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
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