John the Mod;
Originally Posted by JT #2069
gums has made some comments on the F16 stick. I recall from a course years ago (so it might be scratchy) that the initial test article had a zero break out stick arrangement which was unflyable due to low level muscular tremors. If I recall correctly, the initial mod was to introduce a 4lb break out load to get rid of the non-commanded small perturbations.
In manual flight, the A330 sidestick has a breakout force. It is enough to prevent small motions. However, the experience I've had in heavy turbulence is that, even when the elbow and lower arm are planted firmly on the armrest and the sidestick is moved only through the wrist or more likely through just the fingers, it is difficult to not "stir the pot" or more importantly to achieve consistent, steady in puts in one direction, (subtle or large inputs).
The inertia of the arm/hand responds as one would expect in heavy turbulence, and if the stick is gripped firmly instead of being ridden loosely, (while trying to achieve steady inputs in one general direction), the stick inputs will follow the movements of the hand/arm.
In the meantime, the flight controls, even in ALT2, will all be trying to satisfy all movements of the stick (within the limits of ALT2) while trying to satisfy the commands of the flight control laws in keeping the aircraft at its last-commanded attitude. gums mentioned this phenomenon earlier but it didn't get much play. In FBW, the flight controls are not in a steady, fixed state...they are always moving, attempting to keep the aircraft in its last commanded attitude. In manual flight, these inputs are blended with the commands from the sidesticks, to produce what, in flight data work, looks like a mashup instead of steady state control.