Governor¶
The Governor shapes motor throttle response, from holding a fixed idle output through to actively governing motor/rotor RPM, rather than commanding a raw linear throttle-to-motor-output mapping. This is distinct from PID tuning -- it governs how throttle input translates to commanded motor output, independent of attitude stabilization.
It's configured from the Governor section of the Motors tab. Setting a mode other than Off and assigning the GOVERNOR switch on the Modes tab turns that switch into a hard motor interlock, not just something that shapes the bottom of the throttle curve:
- Switch off -- the motor is forced to 0% output. The throttle stick has no authority at all, at any position, until the switch is engaged. This is deliberate: it lets you arm and handle the model on the ground without the motor spinning, the same purpose an idle-up switch serves on a heli or helicopter-style transmitter setup.
- Switch on -- idle hold or RPM governing activates as described below, and above the handover throttle (or across the whole stick in RPM Range mode) the stick drives the motor normally.
Arming is blocked while the GOVERNOR switch is on, because an engaged switch takes the motor to idle (or to Min RPM in RPM Range mode) as soon as the model arms, whatever the stick says. Arm with the switch off, then turn it on. The status shows GOVERNOR as the reason arming is disabled. The in-flight re-arm grace window still allows re-arming with it on.
If a mode other than Off is selected but no switch is assigned to GOVERNOR, the interlock does not apply and the motor behaves as if the governor were Off -- throttle passes straight through at all times. Assign the switch if you want the mode you've configured to actually take effect.
Modes¶
| Mode | Behavior |
|---|---|
| Off | Disables the governor entirely; throttle passes straight through. |
| RPM Idle/Max | Holds a target idle RPM below the handover throttle using RPM feedback, starting from the configured Idle Throttle Floor so the ESC is not commanded to zero during a rapid throttle chop. Above handover, the optional max-RPM limit can prevent overspeed. |
| Throttle Idle | Holds a fixed throttle percentage at idle; needs no RPM source, but won't correct for load or battery sag. |
| RPM Range | Maps the throttle stick across a Min RPM (0%) to Max RPM (100%) range, governing speed through the whole flight rather than just at idle. |
RPM Idle/Max and RPM Range modes require an RPM source: bidirectional DShot
telemetry or a frequency sensor. esc_sensor_protocol = FBUS or
crsf_sensors_use_rpm = ON (CRSF Sensors)
can also feed the governor -- nothing in firmware stops it -- but those
update far too slowly and infrequently for closed-loop RPM control to react
safely. Treat that as use at your own risk, not a supported governor
RPM source; see the Gyro
tab's own note on the same limitation for RPM Filter.
Tuning¶
RPM Idle/Max uses Idle Throttle Floor as the minimum powered idle output while the governor is active below handover. The RPM controller then adds P/I correction above that floor to reach the configured Idle RPM. This keeps the motor spinning instead of letting an RPM overshoot drive the command to 0% throttle, which can make the ESC struggle to spool back up.
Set Idle Throttle Floor high enough that the motor keeps turning reliably after a quick throttle chop, but not so high that the aircraft idles faster than you want. If the floor alone produces more RPM than the configured Idle RPM, RPM Idle/Max will not pull below the floor; lower the floor or raise the Idle RPM target. Throttle Ceiling remains the hard maximum output the governor may command, and also caps the effective idle floor.
RPM-governing modes hold their target using a filtered P/I loop: P gain corrects RPM error but always settles a little below target, and I gain closes that remaining gap. Handover Throttle sets the stick position below which RPM Idle/Max or Throttle Idle takes over (not used in RPM Range mode, which spans the whole stick). When the stick rises past Handover Throttle while the held idle is higher than the stick, the output eases down to the stick instead of stepping; raising the stick further takes over at once.
Throttle Ceiling defaults to 30%
Throttle Ceiling defaults to 30%. That is a sensible cap for an idle hold, but in RPM Range mode it also limits the whole flight, so the motor cannot go above 30% throttle. Raise it (usually to 100%) when you use RPM Range.