Hi Juergen,
Re routing the return line in this way is negating the main reason to have
it in the first place.
The main reason for the return line is to purge vapour and hot fuel trapped
in the lines close to the carbs, back into the tank. The Manual instructs
to have the return line as close as possible to the port [ second in the li
ne] carb, so all of it gets purged.
Returning fuel to the tank from the line before the transducer, leaves all
the fuel downstream of that, forward of the firewall to the carbs, in the
hot cowl after shut down.
When plumbed as per Manual, the hot fuel gets returned to the tank, with fr
esh, cool fuel feeding the engine, [ and cooling the lines at the same time
].
If installed in the standard Europa XS cowl, this area gets up to, and some
times above 80C for a while after shut down on a hot day. If installed as y
ou are describing, you have an accident waiting to happen. [vapour lock in
the climbout after a short shutdown].
Fire sleeve / insulation of the lines is only a half way fix.
Regards,
Nev.
-----Original Message-----
From: europapa <experimental@online.de>
Sent: Tue, 25 Sep 2012 22:51
Subject: Europa-List: Re: fuel flow
I made my experiences with the installation of only one transducer.
am using the floscan transducer and a separate fuel computer.
he quantity of fuel that returns may nearly be constant ( not in my
nstallation, as the fuel pressure is for any reason not always the same ) b
ut
ou can only trick the computer with an matching K-factor for only one defin
ed
ower setting.
ne of the most important questions to the fuel computer for me is: how much
uel is left in tank after for example two hours flying?
ut in a flight we use different power settings so the number the computer
howed was rubbish.
o I redesigned the fuel routing:
he fuel line from the mechanical fuel pump now goes all the way back throug
h
he fire wall to the cavity where the fuel select switch is.
here I installed a y peace. One line goes with the restrictor in it back to
the
ank while the other goes in a strait line and with the transducer in line b
ack
hrough the fire wall to the carburetors.
o only the fuel used by the carburetors is measured and the accuracy is
utstanding. After burning 40 liters there is only a discrepancy of half a
iter.
nd I have too all the benefits Raimo mentioned and I agree with him that th
is
ystem should be mandatory.
orry for my bad phrasing.
Juergen
ead this topic online here:
http://forums.matronics.com/viewtopic.php?p=383996#383996
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