reduction of 23-to-8. Wilbur had calculated that slower turning blades generated greater thrust, and two of them were better than a single blade turning faster. Made from three laminations of spruce, the tips were covered with duck canvas, and the entire propeller painted with aluminum paint. On November 5, 1903, the brothers tested their engine on the Wright Flyer at Kitty Hawk, but before they could tune the engine, the propeller hubs came loose. The drive shafts were sent back to Dayton for repair, and returned on 20 November. A hairline crack was discovered in one of the propeller shafts. Orville returned to Dayton on 30 November to make new spring steel shafts. On December 12, the brothers installed the new shafts on the Wright Flyer and tested it on their launching rail system that included a wheeled launching dolly. According to Orville: In practice tests, they were able to achieve a propeller rpm of 351, with a thrust of , more than enough for their flyer. The Wright Flyer was a canard biplane configuration, with a wingspan of , a camber of 1-20, a wing area of , and a length of . The right wing was longer because the engine was heavier than Orville or Wilbur. Unoccupied, the machine weighed . As with the gliders, the pilot flew lying on his stomach on the lower wing with his head toward the front of the craft in an effort to reduce drag. The pilot was left of center while the engine was right of center. He steered by moving a hip cradle in the direction he wished to fly. The cradle pulled wires to warp the wings, and simultaneously turn the rudder, for coordinated flight. The pilot operated the elevator lever with his left hand, while holding a strut with his right. The Wright Flyers "runway" was a track of 2x4s, which the brothers nicknamed the "Junction Railroad". The Wright Flyer skids rested on a launching dolly, consisting of a plank, with a wheeled wooden section. The two tandem ball bearing wheels were made from bicycle hubs. A restraining wire held the plane back, while the engine was running and the propellers turning, until the pilot was ready to be released. The Wright Flyer had three instruments onboard. A Veeder engine revolution recorder measured the number of propeller turns. A stopwatch recorded the flight time, and a Richard hand