Miracle at Kitty Hawk: Unpublished Letters of the Wright Brothers (Part II)

This article by Orville and Wilbur Wright's official biographer, Fred C. Kelly, includes a number of letters written by the Wrights during the years leading up to and just after their first flight.

At the end of 1901 the Wrights had confirmed, by ingenious wind-tunnel experiments, their belief that all published tables of air pressures on curved surfaces were in error. Their gliding at Kitty Hawk had convinced them that even Otto Lilienthal, the German whom they greatly admired, had lacked knowledge of what curvature wing surfaces should be for successful flight—though he had been the first to know why curved surfaces in a flying machine were superior to flat. Reluctantly, the Wrights had discontinued their research. They still had to look after their bicycle business and earn a living.

Now Chanute, who had himself experimented with gliders, and was the best historian of attempts of man to fly, perceived that the Wrights were already far ahead of all their predecessors; he knew it would be a loss to science if they did not continue their investigations. So he offered to try to get Andrew Carnegie to supply funds.

December 23,1901

As to your suggestion in regard to Mr. Carnegie, of course nothing would give me greater pleasure than to devote my entire time to scientific investigations; and a salary of ten or twenty thousand a year would be no insuperable objection, but I think it possible that Andrew is too hard-headed a Scotch-man to become interested in such a visionary pursuit as flying. But to discuss the matter more seriously, I will say that several times in the years that are past I have had thoughts of a scientific career, but the lack of a suitable opening, and the knowledge that I had no special preparation in any particular line, kept me from entertaining the idea very seriously. I do not think it would be wise for me to accept help in carrying our present investigations further, unless it was with the intention of cutting loose from business entirely and taking up a different line of life work. There are limits to the neglect that business will endure; and a little pay for the time spent in neglecting it would only increase the neglect, without bringing in enough to offset the damage resulting from a wrecked business. So while I would give serious consideration to a chance to enter upon a new line of work, I would not think it wise to make outside work too pronounced a feature of a business life.
January 5, 1902

The relation of men of wealth to the flying problem presents many points of similarity to that of North Pole hunting. It would be folly to back such attempts as business propositions, or at least it could be considered nothing better than the very rashest speculation. Although I personally believe that constant systematic effort would bring about a successful machine in the course of a very few years, yet in view of the universal failures of the past no man could honestly make such a belief the basis of an appeal to some rich man for help on a business basis. If wealth is to be interested it would more properly be in the line of instituting a fund to be known as "The Croesus Fund for the promotion of Aeronautical Science," with the condition that all experiments should be published as "Croesus Fund" experiments and that the successful machine should in some way have this name linked with it. Another plan would be to offer a permanent prize of a considerable amount to be awarded only for a machine which was capable of meeting rigid tests, but the interest each year to be awarded to the most valuable improvement or contribution to aeronautical science made during the year.

The first plan would be somewhat on the plan of the Smithsonian Institution, or the recent Carnegie Institute, only on a much smaller scale of course and with no permanent buildings, etc. The other would be similar to that of the Nobel Fund except that the endowment would become the grand prize in case of absolute success.

Since donations of ten to thirty millions have become the style, little fame is to be obtained by comparatively small gifts to colleges. For the money expended, an aeronautical fund would probably give a man as much fame as any that could be named, as the newspapers keep a closer watch on colleges.

If wealth is to be interested on a mixed basis of benevolence and hope of pecuniary return, it ought to be made sufficiently clear that the latter could hardly be considered a satisfactory insurance against finally resting in a pauper's grave.

Your news in regards to the St. Louis Exposition is interesting certainly. If the plan is carried through, it will undoubtedly have the effect of greatly stimulating public interest at least, and may bring some new workers into the field. Whether it will have much immediate effect so far as a complete flying machine is concerned, I much doubt, because where all is attempted at once in haste, no one point receives sufficient attention to lead to a real advance. The probability is that the department of aviation would be a competition between engine builders rather than flying machine builders.
DAYTON, OHIO, January 19, 1902

I am sending you herewith photo and description of our pressure testing machine. It is our belief that the method and construction employed entirely avoid errors from the following sources: (1) Variation in wind velocity; (2) Variations in temperature and density of the atmosphere; (3) Travel of center of pressure; (4) Variation in angle of incidence owing to movements of the mounting arms, The first two causes gave Mr. Langley trouble; while the third and fourth vitiate somewhat the natural wind experiments of Lilienthal. Gravity and centrifugal force are also rendered nugatory.

Our greatest trouble was in obtaining a perfectly straight current of wind, but finally by using a wind straightener, and changing the resistance plane to a position where its ill influence was much reduced and also by breaking it up into a number of narrow vertical surfaces instead of a single square, we obtained a current very nearly constant in direction. The instrument itself was mounted in a long square tube or trough having a glass cover. After we began to make our record measurements we allowed no large object in the room to be moved, and no one except the observer was allowed to come near the apparatus, and he occupied exactly the same position beside the trough at each observation. We had found by previous experience that these precautions were necessary, as very little is required to deflect a current a -tenth of a degree, which is enough to very seriously affect the results. I will send another batch of data in a few days.

Your letter from St. Louis of course interested us very much. The newspapers of yesterday announce that the fair will be held in 1903 as originally planned. If this be final there will be little time for designing and building a power machine, which is, I suppose, the only kind that could hope to be awarded a prize of any size. Whether we shall compete will depend much on the conditions under which the prizes are offered. I have little of the gambling instinct, and unless there is reasonable hope of getting at least the amount expended in competing, I would enter only after very careful consideration. Mathematically it would be foolish to spend two or three thousand dollars competing for a hundred thousand dollar prize if the chance of winning be only one in a hundred.

The Wrights kept up their correspondence with George A. Spratt, of Coatesville, Pennsylvania, who had visited them at Kitty Hawk in the summer of 1901. He was much interested in aerodynamic problems, and had also had medical training. The Wrights had invited him at the suggestion of Chanute, who was disturbed when he discovered that no doctor was available near their camp.

DAYTON, January 3, 19O2

I see from your remark about the "blues" that you still retain the habit of letting the opinions or doings of others influence you too much. We thought we had partly-cured you of this at Kitty Hawk. It is well for a man to be able to see the merits of others and the weaknesses of himself, but if carried too far it is as bad or even worse than seeing only his own merits and others' weaknesses...

You seem to be having trouble to obtain satisfactory surfaces. Possibly our experience will be of assistance in deciding on proper material. But first you ought to decide on the length, breadth, and thickness of your surface. It ought to be as near as possible proportionate in every dimension to the surfaces to be used in large machines. Now, the experiments of Lilienthal, Langley, Dines, Maxim, Wenharn, and others, as well as our own recent experiments, show that the efficiency at small angles is greatest in surfaces having the latitude much greater than the fore and aft dimension. And this agrees with what we find in birds, as the tip to tip measurement is never less than five times the longitude of wing from front to rear, and in the sea birds, which live on the wing, the tip to tip spread is sometimes twenty times the fore and aft dimension. If you would copy nature your surfaces should have a lateral breadth not less than six times the length fore and aft, nor more than twenty times.
DAYTON, February 7, 1902

The newspapers are fill of accounts of flying machines which have been building in cellars, garrets, stables, and other secret places, each one of which will undoubtedly carry off the $200,000 at St. Louis. They all have the problem "completely solved," but usually there is some insignificant detail yet to be decided, such as whether to use steam, electricity, or a water motor to drive it. Mule power might give greater ascensional force if properly applied, but I fear would be too dangerous unless the mule wore pneumatic shoes. Some of these reports would disgust one, if they were not so irresistibly ludicrous.
DAYTON, February 14, 1902

Your letter and the surfaces received. Sorry you do not find sheet steel applicable to your needs. I recommended it because it is so stiff, so easily formed into any desired shape, and so cheap. In fifteen minutes any curvature desired can be obtained with no other tools than a hammer and anvil, either a plain curve, or spoon shaped, or bowl shaped. Carving surfaces out of wood is all right, but it is awfully tedious work.

Your reasoning in regard to two 6" x 12" being equal to one 6" x 24" in lift is hardly sound. The two halves of a broken pitcher are equal in weight to the unbroken pitcher but they will not hold as much water. Your two surfaces will equal the larger one in area but it does not necessarily follow that they will be equal in any other respect. As a matter of fact the conditions are materially different owing to the fact that in the 6" x 24" surface there are only two ends (tips) for the wind to escape around, while in the two 6" x 12" surfaces there are four such ends. Thus there is less loss in the 6" x 24" surface, and its lift is relatively greater.

You are quite right in saying that a gas engine and tools are in advantage of experimenting. It is possible that in the long run you could do more experimenting in a given time by spending part of your time earning money by running a bicycle pair shop, or something of the kind, and incidentally fitting up with an engine which would come handy in aeronautical work. In the present stage the game aeronautical experimenting alone is not a very sure way of earning bread and-butter.


he Wrights were the first to know that there was a loss of lifting power from placing one wing above another, and how much loss.

DAYTON, March 11, 1902

Your inquiry as to my opinion of the best surfaces to use and how many to superpose, I am unable to answer definitely. There are a number of points which need to be investigated first. Our experiments showed that with surfaces of a given thickness and longitude, the lift and dynamic efficiency increased as the latitude became greater. But as structural reasons demand that the thickness of the lateral spars must increase as the latitude becomes greater, a point is finally reached where a further increase of the relative latitude is harmful in dynamic efficiency—the drift increases faster than the lift. Just what the proper proportions are I do not know, but I think that with a surface 1 foot thick and 8 feet from front to rear, the spread should be from 15 to 25 feet.

As to superposing, our tables give all that I know. A machine with several surfaces will be stronger and possibly more manageable but not quite so efficient as a single surface. It is probable that trial alone will show just how far superposing can be carried with advantage.
DAYTON, March 23, 1902

My idea of the correct use of the terms drift and head resistance is well exemplified by... a man rowing across a rapid stream. If he points the boat directly across the current, it will take just as much work to reach the opposite shore as if the water were still; but he will land much lower down than his starting point. The power required to drive the boat is the "head resistance," while the distance he drifts down stream is the "drift." In both nautics and aeronautics drift is a loss of position rather than a resistance. It is important therefore to carefully distinguish in calculations between the power consumed in overcoming resistance and, the power consumed in recovering position. The man, in order to avoid loss of position, must point his boat somewhat up stream while crossing, and his relative distance rowed will be the actual distance across the river divided by the cosine of his "angle of incidence."...

I think that the St. Louis Exposition authorities will have to increase the amount of their prizes, as I have already been offered so many shares of the prize by various persons who have a cinch on it, that the sum of my shares would amount to more than the total prize. Consequently the St. Louis men must put up more money or take advantage of the bankrupt laws.

Chanute, not intending to attempt any new experiments himself, wanted to have rebuilt some of the gliders he had designed, "to test the comparative merits" of what he had done.

DAYTON, May 29, 1902

We consented to undertake the building of machines for you for the good of the cause. If you make other arrangements, it will be all right with us. To tell the truth, the building of machines for other men to risk their necks on is not a task I particularly relish, and if Mr. Herring is at leisure to take charge of the matter for you it will relieve us.

Our busy season is about over, and if we could depend on proper winds, we would probably spend July and August at Kitty Hawk. These are the months that we would prefer to spend in camp but we are dubious about the winds and weather after our experience of last year. If we go to Kitty Hawk it will probably be some time between August 15th and September 15th. It is a pity that the hills near Chicago are not smooth bare slopes.

Will try to furnish drawings as soon as convenient to do so. I do not think that drawings will reveal very much of the principles of operation of our machines, unless accompanied with somewhat extended explanations, so our secrets are safe enough.

The Wrights did not want to take time for testing or experimenting with gliders designed or built by anyone else, for they wanted to solve the problem themselves. But in dealing with a good friend they were polite!

DAYTON, June 2, 1902

If I understand you properly, you propose to build the multiple-wing and double-deck machines and give them to us as presents. You hinted something of this kind in a former letter, but it surpassed our capacity for belief that you were intending to exercise the virtue of benevolence on so magnificent a scale as your words seemed to imply. The kindness and enthusiasm in the cause which prompted such a generous offer strike a very deep chord in our hearts. We thank you most earnestly. Yet the question arises whether it would be wise to spend so much for such a purpose. It is not certain that we would be able to find opportunity for such extended use of the machines as would justify so great an expenditure on your part. Our use of the machines ought to be an incident rather than the primary purpose of their construction. We are yet in hopes that you may decide to resume experiment on your own account.
DAYTON, July 9, 1902

In our conversation you raised the point of the advisability of sending Mr. Avery or Mr. Herring down to Kitty Hawk. I did not feel prepared to give a definite opinion without full consideration of the matter with my brother. We think that there are reasons that make it very desirable that an expert should be present during the trials of your machines. (1) The expense incurred in building the machines is such as to make it very desirable that the tests should be as perfect as possible. (2) An expert would know just how the machines ought to act, and would at once detect radical imperfections in their actions, and thus materially reduce the time required to "tune up" the machines. (3) We would be very loath to assume sole responsibility for the tests, for if from any cause whatsoever the results obtained should fail to equal those obtained by Messrs. Herring and Avery it might raise a suspicion that we had not acted fairly. We would have no fears of your own personal opinion; but others hearing of the matter might with apparent justice form a very different opinion. We would be very unwilling to subject ourselves to the possibility of such a misapprehension of the facts.
DAYTON, August 20, 1902

The flying machine is in process of making now. Will spins the sewing machine around by the hour while Orv. squats around marking the places to sew. There is no place in the house to live but I'll be lonesome enough by this time next week and wish that I could have some of this racket around.


Though the Wrights had faith in the tables of air pressures they had compiled from their wind- tunnel experiments, and wanted to see them verified in actual gliding, yet so much remained to be discovered, and the whole job seemed so formidable, that Wilbur hesitated about making another trip to Kitty Hawk. Not until a week or so before time to start was Orville sure that he had succeeded in persuading Wilbur to go; and he would not have gone alone.

Kitty Hawk, NORTH CAROLINA, August 31, 1902

We left Dayton at 9 A.M. last Monday and reached Elizabeth City at 5.45 P.M. Tuesday after a very nice trip. We found the schooner Lou Willis, Captain Midgett, lying at the wharf intending to start for Kitty Hawk at 4 A.M. Wednesday morning. To rush back to the station and get our trunks out of the baggage room and our freight out of the freight depot before 6 P.M., the shutting up time, required fast work, but we succeeded. By extraordinary luck we also succeeded in buying a barrel of gasoline just as the men were leaving the Standard Oil Company warehouse, and Orville succeeded in getting an oven by rushing from store to store till he found one where the man was locking up, but reopened long enough to sell an oven. The groceries were mostly closed but we finally found one open and got a few cans of baking powder. It was long after dark before we got our things aboard the boat.

The boat set sail at 8.45 AM. next morning, or rather we poled out, for the wind was too light to sail. At 6 o'clock we had made nearly a mile. At noon we had gone about 6 miles... Then the wind came up a little stronger, but changed its direction so that it came dead ahead, so that while the boat moved through the water, with fair speed it was mostly back and forth across the river and very little onward in the direction we wanted to go. By 3 o'clock we had made about 15 miles, about 1 and a third miles an hour for eleven hours' sailing. As the captain saw that there was no hope of getting to Kitty Hawk till long after midnight he decided to cast anchor till daylight next morning.

On reaching shore we hurried about and soon got Dan Tate and his boat and Captain Hobbs' horse and cart and, putting our trunks, gasoline stove, and a few necessary articles of food in boat and cart, we set out for camp 4 miles south of the wharf, and reached there about 6 o'clock. We found that the wind had blown the sand out from under the ends of our building and let them down about 18 inches so that the floor inside sloped very much like a mountain side each way from the center. However, we got our stove to work and made some beef-extract soup, and this with crackers made us a little supper, and we went to bed happy.
KITTY HAWK, August 31,19O2

We drove our well a few days ago by a method we shall probably patent immediately after returning home, and obtained water suitable for all purposes. It is the best in Kitty Hawk. We also set up our table and covered the top with white oilcloth over two thicknesses of burlap, so you see we have an up-to-date soft-top dining table. Strict orders have been given to set nothing hot on it or anything that can discolor it. We also upholstered our dining-room chairs with excelsior and burlap, and have put in other royal luxuries. So far, in addition to cookery, etc., we have exercised ourselves in the trades of carpentering, furniture making, upholstering, well driving, and will add house moving next week.
KITTY HAWK, September 5,1902

As to the choice of a man to experiment your machines, we wish you to get the one whom you think most available. In a former letter I expressed a preference for Mr. Avery because several things I had heard about Mr. Herring's relations with Mr. Langley and yourself seemed to me to indicate that he might be of a somewhat jealous disposition, and possibly inclined to claim for himself rather more credit than those with whom he might be working would be willing to allow. While I do not anticipate trouble for ourselves on this score, yet I thought that with Mr. Avery there would not be the same risk. If you should find it most convenient to send Mr. Herring it will be entirely satisfactory to us. If you also are in camp during the time that he is here I do not see how any misunderstanding could arise.

KITTY HAWK, September 16, 19O2

Yours of the 9th received. We learned with much regret that there is a possibility that you may not get down here this year, as we had looked forward to your visit with pleasure. Everything is so much more favorable this year than last that it would be a pity to have your ideas of camp life here based on your experience of one year ago. First, we have not seen a dozen mosquitoes in the two weeks and a half we have been here. I have not seen a half dozen myself. Second, we fitted up our living arrangements much more comfortably than last year. Our kitchen is immensely improved, and then we have made beds on the second floor and now sleep aloft. It is an improvement over cots. We have put battens on the cracks of the whole building, including the addition, so it is much tighter and more waterproof than before, as well as more sandproof. Our new well goes down 6 or 8 feet below water mark on the ocean . . . and we now have good water. We, also have a bicycle which runs much better over the sand than we hoped, so that it takes only about an hour to make the round trip to Kitty Hawk instead of three hours as before. There are other improvements too numerous to mention... so we are having a splendid time.

Mr. Chanute is sending down two machines. One built for him by Mr. Herring, and one built by Mr. Lamson (of kite fame). He is expecting to come down himself about October 1st. Mr. Herring will come down to manipulate the Chanute machines.

At present Orville and I are alone in camp. We made arrangements, before coming down, to have Dan Tate with us as soon as we were ready to begin experimenting. This is all the force we absolutely need, as we will do little measuring and photographing till later when we have more men. We do not absolutely need a fourth man, yet he would not be an incumbrance by any means, especially if he was as good a companion as I know you to be.
KITTY HAWK, September 21, l9O2

You should bring warm clothing and not less than the equivalent of two heavy double blankets for bedding, as we may have cool nights in October. We will arrange to have the necessaries of life in the way of food, but as our food was selected according to our own tastes, it may be that it may lack some things you would prefer. If there is anything for which you have a particular fondness you can bring it down, though I much doubt whether you will have much opportunity. My brother and I are sleeping on special cots in the second story of our building. We therefore have the two cots which we used last year in reserve for visitors. If you would prefer to sleep aloft as we do, suitable cots can quickly be improvised if you will bring down two yards of heavy canvas or sail cloth (about 16 oz. would be best) for each cot. We prefer the upper story ourselves.
MONDAY, September 22, 1902

After altering truss wires so as to give an arch to the surfaces making the ends 4 inches lower than the center, and the angle at the tips greater than that at the center, we took the machine out, ready for experiments. We had a steady wind of 11 to 12 meters. After waiting a while for Dan Tate to show up, which he failed to do at all during the day, we took the machine to the small hill, where we flew it as a kite, with very satisfactory results. We found that the trouble experienced heretofore with a cross wind turning up the wing it first struck had been overcome.

TUESDAY, September 23

On my third or fourth glide with the end control loose so that it could be used, I was sailing along smoothly without any trouble at all from the fore and aft control, when I noticed that one wing was gradually getting a little too high and that the machine was slowly sliding off in the opposite direction. I thought that by moving the end control mechanism an inch or so I would bring the wing back again to its proper position, and as I was going along so smoothly with no need of changing the front rudder, I attempted to make the change. The next thing I knew was that the wing was very high in the air, a great deal higher than before, and I thought I must have worked the twisting apparatus the wrong way. Thinking of nothing else than the end control, after reassuring myself as to what was the proper motion, I threw the wing tips to their greatest angle. By this time I found suddenly that I was making a descent backwards toward the low wing from a height of 25 or 30 feet, as a result of the machine having turned up at an angle of nearly 45° in front, which fact I had not noticed at all while occupied in the manipulation of the ends, but which had been witnessed by Will and Dan with alarm, for several seconds before. The result was a heap of flying machine cloth and sticks, with me in the center without a bruise or a scratch. The experiments thereupon suddenly came to a close till the repairs can be made. In spite of this sad catastrophe we are tonight in a hilarious mood as a result of the encouraging performances of the machine, both in control and in angles of flight, which we are convinced will be at least 3 ° better than any machine ever tried before.

WEDNESDAY, September 24

Spent the day in making repairs on the machine. We took the cloth off of last section of both upper and lower surfaces, spliced the broken spars and ribs, and are ready for tacking on cloth again. The Lou Willis came in today with provisions and Mr. Chanute's multiple-wing machine, which Will and Dan Tate carried from the Sound to Camp.

FRIDAY, September 6

Will continued repairs on machine, completing them this evening. The machine is now ready for use at first favorable weather. I put in a part of the day in constructing a "death trap" for a poor mouse that has been annoying us by prowling about our kitchen shelves at night. We are now anxiously awaiting the arrival of the "victim."

SATURDAY, September 27

At 11 o'clock I was awakened by the mouse crawling over my face. Will had advised me that I had better get something to cover my head, or I would have it "chawed" off. I found on getting up that the little fellow had only come to tell me to put another piece of corn bread in the trap. He had disposed of the first piece.

WEDNESDAY, October 8

We took both our own and the multiple-wing machines to the north slope of the large hill, where Mr. Herring attempted to glide on a slope of 13° but could not get sufficient speed to sustain and glide on that angle.

SATURDAY, October 11

Mr. Herring has decided that it is useless to make further experiments with the Mult. Wing. I think that a great deal of the trouble with it came from its structural weakness, as I noticed that in winds which were not even enough for support, the surfaces were badly distorted, twisting so that, while the wind at one end was on the under side, often at the other extreme it was on top. Mr. Chanute seems much disappointed in the way it works.

When Herring left Kitty Hawk, he made a beeline to Washington, where he sought an interview with Professor Langley, perhaps to offer to reveal to him construction details of the Wrights' 1902 glider and its performance. But Langley declined to see him. The Wrights appreciated Langley's ethical attitude.


The experiments with the 1902 glider were almost as important as those the next year with the powered machine, for in 1902 the Wrights had solved most of the problems of stability and control. Their basic patent was on the mechanism of this glider.

KITTY HAwK, October 2, 1902

Our new machine is a very great improvement over anything we had built before, and over anything anyone has built. We have far beaten all records for flatness of glides as we in some cases have descended only 5 and a third° from the horizontal while other machines descended from 7 and a half° to 11°.

This means that in soaring we can descend much slower, and in a power machine can fly with much less power. The new machine is also much more controllable than any heretofore built, so the danger is correspondingly reduced. We are being very careful and will avoid accident of serious nature if possible. Yesterday I tried three glides from the top of the hill and made 506 feet, 504 and a half feet, and 550 feet, respectively, in distance passed over. Everything is so much more satisfactory that we now believe that the flying problem is really nearing its solution.

KITTY HAWK, October 28, 1902

Everybody is out of camp today but Will and myself. Spratt left Monday. We had a good time last week after Chanute and Herring left. The work... was so much easier, besides the fact that the fewer in camp the more there is for each one to eat, that we had lots of time to go over to the woods botanizing and looking after birds. We went to the beach a number of times and have collected a whole bucketful of starfish besides a lot of shells and a couple of king crabs which we will bring home. Spratt is a fine fellow to be with in the woods, for he knows every bird, or bug, or plant that you are likely to run across.

Day before yesterday we had a wind of 16 meters per second or about 30 miles per hour, and glided in it without any trouble. That was the highest wind a gliding machine was ever in, so that we now hold all the records! The largest machine, the longest time in the air, the smallest angle of descent, and the highest wind!!! Well, I'll leave the rest of this "blow" till we get home.

DAYTON, November 2, 1902

We left Kitty Hawk at daybreak on last Tuesday and reached home at 3 P.M. on Friday after a very exciting but tiresome trip.

Into the last ten days of practice we crowded more glides than in all the weeks preceding. In two days we made about two hundred and fifty, all of which were made in winds ranging from 9 to 16 and three fourths meters per second. The duration of these glides ranged from seven to sixteen seconds. This practice enabled us to very greatly increase our skill in the management of the machine. We increased our record for distance to 622 and a half feet, for time to 26 seconds, and for angle to 5° for a glide of 156 feet.

DAYTON, November 12, 1902

We received from Mr. Langley, a few days before we finished our experiments at Kitty Hawk, a telegram and afterwards a letter, inquiring whether there would be time for him to reach us and witness some of our trials before we left. We replied that it would be scarcely possible as we were intending to break camp in a few days. He made no mention of his experiments on the Potomac.

Orville is at work on a new testing machine and it is possible that we may decide to make an entirely new series of measurements covering in part the same ground as before.

DAYTON, December 11, 1902

I thank you for the copy of the Mouillard patent and for your words of advice. We have our patent specifications about complete and hope to have them filed soon...

It is our intention next year to build a machine much larger and about twice as heavy as our present machine. With it we will work out problems relating to starting and handling heavy-weight machines, and, if we find it under satisfactory control in flight, we will proceed to mount a motor.

DAYTON, December 29, 1902

We have recently done a little' experimenting with screws [propellers] and are trying to get a clear understanding of just how they work and why. It is a very perplexing problem indeed.

We are thinking of building a machine next year with 500 sq. ft. surface, about 40 ft. x 6 ft. 6 in. This will give us opportunity to work out problems connected with the management of large machines both in the air and on the ground, such as starting, etc. If all goes well the next step will be to apply a motor.

Part 1 || Part 2 || Part 3

These letters and more are available in Fred C. Kelly's book, Miracle at Kitty Hawk: The Letters of Wilbur and Orville Wright.