Q. Are there any objections to a long connecting rod?
A. A long connecting rod makes a long engine, and makes extra cost in the bed or frame and the room occupied. The longer rod is heavier, and brings extra weight upon the cross-head, guides and crank-pin. The long rod also lacks stiffness unless excessively heavy.
Q. What determines the length of the crank?
A. The stroke.
Q. What limits the stroke?
A. The piston’s speed limits the length of stroke allowable with a given rotative speed, or the number of revolutions per minute with a given stroke.
Q. What is the practical limit of piston’s speed?
A. Engines of from four to six foot stroke can run at from seven to eight hundred feet piston’s speed per minute. Those of shorter stroke should not run over six hundred feet.
Q. Why do high speed engines have a short stroke in comparison with the diameter of their cylinders?