Sunday, June 18, 2017

Redundant Fuel Pump

Fellow Peach State Rotorcraft Club member Louis Gulley helped me remove the old pump that transferred fuel from the auxiliary tanks to the main tank and install this new pump on my gyroplane. It establishes a redundant system to the engine. Both fuel pumps feed off all three tanks. The electric pump will be used to prime the carbs then turned off until take off and remain on throughout the flight.

1 comment:

  1. Testing
    The first test was with the seat tank empty and only 2.5 gallons in the two auxiliary tanks.  The electric fuel pump primed the carbs as planned and the engine ran just fine warming up and taxiing.   I turned the electric fuel pump back on for the takeoff climbed out and made the pattern with no issues.  However, during the descent I decided to throttle back up and fly down the runway and the engine bogged down and would not go back to a cruise setting, so I landed.  It was apparent that the fuel during the descent with the nose down could not get to the pumps and the engine was being starve for fuel.
    I decided to fuel up the seat tank and run one more test.  I flew for 30 minutes to see if the system would draw equally off the seat tanks and auxiliary tanks.  It did not, most of the flight used on fuel from the seat tank.  This would result in the seat tank running out of fuel first and would mean that on a long flight, I would not have a dependable reserve from the auxiliary tanks based on the results from the first test.
    Another issue was also noted during the second test, the electric pump was creating too much pressure for the system to handle and I was getting lots of fuel overflowing the carbs, etc.   So I decided to go back to simply using the fuel pump to transfer fuel to the seat tank from the two axillary tanks.  This setup gives me a full 2 hours of flight time with a 20 minute reserve.  I just have to use a timer and turn the pump on after 45 to 50 minutes of flight.
    This post flight inspection also led me to finding 4 bolts that hold the carb sockets onto the engine being loose, that I quickly tightened.