In order to study the degree of accuracy with which the analytical methods used in crankshaft design would predict the actual operating stresses in the crankshaft of an internal combustion engine, electrical resistance strain gauges were applied to the accessible parts of the crankshaft of a single-cylinder gasoline engine to sense the actual operating strains. From the recorded strains the operating stresses were determined and were compared to the analytically determined stresses.

Oscilloscope and camera were used as the indicating and recording instruments while simplified formulas were used in the calculations. Stresses at various engine speeds and engine loads were determined by both methods and were plotted in curves against engine speeds and crank angles.

In the graphical comparisons, the stresses determined by using electrical resistance strain gages agreed well with the stresses obtained analytically.