At the beginning of 1903, the brothers began shopping around for an engine. None of the inquiries they sent to manufacturers turned up what they needed, so they had to build their own. They bought a lightweight aluminum engine block from the Aluminum Company of America, and their new mechanic, Charlie Taylor, worked at the bike shop to make a motor out of it. The first one cracked during testing when something caused the bearings to freeze. They had to send for another block, which Taylor also transformed into a motor.

While they waited, they turned to the issue of the propellers. They assumed that they could find the technical specifications they needed in the information from the long use of propellers on ships. However, their research showed that this information was insufficient and they’d have to work it out themselves. Taylor considered this one of their greatest accomplishments, saying later, “I don’t believe they ever were given enough credit for that development” (88).

By mid-September, they were back in Kitty Hawk to test out the third version of what they called their “Flyer.” At the end of October, they tested the new engine. However, the tests didn’t go smoothly. First, vibrations from the engine caused the propeller shafts to break loose and become twisted.