DirtyErnie
Renaissance Hick
The basic physics everyone is looking for is CONSTRUCTIVE and DESTRUCTIVE INTERFERENCE. If two forces are happening in lock-step with each other, they will combine to double the total force. (constructive interference) I.E. both pistons stop together at top and bottom of the stroke, putting maximum force into moving the engine up or down in its mounts. With both pistons stopped at their extremes simultaneously (however briefly), it takes maximum power from the crakshaft inertia to re-accelerate them through the next stroke. If the engine is rephased, putting one piston ~90* out of phase with the other, the pistons can't combine their forces against the crankshaft. When one piston is stopped, the other piston is very near its maximum velocity. When one piston is at MAXIMUM ACCELERATION coming from one end of a stroke, the other piston will be at MAXIMUM VELOCITY in the middle of the stroke. You end up with a situation where the pistons trade their momentum back-and-forth. The one that's stopped at the beginning of its stroke is accelerated by the force of the one that needs to stop coming to the end of its stroke.
In a nutshell, the pistons stop thieving torque from the crankshaft and politely trade their forces amongst themselves, and you go faster.
The other thing you feel is that the huge vertical vibration from the pistons is traded for a smaller rocking vibration as the pistons rise and fall at different times, sending their natural imbalance to their end of the engine.
If i'm remembering this right, the 90* offset leads to a reduction in vibrations related to the square-root of 2. So, somewheres around 1.4x less vibration total.
oh yeah, and more torque out the crankshaft.
In a nutshell, the pistons stop thieving torque from the crankshaft and politely trade their forces amongst themselves, and you go faster.
The other thing you feel is that the huge vertical vibration from the pistons is traded for a smaller rocking vibration as the pistons rise and fall at different times, sending their natural imbalance to their end of the engine.
If i'm remembering this right, the 90* offset leads to a reduction in vibrations related to the square-root of 2. So, somewheres around 1.4x less vibration total.
oh yeah, and more torque out the crankshaft.
