Who Were Wilbur and Orville?
1899 1900 1901 1902 1903 1904 1905
1903
Engine
Engine
The Wright engine was a bit crude, even by the standards of the day. It had four horizontal inline cylinders. The 4-inch bore, 4-inch stroke, cast-iron cylinders fit into a cast aluminum crankcase that extended outward to form a water jacket around the cylinder barrels.
The Wright Brothers' Engine
The Wright brothers' engine
 
The engine was cooled by water from a narrow vertical water reservoir mounted on a forward strut. The system was not a radiator in the typical sense, for the water did not circulate. The reservoir simply replenished the water jacket as the water evaporated from it.
The aluminum crankcase: A first
The Wright engine, with its aluminum crankcase, marked the first time this breakthrough material was used in aircraft construction. Lightweight aluminum became essential in aircraft design development and remains a primary construction material for all types of aircraft.
The Wright brothers' engine (detail)

How the Wright engine worked
The Wright engine, with its aluminum crankcase, marked the first time this breakthrough material was used in aircraft construction. Lightweight aluminum became essential in aircraft design development and remains a primary construction material for all types of aircraft.
How the Wright engine worked
The engine had no fuel pump, carburetor, or spark plugs. Nor did it have a throttle. Yet the simple motor produced 12 horsepower, an acceptable margin above the Wrights’ minimum requirement of 8 horsepower. Gasoline was gravity fed from a small quart-and-a-half tank mounted on a strut below the upper wing. The gasoline entered a shallow chamber next to the cylinders and mixed with the incoming air. Heat from the crankcase vaporized the fuel-air mixture, causing it to pass through the intake manifold into the cylinders.
 
Ignition was produced by opening and closing two contact breaker points in the combustion chamber of each cylinder via a camshaft. The initial spark for starting the engine was generated with a coil and four dry-cell batteries, not carried on the airplane. A low-tension magneto driven by a 20-pound flywheel supplied electric current while the engine was running.
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The Wright Engine Aluminum Crankcase
The Wrights contracted a local Dayton foundry, the Buckeye Iron and Brass Works, to cast the aluminum crankcase. Buckeye acquired their raw aluminum from the nearby Pittsburgh Reduction Company, renamed Alcoa in 1907, the world’s leading producer of aluminum.