DETERMINING THE HORSE POWER OF AN ENGINE. Multiply the area of the cylinder by the length of stroke in inches and that product by the number of revolutions per minute then divide by the constant 10000 for two-cycle or 13400 for four-cycle engine, the result will be the I.H.P.
EXAMPLE Four-cycle engine, 4" bore, 4" stroke, 1000 revolutions per minute, constant 13400. Then: 4" bore equals 12.56 area, then 12.56 x 4 equals 50.24 x 1000 equals 50240 divided by 13400 equals 3 I.H.P. for one cylinder, then to find the combined H.P. for multi- cylinder engine, multiply by the number of cylinders.
