Bob,
> If you had a big flow you'd finish up heating all the fuel in the tank
I don't think so - the temperature of the fuel in the return line will vary with
the flow (the higher the flow, the lower the temperature as the fuel spends
less time exposed to heat). So although more fuel is re-entering the tank, it's
temperature is lower. Given the geometry of the system it's hard to see tank
heating being other than a negligible consideration.
The restrictor is to ensure the minimimum specified pressure at the engine fuel
pump/carb inlet can be maintained in all attitudes. The required pressure is
a function of the particular engine type. The orifice needs to be small enough
to produce it (with an adequate margin) but still allow enough flow to prevent
vapour lock in the line between the firewall and the inlet in worst case
conditions.
These will most likely on the ground with the engine running on a hot
day (minimum fuel flow into the engine as it is idling and minimum air cooling).
Providing the pressure criterion is met the exact size should not be critical.
Best regards,
Nick
-----Original Message-----
From: "R.C.Harrison" <ptag.dev@ukonline.co.uk>
Subject: RE: Europa-List: Fuel lines/fuel lines/
Hi! Tony /Troy /All interested.
The restrictor in the fuel return line is purely to return a minimal ammount
of hot fuel back to tank. If you had a big flow you'd finish up heating all
the fuel in the tank..... somewhat pointless then having a return to tank
line!????
Regards
Bob Harrison G-PTAG Europa 337 MKI/Jabiru 3300#084
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