New Propeller Tests - Saturday, February 28, 1903
The History: During the month of February, the Wrights continued their work on the propeller and motor. Their new propeller is 8.5 feet in diameter. Each blade is 6 inches wide and the area of the 2 blades is 2 ft2 (square feet).
In a letter to George Spratt, Wilbur describes the motor to his friend. "We recently built a four-cylinder gasoline engine with 4" piston and 4" stroke, to see how powerful it would be, and what it would weigh. At 670 revolutions per min. it developed 8 1/4 horsepower, brake test. By speeding it up to 1,000 rev. we will easily get eleven horsepower and possibly more at still higher speed, though the increase is not [exactly] proportion to the increase in number of revolutions. The weight including the 30-pound flywheel is 140 lbs."
However, the motor had broken on February 13th. It would take two months for the new aluminum casting to be made for the new motor. In the meantime they used their older motor to test their new propeller.