I have always used 2 pumps for takeoff in Piper Aircraft. In the 914 engine,
there are 2 electric fuel pumps. I have assumed both would be on for takeoff
and landing. The fuel pressure is regulated in that engine to 3.5 psi above
airbox pressure.
When I am at a constant power settling. My fuel pressure increases by 2.2 psi
with the second pump turned on. Rotax only allows a range of 2.0 to 5.0 for
normal differential fuel pressure. Increasing the pressure by 2.2 is almost
the whole range! I also have evidence of rich running, which has subsided
since I started to run with one pump only during takeoff and landing. (My
system will automatically activate the second pumnpm if the first one fails).
I can't see anywhere that Rotax addressees whether or not the two pumps are
meant to be run at the same time for safety purposes. To add to the dilemma,
the Rotax manual has the pumps in series, where Europa has them in parallel.
I have mine per Europa.
Simple question: What are people doing in operation? 1 or 2?
Thanks,
Dave
A227
Mini U2
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