I've read from time to time about their project. It's fascinating to an aviation buff like me. The Wright Brothers were much more than a couple of bicycle builders who got lucky. Armed with only high school educations, they did remarkable and ground breaking work in aeronautical engineering, including wing sections (tested in one of the first wind tunnels ever made), control, engines, and propellors. Their work on propellors alone was some of their most important. Before them, virtually nothing had been written about propellors for aeronautical purposes. Their first prop was about 75% efficient at converting horsepower to thrust, which is just a little less efficient than modern props.

It turns out they must've been pretty skilled pilots as well. Simulators programmed to replicate their early planes are almost unflyable by today's pilots.