Rich,
I'll run mine or Bakers tomorrow, weather permitting, and see what my
fuel pressure does. If memory serves, I start at 4 psi at idle and at
full throttle still see about 4 in line, and about 10.0 off the
regulator (my sender reads a little low). My gut feel is that regulated
fuel pressure is going up with manifold pressure as it should, but if
line pressure is going up to the regulator, that does not pass the
common sense test. On ground tests, the fuel pressure goes up as the
resistance goes up.
Example:
When I set up a fuel system, I disconnect the feed and pressure gauge
---From the engine fuel regulator and pump fuel through the lines past a
direct reading pressure gauge (Tee'd to the aircrafts sender) and
through a valve to a gas can. This allows me to filter the system,
verify flow rates (by timing) and by closing off the valve, I can verify
the fuel pressure, the fuel flow decreases and the pressure goes up well
above 7 psi as I check flows and verify pressure readings. Note: These
readings are done before the regulator.
11.6 psi indicates a strong reduction in flow if reading prior to the
regulator, however if you are reading from the regulator, the regulated
pressure at full power 39.5 MP is about 5 psi boost, and 11.6 psi fuel
pressure is a tad high.
>From Page 9.2.3 of the Rotax maintenance manual, Fuel pressure =Airbox
pressure + 250hPa At takeoff performance the fuel pressure is going to
be about 700hPa or around . 7bar or about 10.15 psi
I'll talk to you after testing.
The shop took a lightning strike and power surge, so I have only one
shop phone left and it blew my shop computer, even with the surge
protectors. Pretty spectacular really. Snap crackle pop all in one. I
will be slow at answering emails for a few more days.
Bud
----- Original Message -----
From: TheSchultzFamily<mailto:Theschultzfamily@comcast.net>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Thursday, July 02, 2009 9:08 PM
Subject: RE: Europa-List: Fuel system - More Questions!
Can anyone verify these "non" differential fuel pressure readings?
MP = 14.3 Fuel = 4.6
MP - 14 Fuel = 4.9
MP = 20 Fuel = 4.9
MP = 25 Fuel = 6.4
MP = 30 Fuel = 9.1
MP = 39.5 Fuel = 11.6
Engine seems to be running fine with these but earlier in the process
the engine was once again surging. Everyone that hears the surging
thinks I have a fuel problem????
Monitoring and testing continues...
Rich Schultz
N262AE
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