Editor's Note: The Aeronautical Congress took place 1,2,3 and 4 August 1893 at the Art Institute of Chiago, IL. This "Opening Address" by Chanute was given on 1 August 1893 and was published in the newly established magazine "Aeronautics" in October 1893. This material was copied from Chanute's typewritten manuscript. Errors (including spelling and grammatical) are original to Chanute and do not derive from the transcription process. GB manually entered the text, along with the html codes, and proofed the copy carefully.
It is well to recognize from the beginning that we have met here for a conference upon an unusual subject; one in which commercial success is not yet to be discerned, and in which the general public, not knowing of the progress really accomplished, has little interest, and still less confidence.
The fascinating, because unsolved, problem of Aerial Navigation has hitherto been associated with failure. Its students have generally been considered as excentric; to speak plainly, as "cranks" and yet a measurable success is now probably in sight with balloons; a success measurable so far that we can already say that it will probably not be a commercial one; while as to flying machines proper, which promise high speeds, we can say that the elements of an eventual success, the commercial uses of which are not as yet very clear, have gradually accumulated during the past half century.
The truth of these assertions, which will be justified further on, seems to indicate that it is not unreasonable for us as Engineers, as mechanics and as investigators to meet together here in order to discuss some of the scientific principles involved and to interchange our knowledge and ideas.
The present is, I believe, the 3rd international conference upon Aerial Navigation. The 2nd took place in Paris in 1889, and a 4th is projected to take place in that city during the exposition of 1900.
The conference of 1889 undoubtedly forwarded the possible solution of the problem; by making the public aware that a number of sane men were studying it in various parts of the world, by making these men acquainted with each other's labors, and by disseminating information concerning the scientific principles involved, the mechanical difficulties to be surmounted, and the practical details of aerial construction generally. Probably as a consequence of this, very considerable advance has been made during the last four years, as will be indicated hereafter, and a number of promising proposals are now in progress of experiment and development.
We may fairly expect similar results to follow from the present conference. We may hope to collate here considerable knowledge concerning the scientific principles involved, to gain information concerning the latest researches, and to establish some concert of action.
Indeed we shall begin our proceedings with the presentation of a paper by Professor Langley concerning what may be said to be the exposition of a new natural law, hitherto but dimly suspected, which seems to hold out promise of important consequence.
We neither expect nor desire the presentation here of new projects for navigable balloons or for flying machines. We have endeavored to secure instead, the statement of general principles and of the results of actual experiments; as facts and positive knowledge are deemed more instructive than projects or speculations.
Success, when it comes, is likely to be reached through a process of gradual evolution and improvement, and the most that we can hope to accomplish at present is to gain such knowledge of the general elements of the problem as to enable us to judge of the probable value of future proposals, both as mechanical or as commercial enterprises.
More important still, we may perhaps help to enlighten a number of worthy but ill equipped inventors who are re-trying old experiments, with no proper understanding of the enormous mechanical difficulties involved.
As a preliminary to our proceedings it will probably be interesting to you to have a brief survey of what has already been accomplished, both with balloons and with flying-machines, and of the advance which has been achieved since 1889.
As regards navigable balloons the latest reliable information is probably contained in an interesting and carefully prepared paper, read by Mr Soreau, C.E., before the French Society of Civil Engineers in February last, and discussed at the April meeting of that Society.
You know that it has been abundantly proved that elongated balloons of large size can be made sufficiently stiff by internal gas pressure, to stand driving at low velocities. The best speed hitherto obtained in any public trials has been 14 miles per hour, which is quite insufficient to stem the wind upon any but rare occasions.
This speed was achieved by Commandant Renard of the French Military Aeronautical department in 1885. The balloon was 165 ft long and 27 1/2 ft in diameter, carrying an electric motor weighing 1174 lbs. which developed 9 horse power. The motor therefore weighed 130 lbs. per horse power.
Now the French technical papers announce, and Mr Soreau confirms, that during the past winter Commandant Renard has been constructing a new war balloon 230 ft long and 42 1/2 ft in diameter, which is provided with a new motor, said to be of 45 horse power and to weigh, with 10 hours supplies, between 2640 and 3080 lbs. or at the rate of about 66 lbs. per horse power. With this apparatus and with a screw some 30 ft in diameter, it is said that Commandant Renard expects to obtain a speed of 24 1/2 miles per hour, and that this will enable him, for about three quarters of the days in the year, to stem the winds that blow.
Granting that the statements made about the motor are true, (and there is nothing improbable about them as we shall presently see) and also that the motor, (the details of which are kept secret,) shall not break down upon trial, I see no good reason to doubt the attainment of the speed estimated, and we may learn any day that it has been performed; although it is understood that the French authorities are maintaining such secrecy as they can concerning this new war engine.
But the Germans also, as well as several other European nations, are said to be in possession of navigable war balloons, and should war break out in Europe (which heaven avert), we might be very soon made aware of the fact that speeds of 25 miles an hour are practicable.
I have no doubt about it myself; but the attainment of this moderate speed requires very large and therefore costly balloons, which carry very few passengers and it is clear that while such craft may be justified by the exegencies of war, they cannot compete commercially with existing modes of transportation.
The difficulty with navigable balloons is that they must be of very great dimensions for even moderate speeds and very light useful loads. As the cubic contents of the gas bag increase at a higher ratio than the surface of its envelope, the relative lifting power increases with the size, and therefore more powerful motors can be taken up, and more speed attained, but we soon reach the limits of practicability. The new French war balloon is 230 ft long (as large as a lake steamer) and it will carry but three or four passengers, at 25 miles an hour, so that it is difficult to conceive how, if they be made of sufficient size of carry over a score of passengers, such enormous and frail craft can be handled, houses or operated without peril of casualty or disaster.
The conditions as to resistance, lifting power, propellers and motors are now pretty well known, the speeds can be calculated with approximate accuracy, and while improvement can doubtless be achieved in the energy of the motor, in the efficiency of the screw, and especially in the form of the navigable balloon to diminish the resistance, it may be affirmed with confidence that railway express train speeds cannot be attained with balloons of practicable dimensions. They may be used for war purposes, or for exploration, but while we may say that the balloon problem is approximately solved, we may also say that the solution does not promise to become a commercial success, or to yield a large money reward to inventors.
With artificial flying machines proper, should a practical one eventually be developed, very much higher speeds may be expected. The pigeon flies at 60 miles an hour, the duck at 90, the swallow at 125, and the martin is said to flash through the air at something like 200 miles an hour. Professor Langley has lately shown, that, within certain limits, high speeds through the air will be more economical of power than low speeds, and recent advance in light steam engines seem to have reduced them to a less weight per horse power than is generally thought to obtain with the motor arrangement of birds. It seems therefore not unreasonable to entertain the hope that man may eventually achieve a mechanical success, (if not a commercial one) in the attempt to compass a mode of transportation which so strongly appeals to the imagination, and that it may result in greater speeds than pertain to our present journeyings.
The mechanical difficulties in obtaining safe support from so intangible a fluid as air are however so great, that men would long ago have given up the attempt, if it had not been for the birds. But then there are the birds, and some of them at least, -- the sailing birds concerning which you will hear something in some of the papers to be read here, -- seem to be able to soar indefinitely upon the wind with no muscular effort whatever, so that the argument that has been made that man cannot hope to float his greater weight than theirs upon the air, would seem not to be well founded.
But as already stated the mechanical difficulties are very great, and it is not surprising that they should have deterred many men competent to advance the solution of the problem from considering it at all, and that it should have mainly been left in the hands of the more imaginative and ill informed inventors, who with imperfect knowledge of the elements of the problem, believe that success is to be achieved through a single happy thought.
It is a mistake to suppose that the problem of Aviation is a single problem. In point of fact it involves many problems, each to be separately solved and these solutions then to be combined. These problems pertain to the motor, to the propelling instrument, to the form, extent, texture and construction of the sustaining surfaces, to the maintenance of the equipoise, to the methods of getting under way, of steering the apparatus in the air, and of alighting safely. They each constitute one problem, involving one or more solution, to be subsequently combined, and these are the elements of success already alluded to as having gradually accumulated, which I propose to pass in review, more particularly to appreciate what has been accomplished since 1889.
First as to air resistances, and the support to be obtained from its inertia, we have the magnificent labors of Professor Langley, published in 1891, showing, by careful experiments, that something like 200 pounds can be sustained in the air by the exertion of one horse power. One half of this weight has already been supported per horse power in some experimental machines.
Then as to the motor, Mr Maxim has recently announced that he has constructed two steam engines of 300 horse power, which, with the engine proper, the boilers, pumps, generators, condensers and the weight of water in the complete circulation, weigh but 8 pounds to the horse power.
With respect to the propelling instrument, Mr Maxim has, since 1889, made a great many experiments with aerial screws. He find, like Commandant Renard before him, that some forms are very much more effective than others, so that the co-efficient of the efficiency, which was less than 35% in the earlier aerial screws, may now be said to be at least double this amount.
On the other hand, Mr Hargrave, who now has built and experimented some 18 different flying machines, all of which fly, says that he has obtained equal propulsive effects from screws and from beating wings, although he rather prefers the latter. A paper from him, giving the results of his latest experiments, and describing his steam engine and boiler, which weigh only 10.7 pounds per horse power, will be submitted to this meeting.
As to the best form, extent, texture and construction of sustaining surfaces, there is yet considerable uncertainty, but there will be submitted here two papers upon materials of aeronautical construction, one by Professor Thurston, and the other by Mr Grosland Taylor, which are well calculated to advance knowledge on this subject, while the experiments of Mr Phillips in England a few months ago, have shown that with peculiarly shaped blades of wood, about 72 pounds per horse power can be supported in the air.
The equipoise is, in my judgment, one of the most important problems yet to be solved in Aviation. No success is to be hoped for unless the apparatus is stable and safe in the air, safe in starting, in sailing and in alighting. Three quarters at least of past failures can directly be traced to lack of equilibrium. This problem seems to be in process of solution, and I may mention in this connection that during the summers of 1891 and 1892, Mr Lilienthal of Berlin has been gliding downward through the air, almost every Sunday and sometimes on weekdays, upon an aeroplane with which he expects eventually to imitate the soaring of the birds, when he has learned to manage it safely.
Several of the papers to be read here propose various methods of first acquiring this necessary skill, for first learning to fly under safe conditions before venturing to launch forth in the air. This bird-science seems to be the first requisite, for safety is indispensable, and it may not be secured in free air until skill has been acquired in handling a machine.
The problems of starting up into the air, of steering and of alighting safely upon the ground, cannot yet be said to be in process of solution. Various methods have been proposed for getting under way, the principal of which have been to gain speed upon the ground, or to get a lifting action from rotating screws, but neither has yet been practically demonstrated as quite practical upon a working scale.
For steering it has generally been proposed to employ two rudders, one vertical and one horizontal, but it yet remains to be known whether they will prove quite effective under the varying circumstances of flight.
The alighting upon the ground is likely to prove the most difficult and dangerous of the problems to be solved. It has been much too little considered by would be inventors of flying machines, and may long prove a bar to the success of such apparatus; for nothing but direct experiment, and that of a perilous kind, will determine how this operation can be successfully performed.
I hope however that you will agree with me that some of the elements of success have gradually been accumulating, and that there has been real, substantial advance within the last few years. There is still much to be done, but a number of experimenters have each been working on one or more of the several problems involved, and they have made it more easy for others to forward the general solution still further.
From this brief review of recent progress, it would appear less unreasonable than it seemed a few years ago to hope for eventual success in navigating the air, and it may now be reasonably prudent to experiment upon a small scale, particularly if the inventor does so at his own expense; for the chances of commercial success seem still too distant to invite others to engage in the actual building of a flying machine, unless they do it with the understanding that they may lose their money. This is the course which has thus far been followed by the three or four experimenters who now seem in the lead, and it may not be long before they achieve such success as fairly to warrant them in proceeding to the construction of a full sized machine.
In any event, without concerning ourselves with the possible commercial uses of such apparatus, we may hope here to advance knowledge upon this interesting problem, and to be of service to those ingenious men who are seeking for its mechanical solution.