REFLECTOR: No management fuel systems

[Andrew Judge]

That sounds right. I've been fighting uneven flow since 1998. It's never sucked the sump dry or even made any impact in the sump, but it will blow all your fuel out if you forget the cap. Mine sometimes drains one side, then goes to the other side. That's one reason I've use the led sump low fuel sensor. It works better than the float.

I know in the past, there have been discussions and accidents blamed on uneven pressure in the tanks. It still worries me in my plane at times.

Andy

From: vance atkinson [mailto:nostromo56 at tx.rr.com]
Sent: Saturday, January 14, 2012 09:48 AM
To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
Subject: REFLECTOR: No management fuel systems

For the Velocity builders,

In response to my letter to Burt Rutan about the T'eed fuel lines, his response is written unedited below.
Vance Atkinson

"Vance,
No, the fuel will not jump an air gap to go overboard.  It will dump out the cap only if you start with more than half fuel total.  If you have both tanks feeding one sump, any change in vent pressure will transfer fuel to the tank that is the lowest pressure.  If you have only 1/4 fuel you can end up with all the fuel in one tank and air in the sump.

I am very concerned about your statement "some fuel pumps" in the line.  Fuel systems often do things not expected.  Check Part 23 FAA regs for certification.  You cannot certify a system that pumps fuel from more than one tank at a time.

The origional POC volkswagon-powered EZ had an unusual system, somewhat like you describe.  It worked for a long time without problems, but failed the engine over Phoenix on the way home from Oshkosh.

If you can fly without a cap on one side and still use all the fuel, I would be very surprised.

Burt"

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