Harper 1912 monoplane
 
 Harper-1912
 
This 50-foot span monoplane, "one of the largest, if not the largest monoplane in the world", was designed by William Harper Jr., of New Bloomfield, PA, USA,, a student of aerodynamics who had worked for several years on a weight-carrying machine that would fly with the least possible horse-power. Flights were made using as little as 10 or 12 hp of its original home-made motor. This was a two-cylinder, two-stroke, revolving engine that could give 50 hp and drove a monster propeller of around 9 ft. diameter with very steep pitch. The machine flew carrying a total weight of around 1600 lbs. The body was long and the elevators big, and all movements of the machine were slow, instead of responding quickly to the slightest gusts. The object was to approximate soaring. The machine was used for passenger flights, carrying as much as three passengers, re-engined with a six-cylinder 60-80 hp Roberts engine. It crashed in November 1912.