Le Roux: I purchased Dennis Haverlah’s nice RV-7A the end of Sept. and now have about 5.6 of the 930 hrs. on it. Dennis followed Tracy’s initial installation where the left tank feeds directly to two (2) filters and then to two (2) Walbro type fuel pumps, located on the floor of the cockpit. The single AN-6 alum. line from the left tank kits a TEE and runs to the filters and pumps (in line), and coming out of the pumps it again Tee’s into a single AN6 which penetrates the firewall and goes to an adjustable fuel regulator. From the regulator it flows to the fuel rails, and returns to the left tank. Dennis connected the right tank to the left tank via another AN-6 line, and there is a facet pump on the floor of the PAX side, and fuel is therefore transferred when needed from right to left tanks.
Since the RV-7A is a side by side fuselage, the one negative I’ve seen with this system is that as fuel is burned down there is a tendency for the right tank get a bit lighter than the left tank, since my weight is left of center, and fuel is also transferred to the left which then tends to also be heavier than the right for much of a flight. It I were doing this again, I therefore would draw from the right tank and feed from the left, which I think would help offset my weight and create a heavy wing situation on long cross country trips.
In this configuration, there also is NOT a way to mechanically turn OFF the fuel to the filters / pumps, and it therefore can only be done by turning off the fuel pumps. Om my 9A “project”, I’m using an Adair valve (w/out auto return), and I initially set it up to pull fuel from the left or right (as selected), and it returns (off the fuel rail) to the left tank. With either configuration the pilot has to make sure too much fuel isn’t transferred or it will flow over the side out the vent line or out a loose fitting tank cap.
Since I now know about the light right wing issue, I’m considering changing the fuel rail return line to go to my right tank...
Doug
RV-7A Renesis flying RV-9A RX-7 / 13B w/4.2 hrs. ground runs
-----Original Message-----
From: Rotary motors in aircraft
Sent: Friday, February 21, 2025 10:15 AM
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: [FlyRotary] Fuel injection Diagram
Hi : Do somebody have a schematic drawing ? Of a typical low wing experimental aircraft fuel system to the 13B.
Can’t find good detail info.
The feed from the wings to the high pressure fuelpumps.
Where to place the low pressure fuel pumps and then to fuel injection pumps.
Must i do a header tank ? or not.Must the high pressure pumps be inside or outside on the firewall?
Regards Le Roux
Sent from my iPhone
Le Roux Breytenbach |