Here is what I found out about the heading and course knobs in the 727.

When trying to change the heading or course knobs while the plane is in  motion, your mouse pointer loses focus on the actual knob, and this causes it to spin out of control. If you can keep the mouse over the knob, which can be hard if you are in turbulence, it will work fine.

Just for an experiment. While you are on the ground and stationary, click on one of the knobs to change the course/heading and drag your mouse away from the knob. As soon as the mouse gets away from its focus on the knob, it will just continue to spin and you can't stop it until you place the mouse pointer over the knob again.

This same thing happens to many of the knobs in my other CS aircraft with the exception of the 707 and B-52.

Mark