The Wright Brothers’ Bicycle Shop Taught Them How to Fly
The two men who solved powered flight for the first time in human history were not physicists or funded by any government or university. They were the proprietors of a bicycle shop in Dayton, Ohio, and almost everything they knew about building a machine that would hold a person in the air, they had learned from selling and fixing bicycles.
Wilbur and Orville Wright rented a storefront on West Third Street in December 1892 and opened the Wright Cycle Exchange the following spring. The name changed to the Wright Cycle Company, and the shop moved several times over the years, settling at last at 1127 West Third — the address where they would build the wind tunnel and the airplane. The timing was perfect. The 1890s were the peak of the American bicycle craze, when a good safety bicycle cost a workingman weeks of wages and everyone wanted one. The brothers repaired them, rented them, and sold them, first other makers’ machines and then, starting in 1896, bicycles of their own design.
The mechanics of the thing
They called their two models the Van Cleve, after an early settler of Dayton, and the St. Clair, after a territorial governor. The Van Cleve was the premium machine, around sixty-five dollars; the St. Clair was cheaper. They never made many — perhaps three hundred in all across their peak years, most of the machine assembled from bought-in parts but built up and finished to order, one at a time, in the back of the shop.
Building bicycles one at a time forces a particular kind of thinking. Even where they bought a part rather than made it, the Wrights were forever solving small mechanical problems and inventing their way around them. Orville worked out an oil-retaining wheel hub that kept its own lubrication sealed in. They threaded their two crank arms in opposite hands so that the ordinary forward motion of pedaling tightened each one instead of slowly working it loose. They designed their own version of the coaster brake to match those hubs. None of this was glamorous. All of it was the habit of looking at a moving mechanical thing and asking how it could be made to behave.
That habit turned out to be the whole game. A bicycle is an unstable machine. Stand one up and let go and it falls over; it only stays upright because a rider is constantly correcting it, leaning and steering by feel, thousands of small adjustments a minute. Almost everyone trying to fly in the 1890s was chasing the opposite idea — a machine so inherently stable it would fly itself, the way a good boat sits level in the water. Wilbur, who had spent years watching people wobble and then master the bicycle, drew the opposite conclusion. A flying machine did not need to be stable. It needed a pilot who could balance it, the same way a person balances a bicycle, by learning the feel and never stopping the corrections.
The box in his hands
The problem was how to give a pilot that control. Birds banked into turns by twisting the trailing edges of their wings, but no one had found a mechanical way to do the same thing to a rigid wing without a nest of hinges and joints that would shake apart.
In the early summer of 1899 — the story goes — a customer came into the shop for an inner tube, itself a product of the recent pneumatic-tire revolution that had remade the bicycle. Wilbur handed it over and, while he talked, kept turning the long thin cardboard box the tube had come in. He pressed the diagonal corners at one end and the opposite corners at the other, and the box twisted along its length, one end tilting up while the other tilted down, and the whole thing stayed rigid as it did.
He was holding the answer. Picture the top and bottom faces of the box as the two wings of a biplane. If you could twist the whole wing that way — warp it, so one side met the air at a steeper angle than the other — one side would lift harder than the other, and the machine would roll into a bank, exactly the way a cyclist leans into a turn. There would be no hinges, just cables pulling the wingtips.
Wing-warping was the Wrights’ first genuinely original contribution to flight, and it came out of an empty inner-tube box on a shop counter. Within weeks Wilbur built a five-foot biplane kite and worked the wings by pulling on cords from the ground, and watched it obey.
A wind tunnel over the workbench
By 1901 the brothers had gliders and a deeper problem. Every wing they built produced far less lift than the published tables promised — tables drawn largely from the work of the German glider pioneer Otto Lilienthal, who had died in a crash in 1896. The Wrights began to suspect the numbers were wrong somewhere, and to test a wing you first need clean air moving over it at a known speed.
Their first instrument was, again, a bicycle. They mounted a third wheel horizontally on the front of one of their bikes, fixed a small model wing and a flat drag plate to it, and rode the bicycle through the streets of Dayton to blow air across the models. The spinning wheel showed which force won. It confirmed the shortfall was real and not their own error — but the wind of a pedaling man is a fickle thing, gusting and slowing, impossible to trust to a decimal.
So they built a wind tunnel on the second floor of the shop, a wooden box about six feet long with a fan at one end. Inside they hung tiny balances they had cut and bent out of hacksaw blades, bicycle spokes, and scrap metal, one to measure lift and one to measure drag. Through the fall of 1901 they ran some two hundred miniature wing shapes through the moving air, then studied the best few dozen in careful detail and wrote down what each one did.
The tunnel revealed where the real error had been. Lilienthal’s measurements of the wings themselves turned out to be largely sound; the trouble lay in a constant everyone had used to convert those figures into lift — the Smeaton coefficient, a value fixed at .005 for more than a century. The Wrights worked out that it was far too high, closer to .0033, which is near the figure engineers use today. A single wrong number, buried in a formula, had made every honest wing look like a failure. What they produced in its place was the first reliable body of aerodynamic data in the world, and it was gathered in the loft of a bicycle store, on instruments made of spokes.
The chain that drove the propellers
When the flying machine finally came together, it was a bicycle shop’s machine down to its bones. The brothers needed a lightweight engine and could not buy one, so their shop mechanic, Charlie Taylor — hired in 1901 to mind the store while they were away — built one on the shop’s lathe and drill press in about six weeks, a rough aluminum-block engine of roughly twelve horsepower.
The engine had to turn two propellers, and here the bicycle came back one last time. The Wrights drove the propellers off the engine with sprockets and chains — the same technology that turned a bicycle’s rear wheel, supplied by a chain maker in Indianapolis. They wanted the two propellers to spin in opposite directions, so that the twisting force of one would cancel the other’s. The solution was pure shop instinct: they ran one drive chain straight and crossed the other into a long figure eight, so the same engine spun one propeller clockwise and the other counterclockwise.
On the morning of December 17, 1903, on the sand at Kitty Hawk, Orville lay flat on the lower wing and the machine rose. It stayed up twelve seconds and covered a hundred and twenty feet into a cold headwind — a distance shorter than the wingspan of a jumbo jet. The controls that held it level were cables warping the wings, worked out on a cardboard box. The lift that carried it was shaped by numbers gathered in a loft on balances of bicycle spoke. The thrust came off chains from a bike.
They had built the first airplane the only way they knew how to build anything — the way they built bicycles.