did look=20 like about 40 something lbs at a 5 lb boost setting.
 
I'm=20 still running rich at low RPM's, but in flight, the mixtures are=20 good.
 
Steve=20 Brooks
 
 
 
-----Original Message-----
From: Rotary motors in = aircraft=20 [mailto:flyrotary@lancaironline.net]On Behalf Of Ed=20 Anderson
Sent: Sunday, January 23, 2005 10:32 = AM
To:=20 Rotary motors in aircraft
Subject: [FlyRotary] 12:1 vs 1:1 = Pressure=20 Regulation

Here is some food for thought for you = turbo=20 folks.  Most of the pressure referenced fuel regulators regulate = the fuel=20 rail pressure on a 1:1 ratio with the manifold pressure change.  = In other=20 words if the manifold pressure changes 1psi (2" HG) the fuel pressure = changes=20 1 psi.  This increase does of course increase the rate at which = the fuel=20 will flow through the injector.  However, the flow rate changes = on the=20 order of the   square root of the pressure increase (as best = I=20 recall).  This means if you double your fuel pressure you Do NOT = double=20 your fuel flow.  
 
With higher boost pressures the = preferred=20 regulation ratio is like 12:1 or 12 psi for each psi of manifold=20 pressure.  Not certain that for the lower boost levels being = used in=20 aircraft whether this is really significant - but, just though I=20 would pass this on in case anyone wants to investigate it = further or=20 comment.
 
3D"BLOX
BLOX FMUs =
The=20 Blox fuel management unit is designed to increase the fuel pressure as = the=20 pressure in the intake manifold increases. The Blox FMU is a = universally=20 design product with a 12:1 fixed ratio. The FMU is used on fuel = injected=20 vehicles, either supercharged or turbocharged, using the factory = electronic=20 engine management system. Blox FMU's are available in blue, red, gold = and gun=20 metal
 
Ed
 
 
Ed Anderson
Rv-6A N494BW Rotary=20 Powered
Matthews, NC
eanderson@carolina.rr.com
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