Power loss on climb with 912UL
in 912 / 914 Technical Questions
7 years ago
On two occasions two months apart I have experienced rpm decreases shortly after takeoff. Examination of the data logs reveals that 2-3 minutes after takeoff the fuel flow suddenly diminishes. I have my hand on the throttle throughout the climb, so the throttle is not backing off unintentionally. Today I did not use the electric boost pump and I returned to the field as soon as the problem occurred so do not know if that would have fixed the problem. On physical examination the Rotax 912 UL revealed no anomalies. All of my fuel lines are in firesleeve. I’m burning RON 92 mogas, and added STP octane booster.
The OAT was between 72-80°F on these early morning flights which commence at sea level. I typically have to sit with the engine idling for 10 minutes for the oil to reach 120°F prior to taxi. On returning to my hangar I did a static run up before shutting down and of course the engine reached 5100 rpm, as it should.
I’ve attached some of the data. The top traces show fuel flow and altitude, so you can see that fun flow drops during the climb.
Bottom traces show rpm and EGT.
I’m not sure what to do to troubleshoot this—or if I should just power on using the electric fuel boost pump the next time this happens and see if this transient problem disappears—maybe vapor locked? Thanks...Adam
The OAT was between 72-80°F on these early morning flights which commence at sea level. I typically have to sit with the engine idling for 10 minutes for the oil to reach 120°F prior to taxi. On returning to my hangar I did a static run up before shutting down and of course the engine reached 5100 rpm, as it should.
I’ve attached some of the data. The top traces show fuel flow and altitude, so you can see that fun flow drops during the climb.
Bottom traces show rpm and EGT.
I’m not sure what to do to troubleshoot this—or if I should just power on using the electric fuel boost pump the next time this happens and see if this transient problem disappears—maybe vapor locked? Thanks...Adam
28_Aug_data.pdf (You do not have access to download this file.)
28_June_logs.pdf (You do not have access to download this file.)
