But we won't know how long time it takes to wind up to constant speed and without running for a while this will attribute to a fairly large error. From the auda

But we won't know how long time it takes to wind up to constant speed and without running for a while this will attribute to a fairly large error. From the audacity FFT plots we see that it takes a fairly long time (100's of ms) to get to the target speed (ie the rise time of a step response).