Keys and MOI - wipp assist

[Fred Sturm]

	In this discussion there have been references to wippen assist springs, 
but no thorough description of exactly what their effect is, particularly 
with regard to "perceived moi". This is something that has long puzzled me. 
With an assist spring, we have stored energy supporting mass, and assisting 
in its acceleration. The hammer mass (and the rest of the action mass) 
remains the same, hence its moi remains the same. The leading of the keys 
is reduced, hence the moi of the key is reduced.
	I guess my main question is, "Is the moi of the hammer assembly, as 
perceived from the key, reduced by the engagement of the spring?" Since the 
stored energy is always present, the energy required to accelerate the 
hammer assembly mass from the front of the key is always reduced. So does 
that, in effect, reduce the moi of the hammer assembly mass? Or how does 
the spring enter into the picture in engineering terms?
	I can imagine "an elephant" on the end of a hammershank, with an 
extraordinarily strong wipp spring, and in imagining that, I suspect that 
the hammer assembly moi will continue to be related mostly to the mass of 
the hammer even as perceived (blind-folded) from the front of the key, 
regardless of the assistance of the spring. But I would like to hear some 
discussion of exactly what a wipp assist spring does to the feel and 
performance of an action, and why, in engineering terms.
Regards,
Fred Sturm
University of New Mexico