The reason for the change to series based pumps is to bring the fuel pressure
down
to that specified by Rotax. If you measure the differential fuel pressure
to airbox pressure as recommended then you'll find that the pressure delivered
by parallel pumps is too high.
Having said that. There are many 914's flying with parallel pumps as this is
what
Rotax used to show in the installation manual.
Unless you intend retrofitting the UMA pressure sensor there is no need to
change.
For new installations the Rotax manual now shows pumps in series with bypass
valves
Tony
|