In an extraordinary letter to Octave Chanute on May 13, 1900, Wilbur Wright reveals for the first time in writing his vision, aeronautical principles and plans to develop a machine that man can fly.
He chooses Chanute for his disclosure because of Chanute’s worldwide reputation as an expert on the history of aviation. In 1894, Chanute had published, “Progress in Flying Machines,” a compendium of practically all significant aeronautical works up to that time. Wilbur became aware of the book after his inquiry for information to the Smithsonian Institution the year before.
Wilbur is just beginning to emerge from the depression that has haunted him from the time he was injured in a hockey accident in high school. He knows that he has the ability to do something significant in his life. Solving the riddle of flight may be just that thing. Now he needs someone important involved in flight to give him confidence to proceed with his vision.
The carefully worded letter does the trick and triggers the beginning of a ten-year close relationship between the two, involving some 400 letters of correspondence until Chanute’s death in 1910.
Chanute was 45 years older than Wilbur. Wilbur was looking for feedback and confirmation from the senior engineer.
Here is the letter. I have taken the liberty to comment on its contents at various intervals.
The letter was written on stationery of the Wright Cycle Company, 1127 West Third Street.
“Mr. Octave Chanute, Esq, Chicago, Ill.”
“For some years I have been afflicted with the belief that flight is possible for man. My disease has increased in severity and I feel that it will soon cost me an increased amount of money if not my life. I have been trying to arrange my affairs in such a way that I can devote my entire time for a few months to experiment in the field.”
Comment: Here we see Wilbur’s passion, desire, and commitment to a task with great odds against success and risk to his life.
“My general ideas of the subject are similar to those held by most practical experimenters, to wit: that what is chiefly needed is skill rather than machinery. The flight of the buzzard and similar sailers is a convincing demonstration of the value of skill and the partial needlessness of motors. It is possible to fly without motors, but not without knowledge and skill. This I conceive to be fortunate, for man by reason of his greater intellect, can more reasonably hope to equal birds in knowledge, than to equal nature in the perfection of her machinery.”
Comment: Wilbur, unlike most if not all other experimenters at the time, points out the importance of a skilled pilot. From his experience with bicycles, he knew that a bicycle rider can control an inherently unstable bicycle once he learns how to do it through practice.
“Assuming then that Lilienthal was correct in his ideas of the principles on which man should proceed, I conceive that his failure was due chiefly to the inadequacy of his method, and of his apparatus. As to his method, the fact that in five years’ time he spent only about five hours, altogether, in actual flight is sufficient to show that his method was inadequate. Even the simplest intellectual or acrobatic feats could never be learned with so short practice, and even Methuselah could never have become an expert stenographer with one hour per year for practice. I also conceive Lilienthal’s apparatus to be inadequate not only from the fact that he failed, but my observations of the flight of birds convince me that birds use more positive and energetic methods of regaining equilibrium than that of shifting the center of gravity.”
Comment: Wilbur had much respect for the German aeronautical pioneer Otto Lilienthal who died in a crash when his glider lost lateral balance in 1896. However, Wilbur points out that Lilienthal was on the wrong track for two reasons. First, Lilienthal failed because his approach was not providing him enough flying time to learn the skills needed to fly. Secondly, his technique was wrong. He tried to maintain equilibrium of his glider by changing the center of gravity through shifting the weight of his body. Sadly, his good intentions, but faulty approach, resulted in his death.
In the next paragraphs Wilbur explains his approach.
“With this general statement of my principles and belief I will proceed to describe the plan and apparatus it is my intention to test. In explaining these, my object is to learn to what extent similar plans have been tested and found to be failures, and also to obtain such suggestions as your great knowledge and experience might enable you to give me. I make no secret of my plans for the reason that I believe no financial profit will accrue to the inventor of the first flying machine, and that only those who are willing to give as well as to receive suggestions can hope to link their names with the honor of its discovery. The problem is too great for one man alone and unaided to solve in secret.”
Comment: Here he lays out his plan to follow the Scientific Method, i.e. gather data, and proceed from hypothesis based on principles and test for practicality. He recognizes that the task is not easy. He will soon change his mind about sharing information with others when he finds that others have little to offer and want to copy his ideas.
“My plan is this. I shall in a suitable locality erect a light tower about one hundred and fifty feet high. A rope passing over a pulley at the top will serve as a sort of kite string. It will be so counterbalanced that when the rope is drawn out one hundred and fifty feet it will sustain a pull equal to the weight of the operator and apparatus or nearly so. The wind will blow the machine out from the base of the tower and the weight will be sustained partly by the upward pull of the rope and partly by the lift of the wind. The counterbalance will be so arranged that the pull decreases as the line becomes shorter and ceases when its length has been decreased to one hundred feet. The aim will be to eventually practice in a wind capable of sustaining the operator at a height equal to the top of the tower. The pull of the rope will take the place of a motor in counteracting drift (drag). I see, of course, that the pull of the rope will introduce complications which are not met in free flight, but if the plan will only enable me to remain in the air for practice by the hour instead of by the second, I hope to acquire skill sufficient to overcome both the difficulties and those inherent to flight.
Knowledge and skill in handling the machine are absolute essentials to flight and it is impossible to obtain them without extensive practice. The method employed by Mr. Pilcher of towing with horses in many respects is better than that I propose to employ, but offers no guarantee that the experimenter will escape accident long enough to acquire skill sufficient to prevent accident. In my plan I rely on the rope and counterbalance to at least break the force of a fall.”
Comment: The Wrights do not use the tower idea during the first visit to Kitty Hawk. At first they flew the glider like a kite. Then Wilbur found he could safely ride the glider in the prone position down the slope of a sand dune. Chanute in his response to this letter had advised Wilbur not to use the tower, rather glide off the dunes.
Percy Pilcher was an assistant lecturer in naval architecture and marine engineering at the University of Glasgow. He was inspired by the gliding experiments of Lilienthal and even visited Lilienthal in Germany. Pilcher constructed a number of gliders and had plans to apply a motor to one of them. While giving a glider demonstration to a group of Englishman on his estate, he crashed and died in 1899.
“My observation of a flight of buzzards leads me to believe that they regain their lateral balance, when partly overturned by a gust of wind by a torsion of the tips of the wings. If the rear edge of the right wing tip is twisted upward and left downward the bird becomes an animated windmill and instantly begins to turn, a line from its head to its tail being the axis. It thus regains its level even if thrown on its beam ends, so to speak, as I have frequently seen them. I think the bird also in general retains its lateral equilibrium partly by presenting its two wings at different angles to the wind, and partly by drawing in one wing, thus reducing its area. I incline to the belief that the first is the more important and usual method.”
Comment: Wilbur describes his discovery of how birds maintain equilibrium. He applies this concept to the building of a five foot, bi-wing kite in 1899. It works! He’s now ready to apply the concept to a glider that he can fly.
” In the apparatus that I intend to employ I make use of the torsion principle. In appearance it is very similar to the double-deck machine with which the experiments of yourself and Mr. Herring were conducted in 1896-7.”
Comment: He tells Chanute he plans to use Chanute’s idea of a bi-wing, Pratt truss design.
“The point on which it differs in principle is that the cross-stays which prevent the upper plane from moving forward and backward are removed, and each end of the upper plane is independently moved forward or backward with respect to the lower plane by a suitable lever or other arrangement. By this plan the whole upper plane may be moved forward or backward, to attain longitudinal equilibrium, by moving both hands forward or backward together. Lateral equilibrium is gained by moving one end more than the other or by moving them in opposite direction. If you will make a square cardboard tube two inches in diameter and eight or ten long and choose two sides for your planes you will at once see the torsional effect of moving one end of the upper plane forward and the other backward, and how this effect is attained without lateral stiffness.”
Comment: Here Wilbur reveals the concept of “wingwarping.” He believes that effective control is the key to successful flight. Wingwarping provides lateral control of an airplane. Lack of such control is what killed Lilienthal and Pilcher.
Wilbur explains the concept by using as the example the now famous bicycle tube box. Wilbur was talking to a customer one day when he absentmindedly twisted the ends of the narrow box in opposite directions. He immediately conceptualized a pair of biplane wings, vertically rigid yet twisted into opposing angles at the tips.
Chanute never does understand the concept of wingwarping. He was focused on developing a way to build automatic stability into his gliders.
“I plan to attach the tail rigidly to the rear upright stays which connect the planes, the effect of which will be that the upper plane is thrown forward the end of the tail is elevated, so that the tail assists gravity in restoring longitudinal balance. My experiments hitherto with this apparatus have been confined to machines spreading about fifteen square feet of surface, and have been sufficiently encouraging to induce me to lay plans for a trial with a full-sized machine.”
Comment: Wilbur’s kite in 1899 was rigged so that he could warp the wings.
The Wrights used a horizontal tail. The vertical tail was first used on the 1902 glider.
“My business requires that my experimental work be confined to the months between September and January and I 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 of too inclement weather. I am certain that such localities are rare.”
Comment: Wilbur explains he doesn’t want his experiments to interfere with the bicycle business.
Chanute suggests locations in San Diego, Pine Island, Florida and the Atlantic Coasts of South Carolina and Georgia.
Wilbur also wrote to the U.S. Weather Bureau, which resulted in the selection of Kitty Hawk.
“I have your Progress in Flying Machines and your articles in the Annuals of ’95, ’96 and ’97, as also your recent articles in the Independent. If you can give me information as to where an account of Pilcher’s experiments can be obtained I would greatly appreciate your kindness.”
Comment: Chanute had little to offer on Pilcher.
Wilbur does receive the response he was looking for from his letter when Chanute responded that he was “pleased to correspond with you further and to have a more detailed account of your proposal.”