Originally Posted by Michael1282
Spoiler deflection cannot be related to IAS or something like that.
It starts at a specific point of control wheel displacement and is proportional to this.)
Well, just for completeness....
there WILL be some speed above which the hinge moment on the spoilers will overcome the capability of the actuation; whether that speed is operationally significant or not is type-dependent, but I'd expect that you'd start seeing effects at about Vmo. (below that, you typically want to have the spoilers available; less need above, so Vmo as a design speed wouldn't be a bad first guess)
Also, it is conceivable that one might vary the wheel-spoiler schedule with speed (perhaps Mach, most likely) to reflect changes in control effectiveness. (Though off the top of my head I don't *think* we do so)