REFLECTOR: Unbalanced fuel flow in flight

[Andrew Judge]

Mine has drained uneven for at least 1/2 the hours I've put on it (300+). You can check the caps by moving them and if the flow follows the cap, then it's probably a cap issue. Not sure how anyone has an airtight seal with caps? Doesn't seem possible.

Sometimes mine drains down to 5 gallons before taking on the other side. I've learned that it will always drain out, but it is annoying. Even more annoying it a flickering sump low indication - which I get at times but not affiliated with the fuel flow.

Andy

________________________________
From: reflector-bounces at tvbf.org <reflector-bounces at tvbf.org>
To: Reflector <reflector at tvbf.org>
Sent: Sun Mar 13 11:02:25 2011
Subject: Re: REFLECTOR: Unbalanced fuel flow in flight

Richard,
This is just a "me too," to what has already been said.  I have an XL with the Atkinson clear fuel sight gauges in the cabin.  I used to check only the RH one in flight and see that it was about right, and never compared it closely to the other which is difficult to see for me due to have to crane my neck around or even half climb out of the pilot seat.  I have a forward facing fuel vent tube out the belly, with a small whole drilled on the back face for an alternate orifice in the chance of ice.  Well I got into a brief but heavy transit thru about 1000 to 1500 feet of cloud in central Penn that surprised me, and it was slow to come off since once on top the outside air was too cold.  So I began to fret that my vent tube was liked iced some.  So I looked at both my sight gauges and they were an inch (aprox 5 gal) or more apart and it scared the hell out of me.  Since then I have learned that they do sort of rachet back and forth and do not come down exactly even.  The flight was uneventful.

John Abraham's yaw string idea is ancient, and quick and easy to do.  Leave it on there for a whole series of flights.   A small hunk of masking tape and a foot or so of knitting yarn works great.  If you have some one with you, you can try scribing your yaw angle if it is off any w/ a water magic marker so you have a ref point for any changes or experiments you might try.  Good luck, but also be sure your vent system works right or it could completely stop your fuel feed.  It's dirt simple, but vital...I'm sure you know that.

Terry

From: richard at naples-air-center.com
Date: Sun, 13 Mar 2011 08:27:03 -0400
To: reflector at tvbf.org
Subject: REFLECTOR: Unbalanced fuel flow in flight


Friday I completed my second test flight.  I found that all the fuel drained from the right side and none from the left while on the one hour flight. (I actually cut the flight short due to this.)

When I landed I verified with my fuel stick that all the fuel did co e from the right tank.

For troubleshooting:

1) I removed the line from the left tank to the sump tank and verified that fuel did flow freely from the left tank.

2) Removed the vent line from the left tank and tested the line in the direction of the left tank and in the direction to the vent/overflow block at the top of my firewall using compressed air.

3) I checked the check valve for the air for correct operation in both directions and verified it was installed in the correct direction for air to enter and that fuel would not vent into the cabin.

4) Verified the overflow line was clear by using compressed air.

I know the picture is hard to follow but this is the fuel system:


Richard Sent from my iPhone 4
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