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Governor Setup

A walk-through for an electric helicopter. For nitro, see Nitro Helicopters. Read Governor first if the terms are new.

Blades off

Do all of this with the main and tail blades removed until the final test.

Before you start

  • RPM measurement works, with the right gear ratios and pole count: the Motors tab shows a sensible rotor speed.
  • The ESC is in fixed-wing / external governor mode -- its own governor off -- so it follows the throttle signal directly. (Some ESCs call this linear throttle or, on FlyRotor, RF Gyro Governor.)
  • The ESC's throttle range is calibrated to the flight controller's Low Throttle and High Throttle on the Motors tab, so 0% is just below motor start and 100% is full power.

1. Global settings -- Governor tab

On the Governor tab:

  1. Governor Mode: ELECTRIC.
  2. Throttle Type: NORMAL for throttle on a switch, SWITCH for several headspeeds on one switch, FUNCTION for ExpressLRS switch channels.
  3. Handover Throttle: the default 20% is fine for most ESCs. The motor must start below it.
  4. Spoolup Time: about 10 s for a gentle spoolup on a large helicopter; shorter for small ones.
  5. Throttle Hold Timeout and Autorotation Timeout if you want those features.

Save and Reboot.

2. Headspeed -- Profiles tab

On the Profiles tab, set Full Headspeed to the headspeed at 100% throttle input. Leave the gains at their defaults for now.

What headspeed?

Use the helicopter manufacturer's recommendation. The governor needs about 15-25% of throttle in reserve to hold the headspeed under load: if the throttle sits near 100% in a hover, the headspeed is too high for the motor, battery and pinion.

3. Throttle on the radio

Rotorflight needs a separate throttle channel (not mixed with collective) and a throttle hold.

One profile, Full Headspeed set to your highest headspeed. The radio sends a different throttle value for each flight mode:

Switch position Throttle Headspeed (Full = 2500)
Throttle hold stop (below 0%) motor off
Idle up 1 70% 1750 rpm
Idle up 2 90% 2250 rpm
Idle up 3 100% 2500 rpm

Simple: one tune covers all headspeeds.

The throttle is either stop (hold) or 100%. A 3-position switch selects a profile through an adjustment, and each profile has its own Full Headspeed -- and its own tune. See Profile Switching.

4. Test

  1. Blades off. Arm, release throttle hold.
  2. The motor should spool up gently and settle at the target headspeed -- watch the Motors tab or the headspeed on your radio.
  3. Flick throttle hold on and off quickly: it should recover fast.
  4. Fit the blades and do the same in a hover. The headspeed should stay steady through collective pumps.

If the headspeed surges or hunts, or drops under load, see Governor Tuning.

ESC notes

FlyRotor

  • In the FlyRotor ESC Configurator, set ESC Mode to RF Gyro Governor, and set Motor ERPM Max (use its speed calculator; aim for 75-85% throttle at your headspeed).
  • FlyRotor's default throttle range is 1100-1940 µs. Set Low and High Throttle on the Motors tab to match, or teach the ESC new endpoints: override to 100%, connect the battery, wait for the beeps, then override to 0% and wait for the beeps.
  • A lower Handover Throttle (10%) works well.
  • Set the ESC telemetry protocol to FLYROTOR, and its telemetry wire for forward programming. On 155A and 280A models, the motor temperature sensor appears as ESC Temp 2 -- enable that telemetry sensor to see it on the radio.
  • If the tail kicks on spool-up, lower Starting Torque in the ESC.

Hobbywing, Scorpion, YGE, Kontronik and others

Set the ESC to its external governor / fixed-wing / linear mode and calibrate its throttle range. Most can be programmed through the flight controller -- see ESC Forward Programming.

Using the ESC's own governor

If you'd rather let the ESC govern, use DIRECT mode: the flight controller still gives you slow spoolup, fast recovery and autorotation bailout, and passes your throttle (the ESC's headspeed setting) through.