Using the equation was now a matter of give and take. Wilbur’s first step was to estimate the total amount of weight his craft would have to lift—his own weight, one hundred forty pounds, plus the weight of the machine itself. A quick check of the tables of weights of materials available in a standard engineering handbook indicated that his kite/glider would weigh perhaps fifty pounds. One hundred and ninety pounds would be the goal—the total amount he planned to lift into the sky.
Next, he had to choose a reasonable velocity—the speed of the wind in which he would fly. A few trial calculations indicated that he would have to operate in a headwind of 10 to 20 miles per hour. A wind velocity as low as 10 miles per hour would require an enormous wing; a 20-mile per hour wind sounded positively dangerous. He used a compromise figure of 15 miles per hour in his calculations.
With these decisions made, Wilbur solved the equation for an estimate of the amount of wing surface area that would be required to operate under his conditions:
L = k X S X V2 X CL
190 (total weight) = .005 X S X 225 (15 mph 2) X .825
(from Lilienthal table)
190 = .928 X S
S = 190/.928
Surface area = 204.74 square feet
The use of the equation was a first step in the design process. Wilbur now knew that a craft weighing one hundred ninety pounds, with a surface area of 200 square feet, would fly in a 15-mile per hour wind. How was he to arrange that surface area?
He had decided that the Chanute biplane glider of 1896 was a distinct improvement over the classic Lilienthal monoplane. Moreover, that design seemed made to order for his wing-twisting control system. Cables linking the front and rear edges of the upper and lower wingtips would connect to a foot control. It was a closed system. By shifting his feet to one side the pilot would pull the trailing edge of the wingtip on one side down, while allowing the leading edge of the tip on the opposite side to rise. The entire wing structure could be twisted to the right, recentered, and twisted to the left at will—just like the cardboard box and the kite.
A great deal of thought went into the design of the airfoil for those wings. Lilienthal, Chanute, and most other experimenters had used the simplest curvature—the arc of a circle. Their wings were evenly curved from front to rear, with the peak of the arch falling at the midpoint. The Wrights chose a different pattern, moving the peak forward to a point only three or four inches back from the leading edge. In addition, they would build a much shallower wing, with a camber of only 1/23, as opposed to the 1/12 selected by Lilienthal and others.
These changes, they realized, might invalidate the Lilienthal lift coefficients on which they had calculated their wing design. They took that chance because of a fear that the wind striking the broad forward slope of the deep Lilienthal wing would significantly increase its resistance. A shallower camber, with a sharp initial rise to a peak much closer to the front, ought to reduce the problem, producing a more stable wing.
They placed an elevator in front of the wings rather than at the rear of the craft, as they had with the small fixed surface of the 1899 kite. French experimenters would refer to such a machine as a canard, because of its resemblance to a duck in flight, with its small head carried far forward at the end of a long neck. The Wrights did not invent that design, but it was not the obvious choice.
Why did they choose the canard pattern? Imagine a board standing on one edge with its flat face to the wind. The center of the wind pressure (CP) is on a line running the length of the board at the very center. As the top, or leading edge, of the board is brought forward, angling the surface toward the horizontal, the center of pressure moves forward as well. Less surface area is being exposed. As the angle of attack decreases, the CP continues to move toward the front until, when the board is horizontal, the CP rests on the narrow leading edge, the only surface now exposed to the wind.
Earlier theorists had assumed that CP would travel to the leading edge of a cambered wing at a zero angle of attack, just as it did on a flat board. If so, the Wrights reasoned that a forward elevator would be more effective than one on the tail of the craft. If the CP moved forward onto the elevator itself, pitch control would become much more precise than if the surface was located at the rear. A surface set forward of the wings with a slightly negative angle of attack when at rest might also provide some pitch stability.
The rough lineaments of the first Wright glider were in place by the end of September 1899, three months after Wilbur had sent his first letter to the Smithsonian. Having determined to fly, he was not wasting any time. He would tackle the construction problems one by one as the work progressed. The conception—the design—was the important thing. And in that area Wilbur now felt a real confidence.
chapter 14
“KITTY HAWK, O KITTY”
October 1899~October 1900
The construction of the machine would have to wait a while. The brothers spent the fall and winter of 1899–1900 assembling their next year’s stock of Wright bicycles. Business at the shop would keep them busy through the following spring and summer.
Wilbur was able to devote a few idle hours to the selection of a testing ground. The kite/glider could not be flown in Dayton—the machine would not lift in a wind of much less than 12 to 15 miles per hour. If Wilbur was to remain in the air for any length of time, he had to find a spot where there were strong, steady winds day in and day out. The ideal site would also offer seclusion, hills for gliding, and soft sand to ease the shock of landing.
Casting about for advice, Wilbur wrote to Octave Chanute for the first time on May 13, 1900. He was familiar with Chanute’s work, having read Progress in Flying Machines and a handful of his magazine articles. Wilbur introduced himself with characteristic humor as a fellow “afflicted with the belief that flight is possible to man. My disease has increased in severity,” he added, “and I feel that it will soon cost me an increased amount of money, if not my life.”1
He explained that the bicycle business required his full attention for nine months each year. Any “experimental work” had to be confined to the slack months from September to January. Wilbur asked for comment on his plan to kite a man-carrying machine from a tower, adding that he would be “particularly thankful for advice as to a suitable locality where I could depend on winds of about fifteen miles per hour without rain or too inclement weather.”
Chanute, always happy to welcome a new enthusiast, sent a prompt reply. He was encouraging, but did not fully approve of Wilbur’s plan for tethering his machine to a tower. Restraining ropes were both an unnecessary complication and a safety hazard.
As for a test site, Chanute “preferred preliminary learning on a sand hill and trying ambitious feats over water.” San Diego, California, and St. James City, Florida, both offered constant offshore winds, but neither had the advantage of sand. Some other spot “on the Atlantic coast of South Carolina or Georgia” might be preferable.2
Wilbur refused to indulge in guesswork when he could lay his hands on solid fact. He wrote to the U.S. Weather Bureau in Washington requesting information on prevailing wind conditions in various parts of the United States. Bureau chief Willis Moore responded by sending the August and September 1899 numbers of the official Monthly Weather Review. The September issue, which included articles on several experimental instrument kite programs and a table of the average hourly wind velocities recorded at 120 Weather Bureau stations, was especially interesting.3
The table confirmed that Chicago was the windiest city, with an average daily velocity of 16.9 miles per hour for the month of September. But Wilbur had already rejected Chicago, and all other urban areas. Chanute’s experience in 1896 had shown that any flying-machine experiments conducted near a city would immediately attract the attention of the press, something Wilbur hoped to avoid at all cost. Nor could any of the other four stations recording average winds of over 13.5 miles per hour meet the requirements of isolation, suitable hills, and sand.
Movi
ng down the list, Wilbur discovered that the sixth-highest average wind in the United States (13.4 mph) had been recorded at Kitty Hawk, North Carolina. He had never heard of the place. Few people had. Still, while the average wind was on the low side for the calculated performance of the planned kite/glider, additional tables in the journal indicated that Kitty Hawk offered a reasonable number of clear, rain-free days each fall, with occasional winds much above the average. It would bear looking into.4
On August 3, 1900, Wilbur wrote to the Weather Bureau office at Kitty Hawk. Joseph J. Dosher, the sole bureau employee there, sent a short reply indicating that the beach near his station was a mile wide and clear of trees and other obstructions. The winds in September and October blew from the north and northeast. Wilbur could board in the village, but housing would be a problem—he would have to bring a tent and camp out.5
As an afterthought, Dosher passed Wilbur’s letter on to William J. Tate, a local postmaster, notary, and Currituck County commissioner. Bill Tate responded on his own, mentioning the “relative fitness of Kitty Hawk as a place to practice or experiment with a flying machine, etc.”
In answering, I would say that you would find here nearly any type of ground you could wish; you could, for instance, get a stretch of sandy land one mile by five with a bare hill in the center 80 feet high, not a tree or bush anywhere to break the evenness of the wind current. This in my opinion would be a fine place; our winds are always steady, generally from 10 to 20 miles velocity per hour.
Tate was obviously a man of some warmth. He closed his letter with an invitation that was difficult to resist: “If you decide to try your machine here & come, I will take pleasure in doing all I can for your convenience & success & pleasure, & I assure you you will find a hospitable people when you come among us.”6 Kitty Hawk it would be.
On August 10, Wilbur told Chanute that “It is my intention to begin shortly the construction of a full-size glider.” The work of building this machine was split between Dayton and Kitty Hawk. Before his departure, Wilbur cut, steamed, and bent the ash ribs that would give shape to his wings, and carefully fashioned the fifty or so additional wooden pieces. Components that could not be obtained at Kitty Hawk, including metal fittings and fasteners and spools of the 15-gauge spring steel wire for trussing the wings, were purchased at home and packaged for shipment. Yards of glistening sateen fabric were cut and sewn into the panels that would cover the finished wings.
Unable to find long pieces of spruce for the main wing spars and elevator support at a local lumberyard, Wilbur asked Chanute for advice. He recommended a Chicago lumberyard, but suggested that the material could surely be obtained in Cincinnati.7 Rather than continuing the search at home, Wilbur decided to take a chance on being able to purchase the spars cut to size in Norfolk, Virginia, the largest city on his route to the Outer Banks.
Wilbur could no longer avoid breaking the news to Milton. The bishop was aware of his son’s interest in flight, but he had no idea that Wilbur planned to take to the air himself. “I am intending to start in a few days for a trip to the coast of North Carolina in the vicinity of Roanoke Island, for the purpose of making some experiments with a flying machine,” Wilbur admitted on September 3.
It is my belief that flight is possible, and, while I am taking up the investigation for pleasure rather than profit, I think there is a slight possibility of achieving fame and fortune from it. It is almost the only great problem which has not been pursued by a multitude of investigators, and therefore carried to a point where further progress is very difficult. I am certain I can reach a point much in advance of any previous workers in the field even if complete success is not attained just at present. At any rate, I shall have an outing of several weeks and see a part of the world I have never before visited.8
We have no way of knowing how Milton, always so concerned about the physical welfare of his children, reacted to the news. Katharine tried to soften the blow, following Will’s letter with one of her own two days later. “We are in an uproar getting Will off,” she noted. “The trip will do him good. I don’t think he will be reckless. If they can arrange it, Orv will go down as soon as Will gets the machine ready.”9
Wilbur boarded a Big Four train at Union Station at six-thirty on the evening of Thursday, September 6. He was setting off on the great adventure of his life. Other than the trip to the World’s Columbian Exposition in 1893, he had ventured no farther than a bicycle ride from Dayton in the past decade. Now he was traveling southeast through the night toward the most remote and isolated spot on the East Coast of the United States.
Arriving at Old Point Comfort at six o’clock the following evening, he loaded his gear onto the steamer Pennsylvania for the short trip across historic Hampton Roads, where the James and York rivers flow across the mouth of the Chesapeake Bay into the Atlantic. Saturday morning was spent in a futile search for the spruce wing spars. He had no more luck in Norfolk than in Dayton. Close to collapse in the humid, 100-degree heat of Indian summer on the Virginia peninsula, Wilbur finally settled for white pine spars. Even so, he could only find the substitute material in sixteen-foot lengths, two feet shorter than required for a wing designed to fly in a 12-mile per hour wind. He would simply have to wait for a wind above 15 miles per hour.
Wilbur had studied his maps, and knew that here in Norfolk he was within sixty miles of his destination. Kitty Hawk lay midway down the first leg of a long ribbon of sand that began at the southern edge of the city and ran south in a great arc paralleling the coast of North Carolina. These were the fabled Outer Banks, a thin chain of barrier sand islands ranging from a few hundred feet at the narrowest point to perhaps three or four miles at the widest, broken by a series of channels or inlets that connected the wild Atlantic to the shallow inland sounds separating the back of the Banks from the swampy wilderness of mainland Carolina.
But there was no way for a traveler to make his way down the length of the Banks; there were no roads, and no bridges across the inlets or the sounds. Wilbur boarded another train that carried him south to Elizabeth City, North Carolina, a few miles above the spot where the Pasquotank River entered Albermarle Sound.
Arriving at four-thirty on the afternoon of September 8, he checked into the Arlington Hotel and visited the city docks to find out the price of transport to Kitty Hawk. Wilbur was startled to discover that “no one seemed to know anything about the place, or how to get there.” Not until Tuesday, the 11th, was he able to find a boatman, Israel Perry, willing to ferry him down the Sound and across the head of Roanoke Island to the Outer Banks. Perry explained that his boat, a flat-bottomed fishing schooner, was anchored three miles down the Pasquotank, in the relatively deep water mid-channel just inside the entrance to the Sound.
“We started in his skiff,” Wilbur recalled,
which was loaded to the gunwale with three men, my heavy trunk and lumber. The boat leaked very badly and frequently dipped water, but by constant bailing we managed to reach the schooner in safety. The weather was very fine with a light west wind blowing. When I mounted the deck of the larger boat I discovered at a glance that it was in worse condition if possible than the skiff. The sails were rotten, the ropes badly worn and the rudder post half rotted off, and the cabin so dirty and vermin-infested that I kept out of it from first to last.10
They started down the Pasquotank immediately after dinner in a wind so light that it was nearly dark by the time they entered the Sound and turned east toward the Banks. “The water was much rougher than the light wind would have led us to expect,” Wilbur noted. “Israel spoke of it several times and seemed a little uneasy.” The reason for the skipper’s unease became apparent when the wind shifted to the south and east and began to grow stronger. Even a landlubber like Wilbur could see that Perry’s flat-bottomed scow, with its large deck cabin and light load, was ill-equipped to make its way against the growing headwind. “The waves which were now running quite high struck the boat from below with a heavy shock and threw it back
about as fast as it went forward. The leeway was greater than the headway. The strain of rolling and pitching sprang a leak and this, together with what water came over the bow at times, made it necessary to bail frequently.”11
By eleven o’clock that night high winds were driving the boat dangerously close to the north shore. Perry was struggling to make his way past the North Point light so that he could swing up into the channel of the North River and take shelter behind the point. Just as they drew abreast of the river, a gust blew the foresail loose from the boom with a “terrible roar.” “The boy and I finally succeeded in taking it in,” Wilbur reported in his journal,
… though it was rather dangerous work in the dark with the boat rolling so badly. By the time we had reached a point even with the end of the point it became doubtful whether we would be able to round the light, which lay at the end of a bar extending out a quarter of a mile from the shore. The suspense was ended by another roaring of the canvass as the mainsail also tore loose from the boom, and shook fiercely in the gale. The only chance was to make a straight run over the bar under nothing but a jib, so we took in the mainsail and let the boat swing round stern to the wind. This was a very dangerous maneuver in such a sea but was in some way accomplished without capsizing. The waves were very high on the bar and broke over the stern very badly.12
The condition of Perry’s schooner belied his seamanship. Stern to the wind, he worked the craft around and back up into the safety of the river channel. The three men—skipper, deck hand, and passenger—collapsed on the deck, drenched by the waves, exhausted but relieved. Through it all, Wilbur maintained his sense of humor. “Israel,” he noted, “had been so long a stranger to the touch of water upon his skin that it affects him very much.”
The Bishop's Boys: A Life of Wilbur and Orville Wright Page 20
