The Thrill of Invention

That's the 1901 Wright glider out there, darting about at the end of its kite tether 10 feet in the air. Up here on a great dune, whipped by the blowing sand and a wind gusting to 25 mph, one of the historic photographs taken by the Wright brothers seems to have come to life. The effect is stunning and a bit surreal.

In the old photos, the familiar figure of Wilbur Wright is stretched out in the open space in the center of the lower wing, his hand on the elevator control, his gaze fixed on the sandy slope in front of him. But the pilot I'm watching is a tall, athletic young woman clad in jeans and an A-2 flight jacket, her short golden hair swept straight back by the wind.

"She looks like a blond goddess," someone remarks. "I like to think so," her father responds.

The intrepid aviator is Jacquelyn "Jay" Grattan, a twenty-something lawyer on leave from her duties as an officer and judge advocate with the U. S. Marine Corps. She has just become the first person since Wilbur Wright to fly the most discouraging, frightening, and instructive of the three historic gliders that were the final stepping stones to the invention of the airplane. And her aircraft is also the best replica of that glider that we are likely to see.

Back on the ground after less than two minutes of tethered flight, Jay is not pleased. "Pitch control is a struggle," she remarks to her father. "Now I understand why Wilbur and Orville were so worried about this one."

Jay is not a licensed pilot, but she can scarcely remember a time when the Wright brothers were not a part of her life. Her father, who is standing next to me watching her ride the wind, is Rick Young, a Virginia restaurateur with an abiding passion for the story of the two brothers from Dayton. Young has many years of experience building and flying reproductions of the gliders that led to the airplane as we know it today -- a fully controllable flying machine. "Think about it," he explains. "The Wright brothers didn't even patent a powered airplane. They patented their 1902 glider. It embodied the lessons that were the foundation for the invention of the airplane, the critically important ideas that had to be protected."

At the beginning of their career in aeronautics, the brothers recognized that heavier-than-air flight would require wings capable of lifting the weight of machine and pilot into the air, a reasonably lightweight propulsion system, and a means of balancing and steering the craft in flight. "Of these difficulties," Wilbur Wright wrote in 1901 (compiled by M. W. McFarland in The Papers of Wilbur and Orville Wright), the first "two are to a certain extent solved." Balance and steering were the hard parts.

The brothers set out in 1900 to develop a winged aircraft that would, for the first time, be completely controlled by the pilot. To this end, they designed, built, and tested an evolutionary chain of four experimental aircraft, one kite (1899) and three gliders (1900, 1901, 1902), and conducted an important series of wind tunnel tests during the fall and winter of 1901.

It was not smooth sailing. Frustration and disappointment were as much a part of the process as the euphoria of discovery. As Young notes, "They were masters at the art of learning from their mistakes." And the gliders were the keys to their success, enabling them to find and overcome problems, to establish the basic principles of aircraft design, and most important, to learn to fly.

Young wants to rediscover the precise details of the Wrights' technology, and reproducing their gliders is simply a means to that end. "They had to translate their deepest insights and most important discoveries into the design and construction details of those amazing gliders," Young explains. "And there is no better way to acquire a genuine grasp of those essential lost details than to build and fly accurate replicas of the historic machines."

Rick Young began his quest in 1975, when he and his brother Bill built a reproduction of the 1900 glider and flew it in a NASA promotional film entitled Flying Machines. Five years later, Young began work on a reproduction of the 1902 Wright glider in his basement. Jay and her brother David were not yet teenagers when their father kited them aloft aboard that aircraft.

Over the next decade, Rick and his 1902 glider appeared in television commercials, on the Disney Channel, and as stars of the IMAX film On the Wing. The glider was exhibited at the Museum of Science in Richmond, Virginia, but was withdrawn and refurbished in 1994 for a role in The Wright Stuff, a film for PBS. That same year, Young forged an alliance with Ken Hyde, an airline pilot and nationally recognized restorer of historic aircraft. A Wright Model B (see "What Makes It Wright?" June/July 1994) that Hyde's shop produced for the U.S. Army Aviation Museum at Fort Rucker, Alabama, also in 1994, is perhaps the finest reproduction of a powered Wright aircraft anywhere.

Hyde and Young were natural partners and formed a joint venture, The Wright Experience, in which they share a dedication to meticulous accuracy along with a goal of reproducing a full range of Wright aircraft. Hyde plans to build and fly another one or two powered Wright airplanes by 1999 or 2000. Young has reproduced all three of the Wright gliders, and Hyde and Young's first powered Wright airplane is under construction, with its first test flight scheduled for this fall.

The notion of telling the story of the Wright brothers through the experiences of two talented men determined to retrace the path to powered flight intrigued the producers of the television series "Nova." "Here was an opportunity to do something more than simply capture breathtaking images of Wright machines in the air," producer Michael Barnes says. "Although a little of that would be just fine, thank you very much." He and his colleagues at WGBH, the public television station in Boston, recognized a rare opportunity to walk viewers through the process of invention.

Young would refurbish and fly his existing 1902 reproduction. The 1900 replica originally built in the mid-1970s was long gone, however, and Young had never attempted to reproduce the 1901 machine. Research was the essential first step in building the new gliders.

Young searched for fresh information by carefully reexamining the surviving original photographs of the gliders. It's hard to believe, but only 12 of the 303 original Wright brothers glass plate photographs at the Library of Congress show the first two Wright aircraft.

Rather than attempting to work with the fragile originals, Young traveled to the Archives and Special Collections Unit of the Paul Lawrence Dunbar Library at Wright State University in Dayton, Ohio, where the Wright family collection of first-generation prints of the photographs is preserved.

After scanning these crystal-clear prints into his computer, Young could examine the digitized images with ease. In this way, he was able to understand the very different ways in which the fabric was applied to the wings of the gliders. He could also sort out the confusion of trussing and control wires barely visible in the photos. Even the size and shape of small fittings could be studied in detail and at leisure.

The replicas were built in a shop near Young's restaurant and at Ken Hyde's facility in the rolling country a few miles north of Warrenton, Virginia. Young started in the early summer of 1997 and finished in early October, when the three machines, along with considerable crew, traveled to Jockey's Ridge State Park, four miles south of the Wright Brothers National Memorial and eight miles south of what was once the fishing village of Kitty Hawk, on the Outer Banks of North Carolina.

The largest sand hill in the eastern United States, Jockey's Ridge is familiar to the thousands of tourists who flock to the Outer Banks each summer. It still offers the combination of wind, sand, and slope that first attracted the Wright brothers to the Outer Banks in 1900. Had you trudged to the top of the great dune on almost any good-weather day last October, you would have found yourself transported back almost a century to the days when Wilbur and Orville Wright were testing their gliders.

For Wright glider pilots, the rule is "lighter is better." As a result, Young's wife, Sue, had performed much of the flying for the IMAX film. Rick was so determined to fly for the "Nova" cameras that he lost 40 pounds in the two months prior to the 1997 trials. Jay, who had flown for the PBS program, was on leave from the Marines and accompanied the team just in case she was needed. Both father and daughter had plenty of opportunities to fly.

Young and his crew flight tested each of the reproductions in turn, and three years worth of experiments were collapsed into three short weeks of combined flight testing and flying. The letters, diaries, notebooks, and photographs of the Wright brothers came to life for those of us who took part in the events unfolding on Jockey's Ridge. There was a sense of having shared some of the excitement that the brothers had experienced and of having come to a new understanding of the process of invention.

1900:The brothers started their active experiments in Dayton in July 1899, when Wilbur first flew a biplane kite with a five-foot wingspan designed to test a new approach to roll and pitch control. By manipulating two pairs of strings tied to the leading edges of both wings, the operator could shift the upper wing in front of or back of the lower wing's leading edge, or twist the two wings "so as to present their surfaces to the air at different angles of incidence and thus secure unequal lifts on the two sides," as Orville explained.

From the outset, the Wrights thought like engineers. In 1900 and 1901, they relied on data from German pioneer Otto Lilienthal to calculate the wing area required to lift the estimated weight of their aircraft at a particular wind speed. The brothers planned to test their first full-scale machine as a kite. They hoped that they would be able to fly "for hours at a time" tethered to the top of a derrick and grow accustomed to the wing warping and the use of the forward elevator to control pitch, "getting in this way a maximum of practice with a minimum of effort."

The 1900 glider featured ash ribs bent to shape with steam, but even during the short service life of the aircraft, the ribs gradually flattened out. On the way to Kitty Hawk, Wilbur had intended to buy 18-foot lengths of spruce to serve as wing spars. But he could find no lumberyard that carried spruce in that length, and he was forced to settle for white pine spars two feet shorter.

"The covering of the machine was French sateen [a closely woven cotton], and it was put on the bias, so that no wire stays were needed to brace the surfaces diagonally," Wilbur wrote. Applied this way, so that the fibers aligned like cross-bracing wires, the fabric became a key element of the structure, holding the ribs and spars in place and distributing flight loads across the wing. The result was a tough, flexible wing capable of absorbing punishment that would probably break a more rigid structure.

The career of the first full-scale Wright aircraft lasted less than two weeks, from October 5 to 18. It was apparent from the outset that the wings developed far less lift than the calculations based on the Lilienthal tables had predicted. After one or two tries, the notion of tethering the kite to a tower was abandoned.

Since prevailing winds were almost never strong enough to lift the weight of a pilot, virtually all of the 1900 tests were conducted with the machine flown as an empty kite, or carrying a load of sand or chain. The brothers turned the situation to their advantage, measuring the actual performance of their glider and setting the stage for the creation of accurate aerodynamic tables.

They attached a grocer's scale to the kite line to measure the combined lift and drag force on the kite. They used an anemometer to record wind speed and measured the angle of the line to the horizontal with a clinometer. With that information, they calculated that their wings were generating only two-thirds the lift predicted by Lilienthal's table. They offered Tom Tate, the young son of one of their local helpers, some thrilling rides and thereby calculated the drag of an upright body. And they demonstrated the effectiveness of their control system with separate lines running to an operator on the ground.

To attempt some free glides, they moved to the nearest elevation, some small dunes known locally as the Kill Devil Hills, about four miles south of Kitty Hawk. Having lugged the glider part of the way up the slope of the tallest (100-foot) hill, they found the wind gusting to 25 mph. "As we hadÉno experience at all in gliding," Wilbur wrote, "we deemed it unsafe to attempt to leave the ground."

The next day was calmer and Wilbur made a dozen free glides totalling less than two minutes. The day produced one other pleasant surprise: They had planned for the pilot to run along the ground for takeoff, assume a prone flying position between the two halves of the lower wing, then land on his feet. They discovered, however, that two men could launch the glider, and that the pilot had no trouble landing while prone.

At the end of the day they returned to Kitty Hawk alone, having abandoned the machine that first carried them into the sky on the spot where it made its last landing. Mrs. Addie Tate, postmistress of Kitty Hawk and the brothers' hostess on the Outer Banks, asked them for the fabric to make dresses for her two daughters. The skeleton of the machine remained at the base of the Kill Devil Hills for some months, finally disappearing in a July 1901 gale. The 1900 Wright kite/glider is the least documented of the three vehicles. There are no contemporary drawings of either of the first two machines. Worse, in the entire collection of Wright photos, there are only three images of the 1900 machine. The brothers took a picture of Tom Tate proudly displaying a large drum fish with the glider in the background, but they neglected to photograph the details of the glider during assembly, the tower from which they flew it, or any of the free flights.

Fortunately, one surviving photo shows the glider being flown as a kite. An image of the sad remains of the craft following an accident on October 10 also proved to be very useful. Young's finished glider weighs 65 pounds, 15 more than the original. Instead of lightweight pine he used tougher, heavier fir and substituted muslin of the sort used on all later Wright aircraft. The trussing cables and even the fittings, while closely patterned after what can be seen in the digitized photographs, are nevertheless heavier than those in the original.

Based on the Wrights' experience, Young never had much chance of achieving significant glides in the 1900 version, and even Jay was too heavy to be kited aloft. Like the Wright brothers, Young and his crew gathered performance data with a scale to measure the total force exerted on the aircraft. The results seemed to match the performance of the 1900 glider under similar conditions.

In the interest of safety, and in view of the complete absence of information on how the Wrights operated the warping system, the glider was rigidly trussed. The elevator was tested using a "dunking line," as the Wrights called it, leading from the elevator to a handler on the ground. As the Wrights reported, it was very effective.

1901: "When the time came to design our new machine for 1901," Wilbur wrote, "we decided to make it exactly like the previous machine in theory and method of operation." To improve upon the lift of the 1900 aircraft they used a less porous muslin wing covering, increased the curvature of the airfoil to match that on which the Lilienthal table had been based, and enlarged the wing area from 165 square feet to 290. It would be the largest glider ever flown. Operating from a new shed at the base of the Kill Devil Hills, the Wrights made 50 to 100 free glides and kite tests between July 27 and August 17, 1901.

Problems were apparent from the outset. On Wilbur's first attempt to glide, the machine nosed sharply into the sand after flying only a few yards. After a series of trials in which the pilot kept moving farther to the rear, he was finally able to complete "an undulating flight" of a little more than 300 feet. "It was apparent," Wilbur admitted, "that something was radically wrong."

The cause of the problem was the relatively thin ribs, which spanned almost five feet between the spars and were so flexible that they would bend at the midpoint. The airfoil changed shape, allowing the center of pressure to shift to the rear of the center of gravity and caused the aircraft to nose into the ground. The brothers devised a complex fix, trussing down the ribs of both the upper and lower wings. When testing resumed, the elevator proved far more effective. Flights in excess of 350 feet and lasting as long as 17 seconds were the order of the day.

As the flights grew longer, however, it was apparent that the new craft, like its predecessor, developed much less lift than had been predicted. Moreover, the brothers now encountered a new and quite unexpected problem with the lateral control system. In wing warping, the pilot increases the angle of attack on one end of the wing and decreases the angle on the opposite end. As flights grew longer, it became apparent that the wing on which the angle of attack was being increased would lose speed and drop, rather than rise. It was the first step in a frightening sequence of events that led to the aircraft spinning into the sand. "Well-digging," the Wrights called it.

The brothers left the 1901 glider packed away in the shed when they returned to Dayton. Back in camp the following year, they hauled the old machine outside so they could repair the damage done to the building by winter storms and straighten things up. Suddenly, a gust lifted the old glider into the air for the last time. "Machine raised off ground and came bouncing over & over towards the camp," Orville noted in his diary that evening. "Was stopped after going about 150 ft. and breaking one upper spar." The Wrights salvaged the uprights for use with the 1902 glider and abandoned the rest of the machine.

"The boys walked in unexpectedly on Thursday," their sister Katharine wrote to their father on August 26, 1901. "[They] haven't had much to say about flying." Small wonder. But if their second glider had been something of a disappointment, it had also taught them a great deal about the movement of the center of pressure and underscored the need for a wing structure that would not deform under flight loads. It further confirmed that there was a problem with the data used to calculate performance and also revealed a dangerous flaw in the control system.

In order to demonstrate the way in which the Wrights discovered problems with aircraft design that enabled them to move forward, Young decided to build the original version of the 1901 glider. The Wright collection of glass plate photographs contains nine images of the glider, none of which show the aircraft as it was originally constructed. Since the modifications are obvious, however, Young had no trouble reproducing an aircraft that had not been captured by the camera -- in fact, a machine that no one has seen since 1901. In the interest of simplicity and safety, and because it would have no technical impact, he substituted the hip cradle wing warping control of the 1902 glider for the foot control actually employed on the 1901 glider.

Jay, who made the first tethered flights with the machine, discovered that, like Wilbur, she had to move well back of what would seem to be a natural flying position in order to keep the 1901 machine balanced. Young's early glides with the machine were also a replay of Wilbur's experience, complete with a landing hard enough to damage the structure.

With some worrisome flight test experience under their belts, the cause of the problem was as apparent to The Wright Experience team as it had been to Wilbur and Orville. As the aircraft sits flat on the ground headed into the wind with no flight load, the ribs deflect as much as an inch and a half at the midpoint between the spars. You can send a distorting wave moving the length of the wing simply by tapping your hand on top of one wingtip. It is one of those perfect cases in which the "Nova" crew can film the problems that beset the airplane in the air, then provide viewers with a close look at the cause: those flexible ribs.

1902: The 1902 Wright glider was the product of two years of flight testing and a few weeks of priceless wind tunnel data gathered in the back room of a bicycle shop in Dayton, Ohio. The machine had recognizably different proportions than its predecessors. It was also the first Wright glider to sport a rudder.

Determined to calculate performance accurately, the Wrights designed and built a wind tunnel and a pair of brilliantly contrived aerodynamic balances, then gathered the data with which to prepare their own tables of lift and drag coefficients. During the fall and winter of 1901, the tunnel also enabled them to study the most efficient proportions for a wing, the impact of varying wingtip shapes on performance, and the ideal gap between the wings of a biplane.

The Wrights recognized that the "well-digging" problem was the result of adverse yaw, an increase in drag that caused a positively warped wing to "fall behind," as they put it, rather than rise. They reasoned that a fixed vertical rudder at the rear of the craft would counteract the adverse yaw and keep the aircraft moving straight ahead. Once in camp, however, they recognized that the rudder would be even more effective if linked to the wing warping system, so as to automatically turn in the appropriate direction. The final rudder configuration -- twin vanes linked to move with the wing-warping system -- was installed on the glider for the 1903 season.

The Wrights completed 700 to 1,000 glides with the new machine during the 1902 season (September 19 to October 24). They made an additional 175 to 235 flights between September 28 and November 7, 1903, while they were assembling and testing the first powered airplane. The record distance for both seasons was something in excess of 610 feet. Their best time in the air, achieved on October 26, 1903, was 1 minute, 11.8 seconds.

When they left for Dayton in December 1903, the Wright brothers packed the 1902 glider away in the rafters of the hangar at the Kill Devil Hills. When they returned to their camp in the spring of 1908, they found that the building had collapsed. The remnants of one of the most significant aircraft in the history of flight were poking up through the sand.

The 1902 glider was much better documented than any of its predecessors. The brothers took a great many photographs of the machine both in the air and on the ground. Octave Chanute published dimensional drawings of the glider in a French aeronautical journal in the summer of 1903. In addition, Orville Wright prepared drawings on which to base a replica of the glider that was constructed in 1934.

Though there have been a few replicas of the 1902 glider over the years, Rick Young's is the most accurate and the only one that has carried a pilot aloft. Originally constructed in 1980, the glider has appeared in so many films over the past 17 years that it qualifies as a historic object in its own right. It has been refurbished, recovered, and rebuilt so often that virtually nothing remains of the original.

It was originally constructed with the single-vane rudder linked to the wing warping system, representing the aircraft as flown during most of the 1902 tests. When flown for the WGBH film crew last year, Young substituted the twin-vane rudder installed in 1903.

Young's glider has had a much longer career than the original, but it has not come close to matching the Wright brothers' record for either distance or time in the air. That is almost certainly because Young's glider has been flown only at Jockey's Ridge, where the best slopes for long glides can seldom be used because of the wind direction. The Kill Devil Hills, although not as tall as Jockey's Ridge, offered longer slopes facing into the wind. There is every indication that under similar conditions, Young's glider would fly as far and remain aloft as long as the original.

Substantial problems remained as the brothers developed a practical flying machine during the years 1903 to 1905, but the core of their achievement was in place with the end of the 1902 glider trials. Had Wilbur and Orville Wright stopped at that point, they would still have to be regarded as the most significant figures in the story of the airplane's development. The Wrights had one failing: They did not preserve the historic craft that brought them to the brink of the invention of the airplane. Rick Young has brought the gliders, and the process of invention, back to life for us.