Variable-Pitch Propellers

The first proposal for a variable-pitch propeller was made in 1871 by a Frenchman named J. CroceSpinelli. Croce-Spinelli proposed a design for a propeller whose pitch was changed by hydraulic pressure (forcing oil through a tube). Croce-Spinelli claimed that this would be most useful during takeoff, when an airplane needed the most power (Croce-Spinelli was one of two men who died in 1875 when they went too high in a balloon). Another Frenchman, Alphonse Pénaud, also proposed using a variable-pitch propeller in his patent on airplane design in 1876.