The Story of Gustave Whitehead - Before The Wrights Flew,
Stella Randolph, 1966, p. 88
Mr. Pirozzoli was one of two young men who worked with Whitehead in the construction of one plane, and it is believed gave some assistance with construction of a helicopter which Whitehead undertook to build. The plane, which failed to fly at a time when Mr. Pirozzoli believes must have been 1908, had propellers which were placed too low. When tested, the plane started to rise, but not far enough to avoid a depression in the ground which caused it to nose forward, breaking a propeller. Except for this accident, Mr. Pirozzoli believes the plane would have become airborne in another fifty yards. According to his report the plane had sprockets for the propellers which turned in reverse.