There seems to be some thread drift away from the original query which was about when parallel yaw dampers were used! I seem to remember a rudder pedal force of 150lbs being required on the B707 with an outboard engine out - serious `leg shake` quickly followed if the rudder was not trimmed soon thereafter. Somewhat more physically taxing than what I now do on my Airbus! What I think 411A has been alluding to is the greater emphasis on pure aircraft handling on the older generation of aircraft (due mainly to the very crude automatics) compared to the way that we are trained to operate modern aircraft. I am sure that there are not many civilian pilots trained in the last 15 years who will have hand flown: emergency descents in the aircraft, two engine out landings (on a quad) and simulated jammed stabiliser landings on an aircraft. These things were quite common due to poor simulator fidelity - but they did result in many accidents and were VERY EXPENSIVE on the training budget.