13.4. Main motor setup

13.4.1. Transmitter throttle reverse setup

If you have a Futaba transmitter and a Castle Creations or Schulze ESC, then you will need to reverse the throttle for this step. The throttle reverse may be necessary for other transmitter and controller combinations as well.

13.4.2. ESC programming

[Note]Note

Be sure to remove the motor pinion when programming the ESC! This will ensure the main rotor will not spin accidentally.

If you are using a programmable ESC which uses the transmitter to set the ESC options and you have previously set a throttle curve for this model, then you may need to reset the throttle curve to default (e.g. linear from 0 to 100%) to program the ESC otherwise the ESC may not be able to recognize the low-middle-high stick positions.

13.4.2.1. Castle Creations ESC parameters for the MAIN motor

  • Cutoff Voltage: as low as possible so the heli will not fall out of the sky. If you are using lithium polymer batteries, you will need to be careful not to drain the batteries beyond the recommended minimum voltage.

  • Current Limiting: insensitive

  • Brake: disabled - so we don't strip the main gear when the motor spools down.

  • Throttle Type:

    • For FP helis: fixed endpoint

    • For CP helis: If you are learning hovering (and are planning to fly in normal mode) then you must use the fixed endpoint mode. Otherwise, if you plan to use the idle-up mode, you should use try the low governor mode first, and if there is not enough headspeed, try the high governor mode.

  • Timing Advance: depends on motor, choose standard if unknown

  • Cutoff: soft

  • Soft start:

    FP helis: fast start (soft start has problems when used with FP helis on some firmware versions)

    CP helis: softest start

  • PWM Switching Rate: for coreless (non-cogging) motors, set to the highest switching frequency; for other motors, set to a lower frequency.

[Note]Note

Do NOT use autocalibrate mode. This mode only works properly if the throttle is moved to full throttle to set the high throttle endpoint position. This cannot be safely done on a helicopter because the helicopter will climb very rapidly.

13.4.2.2. Castle Creations ESC parameters for the TAIL motor

If you have a tail motor ESC, then it will require programming as well. You should temporarily plug the tail motor ESC into the throttle channel on the receiver to program it.

For the Castle Creations ESCs used as the TAIL motor ESC, the following parameters should be used:

  • Cutoff Voltage: as low as possible so the heli will not fall out of the sky. If you are using lithium polymer batteries, you will need to be careful not to drain the batteries beyond the recommended minimum voltage.

  • Current Limiting: insensitive

  • Brake: disabled - so we don't strip the main gear when the motor spools down.

  • Throttle Type: fixed endpoint

  • Timing Advance: depends on motor, choose standard if unknown

  • Cutoff: soft

  • Soft start: Choose fast start

  • PWM Switching Rate: depends on motor, but 11 khz is fine for most tail motors

13.4.2.3. Schulze ESC parameters for MAIN motor

[Note]Note

0 = switch in LEFT position with label readable

1 = switch in RIGHT position with label readable

1. Switch 1: 0 - aircraft mode

2. Switch 2: 1 - helicopter mode

3. Switch 3:

FP helis: 0 - normal speed controller

CP helis: 1 - governor mode

4. Switch 4: 0 - high rpm mode

5. Switch 5: 1 - soft timing

6. Switch 6: Set to 1 (19 khz) for coreless (non-cogging) motors; for other motors, set to 0 (9khz)

For other ESCs, set the parameters using the above parameters as a general guide.

If you have a programmable ESC which is programmed using beeps then you should carefully watch the tail servo when the ESC beeps. If your tail servo wiggles every time the ESC beeps, then your gyro or gyro wires are too close to the ESC.

13.4.3. Transmitter throttle setup

  1. Remove the MAIN BLADES from the helicopter

  2. Secure the helicopter so it cannot move.

    For a nonmicro heli, put a wooden beam or two-by-four through the skids and place a brick or other heavy object on each end of the beam. For a micro heli, put a piece of wood through the skids and clamp the wood to a table on both sides. Also, make sure the tail rotor is away from any objects.

  3. Install a battery in your heli, then follow the ESC directions to arm the ESC. If your ESC does not arm, then you may need to reverse or unreverse the throttle direction.

  4. Give just enough throttle on your transmitter to make the head spin a little.

  5. If your main rotor blades are spinning backwards, and

    1. If you have a brushed motor and a brushed motor controller, then you need to swap the two motor wires.

      If you have a diode (looks like a black barrel with a grey stripe around it, and two wires at either end of the barrel) wired to your motor, then be sure to swap this also because the grey band should be on the positive (red) wire to the motor. The capacitors (usually yellow discs with two leads) are not polarized and do not need to be swapped.

    2. If you have a sensored or sensorless brushless motor and a sensorless brushless motor controller, then you should swap any two of the three motor wires.

    3. If you have a sensored brushless motor and a sensored brushless motor controller, then you should consult your motor manufacturer. This usually requires the motor to be sent back to the factory to have the motor retimed.

13.4.4. Transmitter throttle hold setup

You should follow the transmitter manual directions to enable the throttle hold function on your transmitter.

Throttle hold is very good because it prevents the heli from throttling up if you must work on the heli while it's powered and something bumps the joysticks.

[Note]Note

The throttle hold mode may have its own pitch curve.

If this is the case, you will need to set this the same as your normal mode or idle-up mode to ensure the heli does not "hop" when you hit throttle hold to spool down the heli.

13.4.5. Transmitter throttle curve setup (FP heli only)

For a fixed pitch heli the throttle curve should be left as default - linear from 0 to 100%. It is not necessary to check the headspeed because you are unlikely to exceed the maximum headspeed, as the heli will take off like a rocket if the headspeed is too high.

13.4.6. Transmitter throttle curve setup (CP heli only)

[Note]Note

This step should be performed outdoors for two reasons.

The first reason is: tachometers do not work well with flourescent light because the light flickers at high speed.

The second reason is: It is very difficult to dodge an out-of-control helicopter inside a small room.

For this step you will need a tachometer. Borrow one from a friend if necessary.

First, set your normal mode throttle curve using these settings:

  • Five point throttle curve: 0-50-90-90-90
  • Three point throttle curve: 0-90-90

Second, determine the your desired headspeed using this table:

Table 13.2. Recommended headspeeds

 Headspeed
CP micro heli2000-2400 rpm
ECO 81400-1800 rpm
Other CP nonmicro heli1600-2000 rpm

If you are a beginner, then use a headspeed at the lower end of the range. If you are experienced, then use a headspeed at the upper end of the range.

Third, immobilize your heli so it will not fly by weighting it. For a micro heli, you can put a small ruler on top of the skids and weigh down the ruler with bricks on both ends. For a nonmicro, you can use a larger piece of wood and cinder blocks. Be sure to use a heavy weight on both ends. Make sure your landing skids will not separate from the helicopter frame.

Fourth, select the two-blade propeller mode on the tachometer. Next, place the tachometer underneath the helicopter so the sensor points upward and the rotor blades will pass over the sensor. Make sure the flybar and flybar paddles do not pass over the sensor because this will cause an incorrect headspeed reading.

Now follow the helicopter power-on procedure and arm the helicopter ESC. Be sure to stand a reasonable distance away. Slowly spool up the helicopter using the throttle stick and watch the tachometer reading. If the headspeed goes beyond the upper expected range, stop immediately, because the helicopter may throw a blade if the headspeed is too high.

If your headspeed is too high before you reach half stick (90% throttle), then you should use a pinion with a lower tooth count. If you are already using the smallest tooth count pinion, then you may need to lower the maximum throttle values to 85% or so to lower the headspeed slightly. Do not use a maximum throttle value of less than 85% because this may overheat the motor. See Section 30.1.10, “How ESCs work” for an explanation.

If your headspeed is still too low by the time you reach half stick (90% throttle) then you should try a pinion with a higher tooth count.

After you have adjusted the headspeed properly, copy the maximum throttle value to all points on the idle-up 1 throttle curve. If your maximum throttle value is still 90%, the idle-up 1 throttle curve should be:

  • Five point throttle curve: 90-90-90-90-90
  • Three point throttle curve: 90-90-90