Mailing List lml@lancaironline.net Message #7565
From: <Theo_Green@firstar.com>
Subject: Re: Commander singles fuel system
Date: Tue, 14 Nov 2000 10:49:44 -0600
To: <lancair.list@olsusa.com>
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I will preface my comments with, "I don't know how the Lancair tanks are
configured," that being said...

The Glasair is typically built with one main tank. This tank fills the LE area
and drains to a common sump in the center section. If you unport it, it's
probably because you're down to 3-4 gallons and doing weird things with the
stick. Fuel is free to slosh from one side to the other, but is controlled by
flapper valves in the center section that will let fuel in, but not out (or
toward the tips.) Bottom line -- I don't see how the unporting threat is any
more significant with a single tank in the normal category regime. But please
correct me if I'm wrong! I do see how (especially without a wing-leveler/aileron
servo) balance could be a factor. The fact is that high performance aircraft
really enjoy the spiral mode and tend to lean that way without much pushing
(couldn't help that one <G>.) I would be interested to hear other opinions on
how helpful switching tanks is -- besides keeping your head in the game.

The second thing I would advise is not trusting ANY gauge to try and max out
endurance times (even fuel flow meters.) Unless you have a way to see in a tank
to ascertain its level, I would not push the numbers calculated in preflight and
verified in flight. I also like the idea of a header tank to switch to in case
I put myself behind the eight-ball and need an extra 45 minutes to make a field.

I want to research the feasibility of a facet pump continually feeding the
header and controlled with some sort of automatic switch. Any good plans out
there?



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