December 04, 1919
Extraordinary Orville Wright Letter Discussing the Birth of Manned Flight at Kitty Hawk
When the bicycle-building, kite-flying Wright brothers of Dayton, Ohio, took up aeronautics as a sport in 1896, they little expected they would become, by 1903, the pioneers in the science of flight. In this extraordinary letter, Orville, in answering a question about what he considered "the most interesting or significant episode in the birth of flying at Kitty Hawk,” essentially tells the story of how he and Wilbur invented the first successful airplane, and became the first men to make a motorized flight.
Wright begins with a description of their earliest non-motorized flights at Kitty Hawk, the “laboratory work,” he says, “that made possible the construction of our first power flyer":
Our experiments at Kitty Hawk in 1901 proved conclusively to us that the tables of air pressure then in existence were entirely unreliable. From this we were led into the designing and construction of a wind tunnel and apparatus to be used in the tunnel for measuring the lift and drift and the center of pressure on airfoils. This was in the Fall and Winter of 1901-02. ...Our early experiments at Kitty Hawk were conducted for the purpose of developing a method of maintaining equilibrium in the air and also to learn something about soaring flight. It was from reading accounts of Lilienthal's experiments that we became interested in this.
What the Wright Brothers observed during this period – and this was a crucial element of their success – was that birds changed the angle of the ends of their wings to make their bodies roll right or left; Wright introduces that thought, which he will return to again and again:
At Kitty Hawk we had the opportunity of witnessing daily the soaring flight of buzzards, fish and chicken hawks, and eagles. Attempts to imitate their flights without a motor have not been very successful, although in 1902 and 1903 we made a dozen or more flights in which we remained in the air for a minute with no, or scarcely any descent; and in 1911. Mr. Alex Ogilvie and I continued the soaring experiments at Kitty Hawk and succeeded in making a number of flights of more than five minutes duration (the longest of which was nine and three-quarter minutes) without any loss of height at all. In many cases we landed at a higher point than the one from which we started. I see no reason why flights of several hours duration cannot be made without use of a motor. But, of course, these flights must be made in rising trends of air--a condition required by all birds for soaring flight.
Wright then answers Driggs’ question - "the most interesting or significant episode in the birth of flying at Kitty Hawk" - before returning to the nature of flight as observed in birds:
While making a motor flight at Montgomery, Alabama, in the Spring of 1910 I had a most unusual experience. I had ascended to a height of a little over one-half mile and was descending when, at a height of about fifteen hundred feet, I suddenly discovered that I was not able to descend further, although my motor was throttled to the limit and the machine was pointed downward as steeply as I felt it safe to descend. I remained at a height of about fifteen hundred feet for a period of five minutes without making any appreciable descent. Suddenly the machine again began to descend and I was on the ground in about half of a minute. The sensation was one such as I had never experienced before, nor as a matter of fact since, and was most thrilling. I have always supposed that I got into a rising current of air of unusually large diameter. At the time of the flight the air seemed perfectly calm. The descent was made in a spiral course of not more than five or six hundred feet in diameter. This probably accounted for the long time the machine remained in the up-trend of air. No doubt, if I had steered out of the spiral into a straight course, I would have been out of the rising current in a few seconds; but I did not think of this at the time. In fact, I was so astonished that I did not think of any reason for the phenomenon, but rather began to think that it was a dream, such as one sometimes has, in which, although the legs are moved violently, no progress is made. I have frequently struck currents of air, which have suddenly lifted the machine fifty or seventy-five feet; but the machine remained in these rising trends usually only a few seconds. It is possible that we sometimes run into rising trends of air of as large diameter as the one encountered at Montgomery, but as most of the flights are comparatively straight away, we do not have the luck of staying in them more than just a few seconds.
The most remarkable example of soaring that I have ever seen was witnessed by Wilbur and myself near Kitty Hawk in 1900. The remarkable feature of the flight was in the intelligence or the instinct of the birds which led them to create for themselves a soaring condition where it did not already exist. One morning after a cold night we saw a number of buzzards, probably fifteen in number, and several fish hawks, begin by flapping their wings vigorously and flying together in s small circle, not more than fifty or seventy-five feet in diameter, at a height of twenty-five or thirty feet from the ground. They all kept well together in the circle, gradually working upward. When at an altitude of approximately fifty feet they suddenly quit flapping and then rose rapidly on stationary wings. As they rose higher they spread out into larger circles. When they reached an altitude of about one thousand feet they began to separate, each gliding off in a straight line. After leaving the circle they all lost altitude. In fact the gliding angle of the buzzard is not better than that of an aeroplane. The warm sun had no doubt created a warm stratum of air immediately above the ground, which was a sand plain. The birds through concerted action made an opening through the cold stratum above and started a rush of warm air upward, and then used this upward rush of air to gain altitude.
Driggs wrote at length about the Wright Brothers in his 1929 book Heroes of Aviation. But if all he had done for the history of early flight was to elicit and preserve this letter, he still would have done enough.
Typed Letter Signed, 3 pages, quarto, on his personal letterhead, Dayton, Ohio, December 4, 1919. To Lawrence L. Driggs of the American Flying Club in New York City.