In late 1905, the Wrights developed the parabolic cross-section bent-end propellers that, when producing thrust, bent into a straight shape, and producing a combined 210 pounds of thrust.

Due to wear polishing the cylinders during 1904 and 1905, the 1904 motor was producing up to 21 horsepower. This motor was restored under Orville's direction in 1947. To replace the parts that had been borrowed for the 1928 restoration of the 1903 engine, Orville borrowed the crankshaft from the 1904 test engine a made other parts anew. The rebuilt engine and the original propellers are now on the restored 1905 Flyer 3 displayed at Carillon Park, Dayton, OH.

 References:

• Wright, 1921.
• McFarland, 1953, p 1214-1215.
• Lippincott, 1987, pp 79-82; 86.
•  Orville Wright, deposition in Montgomery vs. the United States, 2 Feb 1921
• McFarland, Marvin W. (ed) The papers of Wilbur and Orville Wright. McGraw-Hill Book Co., New York, 1953, p 1214-1215.
• Lippincott, Harvey H. Propulsion System of the Wright Brothers. In Wolko, Howard S. (editor), The Wright Flyer, an Engineering Perspective. The Smithsonian Institution Press, 1987, pp 79-82; 86.

[Submitted by Joe W. McDaniel]

A bent-end prop installed on a Wright Model A in 1910.

The Wrights used the same engine in both the 1904 Flyer 2 and the 1905 Flyer 3.

• The Real McCoy -- Get up close and personal with the world's first practical aircraft, including the engine, drive train, and propellers.