Return-Path: Received: from [24.25.9.100] (HELO ms-smtp-01-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2.8) with ESMTP id 618345 for flyrotary@lancaironline.net; Sun, 23 Jan 2005 11:58:35 -0500 Received-SPF: none receiver=logan.com; client-ip=24.25.9.100; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-185-127.carolina.rr.com [24.74.185.127]) by ms-smtp-01-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j0NGw3Kk021017; Sun, 23 Jan 2005 11:58:04 -0500 (EST) Message-ID: <000d01c5016d$02ec49b0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" , References: Subject: Re: [FlyRotary] Re: 12:1 vs 1:1 Pressure Regulation Date: Sun, 23 Jan 2005 12:00:15 -0500 MIME-Version: 1.0 Content-Type: multipart/related; type="multipart/alternative"; boundary="----=_NextPart_000_0009_01C50143.19C9F670" 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_0009_01C50143.19C9F670 Content-Type: multipart/alternative; boundary="----=_NextPart_001_000A_01C50143.19C9F670" ------=_NextPart_001_000A_01C50143.19C9F670 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable =20 Steve, Here is what I was referring to from an on-line source. Flow Q = is equal to some constant K (depends on shape and size of orifice) time = the square root of the pressure P. So if you were getting 10 gph fuel = flow at 40 psi then increasing the fuel pressure to 45 psi (assuming K = =3D 1 for simplicity) would give you an increase of 10 ghp + sqrt(5) =3D = 10 + 2.23 =3D 12.23 GPH. If you went from 40 to 96 psi then 10 + = sqrt(96-40) =3D 10 + sqrt(56) =3D 10 + 7.48 =3D 17.48 gph. So if this = calculation is correct then there is not as much a fuel flow increase = using the 12:1 ratio as you might initially think. I expect the big = boost (perhaps > 15 psi) may be the ones that need the 12:1 ratio = regulator. But, in any case, I only raised it as perhaps a topic of interest to = those who are involved/interested in turbocharging. Signing off on the = topic. Ed A Flow through Orifices Using the conservation of energy described earlier it is possible to = describe the discharge of water through the orifice. To simplify the = determination of flow from individual sprinklers, the discharge = coefficient is lumped with the constant and the orifice diameter as = follows:=20 =20 Where Q is in gallons per minute, K is the K-factor and P i s in psi. = The K-factor is determined by testing laboratories for each sprinkler = model. A sprinkler is flowed at a large range of pressures from a fairly = large reservoir. The discharge is measured and a value of K is = determined at each pressure, the average of all the K's at different = pressures is the K-factor. In the 1970's the idea of taking into account = velocity pressures effect on water flow was introduced. However, the = difference in predicted water flow is small when compared to the = differences occurred when choosing different Hazen-Williams C-factors. = Therefore, in the United States, it is still general practice to let the = design engineer decide if he is going to calculate the effects of = velocity pressure[8]=20 ----- Original Message -----=20 From: Steve Brooks=20 To: Rotary motors in aircraft=20 Sent: Sunday, January 23, 2005 11:22 AM Subject: [FlyRotary] Re: 12:1 vs 1:1 Pressure Regulation 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. = =20 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=20 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=20 Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com ------=_NextPart_001_000A_01C50143.19C9F670 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
Steve, Here is what I was referring to = from an=20 on-line source.  Flow Q is equal to some constant K (depends on = shape and=20 size of orifice) time the square root of the pressure P.  So if you = were=20 getting 10 gph fuel flow at 40 psi then increasing the fuel pressure to = 45 psi=20 (assuming K =3D 1 for simplicity) would give you an increase of 10 ghp + = sqrt(5) =3D=20 10 + 2.23 =3D 12.23 GPH.  If you went from 40 to 96 psi then 10 + = sqrt(96-40)=20 =3D 10 + sqrt(56) =3D 10 + 7.48 =3D 17.48 gph.  So if this = calculation is correct=20 then there is not as much a fuel flow increase using the 12:1 ratio as = you might=20 initially think.  I expect the big boost (perhaps > 15 psi) may = be the=20 ones that need the 12:1 ratio regulator.
 
 But, in any case, I only raised = it as perhaps=20 a topic of interest to those who are involved/interested in = turbocharging. =20 Signing off on the topic.
 
Ed A
 

Flow through Orifices

Using the conservation of energy described earlier it is possible to = describe=20 the discharge of water through the orifice. To simplify the = determination of=20 flow from individual sprinklers, the discharge coefficient is lumped = with the=20 constant and the orifice diameter as follows:=20

3D""=20=20

Where Q is in gallons per minute, K is the K-factor and P i s in psi. = The=20 K-factor is determined by testing laboratories for each sprinkler model. = A=20 sprinkler is flowed at a large range of pressures from a fairly large = reservoir.=20 The discharge is measured and a value of K is determined at each = pressure, the=20 average of all the K's at different pressures is the K-factor. In the = 1970's the=20 idea of taking into account velocity pressures effect on water flow was=20 introduced. However, the difference in predicted water flow is small = when=20 compared to the differences occurred when choosing different = Hazen-Williams=20 C-factors. Therefore, in the United States, it is still general practice = to let=20 the design engineer decide if he is going to calculate the effects of = velocity=20 pressure[8]=20

----- Original Message -----
From:=20 Steve=20 Brooks
Sent: Sunday, January 23, 2005 = 11:22=20 AM
Subject: [FlyRotary] Re: 12:1 = vs 1:1=20 Pressure Regulation

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=20 boost, that would be an increase of 96 lbs (8*12), on top of a static = (0) fuel=20 pressure of 38 lbs, that would be a whopping 134 lbs of fuel = pressure  if=20 I 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. =20 It, as you stated is a 1:1 ratio of adjustment.  I don't have a = panel=20 mounted fuel pressure gauge, but I do have a sender installed which I = can=20 attach an analog gauge to for testing, and also for the day I put in = an=20 EM-2.  With a 38 lb static fuel pressure, the fuel pressure at an = idle=20 was down to about 20 lbs.  It did go up with boost, but being on = the=20 ground, it was hard to get an exact reading on the gauge.  It = responds=20 kind of slow, and I was also watching where I was going, more so than = watching=20 the gauge.  It did look like about 40 something lbs at a 5 lb = boost=20 setting.
 
I'm=20 still running rich at low RPM's, but in flight, the mixtures are=20 good.
 
Steve 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 Regulation

Here is some food for thought for = you turbo=20 folks.  Most of the pressure referenced fuel regulators = regulate the=20 fuel rail pressure on a 1:1 ratio with the manifold pressure = change. =20 In other words if the manifold pressure changes 1psi (2" HG) the = fuel=20 pressure changes 1 psi.  This increase does of course increase = the rate=20 at which the fuel will flow through the injector.  However, the = flow=20 rate changes on the order of the   square root of the = pressure=20 increase (as best I recall).  This means if you double your = fuel=20 pressure you Do NOT double 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=20 in aircraft whether this is really significant - but, just though I=20 would pass this on in case anyone wants to investigate it = further=20 or 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=20 gun metal
 
Ed
 
 
Ed Anderson
Rv-6A N494BW Rotary=20 Powered
Matthews, NC
eanderson@carolina.rr.com
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