Return-Path: Received: from grebe.mail.pas.earthlink.net ([207.217.120.46] verified) by logan.com (CommuniGate Pro SMTP 4.2b3) with ESMTP id 92862 for flyrotary@lancaironline.net; Thu, 27 May 2004 10:50:10 -0400 Received: from user-2injqqp.dialup.mindspring.com ([165.121.235.89] helo=Carol) by grebe.mail.pas.earthlink.net with smtp (Exim 3.33 #1) id 1BTMCQ-0004m3-00 for flyrotary@lancaironline.net; Thu, 27 May 2004 07:49:40 -0700 Message-ID: <006a01c443f9$c9966190$0000a398@Carol> From: "sqpilot@earthlink" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Fuel Pump Design Date: Thu, 27 May 2004 09:45:55 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0060_01C443CF.683A9EE0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2720.3000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2739.300 This is a multi-part message in MIME format. ------=_NextPart_000_0060_01C443CF.683A9EE0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable ----- Original Message -----=20 From: Bob Perkinson=20 To: Rotary motors in aircraft=20 Sent: Thursday, May 27, 2004 9:09 AM Subject: [FlyRotary] Re: Fuel Pump Design The attached drawing is my idea of a simple fuel system for the 9a = that I am building, with Aux fuel tanks akin to Berne Kerr's Project. I = would like some feed back as to what problems this arrangement might = pose, and what the remedy would be for such problems. The plan is to = use large diameter pipe between the main fuel tanks so as to allow the = fuel to equalize =20 Bob Perkinson.=20 -----Original Message----- From: Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net]On Behalf Of Mark Steitle Sent: Tuesday, May 25, 2004 3:06 PM To: Rotary motors in aircraft Subject: [FlyRotary] Fuel Pump Design Fuel system design hasn't come up in quite a while. But since a = large portion of accidents are fuel related, I thought this would be = worthy of discussion. I have experienced a failure mode during ground runs on my Lancair = ES with 20B that seems to be a problem with other types of installations = as well. I recently read a first flight report by a professional test = pilot, David Allen, that almost had to set a Lancair ES, N711RG, down on = I-70 due to the inability to restart the engine after running a tank = dry. (See www.geocities.com/daveandjj for the full story.) This was a = certified fuel-injected engine installation. Also, the Subaru guys (I = have been lurking on the Eggenfelder Subie site today) had a similar = situation, resulting in some glider time and a dead-stick landing. =20 The problem is that after exhausting the fuel in one tank an airlock = forms between the fuel pump(s) and the fuel pressure regulator that the = efi pump cannot overcome due to lack of fuel in the supply line. This = is what I have experienced with my installation on ground runs. I can't = get the efi pumps to re-prime unless I momentarily break a line loose = between the pump outlet and the pressure regulator. As soon as I do = that the pump will re-prime and all is well. =20 For the record, I have two of Tracy's efi pumps, with two efi = filters, hooked in parallel. They are mounted low on the fire wall. = Upstream is a gascolator and an Andair 6-port selector valve. = Downstream of the pumps/filters is a map sensing pressure regulator. = There is a -6AN going to the fuel rail, and a -4 return line back to the = Andair valve/tank. I was curious if anyone else has had this happen and what they did = to resolve the issue. I have come up with two possible solutions. =20 1. Tee off the pump output and put an electric solenoid valve in = the line and tee the outlet of the solenoid to the fuel return line, = past the regulator. Push-button switch on panel would activate the = solenoid. If needed, a second or two of activation should relieve the = air-lock and allow the pumps to re-prime. 2. Install a bleed line around the pressure regulator with a small = metering orifice (.020-.030") that would bleed off any air that might = get trapped. (This appears to be the solution the Subaru group is = focusing on). This would be a full time bypass. This seems to be the = simpler solution. 3. Install a low pressure, high volume fuel pump in one, or both, = of the wing tanks. Procedure would be to always keep reserve fuel in = this tank. =20 Any comments from seasoned flyers would be welcomed. Mark S.=20 Hi, Mark.....looking at the drawing, I noted that there are two spring = loaded ball check valves after the two fuel pumps. In order to possibly = simplify the installation, might I suggest using fuel pumps such as the = MSD high pressure fuel pumps, as they already have a built-in check = valve inside each pump. I am unfamiliar with Tracy's pumps, so I don't = know if his has the check valve built into it as well? Paul Conner=20 -------------------------------------------------------------------------= ----- >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0060_01C443CF.683A9EE0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
----- Original Message -----
From:=20 Bob=20 Perkinson
Sent: Thursday, May 27, 2004 = 9:09=20 AM
Subject: [FlyRotary] Re: Fuel = Pump=20 Design

The=20 attached drawing is my idea of a simple fuel system for the 9a that I = am=20 building, with Aux fuel tanks akin to Berne Kerr=92s Project.  I would like some feed back = as to what=20 problems this arrangement might pose, and what the remedy would be for = such=20 problems.  The plan is = to use=20 large diameter pipe between the main fuel tanks so as to allow the = fuel to=20 equalize 

Bob Perkinson.

-----Original Message-----
From: Rotary motors in = aircraft=20 [mailto:flyrotary@lancaironline.net]On Behalf Of Mark=20 Steitle
Sent: Tuesday, May 25, 2004 3:06 PM
To: = Rotary=20 motors in aircraft
Subject: [FlyRotary] Fuel Pump=20 Design

Fuel system design hasn't come up in = quite a=20 while.  But since a large portion of accidents are fuel = related, I=20 thought this would be worthy of discussion.

I have = experienced a=20 failure mode during ground runs on my Lancair ES with 20B that seems = to be a=20 problem with other types of installations as well.  I recently = read a=20 first flight report by a professional test pilot, David Allen, that = almost=20 had to set a Lancair ES, N711RG, down on I-70 due to the inability = to=20 restart the engine after running a tank dry.  (See www.geocities.com/daveandjj for the = full=20 story.)  This was a certified fuel-injected engine = installation. =20 Also, the Subaru guys (I have been lurking on the Eggenfelder Subie = site=20 today) had a similar situation, resulting in some glider time and a=20 dead-stick landing. 

The problem is that after = exhausting the=20 fuel in one tank an airlock forms between the fuel pump(s) and the = fuel=20 pressure regulator that the efi pump cannot overcome due to lack of = fuel in=20 the supply line.  This is what I have experienced with my = installation=20 on ground runs.  I can't get the efi pumps to re-prime unless I = momentarily break a line loose between the pump outlet and the = pressure=20 regulator.  As soon as I do that the pump will re-prime and all = is=20 well. 

For the record, I have two of Tracy's efi pumps, = with=20 two efi filters, hooked in parallel.  They are mounted low on = the fire=20 wall.  Upstream is a gascolator and an Andair 6-port selector=20 valve.  Downstream of the pumps/filters is a map sensing = pressure=20 regulator.  There is a -6AN going to the fuel rail, and a -4 = return=20 line back to the Andair valve/tank.

I was curious if anyone = else has=20 had this happen and what they did to resolve the issue.  I have = come up=20 with two possible solutions. 

1.  Tee off the pump = output=20 and put an electric solenoid valve in the line and tee the outlet of = the=20 solenoid to the fuel return line, past the regulator.  = Push-button=20 switch on panel would activate the solenoid.  If needed, a = second or=20 two of activation should relieve the air-lock and allow the pumps to = re-prime.

2.  Install a bleed line around the pressure = regulator=20 with a small metering orifice (.020-.030") that would bleed off any = air that=20 might get trapped.  (This appears to be the solution the Subaru = group=20 is focusing on).  This would be a full time bypass.  This = seems to=20 be the simpler solution.

3.  Install a low pressure, = high volume=20 fuel pump in one, or both, of the wing tanks.  Procedure would = be to=20 always keep reserve fuel in this tank. 

Any comments = from=20 seasoned flyers would be welcomed.

Mark S.

Hi, Mark.....looking at the drawing, I noted that there are two = spring=20 loaded ball check valves after the two fuel pumps.  In order to = possibly=20 simplify the installation, might I suggest using fuel pumps such as = the MSD=20 high pressure fuel pumps, as they already have a built-in check valve = inside=20 each pump. I am unfamiliar with Tracy's pumps, so I don't know if his = has the=20 check valve built into it as well?   Paul Conner=20

>>  Homepage: =20 http://www.flyrotary.com/
>>  Archive:  =20 = http://lancaironline.net/lists/flyrotary/List.html
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