Simanaitis Says

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IN PART 1 yesterday, we learned that the 1903 Wright Flyer was powered by a horizontally aligned inline-four designed and fabricated by the brothers themselves and their mechanician Charlie Taylor. Their design criteria were simple: ample power, yet light weight. Several of their engineering responses were innovative indeed, for example. the aluminum alloy crankcase described in Part 1 and shown here. In Part 2, we’ll examine other aspects that were perhaps more traditional.

The innovative crankcase of the 1903 Wright engine; its cover removed. Buckeye Iron and Brass Works acquired its aluminum from the Pittsburgh Reduction Company, renamed Alcoa in 1907. Image from

Other features of the Wright engine were relatively unsophisticated. Its intake valves, on the upside of the engine, were of the atmospheric variety, opened solely by partial vacuum created by the pistons’ intake stroke.

The 1903 Wright engine. This and other images from

The exhaust valves below the combustion chambers were mechanically actuated, their camshaft doing double duty in operating each cylinder’s make-and-break ignition. No spark plugs were fitted.

1. Crankcase. 2. Flywheel. 3. Camshaft drive chain. 4. Block, topside. 5. Cooling water plumbing. 6. Fuel line. 7. Chain drive to port pusher propeller. 8. Lower wing. 9. Padded cradle for prone pilot. Image from The Lore of Flight, Crescent Books, 1978.

The engine was water-cooled, its cylinders (but not combustion chambers) encased in a jacket fed from a radiator mounted to a wing strut. One source claims this was solely for replenishment with neither circulation nor heat transfer. I’m more confident with an analysis offered by NASA’s Glenn Research Center describing this system’s gravity-feed (that is, sans water pump) operation.

Images from

Taylor described the engine’s ignition: “The spark was made by the opening and closing of two contact points inside the combustion chamber. These were operated by shafts and cams geared to the main camshaft. The ignition switch was an ordinary single-throw knife switch we bought from a hardware store.”

This detail shows the mechanism that opens and closes the ignition points. Image from

“Dry batteries,” Taylor said, “were used for starting the engine, and then we switched onto a magneto bought from Dayton Electric Company.”

Fuel delivery was rudimentary: A 22-oz. canister was attached to a wing strut, its gasoline fed by gravity alone down a tube to the engine. There was no throttle; a simple petcock controlled flow.

“There was no carburetor as we know it today,” Taylor said. “The fuel was fed into a shallow chamber in the manifold. Raw gas blended with air in this chamber, which was next to the cylinder and heat up rather quickly, thus helping to vaporize the mixture. The engine was started by priming each cylinder with a few drops of raw gas.”

The original Wright Flyer powerplant was first run on February 12, 1903. According to, “The very next day it overheated and seized up on the bench during a test run. New castings arrived from the foundry on 20 April 1903 and Charlie had the engine rebuilt and read to go by early June.”

On December 17, 1903, near Kitty Hawk, North Carolina, the engine ran just fine. It initially propelled Orville for 120 ft. and 12 seconds. Before the day was over, Wilbur traveled 852 ft. in 59 seconds, averaging about 9.8 mph. Not bad for a 12-hp aircraft. Not bad at all. ds

© Dennis Simanaitis,, 2018

One comment on “THE WRIGHT ENGINE PART 2

  1. Skip
    August 2, 2018

    Dennis, great posting, as always. I’d much rather learn about what it took to achieve the first powered, heavier-than-air controllable flight than to read about the SR-71 Mach II mumbo jumbo. All that is just the result of incremental development on the original breakthrough. Of course one could make the case the Wrights’ breakthrough was in turn just an incremental development of all the contemporary technologies, but in the end, they did it first and it was something special.

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