The Wright Brothers’ Innovative Engine

When Orville Wright took flight on December 17, 1903, the custom-built aircraft that carried him was powered by a no less extraordinary engine.

The brothers who ushered in the age of aircraft weren’t trained engineers. But they were brilliant innovators. By the time Orville and Wilbur became interested in gliders, in the 1890s, they’d already built their own printing press and manufactured a line of bicycles. Obsessed with newspaper stories of experimental aircraft, they set to work creating an plane and custom engine using the lathe, drill press, and tools in their machine shop.

By the Wrights’ calculation, the engine had to produce at least 8 horsepower but weigh no more than 180lbs. This presented quite a challenge. The engines then built by leading automotive companies were all far too heavy to meet the criteria for flight. But an acquaintance at a nearby iron works thought that they might be able to use a new innovative alloy to lighten the load. The material was aluminum.

Strong and lightweight, the crankcase of the Wright brothers’ engine was the first instance in which aluminum was ever used in an aircraft. To this day, aluminum is an essential material in aircraft construction, accounting for anywhere from two-thirds to three-quarters of the weight of an average passenger plane.

After the Wrights’ aluminum breakthrough, the design and assembly of the other engine components took only 6 weeks. Most of the work was completed by the brothers’ staff bike “mechanician” Charlie Taylor. After talking through the details of a part with Wilbur and Orville, Taylor would make a rough sketch of the component and tack it above his workbench as a guide. Nearly every part of the engine was handmade and hand fitted.

The finished prototype was somewhat crude, but it worked. The design ingeniously functioned without spark plugs, fuel pump, carburetor, or throttle—saving much-needed weight without compromising output.

A small fuel tank mounted below the upper wing used gravity to feed gasoline into a chamber where the gas mixed with air and became vaporized by the heat of the crankcase. The vapor was then drawn through the intake manifold and into the combustion chambers of the engine’s four horizontal cylinders. Ignited by “make-and-break” contact breaker points on the camshaft, each burst of combustion helped turn the simple chain-and-sprocket system connected to the twin propellers mounted on the rear of the glider. The engine was controlled with a simple electrical kill switch rather than a throttle, saving weight and complexity.

The Wrights’ final engine ended up weighing about 200lbs, but produced 12 horsepower—a significantly higher power-to-weight ratio than any engine that had come before.

The engine powered four successful flights at Kitty Hawk on December 17, 1903, before a gust of wind flipped the glider and irreparably damaged the aluminum crankcase. But that one day of functionality was enough to change the world.

The Wrights’ innovative engine not only powered the first manned flight, it helped ignite the imaginations of thousands of people around the globe, inspiring others to take us higher, farther, and faster than ever before.