Originally Posted by
FCeng84
Got it, thanks for expanding. What I was wanting to know was if you were pointing to an explicit command limit within the control system that would keep from asking more of the elevator actuators than they can deliver vs. a system that asks for everything that is available and takes what it gets when elevator actuators are driven with full available hydraulic pressure. I am familiar with both types of systems. In the case of the 737 the limit is hydro-mechanical in that the elevator actuator control valves are wide open but the elevator hinge moment is more than the actuators can deliver so the surface ends up at a less than full travel position. I am familiar with this being referred to as either "blowdown" or "blowback". Note that if you are flying with high enough dynamic pressure for that to be the limiting factor and you command full elevator with full column and you hold that column and you speed up, the elevator deflection will decrease as dynamic pressure increases. With reference to Star Trek, that's when Scotty says "She's give'n you all there is, there just isn't any more to be had." Glad to provide this answer once I was certain of your question.
The Q limiter was pure mechanical and it limited rudder (DC-9). Same vintage as original B737. I don’t know what the MAX or NG has but I believe all modern jet transport aircraft limit fight controls as Q increases as well as Mach.
My point.... and I do have one.... is that the elevator may have increasingly limited authority as the aircraft AS increased.