I don't know if this has been posted earlier in this thread (TL:DR ), but I have head great success using Infernal Robotics rotating actuator parts as pitch trim actuators for my aircraft. Set the speed to lowest in the editor, and set up the IR grouping. You could use it for roll and yaw trim, too, but I tend to build aircraft that are fairly stable in roll, and yaw tends to look after itself. It does make the joint a bit wobbly at high speeds, though.