okay, so far we've determined that x-plane, y-plane and z-plane harmonics are not really an issue for this motor. what does that mean, exactly? this doesn't mean that the harmonics don't exist; some are cancelled, but some DO exist. it simply means that they don't exist with enough AMPLITUDE to cause an excited harmonic state. it's a lot like that glass in physics class: even if the frequency is right, without enough volume, the glass is unaffected.
at certain RPM, harmonics create, in effect, a standing wave throughout the crankshaft. that standing wave exists at the NF, but with amplitude insufficient to feed itself. were it to be excited further by some external force at the same frequency, its amplitude would grow exponentially until it is either effectively damped by the rest of the assembly OR until something breaks.....
more to come
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