Servo trimming
Because the neutral position of each servoactuator is slightly different, servo trim needs to be set for each Flapper individually. The servo trim is already set in production, however, you might need to redo this step if you notice that the Flapper tends to fly forward or backward even at zero pitch input, or if it tends to turn left or right. This can happen e.g. if the servos get a big hit due to a crash. You will also need to follow this procedure if you replace the servos or the flight control board, or in some cases after a firmware upgrade.
To set the servo trim, you need to have the cfclient application installed on your PC and you will also need the Crazyradio 2 or Crazyradio PA USB dongle.
This guide assumes your Flapper is running the latest firmware. For very old firmware versions, if upgrading to the latest firmware is not desirable, please contact our support for legacy instructions.
1. Launch the cflient, e.g. by opening your Terminal/Power Shell and typing:
cfclient
Make sure your Crazyradio dongle is connected before starting the client.
2. Connect to the Flapper by clicking “Scan” (1), selecting the interface "radio://..." from the drop-down menu (2) and clicking “Connect” (3):
3. Go to the Parameters Tab (1) and open the “flapper” (“_flapper” in older firmware versions) parameter group (2) to adjust the values of the servo-trims. “servPitchNeutr” corresponds to the pitch (top) servo (3). The value represents the percentage of the servo stroke, and is set to 50% by default. It may have already been set to a different value at the factory. Typically, you should only need to adjust this value by a few percent, but a range of 25% to 75% is allowed.
If you do not see the “Parameters” tab, you can enable it in the main menu (“View” –> “Tabs”)
Keep adjusting the pitch servo trim by typing a new value (4) and clicking Set (5) until the wing leading edges are aligned:
Finally, click on Store (6) to save this value permanently and make sure the new stored value is displayed. You might need to clear the previously stored value first. Now the Flapper will use the stored value also after reboot (power-off –> power on).
4. Follow the same procedure and adjust the yaw servo trim value “servYawNeutr” until the yaw arm is aligned with the servo housing. Do not forget to store the final value!
