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From: David Weinsweig <weinsweigd@gmail.com>
Subject: Re: [LML] Propjet belly tank

Yes there are potential issues with the standard Lancair Propjet fuel system=
. First is the fuel in the belly in the event of a gear up landing though I h=
ave not heard of this ever having created a true problem.=20

Second which as far as I know HAS been an issue is refueling after burning f=
uel in the belly tank. The wings feed the belly tank which feeds the engine.=
 Refueling occurs only in the wings. If the belly tank is say half full and t=
he wings are topped off it takes some time for the belly to refill which wil=
l drain the wings. I have heard the fuel draining into the belly tank throug=
h the fuel lines. This can give a false sense of full fuel. If you takeoff b=
efore the belly is full ie still with air in the belly a high climb angle ca=
n unport the engine causing flameout.=20

I believe that there can be other scenarios such as uncoordinated flight whi=
ch may force air into the belly tank but paying attention to the center(bell=
y) tank fuel gauge should alert the pilot to this issue.=20

IMHO as long as these issues are recognized the standard fuel system is simp=
le and works fine. Left, right, or both-that's it.=20

There have been modifications to the Propjet fuel system with a small header=
 tank which in theory cannot be unported but as far as I know this involves h=
aving to actively transfer fuel between tanks which IMHO may create other is=
sues.=20

For me, I know my system and it works fine. If someone is interested in chan=
ging their fuel system, talk to John Cook.=20

David=20

On Jun 8, 2013, at 12:58 PM, "Craig Jimenez" <cj@AwlBiz.com> wrote:

>> or change the fuel system all together which has
>> been advocated by some but that opens a whole new conversation thread.
>=20
> What's considered state of the art fuel system plumbing to avoid unporting=

> the belly tank (to include avoiding a complex or time-consuming fueling
> process after you've started to use the belly fuel)?  I've heard some have=

> "updated" their configuration in recent years.
>=20
> I've heard of one propjet that has left, right, or both wing tanks feeding=

> the belly tank, which then feeds a header tank that is designed to
> eliminate any air.
>=20
> Craig
>=20