Re: Pulling a Stop to Runway Overruns
OVERTALK, your description of back stick “acting against the distant nose-gear fulcrum to lever the main-gear INTO the deck” requires the nose oleo to act as a solid structure whilst the main oleos compress as indicated in your diagram, the result of which will increase the AOA and wing lift, and thus defeats the objective.
A better example would be to consider the compromise between a compressible and a rigid oleo for both the nose and main gear. At some point, the fulcrum moves to the main gear – a first order lever, and the aircraft will rotate about the ‘rigid’ main oleo. This is the opposite of de-rotating after touchdown, where the aircraft rotates about the main gear as the amount of up-elevator is reduced, transferring some load to the nose gear..
Putting the rotational issues aside, the problem is actually about the transference of load on the gear. Aircraft designs are such that the majority of this is carried on the main gear; the load on the nose gear provides directional control, particularly as airspeed reduces.
Thus, as MFS indicates the % of load that can be transferred to the main gear is proportionally small and depends on many variables in the aircraft geometry and control characteristics. Thus, it is extremely difficult to judge any benefit to be gained, and if any, the effect diminishes rapidly with speed (V*2).
What many pilots perceive is that up-elevator feels as though it helps, but we should remember that the forces being sensed during decelerations can be misleading, particularly so in a simulator.
The simple overview is that the majority of the theory is correct, but in practice, there are too many variables for crews to judge.Thus they should not deviate from the manufacturer’s advice.
OVERTALK your picture links suggest that you have a close association with IASA. If that is so, I suggest that you restrict the more extreme views on how to enhance flight safety, however well intention they might be, to the IASA web site; along with the comments from possible ‘associates’ participating in this thread.