As an aircraft engineer I was interested in the 'alleged' building of the engine by charlie,wilbur and orville
They built it by 'keeping it simple' and ultra conservative...
Contemporary automotive practice seems to have been the model for the water-cooled four-cylinder inline layout and influenced many of the details of the design.
The bore and stroke were both 4" for a total displacement of 200 cubic inches. Why the brothers selected such a short stroke, when most engines of the period were "under square" is unknown. Perhaps it had to do with the maximum center offset of their lathe. The compression ratio was about 4.5:1 and suitable for the 60 octane gasoline then available.
No throttle was fitted. The engine appears to have been designed to run at constant power throughout the whole flight envelope. Ignition could be manually retarded as an aid to starting, but there is disagreement about whether timing could be adjusted in flight. At any rate, the control over engine speed provided by retard would not have been dramatic.
The originality of the Wright design was in the extensive use of aluminum to save weight and in the ways in which the design was adapted to the limitations of their tooling. Some fabrication work may have been farmed out to local machine shops, but the bulk of it was done in-house on a lathe and drill press. Someday in that great shop in the sky, I would like to ask Wilbur and Orville why they did not purchase critical, hard-to-make parts, such as the crankshaft and connecting rods. Perhaps, caught up in the rhythm of the work, the idea of going to outside suppliers, working around someone else's givens, would have been a kind of violation.
Even so, Engine No. 1 did not approach the state-of-the-art of 1902. Some features, such as splash lubrication, vacuum-actuated intake valves and make-and- break ignition were obsolescent. Nor was the performance goal of 8 hp at 180 lb anything to write home about. But conservatism has appeal for aircraft engine designers.