Message-ID: <001701bf5b3a$35cfb9e0$9a31143f@oemcomputer>
Reply-To: "dfs" <dfs@gateway.net>
From: "dfs" <dfs@gateway.net>
To: "Lancair List" <lancair.list@olsusa.com>
Subject: LNC 20 Fuel Vents and Aileron Bracket
Date: Sun, 9 Jan 2000 23:13:34 -0800
Mime-Version: 1.0

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In answer to Jeremy F Fisher's question about the adequacy of 1/4" vent
lines. Should do the trick, Jeremy; I don't know which engine you're using
but even if your fuel flow at max take-off power is say, 20 GPH, that's only
about 0.33 gals/ min and since air is less dense than fuel, it should flow
at that rate ealily without bogging down. during cruise, when flows are more
reasonable, it's even better. Cutting the end of the external tube at a 45
degree angle with the opening facing the slip-stream should also help.

Thanks for the vote of confidence re: the method of running your internal
vent lines. I've never had fuel drain out of topped off tanks even when
parked on a decidedly sloped ramp. Just be sure that the vent lines run from
as far outboard as possible along the highest part of the inside of the
tank, and as far inboard as possible before turning downward 90 degrees to
penetrate the bottom of the tank.

For you others out there, if you visualize the geometry of such routing, you
can see that they are reasonably leak-proof.

An additional fillup for your consideration. At each vent outlet from it's
respective tank, I installed a "T" fitting. Straight thru to the vent outlet
on the bottom of the wing (or fuselage for the header) and to the "T" tap, I
installed a very low cracking check-valve which will vent the tank in case
the external one gets plugged with bugs or ice or whatever. The inlet end of
the check-valve is covered with a couple of layers of cheese cloth (to
discourage any bugs from taking up residence) held on with a small tie-wrap.
Getting the vents plugged has always been one of my nightmares - I could
just visualize the wing collapsing as I pumped out the fuel. The valves will
preclude this.

Dan Schaefer

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