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you're thinking about this the wrong way. earlier, you said that harmonics were a red herring. they are not; there are force multipliers to consider that make that 425lb load increase by MANY multiples.
one is simple leverage; the flywheel actually sits several inches away from the first bearing inside the case. you have the flywheel flange, some seal surface, some chain sprockets, a little more dead space, and FINALLY a bearing. the 425lb bending moment is actually multiplied several-fold at the point of the first main bearing.
second: harmonics.
consider this: are the pressure waves from my voice strong enough to break a glass? hell no. i can yell at a glass all day long and nothing will happen. however, if ella fitzgerald hits the natural frequency of that glass, it will shatter in a hurry. it's not the force of her voice that does it; it's the fact that she puts the glass into an excited harmonic state that eventually causes enough amplitude to fracture the glass.
if you ever did the glass breaking experiment in physics, you noticed a few things:
1. it WORKS
2. you have to turn up the sound a little bit; if it's too quiet, it doesn't work
3. when you get it loud enough, the glass breaks almost IMMEDIATELY
so to get an object into an excited harmonic state, you need two things:
1. the proper frequency
2. AMPLITUDE: you need enough initial force per cycle to start the runaway harmonic exitation
now on to the engine. there are several forces occuring at once. let's simplify and break them into three planes and a twisting moment:
x plane is axial: along the crankshaft and level with the ground
y plane is axial: along the crankshaft and perpendicular to the ground
z plane is radial: like the flywheel
twisting moment obviously twists the crankshaft
i'm breaking this into multiple posts......post 1 complete.
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