Off-the-shelf Active Control Loading for a 737 simulator

2 min readMar 12, 2022


Here is some information about how I have added Active Load Control (ACL) To my flight simulator using off-the-shelf hardware and my own software.

Works with Pro-Sim and MSFS or P3D.

Sample Videos

Auto Pilot

Hydraulic Power

Aileron Trim



ACL Software Features:

The AC servo motors are very strong. They come with a driver that controls the position and torque. Torque can be as high to the point you can’t move them by hand.

Be default the servo tries to keep the starting position. When forcing against the center position, the servo will try to auto-center. This is what self-centers the controls.

The amount of force (torque) it takes to move the controls can be controlled via the software. Also the position for Auto Pilot can be controlled.

  • The servo motors are controlled by a servo driver they come with.
  • The driver’s position is controlled by Arduino
  • The driver’s torque is controlled via USB/RS485
  • The ACL software is the layer between pro-sim and Arduino/RS485 com.

Softare Download:


Source code:

Connection Diagram.

Please contact me for full details on how to connect it all together.