The Engine RPMs calculator computes the revolutions per minute (RPMS) based on the average (mean) speed of the pistons, and the stroke length.One rev
INSTRUCTIONS: Choose units and enter the following:
Engine RPMs: The calculator returns the engines RPMs.
The equation for the RPMs of an engine is as follows:
`RPMs = (ps)/(s*2)`
The Piston Speed equation calculates the mean velocity of the piston based on the cylinder stroke length and the RPMs. The piston's speed of travel up and down the cylinder is always changing and actually comes to an instantaneous stop at both the upper and lower ends of the stroke at the beginning and end of a single revolution. Therefor we can only calculate the average (mean) velocity based on RPMs. In one minute, the pistons travel two times the stroke length times the number of revolutions (2 * Stroke * Revs). Divide that by one minute and you have the mean piston speed.