To Fly!
A new book traces the Wright brothers' triumph 100 years ago to an innovative design and meticulous attention to detail
- By James Tobin
- Smithsonian magazine, April 2003, Subscribe
(Page 5 of 8)
Their long glides had grown out of their aptitude for learning how to do a difficult thing. It was a simple method but rare. They broke a job into its parts and proceeded one part at a time. They practiced each small task until they mastered it, then moved on. The best example was their habit of staying very close to the ground in their glides, sometimes just inches off the sand. “While the high flights were more spectacular, the low ones were fully as valuable for training purposes,” Wilbur said. “Skill comes by the constant repetition of familiar feats rather than by a few overbold attempts at feats for which the performer is yet poorly prepared.” They were conservative daredevils, cautious prophets. “Athousand glides is equivalent to about four hours of steady practice,” Wilbur said, “far too little to give anyone a complete mastery of the art of flying.”Langley and Manly had spent most of four years building an extraordinary engine to lift their heavy flying machine. The Wrights had spent most of four years building a flying machine so artfully designed that it could be propelled into the air by a fairly ordinary internal combustion engine. Still, they had expended a minimum of thought and energy on their power plant. At first they hoped simply to buy an engine. But when they sent inquiries to manufacturers, specifying one of less than 200 pounds that would make at least eight horsepower, only one manufacturer said he had such an engine, and the brothers concluded he was overrating its power. So, back in Dayton in the winter of 1902, they sketched a design of their own and handed it to their bicycle shop machinist Charlie Taylor, who did most of the work in the back room. After six weeks, he produced a simplified four-cylinder auto engine without a carburetor, spark plugs or fuel pump. In February 1903, the engine block cracked in a shop test. When a new block was delivered and the engine reassembled, it made 12 horsepower at 1,025 revolutions per minute. With four more horsepower than the brothers believed they needed, and 20 pounds fewer than their maximum, the engine, said Orville, was “a very pleasant surprise.”
The brothers had assumed that propellers would cause them less trouble than the engine, but they soon learned that ships’ propellers were designed by trial and error, vessel by vessel. No one knew exactly how they worked, so no one had worked out a theory of propeller design, least of all for flying machines. So the brothers had no choice but to plumb the mystery themselves. They began to consider the problem seriously soon after their return to Dayton from Kitty Hawk in 1902, and “it was not till several months had passed,” Orville recalled, “and every phase of the problem had been thrashed over, that the various reactions began to untangle themselves.”
Naval engineers had proposed that a marine propeller cuts through water as a screw cuts through wood. The brothers conceived a different image. To them, “it was apparent that a propeller was simply an aeroplane [that is, a plane surface in the curved shape of a wing] traveling in a spiral course.” The problem sounded simple. But, wrote Orville, it “became more complex the longer we studied it. With the machine moving forward, the air flying backward, the propellers turning sidewise, and nothing standing still, it seemed impossible to find a starting- point from which to trace the various simultaneous reactions.”
“We worked out a theory,” Orville wrote in a June letter to Spratt, “on the subject, and discovered, as we usually do, that all the propellers built heretofore are all wrong, and then built a pair of propellers 8 1/8 ft. in diameter, based on our theory, which are all right! (till we have a chance to test them at Kitty Hawk and find out differently). Isn’t it astonishing that all these secrets have been preserved for so many years just so that we could discover them!!”
After waiting days for calm weather, Langley’s young engineer, Charles Manly, catapulted his boss’s aerodrome off a houseboat moored in the Potomac River near Quantico, Virginia, just after 10 a.m., October 7, 1903. Manly’s “indescribable sensation of being free in the air” gave way to “the important fact . . . that the machine was plunging downward at a very sharp angle.’ The front wings struck the water and disintegrated.” Soon after, back in Kitty Hawk for their fourth season (they returned September 25, 1903),Wilbur wrote to Octave Chanute, a distinguished civil engineer and aviation authority he had befriended: “I see that Langley has had his fling, and failed. It seems to be our turn to throw now, and I wonder what our luck will be.”
Until now, construction of what would become their famous “Flyer” had proceeded smoothly. But in a test on November 5, a misfiring engine conspired with loose propellers and loose sprockets to make a disaster. The propeller shafts tore loose from their mountings and twisted. The Wrights had no choice but to send the shafts back to Charlie Taylor to be repaired. Without them, there would be no powered flight for many days, and Chanute, who had arrived in Kitty Hawk November 6 for a visit, said he couldn’t stay that long. For his benefit the brothers labored up the slopes to make a few more glides in the 1902 machine. But the wood had grown dry and rickety in the heat of the shed, and they decided the glider was no longer safe. For most of their friend’s stay the weather remained so bad the three men did little but sit close to the stove and talk.
Chanute questioned the brothers closely about the mathematical calculations they had used in building their engine, and he didn’t like what they told him. Engineers usually allowed for a 20 percent loss of an engine’s power, yet the Wrights had only allowed for 5 percent. This worried the brothers. Unable to work because of the missing shafts, “We had lots of time for thinking, and the more we thought, the harder our machine got to running and the less the power of the engine became,” Orville wrote to Milton and Kate, “We are now quite in doubt as to whether the engine will be able to pull [the Flyer] at all with the present gears.” The brothers estimated their odds of success at no more than even.
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