From:
Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Al Gietzen
Sent: Tuesday, February 08, 2005 5:55
PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Bad day at the
airport
Do you have a bleed circuit between your pump and fuel
pressure
regulator? Do you have heat shields on your fuel
lines? My guess is that
you may have experienced vapor lock. Without a
bleed circuit, the fuel
pump can't produce enough pressure to overcome the
fuel pressure
regulator
This should only
be an issue if the pump is not located at the lowest point in the line from
the tank. As long as there is liquid at the pump inlet – no
problem.
Al
Al,
What happens if the
lines in the engine bay and fuel pumps get hot enough for the fuel to boil
inside them? Are the pumps still going to produce enough pressure to
function normally? My guess is no. Paul said his coolant
temp was 210+. He had been doing extended ground runs followed by some
taxiing, which would allow for lots of heat soak and little cooling air.
I imagine the fuel pumps and lines were pretty warm. Maybe warm enough
to cause vapor lock.
I would also like to
know what type of fuel he was using at the time? If he was running
mogas, has he checked the vapor pressure of the fuel?
Paul, do you have a
return on your fuel system? If so, where does it return to? What
size lines?
Mark
S.