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Return-Path: Received: from fed1rmmtao02.cox.net ([68.230.241.37] verified) by logan.com (CommuniGate Pro SMTP 4.2b6) with ESMTP id 230997 for flyrotary@lancaironline.net; Tue, 29 Jun 2004 15:00:18 -0400 Received: from smtp.west.cox.net ([172.18.180.53]) by fed1rmmtao02.cox.net (InterMail vM.6.01.03.02 201-2131-111-104-20040324) with SMTP id <20040629185947.WPRY24778.fed1rmmtao02.cox.net@smtp.west.cox.net> for ; Tue, 29 Jun 2004 14:59:47 -0400 From: To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: Fuel System Question Date: Tue, 29 Jun 2004 14:59:45 -0400 MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=____1088535585976_SlnEYOboSZ" Message-Id: <20040629185947.WPRY24778.fed1rmmtao02.cox.net@smtp.west.cox.net> This is a multi-part message in MIME format. ------=____1088535585976_SlnEYOboSZ Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Thanks Rusty. Your set up is exactly what I was envisioning except for a check valve to prevent back flow into the non feed tank. Which means if the non feed tank has more quantity it will equalize. Ron Milligan RV7 QB Fuse Aliso Viejo, CA > > From: "Russell Duffy" <13brv3@bellsouth.net> > Date: 2004/06/29 Tue PM 02:40:21 EDT > To: "Rotary motors in aircraft" > Subject: [FlyRotary] Re: Fuel System Question > > I want to know what the pressure is in the line after the fuel > regulator. If it is greater than the pump output pressure of the > transfer pump then I will never be able to transfer fuel. If that is > the case I will have to plumb two extra return lines to the tank. > > > Hi Ron, > > My system is generally like Tracy's, though I can't confirm the minute > details of his plumbing. I added one return line to the tank, and use > the same line for fuel return, and transfer pump. I don't believe > there's going to be any problem with this, but mine hasn't been > extensively tested. For the most part, my flights have been so short > that I've had no real need to transfer fuel. As a part of my preflight, > I transfer fuel to the feed tank, so that it's about 5 gallons higher > than the non-feed tank. I've turned on the pump in flight, and believe > it actually was transferring fuel (gauges are useless), but I can't say > if it was as fast as it would have been if the engine wasn't running. > Eventually, I'll get a better feel for this, and could even test it on > the ground if I ever find myself fairly low on fuel. I could use the > transfer pump to empty the non-feed tank, then add a couple gallons of > fuel and see how long it takes to pump that out. I could repeat the > same test with both EFI fuel pumps on, which would be worst case. I > would expect they would be very close to the same time, but it would be > a good test to do some day. > > BTW, I installed my fuel return fitting toward the top of the removable > cover of the tank. That means that it's often below the level of the > fuel, which has caused me a slight problem. The Facet pump doesn't have > a leak-proof check valve in it, so over the period of a week, fuel will > equalize between tanks to some extent. Tracy has his plumbed like the > vent line, to the top of the outboard end of the tank, so it's almost > always in the air-space above the fuel, so he doesn't have this problem. > If I were doing it again, I would make an attempt to plumb it higher, > via a tube inside the tank. > > Cheers, > Rusty (spent the best weekend we've had building my new supercomputer) > > > > > > > > ------=____1088535585976_SlnEYOboSZ Content-Type: text/html; name="reply" Content-Disposition: inline; filename="reply" Message

I want to know what the pressure is in the line after the fuel regulator. If it is greater than the pump output pressure of the transfer pump then I will never be able to transfer fuel. If that is the case I will have to plumb two extra return lines to the tank.

Hi Ron,

My system is generally like Tracy's, though I can't confirm the minute details of his plumbing. I added one return line to the tank, and use the same line for fuel return, and transfer pump. I don't believe there's going to be any problem with this, but mine hasn't been extensively tested. For the most part, my flights have been so short that I've had no real need to transfer fuel. As a part of my preflight, I transfer fuel to the feed tank, so that it's about 5 gallons higher than the non-feed tank. I've turned on the pump in flight, and believe it actually was transferring fuel (gauges are useless), but I can't say if it was as fast as it would have been if the engine wasn't running. Eventually, I'll get a better feel for this, and could even test it on the ground if I ever find myself fairly low on fuel. I could use the transfer pump to empty the non-feed tank, then add a couple gallons of fuel and see how long it takes to pump that out. I could repeat the same test with both EFI fuel pumps on, which would be worst case. I would expect they would be very close to the same time, but it would be a good test to do some day.

BTW, I installed my fuel return fitting toward the top of the removable cover of the tank. That means that it's often below the level of the fuel, which has caused me a slight problem. The Facet pump doesn't have a leak-proof check valve in it, so over the period of a week, fuel will equalize between tanks to some extent. Tracy has his plumbed like the vent line, to the top of the outboard end of the tank, so it's almost always in the air-space above the fuel, so he doesn't have this problem. If I were doing it again, I would make an attempt to plumb it higher, via a tube inside the tank.

Cheers,

Rusty (spent the best weekend we've had building my new supercomputer)

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