Rich,
Call on the cell as I'm all over the place this week.
My runup on Saturday was on Baker's 914
The FP was 4 psi solid until boost started to kick in.
4 PSI until passing 30 inches.
Max continuous 100% throttle at 35 inches mp, airbox at about 2.5 psi
boost fuel pressure 5.9 to 6.2
Full 115% throttle at 40 inched mp, airbox at about 4.8 psi boost, fuel
pressure 9.8-10.
At full it should have only gone to about 9 for the atmospheric
pressure, but I read 10, and that's in limits.
Setup was a boost gauge on the airbox, direct reading gauge on the fuel
pressure nipple with the restrictor pressed into the end of the brass
banjo. Sure wish I had it mounted better, what a vibrating nightmare
until I wire tied the mess together.
Look at the maintenance manual and you can see by all accounts you are
reading just a little high.
Pay attention to the chart on page 9.5.2 of the maintenance manual, and
do the conversions for the airbox pressure, and fuel pressure.
I'll be on the cell as I have UCF students doing their project and test
flying this evening weather permitting.
Bud
----- Original Message -----
From: TheSchultzFamily<mailto:Theschultzfamily@comcast.net>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Friday, July 03, 2009 9:52 AM
Subject: RE: Europa-List: Fuel system - More Questions!
Bud,
The reading was taken off the double banjo that feeds the passenger
side carb. This as done when the engine seemed to be running correctly.
Being at sea level and with about a 29.8pressure day I figured these
did not sound too bad. I do have the original differential pressure
sender. I will fire it up at work on Monday and see if it is reading
correctly before installing it or ordering a new one. Aircraft spruce is
very proud of that little sender now days.
-------------------------------------------------------------------------
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From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of
ofamerica.com YERLY
Sent: Thursday, July 02, 2009 11:11 PM
To: europa-list@matronics.com
Subject: Re: Europa-List: Fuel system - More Questions!
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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