Volume 2 - No. 4 - 1907 April
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The American Magazine of Aeronautics was the first commercial magazine in the United States of America about national and international aviation. There were reports on patents and flight contests. The journal was published from July 1907 to July 1915. All pages from the years 1907 to 1915 are available with photos and illustrations as full text, for free.
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AMERICAN MAGAZINE OF AERONAUTICS CO. Ernest L-aRue Jones, Editor and Owner Thoroughfare Building, 1777 Broadway, New York, U. S. A.
Vol. II April, iyo8 No. 4
Aeronautics is issued on the tenth of each month. It furnishes the latest and most authoritative information on all matters relating to Aeronautics. Contributions are solicited.
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AN AVIATION PRIZE IN AMERICA?
With the announcement abroad almost daily of a new prize for the encouragement of the study of aeronautical science it does seem as though some one in America should at least be "willing," if not anxious, to contribute a sum suitably large in comparison with those offered abroad.
Not a money prize im America for dynamic flight! We have an Aero Club whose members are worth $50,000,000—or more and an attempt to raise a thousandth part of that sum, $50,000, failed of accomplishment.
In this land of big projects, it would seem almost likely that a goodly prize would be offered merely for the honor of the country, not to mention an interest in the subject. But up to date there has been no apparent "run" on honor's bank.
We have either no wish to fly through the air, no money, or no desire to aid. The first is not the case; the second cannot be true, for we daily hear reports of the well filled pocketbook of the public; it must be, then, though most preposterous, that we do not want to aid. On reflection, however, this latter cannot be correct, for have we not an Aero Club "to advance the development of the science of aeronautics, * * * * * to encourage ***** aerial navigation" and to "do everything necessary, suitable and proper for the accomplishment of any of the purposes hereinbefore set forth?"
In what way can the science be furthered more than by offering prizes? Judging from the results accomplished by offering prizes in France, this seems to be the best way to "advance the development."
In France, at the end of his resources, Farman wins $io,ooo(. Result—the first machine improved, the distance capable of being flown tripled, and a new machine under construction!
In America, no prizes and no flights.
If the offering of prizes is the quickest way to success, are not Aero Club members bound by their constitution to offer prizes?
NEW PRIZES—ABROAD. Michelin.
Messrs. Michelin, the well known tire manufacturers, have offered $52,000. Thiè amount is divided into two sections. It was first announced that a $2000 cup and a cash sum of $3000 would be given annually for ten years to the aviator who, between January 31 and December 31 in each year, would cover the greatest distance, either in France or in one of the countries whose aero club is affiliated with the Aero Club of France. The distance was to have been at least double that of the previous year. That is, the winner for 1908 must cover twice the distance made by Farman on January 13 last. The cup to be handed by one club to another as won, the cash going to the aviator.
This has now been changed. $4000 is offered annually for eight years, beginning in 1908. This sum will reward the aviator who makes the greatest distance during the year, the minimum to be 20 kilometers. Of course, the apparatus will not be allowed to touch the ground while flying and the aviator will have to be officially controlled. The prize is open for competition, beginning April 10. For 1909 to 1915 the official regulations may be modified yearly by the Aero Club of France to conform to the progress of aviation, without, however, making too difficult conditions. If during one year the prize is not won the sum will be added to the one of the following year.
There is also the grand prize of $20,000. If, before the first of January, 1918, an aviator piloting a machine carrying one passenger, establishes the following record in accordance with the A. C. F. rules he will win the sum of $20,000:
The flight must be from any place in the Departments of the Seine or Seine-et-Oisc, a turn being made around the Arch de Triomphe, at Paris, another turn around the cathedral of Clermont-Ferrand and then a landing on top of the Puy-de-Dome, which has an altitude of 1456 meters (4777 feet), in the total time from the Arch of Triumph to Puy-de-Dome of 6 hours. The distance from Paris to Puy-de-Dome in a straight line is about 350 kilometers (217 miles). The speed would have to be, therefore, a little over 36 miles an hour.
M. Archdeacon calls attention to the possible difficulty on account of the drop in pressure from 760 to 620 mm. at the altitude to which Puy-de-Dome rises. Theoretically the motor would give slightly less efficiency.
Prince Roland Bonaparte.
The sum of $20,000 has been offered by Prince Roland Bonaparte as the nucleus of a fund for scholars and inventors, some of which money will be devoted to the progress of aviation and dirigible balloons.
Karl Lanz, a merchant of Mannheim, has offered $10,000 to found an aviation prize. $2500 will also be devoted to the aid of indigent German inventors.
Aero Club of France.
A prize of $1000 is offered by the A. C. F. for a flight of s kilometers.
A prize (no sum yet mentioned) has been offered by Georges Dubois and Omet-Decugis and others, for a flight of 50 meters at a height of 25 meters.
On February 28 M. Charron paid Ernest Archdeacon $200 toward a prize for the encouragement of aviation. Following this came a contribution from Mme. Heriot, owner of the Louvre.
AVIATION PRIZES. England.
* $50,000, London, Daily Mail, to the flying machine, preferably aeroplane, starting within five miles of Daily Mail Office, London, and landing within five miles of Daily Mail Office at Manchester. Distance, 160 miles.
$10,000, Adams Mfg. Co., if the motor and apparatus winning the Daily Mail prize be entirely constructed in Great Britain.
$2,500, Autocar, to the maker of the motor, if English, above competition.
* Also a gold medal offered by Santos-Dumont in connection with the above competition.
* $5,000, London Daily Graphic for a flight of one mile at Brooklands.'
* $2,500, Lord Montagu, to the machine which makes the longest flight in any one year. Contest must be in England. $25.00 a mile in addition for every mile flown up to 25 miles.
* $12,500, Brooklands Racing Club, to the first machine which makes a flight of three miles above the (egg-shaped) Brooklands course, at a height of three to fifty feet. Speed must be at least ten miles per hour.
* $2,500, Ruinart Pere et Fils, to the first aviator to fly from France to England or vice versa before 1910. This contest is international. The shortest distance is from Cape Gris Nez to Dover, 30 kilometers.
* $2,000, M. Armengaud, Jr., to the first aviator who remains in the air fifteen minutes.
* $1,000, Aero Club of France, for a flight of five kilometers.
* $200, M. Pepin, to the first aviator to fly across the Garonne.
* $4,000 in cash to be won by aeroplanes at Vichy in the Fall of 1908, conditions to be announced later.
* $52,000, MM. Michclin, consisting of $4,000 to be won each year for 8 years, the last holder to become owner; also $20,000 for a flight from Paris to Clermont, 217 miles, in 6 hours.
*$I20 in three prizes of $40 each and three silver plaques offered by Aviation Commission of Aero Club of France for flights of 200 meters. One of these has just been won by Farman.
Various prizes for aeroplane contests at Bordeaux in July.
* $11,100 in cash in aeroplane races at Spa, in July, 1908. The largest prize is for a flight of 23 kilometers.
* $2,500, Dr. Ganz, at Munich Exposition. Aviator must stay in air 10 minutes over a specified course.
$10,000, Karl Lanz, of Mannheim. Machines must be constructed in Germany of German material. Also $2,500 to aid poor German inventors.
*$ioo, A. C. Triaca, for the longest flight during 1908. Open to members of Aero Club of France and Aero Club of America.
* $5,000 for an international aeroplane contest at Venice in October.
* The majority of these prizes are available to American competitors, or those of any other country, provided that in some cases the flights be made in the country in which the prizes are offered. •>
The only prize for dirigibles is that of M. Archdeacon. $4,000 cash and a $2,000 trophy, both annually during 1908-9, open from March 1 to October 31, for a flight of 200 kilometers, passing above St. Germain, Senlis, Meaux, Melun and St. Germain. This is international, open to any affiliated F. A. 1. club. Landings for gasolene, etc.. permitted.
THE ADVANTAGES OF THE HELICOPTER OVER THE AEROPLANE.
By Otto G. Luyties.
The helicopter type of flying machine has been comparatively neglected. Although suggested several centuries ago, supposedly by Leonardo da Vinci in 1500, much less work has been done on it than on other types of flying machines. Not even one man-carrying helicopter has ever been flown in free flight.
This neglect of the helicopter-type appears to have been due to a general impression that it does not offer :a likelihood of success equal to that of the aeroplane or even of the ornithopter! It "has, in fact, frequently been contended that even if one of large size could actually be constructed, and- should be found convenient in operation,, it would still be found very low in efficiency.
It will be the effort of the writer to briefly recount the occasionally admitted advantages of operation, and then to demonstrate that the mechanical efficiency of
a properly constructed rotatory machine is actually higher than that of the aeroplane. For convenience we may itemize the points to be discussed as follows:
1. Starting 7. Simplicity
2. Ascending 8. Safety
3. Balancing 9. Head Resistance
4. Hovering 10. Lift per square foot.
5. Descending 11. Lift per horsepower
6. Landing 12. Horizontal speed
1. The starting of a helicoper is comparatively simple, especially if it be of the vertically ascending type. It is merely a matter of starting up the propellers without requiring a special launching device or a long run on a smooth ground, as required by the aeroplane. This is important because such launching devices will not always be available and because large smooth open spaces are uncommon.
2. A helicopter can ascend nearly vertically. It can therefore arise from small starting places such as a small field surrounded by large trees. In actual use flying machines will encounter many obstacles such as high houses or steep hillsides. Such obstacles a helicopter will be able to surmount by simply rising at a steep angle whereas an aeroplane will be compelled to turn completely around and ascend in a large spiral. It is evident that the ability to fly at any angle with the horizontal will be of great advantage to the helicopter.
3. The balance of a helicopter may be made practically automatic. It is evident that the simplest way to secure equilibrium is by using a very low centre of gravity. The known objection to this construction is that it causes excessive pitching and rolling. Now in an aeroplane, violent pitching absolutely destroys its power to fly as it spoils the all-important angle of incidence of the supporting planes. But in a helicopter the essential angle of incidence is the angle of the blades with the shaft, which remains practically constant whether the machine as a whole pitches or not. Therefore a helicopter can be arranged to have a more pronounced pendular stability than is possible with an aeroplane. The helicopter, furthermore may readily be designed to have gyroscopic stability, without requiring as much special apparatus for this purpose as would be required by an aeroplane.
4. A practical helicopter will be able to hover over a selected point, whereas an aeroplane must continually move horizontally in order to retain its elevation. The ability to hover should prove a great advantage, for instance in taking observations and in selecting a suitable landing place.
5. A helicopter under good control could descend at any desired speed and at any angle, or vertically if preferred. It could, in an emergency, descend in a contracted space much too small for the flight of an aeroplane.
6. Landing will always be difficult. It is particularly dangerous in an aeroplane owing to the high horizontal velocity. At present aeroplanes can only land safely on smooth ground in large open spaces. It may be found possible in later models, to suddenly check the horizontal velocity at the exact moment of landing, but the general nature of the difficulty will still remain the same.
A practical helicopter would be able to descend slowly in any open space of moderate size and land safely whether the ground be smooth or not. If under perfect control it could land without any horizontal velocity either in a calm or in any moderate wind.
The above described favorable characteristics of a practical helicopter have been pointed out by other writers and are here repeated only for convenience. With one or two possible exceptions they have been described by Penaud, Chanute and Hastings.
The mechanical efficiency of the helicopter, however, has apparently not been so carefully studied nor so correctly judged, so that it merits further examination and discussion.
7. The helicopter can be constructed more simply than the aeroplane. In the former, the power is applied directly to the inclined surfaces, whereas in the latter the power is transmitted to a propelling device, and the resultant thrust applied to the planes. It will be clear, without elaborate explanation, that simplicity is especially desirable in flying machines, as weight and power are both limited, and as simplicity in these fragile structures favors reliability and safety. As this article is intended to deal only with general principles, details of structure will not be here discussed.
8. The achievement of reasonable safety is essential to practical flight. Special provision must be made against the occurrence of an unretarded fall and consequent complete destruction. Of course all hcavier-than-air flying devices must fall in case of serious accident to their means of sustentation. In this contingency, however, they should not drop too rapidly nor upset in falling.
Now the supporting power and stability of an aeroplane are largely dependent
upon the continuance of its motive force. Stoppage of the motor means a sudden drop and a sudden backward shift of the centre of pressure. This is liable to cause a complete somersault particularly as the centre of gravity in an aeroplane is necessarily high and as curved surfaces such as are usually employed are in themselves unstable with the concave side downwards. An expert operator may occasionally, if the motor stops, be able to glide to the ground in an aeroplane as if with a gliding machine, but the actual landing is then likely to occur at a dangerous horizontal velocity.
Of course a helicopter will also drop if its motor stops but its stability need not be seriously affected. The drop may be made vertical if preferred, or given a slight horizontal component. The speed of falling will depend largely upon the weight per square foot, so that the advantage of large areas in this contingency is apparent. The low centre of gravity will tend to keep the machine right side up. In addition to this, the supporting surfaces may be arranged to have a slow reverse rotation about their shafts, thus forming an efficient and stable rotatory parachute. The rate of fall probably need not exceed 20 to 30 miles per hour with weights of one or two pounds per square foot, or about the landing speed of a man jumping from a height of 15 to 25 feet. An emergency descent at this rate would not generally seriously endanger the life of the operator.
9. The helicopter has a considerable advantage over the aeroplane in the matter of head resistance. Considering only the forward progress of the machine as a whole it will be clear without explanation that a helicopter Hying with about three quarters of the horizontal velocity of an aeroplane will have approximately half its head resistance if the bulks are about equal. In order to analyze the matter, however, we may divide the total head resistance into two parts, namely the back pressure of the supporting surfaces, sometimes called the drift, and the head resistance of the car and body of the machine. The back pressure of the supporting planes may be divided into three parts, the head resistance of the front edges, the skin friction, and the horizontal component of the normal pressure.
Now as far as the head resistance of the car and body is concerned, the helicopter has the advantage of a slower horizontal speed. At the time of starting this advantage is most pronounced as the aeroplane has to overcome its full head resistance when first leaving the ground, whereas the car and body of the helicopter offer no horizontal head resistance at all during the difficult period of starting.
The head resistance of the supporting surfaces has heretofore generally been higher on models of helicopters than on aeroplanes. This is, however, entirely unnecessary as it is only a question of using proper areas, speeds, and angles to get the same ratio of lift to drift in a helicopter blade as in an aeroplane surface, provided that proper allowance be made for the helicopter blades working in disturbed air.
We may reasonably conclude that the head resistance of the supporting surfaces of a properly designed helicopter will be about the same as that of an aeroplane, and that the head resistance' of the car and body will generally be less, principally owing to the slower horizontal velocity.
to. In the matter of lift per square foot the helicopter has this advantage over the aeroplane, that it may be designed with any desired lift per square foot within wide limits without materially affecting the horizontal velocity of the whole machine or the head resistance of the car and body.
It has been urged in favor of the helicopter that this fact will permit of the use of very small areas thereby reducing the weight of the supporting surfaces. The writer does not recommend this construction, particularly not for use during the present early stage of the art, as it is dangerous in case of a sudden fall, and as it' requires very light construction and inordinately powerful motors. It should also be observed that the use of high speed and very small areas reduces the lift per horsepower and consequently the efficiency of the helicopter as a lifting device.
Nevertheless, the fact that the lift is practically independent of the horizontal velocity of the machine as a whole is a great advantage of the helicopter over the aeroplane and itself accounts for the majority of the advantages in operation referred to earlier in this article.
11. In the matter of lift per horsepower the helicopter has heretofore been stated to compare unfavorably with the aeroplane. A number of authorities including Chanute * give the lift per horsepower of a helicopter as about half that of an aeroplane. As this question is of considerable importance and as the author believes his deductions to be original the matter will be discussed in some detail.
It will probably be granted that the blades of a helicopter may be considered as aeroplane surfaces of the same area and inclination moving with the same linear velocity, provided that proper allowance be made for the effects of rotation, particularly centrifugal force and operation in disturbed air. The writer contends that the
"Progress in Flying Machines."
helicopter provides a simple and efficient method of direct drive for the supporting surfaces. The lifting force of a helicopter will be the full thrust of the shaft or in other words, the full lift of the supporting surfaces directly driven by the motor.
Now in an aeroplane, the supporting surfaces are indirectly driven by the motor through the horizontal thrust exerted by the propeller. This has been described as a means of actual increasing the efficiency as the total lift of an aeroplane is equal to the thrust of the propeller multiplied by the ratio of lift to drift of the supporting surfaces. Thus it has been found, for instance, that a propeller giving a thrust of eight pounds per horsepower when driving an aeroplane with a ratio of lift to drift of 5 to l would support a total weight of 40 pounds per horsepower. This has been described as a method of increasing the lift per horsepower because the same propeller used directly as a helicopter would evidently support only eight pounds per horsepower
The error lies in the assumption that this same propeller would actually be used in this way, whereas propellers intended for use as helicopters can actually be constructed to give a thrust of over 50 pounds per horsepower. The reader may wonder why, if this be correct, propellers giving such a large thrust are not used on aeroplanes thus obtaining a still larger lift and preserving the supposed advantage of the aeroplane.
It should be remembered that the screw propeller is simply a mechanical device for exerting thrust or pressure. As soon as this pressure is exerted over a giA'en distance the work done can be expres>cd in foot pounds or horsepower. For any given efficiency, therefore, the thrust that can be obtained per horsepower will vary inversely as the distance through which it is exerted. A propeller of perfect efficiency for instance could give a thrust of 8 pounds per horsepower at a velocity of 69 feet a second or about 46 miles an hour. Another propeller also of perfect efficiency might give a thrust of 50 pounds through a distance of 11 feet per second or about 7}4 miles per hour. These are the theoretical maxima for the given speeds, the distances per second through which these thrusts could actually be exerted being much less, owing to the yielding of the air, skin friction, etc. Now it is well known that the yielding of the air is relatively larger for propellers progressing slowly along their axes, but even so, the largest thrusts can be exerted at the slowest speeds if the propellers are properly designed for their work.
If the slip in the cases suggested above be assumed as 8 miles per hour in one instance, and 5 miles in the other, being about 17 per cent, in one case and 67 per cent, in the other, the first propeller will give a thrust per horsepower of 8 pounds at 38 miles an hour, the second a thrust per horsepower of 50 pounds at 2^2 miles. These figures are fair examples that might occur in actual construction.
As aeroplanes require a considerable horizontal velocity in order to fly at all, it is evident that they will always be limited to the use of propellers giving only moderate thrusts per horsepower. It is the contention of the author that this more than balances the advantage of the favorable ratio of lift to drift of the supporting surfaces. The aeroplane, considered as a supporting device, also has in its propelling mechanism a source of inefficiency not occuring in the helicopter.
The helicopter is handicapped by having its blades work in disturbed air. This •disadvantage is a serious one but is not quite as great as generally supposed, because the drift is reduced at the same time as the lift and nearly in the same proportion. As soon as the helicopter moves horizontally its blades act on fresh air and the lift is slightly increased.
The helicopter is sometimes stated to lose in efficiency owing to the action of •centrifugal force. It is assumed that air is thrown outwards requiring power without giving an adequate supporting reaction. Now as a matter of fact the centrifugal action must be very small if it occurs at all, because it is shown by experiment that there is an actual inrush of air around the circumference of a helicopter and even for a short distance below its blades. In any case, as centrifugal force depends largely upon the angular velocity it may be reduced by using large diameters and low speeds and by adopting an efficient form of blade.
Considering both types of machines in a general way the incidental head resis tance will also reduce the lifting efficiency, but as the helicopter at its usual slower speeds will have a smaller head resistance of car and body than the aeroplane, it will lose power from this source. The writer is inclined to believe that the advantage of reduced head resistance will balance the disadvantage of working in disturbed air, but this can be definitely determined only by actual experiment on a large scale.
As far as theory is concerned the author holds that the direct drive of the helicopter is more effective than the indirect drive of the aeroplane, and that with suitable construction the helicopter will actually give a larger lift per horsepower.
12. The writer contends that the helicopter will have a higher horizontal speed and greater translational efficiency than, heretofore supposed. It is apparently generally believed that the velocity of the forward motion will depend simply upon the
cosine of the angle of inclination of the main shaft with the horizontal. This would make the maximum attainable horizontal speed equal to the maximum theoretical pitch velocity times the cosine of the angle. The actual horizontal speed would naturally be estimated at less than this owing to the head resistance of the car and body.
But the author contends that the horizontal speed will exceed this supposed theoretical maximum and may even exceed the full theoretical pitch velocity. This is a striking paradox, but if correct is important and therefore worthy of careful analysis.
Let us consider the thrust along the inclined shaft to be divided into two components, the one vertical, the other horizontal. Let us assume the vertical component to be balanced bv the weight. Let us further assume the effective pitch angl* of the blades to be for example 12 degrees and the angle of the main shaft with the horizontal 78 degrees. The currently accepted computation would then give a maximum horizontal speed of about one-fifth of the pitch velocity.
Let us now analyze the action of the blades. In the assumed case they will make no angle with the horizontal on the forward stroke and double the pitch angle with the horizontal on the back stroke. Then the forward stroke will have a lifting effect but practically no horizontal component. This is because the pressure on an inclined plane is always perpendicular to the surface.* Of course there may be a slight backward horizontal pressure due to skin friction, or a slight forward horizontal component, if the surface be slightly curved, due to the tangential force described by Lilienthal,** but for practical purposes the pressure on the forward stroke may be considered vertical.
The back stroke will give a strong forward thrust on account of the pronounced angle of the blades with the horizontal. This will continue as long as the blades move backwards faster than the whole machine moves forwards. This forward thrust, at least during the central part of the back stroke, will not disappear entirely until the horizontal velocity of the whole machine equals the linear rotational velocity of the blades. But the linear velocity exceeds the pitch velocity if the pitch be less than unity.
Therefore the attainable horizontal velocity exceeds the pitch velocity times the cosine of the angle and may even exceed the full theoretical pitch velocity. It is thus a fact that a slightly inclined helicopter may travel horizontally faster than it would if used directly as a horizontal propeller.
It immediately follows from the above that the horsepower required for horizontal motion will not be as high as might otherwise be the case, the power for vertical support being separately considered. The efficiency of a helicopter as a vehicle for horizontal transit will also be fairly good if driven by a special horizontal propeller intended to increase the horizontal velocity, provided that the main shaft be inclined forward at a suitable angle in order to take advantage of the above described peculiar feathering action of the main blades.
It thus appears that the maximum horizontal velocity and transit efficiency of the helicopter although lower than those of the aeroplane will be sufficiently high for practical use and very much higher than heretofore supposed. It will always be an advantage that the horizontal velocity can be regulated, and especially that it can be reduced to practically nothing whenever desired.
In summarizing our conclusions we may say that the helicopter can be made superior to the aeroplane in the first nine points considered, namely: starting, ascending, balancing, hovering, descending, landing, simplicity, safety and head-resistance. The author also contends that the helicopter may be designed to have a very large lift per square foot, or a very large lift per horsepower, and that its horizontal velocity, although less than that of the aeroplane, will be considerable, variable and sufficient.
As this article is limited to a theoretical discussion the desirability of testing the conclusion in practice is evident. The author is engaged in experiments along this line and expects soon to publish the results of some tests of a large helicopter. The important questions of lift per horsepower and of horizontal velocity appear to be especially worthy of discussion and experiment. The author hopes that this article may serve to arouse greater interest in the comparatively neglected helicopter-type of flying machine and that the merits here asserted and discussed may be fully confirmed in actual practice. Baltimore, Aid., March, 1908.
*See "Aeronautics," Vol. I, No. 3; Page 11, Sept., 1907. **See Moedebeck's Handbook, English Edition, p. 289.
WHAT THE AERONAUT CAN DO FOR METEOROLOGY. By Professor Cleveland Abbe, Editor U. S. Monthly Weather Review. I
In an aerial voyage the aeronaut and his assistants usually have certain special objects in view that demand their full attention—but still, it is easily possible for an earnest man to make every voyage tell along the special lines in avhich students of the atmosphere are interested. No generous minded navigator of the ocean omits to keep a full record of wind and weather, barometer and thermometer, ocean currents and temperatures, and whatever can be considered as appertaining to navigation. He does this partly for his own information, partly as the habit of a cautious man— principally because he knows that the pilot chart of the ocean that he uses daily is compiled from thousands of such records gratuitously contributed for many years to the. central national hydrographic offices at London, Paris, Hamburg and Washington where the charts are published.
Those who contribute this observational data receive the "pilot charts" in return, or a thousandfold more than they give.
Precisely analogous arrangements should be made by the aeronauts with their central meteorological offices. They can hardly expect the meteorologist to tell them beforehand what upper winds and temperatures to expect on a given day unless they furnish from past voyages the material that is needed for such predictions. The students of the atmosphere who are employed in Government weather bureaus get daily reports as to conditions at the earth's surface and as to the clouds, if any are visible, and they have these many years asked for regular reports from balloons and kites as to upper air conditions—but asked in vain, because this branch of meteorological work has been expensive and has only lately been developed. An aeronaut is but helping himself when he sends us copies of his records, since he is sure to receive in return items of valuable knowledge generalized from numerous other corresponding reports.
For instance, in December, 1871, the veteran aeronaut, Prof. Samuel A. King, who is still living and active in Philadelphia, communicated to me the records that he had saved up relative to his early voyages. From these I compiled a table and deduced a law that was at once published by the Philosophical Society of Washington, showing that in general, with scarcely a single exception, the higher he ascended so much the more did the direction of the movement of the balloon and the air deviate from that near the ground, the deviation being always toward the right, and frequently amounting to a semi-circle by the time that he reached the highest current flowing eastward. Of course, such a law as this when once well established would become most important for all long voyages in North America and equally important when one has to calculate for his descent and choose a landing spot on the shore of lake or ocean. I was at that time wholly absorbed in the study of the daily weather maps and the practical forecasting of the winds and weather (telegrams and forecasts were made daily at 10 a. m., 5 p. m. and midnight). The same law had just been revealed by the comparison of these telegraphic reports of the motions of the winds, lower clouds and upper clouds, but the continuous records of balloon voyages, when the sky was cloudless, now extended this local rule into a generalization of the broadest character. Subsequently I found that Clement Ley, from cloud observations in England, had arrived at the same result and eventually I found that Henry Allan Broun had announced it at Edinburgh in 1845.
The international cloud work of i8q6-'97 has served to reveal the universality of the law that the upper winds deviate from the lower winds toward the right in the northern but toward the left in the southern hemisphere.
It will be a fine contribution to our knowledge if some aeronaut following Professor King's habit of keeping careful records of his voyages shall show us when and why exceptions to this rule occur—as their probably do occasionally.
The records of the recent long distance competition of 1907 in which the balloon "Pommern" exceeded by a few miles the long voyage of 791 miles by John Wise on 1st and 2nd, 1859, show that some of the aeronauts took advantage of this law.
In order to get a good record of the varying directions of travel the aeronaut has only to keep his map at hand and mark thereon by numbers within circles (1), (2), etc., the position immediately below him as often as he can possibly identify it. But he doubles the value of his record if he also adds the minute and second (or minute and tenth of a minute if his watch has no second hand), for thus he gives the meteorologist the one datum that we can only get from free balloons, namely, the true velocity of the movement of the free air.
The heat that we get from the sun starts the atmosphere in motion. From these movements when actually known we may reason back to the heat that caused them or forward to the results that must follow. The movement of each part of the atmosphere is the fundamental need of meteorology. The chart and watch, the barograph and thermograph of the aeronaut can alone give us what we so sorely need.
Every wise aeronaut, every amateur balloonist, will contribute his little to the common fund of knowledge. ,
The Weather Bureau is now preparing ascension record blanks which will call
for data of value to the Bureau. These will be distributed gratis to balloonists.
The forms will be reproduced, with the instructions, in the May number of Aeronautics.
OUR 52-HOUR BALLOON TRIP.
By Dr. Kurt Wegener.
On the first Thursday of each month at a number of institutions of learning, aeronautical experiments are carried on^to^ determine various questions regarding the atmospheric conditions, to a certain extent; they include free ballooning, captive ballooning, and balloon ascensions with registering instruments, etc.
As before, the free balloon continues to be the one to help these experiments more than any other, gives results that can be depended upon, and is independent of the weather which gives the scientists so many opportunities to carry on important experiments.
The following described trip, which was made from the Observatory at Linden-berg, should have begun without fail on the evening of Wednesday, April 4th, 1906, so as to enable the companion, my brother, Dr. Alfred Wegener, who had made many observations by day, to likewise make observations by night. We desired on the following day to ascertain the meteorological conditions at a high altitude.
At the inflation, which, as usual, was made by the balloon battalion at Reinickendorf, the net of our balloon "Brandenburg" became damaged, and w7e were able to only make our ascension at 9 o'clock in the morning of April 5th in another balloon hurriedly made ready.
Because of this our plans had to be changed; our efforts now had to be bent to make an easy trip the firt,t day in order to be sure to be in position to make the necessary observations during the following
night, and then the following day be able to take the balloon to a higher altitude.
As the balloon started to rise in a thick fog, although above the sky was quite clear, it acted very restless, and directly after we had begun to ascend it settled again on the ground and again rose and settled before we could do anything to remedy the evil.
The mid-day heat made a considerable change in the atmosphere, and we noticed that the partly warmed air rose while the colder air sank away from it. This vertical downward current is the principal enemy of long balloon trips, for it always means a sacrifice of ballast when a balloon is suddenly caught by one of these downward currents.
The balloon flew rapidly over the Tegeler Sea, Neu-Ruppin and Wittstock, and toward noon sailed east from Wismar toward the ocean (Baltic Sea). Soon the ocean became visible in all its greatness below us, and the smoke we could see in the distance showed that we had the same wind as we had before. Cities, forests and water flew past under us.
It was by much hard work that we succeeded in putting the basket in order, and in doing this work we discovered many defects in our equipment which we did not notice in our hurried departure. For provisions we had only for each man one pound of chocolate, two cutlets, one orange and one flask of seltzer. We also discovered we had forgotten something even of more importance. In our hurry to get away we had forgotten to take our heavier coats, and we only wore light Summer jackets.
Soon Fehmarn lay under us; we just cut across its west corner, and we flew further toward Langeland and Funen (a peninsula of Denmark). At this time the sun began to sink. The lessening of the sun's rays cooled the balloon, the gas contracted, and we began to sink. After the sun began to sink we had to sacrifice four bags of ballast.
When over the north coast of Funen it became dark; and when shortly afterward we approached the east coast of Jutland (Denmark) by Fridericia, the earth could only be seen by dim moonlight.
We had lived fairly well the first day; almost three-quarters of a pound of chocolate and one cutlet were used. In spite of this, as a result of our heavy work with the ballast bags and because of the extreme smallness of our basket (i m. x 1.20), we had many pains, which were very noticeable at each movement of the basket.
During the night we had another queer experience. The aeronaut knows that the basket begins to shake slightly when the drag rope drags on the earth. We had decided to remain at 2-300 m. altitude because the current below us travelled too much toward the west, directly toward the North Sea.
The basket began to shake slightly while I lay rolled up in the bottom of the basket vainly trying to sleep. I imagined that my brother, who had assumed command of the balloon, had fallen asleep, and that the balloon had sunk so that it was resting on the guide rope. I called to him: "The guide rope is dragging." But he answered, "No, I am only shivering from the cold." It was he, shaking from the frost, which did not leave him until after we had landed.
The course changed slowly to the north while our speed slackened. We were a little puzzled as to our whereabouts, but determined our position after investigating our charts.
Slowly the balloon, continually turning toward the right, approached a long Fjord (we believed this at first to be the Limfjord, but later it proved to be the Manager Fjord). We then changed our course entirely to the east and approached the Kattegat. Soon the rising sun began to warm us and the balloon continually rose until twelve o'clock noon without using any ballast. When at an altitude of 2500 m. we saw the country we had passed over without knowing our whereabouts stretched out below us like a chart. During the time the balloon was rising, we stood practically still. Only after noon time, when the balloon again began to fall, we found more wind, and drove with increasing speed toward the south, over Funen and Aero, where we crossed our path of the day before toward Kiel, which we passed over at six o'clock in the evening.
Our rations on the second day were cut down some. Six chocolate bonbons, one cutlet and a half orange per person.
The sun when it set on this day also cost us four bags of ballast, so we had left, only 12 bags out of 38 we started with.
The first part of the night we passed very restless. After passing Kiel our course began to turn sharply toward the right, so that we feared we would be driven over the North Sea, and we prepared to land. While we were considering the question of landing, our balloon rose to an altitude of 2400 m., where we suffered considerably from the cold and exposure. It must have been 10 dcg. C. up there, and we could hardly endure it.
Soon, however, the course again changed toward the south, and we again got control of our balloon. During the night the balloon drifted over the Elbe and Hamburg; and over the Luneburger Heide.
Owing to the incompleteness of our charts, we again here lost our position, and were unable to again tell our whereabouts. We were, however, able to determine our course by the aid of astronomy. In the morning the sun again pulled us into a higher
altitude, and we gained an altitude of 3700 m'. and continued to fly over cities and towns. The cold at this altitude—16 deg. C.—combined with our cramped quarters and insufficient nourishment, made it unbearable. After we had been at this altitude about two hours, at 11:30 o'clock we again began to descend, although we still had six bags of ballast.
When we came nearer to the earth we drifted under a heavy cloud and into a strong downward current, and we had to use four bags of ballast in two hours, and were compelled to land near Laufach in Spessart after a trip of 52l/> hours' duration. We had in fact broken the record for duration.
We gained many important points for science on this trip. De La Vaulx in his record trip of 3s hours to Kiew, in southern Russia, was exhausted when he landed. He had a balloon of 2000 m. capacity, well equipped, and with plenty of clothing, etc. We, however, had a balloon of only 1200 cu. m. capacity, with a miserable equipment and insufficient food and clothing. We account for this now that De La Vaulx remained at too high altitudes. During his second night he was at an altitude of 5000 m. According to our records on the third day we did not once reach an altitude of 3700 m. The lesson learned by our long trip was: "Keep your balloon as near the earth as possible all the time." We probably had an advantage over many others, as I did not spend 2V2 years at the Royal Aeronautical Observatory for nothing, testing the atmospheric conditions day after day. During our trip, understanding these conditions as well as we did, we did not once think about any danger.
THE FIRST SUCCESSFUL TRIAL OF THE NEW AEROPLANE "RED WING" OF THE AERIAL EXPERIMENT ASSOCIATION, AT HAMMONDSPORT, N. Y.
By First Lieut. T. Selfridge, First Field Artillery, Secretary.
The motor driven aeroplane "Red Wing" was completed and ready for trial March 9, 1908, in slightly less than seven weeks after she was started. This was the virgin attempt of the Aerial Experiment Association to construct a motor driven aeroplane of this type, and hence we were not over-sanguine of success at the first trials.
Completed, the dimensions of the apparatus are as follows: two superposed aero-curves of a mean depth of 5' 3" (6.3' front to rear at the center and 4' at the extremities) and the same mean distance apart. The front edge of the upper plane extends out 4' beyond the last vertical connecting posts at each end and the silk surface tapers back from this point to the last verticals at each end of the rear edge.
THE RED WING AEKOI'LANE.
The total spread of the upper plane is 43 feet. The total spread of lower plane is 36' 8". The total area of surfaces of the cell is 385.7 sq. ft.
The vertical struts are spindle-shaped, the greatest width of the cross-section being from a fourth to a third of the distance back from the front edge. The horizontal members are likewise spindle-shaped. The large center struts are 4" from front to rear and 1" greatest width. The next struts on either side are successively smaller
down to those at the end., which are 1.5" front to rear, with a thickness of .5". The surfaces are of silk with transverse pockets in which are inclosed the bent laminated wood strips extending from the front to the rear edges of the surfaces to give the surfaces their curved form. Above each strut a T-shaped wood strip extends from front to rear and helps to strengthen the structure. The spacing of the vertical struts decreases from the center toward the lateral extremities. The two center struts at the front and rear edges are about 22" apart; the first strut on either side of these two is 6.5' distant, the next 5.5' and then 5' to the outer struts. The framework is still further strengthened by steel cable gu3rs 1-32" diameter.
The tail consists of a single surface 14' 10" by 3', whose front edge is 10' in the rear of the rear edge of the main surfaces.
In the center of the tail, and above, is placed a balanced vertical rudder 4' by 4'. The tail is set at a fixed angle of 7.5 degrees with the front surfaces. A horizontal rudder 8' by 2' is supported at the end of a pointed bow of rectangular cross-section (22" by 22"), which projects from the front of the middle panel. The rear edge of the rudder is 5' in Iront of the front edge of the main planes, making the maximum longitudinal dimensions of the machine 26' 3".
The engine is an S-cylinder air-cooled Curtiss, a carburetor to each cylinder, developing 40 horse-power at iSoo r.p.m. It has 3^4" bore and 3*^5" stroke and weighs
145 pounds. The ignition is by jump spark from a single coil and distributor. The intake valves are automatic. The crank shaft is of Vanadium steel i^",-in diameter, made hollow. The cylinders, pistons and rings are cast from a specially treated pattern and are ground carefully to fit. The crank case is cast from the new light aluminum alloy "McAdamite." The total weight of the engine, batteries and coil, gas and oil tank, fuel and propeller, is 200 pounds. The engine is mounted between the main surfaces and drives direct a 6' 2" propeller of two blades having approximately a 4' pitch. The operator sits inside the bow, which is covered with silk, about 6" in front of the front edge of the planes.
The total weight of the apparatus, without engine or operator, is 185 pounds. The operator weighs 1S5 pounds. The total weight complete with motor and operator is 570 pounds, to an effective area of 385.7 square feet.
On March 9 the machine, which was fitted with runners for the purpose, was put on the ice with a view to ascertaining the effect of the vertical rudder. The area of ice available was so restricted that it was out of the question to attempt a flight, and no runs of over 100 feet or so were made with the engine running. These trials were quite satisfactory and no alterations were made.
Owing to adverse weather conditions it was impossible to get the machine out on the large expanse of ice on the lower part of Keuka Lake, about five miles from the aerodrome shed, until the morning of the 12th. A steam barge was used to convej' the apparatus to the starting point. The ice was found to be rather soft but in sufficiently good condition to warrant a trial. After assembling the machine, F. W. Bald-
the red wing aeroplane.
win, M. E., of Toronto, Can., mounted it and G. II. Curtiss, of Hammondsport, N. Y.,. its maker, started the engine.
It was hardly expected that the machine would rise at the first attempt. The motor was running with the spark retarded and no effort was made to have it develop its full power. The apparatus gathered momentum very quickly, and, much to the surprise of everyone, left the ice after travelling only 200 feet from the start. She arose to a height varying between 10' and 20', and had flown but a short distance when the right half of the tail buckled up, causing the right wing of the machine to lower and the apparatus to turn to the right, at the same time descending. The right auxiliary runner struck first, breaking the strut above it. while the machine pivoted about this runner and settled on the ice facing the starting point. The switch was then thrown out and the "Red Wing'" came to a stop not far from where she left the ice. her momentum carrying her some distance after the power had been shut oft.
Measured in a direct line from the point where the runners left the ice to the point where they first touched on descending, the distance was exactly 318' 11". The actual distance travelled was somewhat greater than this, as the machine described a curve while in the air. Twenty-five onlookers witnessed the flight.
As it was impossible to make the necessary repairs on the spot, the machine was brought back to her shed, thus terminating the trials for the da}7. The experiments will be resumed at the earliest opportunity, and upon the disappearance of the ice, the apparatus will be placed on wheels.
The actual thrust of the propeller was probabl}- in the neighborhood of 130 pounds, but this was not definitely known, as it had not been measured, and the engine at the time of the flight was certain!}' not developing over 20 horse-power.
MARCH AEROPLANE FLIGHTS AT ISSY.
The first two weeks were miserable, wet and cold. The field at Issy was a veritable lake. Work has been pushed on the machines in the shops of Chauviere and Voisin, and several new ones will be out soon. Kapferer and others are merely waiting for good weather.
• On March 14th Delegrange was out and made 300 meters with an Antoinette 40 h. p. motor, his personal record up to this time. The average height was 6 meters. Farman on the remodeled No. 1 accomplished several flights of 500 to 600 meters, using a 40 h. p. Renault air-cooled motor. The speed made was superior to that heretofore accomplished, as he made a curved flight of 600 meters in 19 seconds, which is equivalent to a speed of 100 kilometers an hour. Several very fortunate improvements have been made in the machine, and he hoped with an automatic process for air cooling, doing away with water, to outdo the results he has already obtained. He has replaced the silk covering of the planes with Continental caoutchouc, which, among other advantages, otters less resistance to the air and has complete impermeability. The extra light Renault motor used gave "the best satisfaction and gives good hopes for the future." General Kovanko, of the Russian Army, who was present, has just given a very important order to Voisin Brothers.
On the 16th Delegrange made five flights, covering in the first three distances between 200 and 500 meters. In the last flight of 700 meters at a height of 5-6 meters he was limited by the fence. The Antoinette 40 h. p. motor worked perfectly, and it is evident that the aviator is now thoroughly acquainted with his machine. Farman was also out, but did not fly, for which the motor might have blamed had it not been deprived of its "demultiplicateur." The monoplane Gastambide-Mengin did not quit its garage at Bagatelle.
The 17th saw Delegrange again in flight. The morning was employed in making adjustments. About 4 o'clock the club was officially notified that the aviator would make an attempt to win the "prize of 200 meters." 200 francs and a silver plaque for a flight of 200 meters. One of these three prizes offered by the A. C. F. had already been won by Farman. Although he covered 700 meters the day before, the flight was not an official trial. At 5:15 he took his position before the starting line. A flag had been planted 200 meters distant. The machine made a false start and touched the ground with two wheels as soon as the line was passed. He came back to the line and in a few minutes made another start and rapidly rose to about 3 meters altitude, keeping good balance. The flight lasted 21 1/5 seconds in a straight line. As soon as the apparatus touched the ground the judges measured the course and found it exactly 269.6 meters. Delegrange did not hide his joy at winning the prize and being placed in the rank with Farman. It may be remembered that Farman with a similar aeroplane covered officially iood meters on January 13, 1908, when he won the Deutsch-Archdeacon prize of $10,000, told in the February AERONAUTICS, and 770 meters
on October 26, 1907; and that Santos Dumont made 220 meters on November 12, 1906, winning two prizes, and 25 meters on October 23, 1906.
March 21—another history-making day! Delegrange and Farman. Decidedly, aviation advances. In the dense fog the frail appearing aeroplanes looked like spectres. Lining the fortifications was a horde of Paris gamins. The weather was uninviting, but expectation was in the atmosphere. Everyone wanted to see Farman beat his former record of the 13th of January, and they wanted to see Delegrange win. After the two flags of the A. C. F. had been planted the 500 meters^apart—exactly, 501.2 meters—the flyers emerged from the garages like two immense birds. After some preliminary flights in the fog, which prevented seeing the distant points, Farman, having changed his Renault for the water-cooled Antoinette, 40, started on his long flight. After rolling 50 meters, he left the ground at a height between 3 and 7 meters. At
p. . . one of the poles were the various
officials of the club. Farman made two complete circuits of the course. The time was 3 minutes 31 seconds for a distance calculated to be 2004.8 meters. Taking into account the curve of the turnt ing, the real course must have been nearly 4 kilometers in that short space of time. Farman had thus beaten his own record by tripling it.
As soon as Farman's machine was put away Delegrange started and made several creditable // flights. At noon he described a
superb loop, which measured 1500 meters, in 2^2 minutes. Delegrange had beaten his own record also, but was unfortunately too late to win the Deutsch-Archdeacon. Then Delegrange offered Farman a seat on the machine The two men stuck very close, one behind the other, and left at good speed. They covered 50 meters close to the ground. This was the first time that two men had ever flown in one machine; and the first that two machines had ever competed together and covered between them 5 kilometers in France.
The two machines are exactly the same model. The sustaining surfaces are made of two superposed slightly curved planes, of oiled canvas for Delegrange and of caoutchouc for Farman. They measure 10 meters in width by 2 meters front to rear. In front is a horizontal rudder for steering vertically, with a movable cell in the rear for guidance to left or right. The total length is 10.5 meters. Behind the aviator is a 40 h. p. Antoinette 8-cylinder water-cooled motor, driving a single 2-bladed aluminum propellor. The whole is mounted on a 4-wheeled chassis. The aeroplane leaves the ground at a speed of 40 kilometers an hour, or at the end of about 50 meters of rolling The wheels are mounted with springs which diminish the shock of landing.
AERO CLUB OF AMERICA.
The second annual banquet was held at the St. Regis on March 14th. The guests of honor were: Hudson Maxim; Gen. George Moore Smith; Major George O. Squier, Signal Corps; Colgate Hoyt, President Automobile Club of America; Dr. Alexander Graham Bell; Cortlandt Field Bishop, President Aero Club of America; Prof. Willis L. Moore, Chief U. S. Weather Bureau; McCready Sykes; Johnson Sherrick, President Aero Club of Ohio; Lieut. Frank P. Lahm, Signal Corps; J. W. Kearney, Secretary Aero Club of St. Louis.
Dr. Bell and the Aerial Experiment Association.
Dr. Bell in his speech told of standing with Prof. Langley and seeing the "flight of his prophetic aerodrome. He proved that navigating the air was a practical thing and within the control of man. The flying machine prophesied by Langley is no longer in the future—it is here. We have no longer to produce a heavier than air flying machine; we have only to perfect it as we have perfected the automobile.
"There are several machines in France that have gotten into the air and I am proud to be a member of the Aerial Experiment Association, that has just succeeded in getting into the air in America. The successful flight with the aerodrome, which has followed along the lines of the Wright brothers, is due to my associates and not one
bit to me. The 'Red Wing' was constructed under the direction of Lieut. Selfridge and generally on plans laid down by him and carried out by the engineers, Messrs. F. W. Baldwin and J. A. D. McCurdy.
"One great success has been worked by Mr. G. H. Curtiss, who has produced a 40 h.p. motor weighing 145 pounds.
"The aeroplane took a circular course, but the distance was taken in a straight line, 318 feet, 11 inches. This was the first public exhibition of the flight of a heavier than air machine in America.
"I think that we have a new agency of great importance in this Aerial Experiment Association, and it was suggested and has been carried out by a lady. It may be interesting, just for a moment, to speak of its origin, as I think it is destined to be productive of great things. In trying to construct my tetrahedral kite into an aerodrome I felt I had reached the limit of my own powers. I was afraid to put a man in the air without more knowledge of engineering. I wanted to be quite sure my structures were sound and so I associated with me two engineers, Messrs. Baldwin and McCurdy. Even with their assistance I didn't feel confidence, for I didn't know anything about motors, and so I associated with the moto'r expert of America, Mr. G. H. Curtiss.
"Along came Lieut. Selfridge from the War Department to see what we were doing. In conversation with this gentleman I found he had made a special study of heavier than air machines and knew everything being done abroad. A powerful combination if we could get together: two engineers, one military expert, one motor expert! M3' wife made the suggestion, 'Why don't you organize yourselves into a scientific association?' Mrs. Bell made the proposition to us that she would supply the capital necessary to carry on the experiments—all go in together to carry on scientific experiments until we got a machine into the air.
"This association started simply to help me to carry out my notion in regard to tetrahedral structures but the men composing it were of independent minds. The association came into existence so that we could help each other. It helped me to complete the tetrahedral structures and advance so far as to put a man into the air. The prediction that the structure had all the stability necessary was verified.
"The Association has established headquarters at Ffammondsport. Here we follow in the footsteps of others. Selfridge, Baldwin, McCurdy and Curtiss have all made numerous gliding flights. They have gone to work to make this aerodrome "Red Wing," have applied a motor to it and have succeeded in putting it into the air."
Professor Moore told of his first ascension, in 1884. Donaldson was advertised to make an ascension at Binghamton and Professor Moore, then reporter on a Bing-hamton paper made the trip with him. When over the Chenango River, the balloon
began to drop very fast. "Can you swim?" said Donaldson, "I can - a great deal
better than I can fly" was the reply, "and I disrobed. Donaldson was in tights— on a trapeze bar. But a breeze came along and we drifted over to land. That was my only experience in a balloon."
"The Chinese have been flying kites for a thousand years but have never made an aeroplane. They make no advance. They do what they do because their ancestors did. There is no Alexander Graham Bell of the Chinese to send the human voice over the metallic circuit, no Caesar, no Nopoleon. There is contentment and stagnation of thought."
He spoke of the high kite flights made at Mt. Weather ever}- day since last September; that on no day was there a variation of temperature; that the air at the six mile level is above the effect of the lower currents. "We know very well that the temperature that causes storms ceases at 6000 feet."
"Now that the flying machine has become an actuality, and as all that now remains to be done is to perfect already existing means and apparatus in order to complete the conquest of the air, it is well for us to forecast some of the adjustments that will be necessary to meet the changed conditions when we shall have our aerial navies of commerce and of war.
"That the flying machine will find very wide application in future warfare, there can be no doubt. Furthermore, it will be the demand as an engine of war that will give to the flying machine industry its greatest stimulus.
"Inventors will have to delve in the depths of their genius in order to develop, perfect and bring the flying machine to the very high efficiency necessary to meet the requirements of government specifications.
"There is no other incentive to invention so great as that which impels to the development and perfection of implements of war, for the very security of property.
country, home and life itself often depends upon a little lead over an enemy in war inventions.
"The result will be that in the not distant future we shall have our aerial battleships, cruisers, torpedo boats, and torpedo boat destroyers, although they will be far different," of course, than those that sail the seas.
"Some terrible things have been predicted for the flying machine as a war engine. Many a sanguine inventor has claimed that with the advent of his flying machine, battleships, coast fortifications and cities coidd be utterly destroyed by dropping dynamite from the air.
"It is comforting to know that no very great loss of life or property would result from dynamite dropped from flying machines for the reason that dynamite requires confinement to work very wide destruction.
"Dynamite must penetrate and explode inside battleships, earthworks and buildings in order to do very great damage. Half a ton of dynamite dropped upon the four-inch deck of a battle ship might kill a few men, wreck some of the superstructure and dent the deck a bit, but the destruction would not be widespread and the crew below would be uninjured. Dropped on coast fortifications the damage would be negligible. Half-ton bombs dropped into the streets of a large city, or on top of the great buildings, would shake a few foundations, break a lot of glass and kill a few people, for the blast of the dynamite not being confined, would rebound up into the air in the form of an inverted cone and the effect in a horizontal plane would be small.
"But the fb'ing machine will have very great use in war as a scouting craft for the purpose of locating an enemy and inspecting his position; but the enemy will have his aerial pickets out, and there will be many a tilt in the air between the warring craft. Then it will be that speed will count for much and there will be intense rivalry between the nations in the production of flying machines that will fly fast and fly high, for those able to fly the highest will have a tremendous advantage over their enemies. It will be the high flyers who will win.
"Do not let the inventor think that the employment of the flying machine as a war engine is an ignoble one, for it is not. It is the most noble use of all."
On Monday, March 4, Mr. Stanley Y. Beach gave a lecture on the machines abroad. The meeting was very well attended.
The following addition to the By-Laws has been proposed: "No member shall take part in-any contest in the United States which is not organized by the club, without the consent of the committee in writing." The name of the "committee" is not given.
Conditions of competition for the Scientific American cup will be made more strict on August 1st, and prospective contestants are urged to "get their machines incondition as soon as possible."
AVIATION SECTION OF THE AERO CLUB OF AMERICA.
The Aero Club of America, at a general meeting on April 6, formed an Aviation Section for the purpose of particularly encouraging experiments and providing opportunities for carrying 011 experiments with gliding machines and all types of gasless apparatus.
A committee, consisting of A. C. Triaca, S. Y. Beach, Lee S. Burridge, Wilbur R. Kimball and D. L. Braine, has been appointed to locate suitable grounds for demonstrations, to provide motors for the use of experimenters, a repair shop for small repairs, etc. It is expected to enlarge this shop to such proportions that entire machines can be constructed at cost price for members of the Section.
A meeting room will be provided as soon as possible for members of the Section at the experimental grounds. The members of the Aero Club of America will, of course, be entitled to visit the grounds, but will not participate in the active privileges of the members of the Section except by joining the Section.
A large membership is earnestly solicited in order to enable the rather extensive program to be carried out. The membership has been decided at $10 annually, to include all privileges of the Section.
Every endeavor will be made to secure offers of prizes to reward creditable flights and enable the successful aviators to further prosecute their researches.
Among the advantages which may be expected to accrue to members of this Section are the following:
The use at any time of the grounds for trial flights;
The use of sheds or the privilege of erecting sheds for the housing of apparatus; The use of a repair shop, which is expected to develop as fast as possible into a
complete machine shop for the building of entire machines; The use of a club room at the grounds;
Weekly bulletins from Paris, already arranged for, mailed to each member; The use of motors belonging to the Section;
Monthly lectures, illustrated with slides and motion pictures of the new machines here and abroad as the}- are tried out.
Aid and advice from mechanical, electrical, aerodynamic and motor experts;
The use of a most complete aeronautic library of old and contemporaneous books and periodicals in all languages;
The privilege of competing for the following prizes: Scientific American Trophy; Michelin annual prize of $4000 for a flight of 12 miles; Triaca annual prize of $100 for the longest flight during the year: and others offered abroad which are international in character.
Contests for cash prizes will be arranged from time to time. Write for circular and information to Aviation Section, Aero Club of America, 12 East 42(1 St., New York.
GORDON BENNETT 1908.
The third contest for this cup will be held on October 11 at Berlin. Twenty-three entries have been received, as follows: America 3, Belgium 3, England 3, France 3, Italy 3, Spain 3, Switzerland 2, Germany 3.
The Italian contestants will be Sr. Usuelli, with the balloon "Ruvensori," of 2250 c.b.m.; Prince Borghese, with the "Aetos," of 2250 c.b.m., and Sr. Frassinetti, with the "Basiliola," 2200 c.b.m. The English contestants will be John Dunville, Prof. A. K. Huntington and Hon. C. S. Rolls. Belgium will be represented by M. Demoor m the "Belgica," of 16S0 c.b.m., M. Leon de Brouckere, in the "Ville de Bruxelles," of 2200 c.b.m, and one other, which will probably be named by the Aero Club des Flandres, an affiliated club of the Aero Club de Belgique. The "Belgica" will be a new Mallet balloon. The Aero Club of St. Louis has made application to enter one balloon in behalf of America.
To represent Germany, 11 balloons have been offered. The Committee sent each of the clubs composing the Deutscher Luftschiffer Verband a notice that as the foreign competitors had all entered large balloons, no offer of a smaller balloon than 2200 c.b.m. could be accepted. Of course, Herr Erbsloh is obviously the first champion. The other two pilots will be selected under the certain conditions. The applicants must give the following information:
The number of prizes won in contests.
The number of kilometers traveled and hours consumed in these contests. The total number of all flights previously made, with total distance and duration.
Record flights or especially long ones.
The answers to these questions must have been received by the Committee by April 1st. If it is impossible to agree upon the selection of any two particular pilots from considering their past records, an elimination contest is to be held between the two applicants, the time and place for same to be decided by April 15.
In referring to the race of 1907 at St. Louis, Major Moedebeck calls attention to the fact that "the French balloon 'Isle de France,' pilot Le Blanc, in the Gordon Bennett 1907, had a capacity of 2400 c.b.m., while the rules place the limit in size at 2200 c.b.m., with an allowance of 5% in excess, or 2310 c.b.m. total." Acting in strict compliance with the rules, the Aero Club of America should have refused the entry of such balloon, which, it will be remembered, made the second best duration record of the world, 44 hours 5 minutes.
On Oct. 10 distance contests and contests for a specified objective point will be held.
The city of Berlin offers free the gas for the Gordon Bennett race.
This is the last year in which a cash prize of $2,500 is offered in addition to the cup, Mr. Gordon Bennett having agreed upon offering the cup to donate $2,500 yearly for three years.
Aviation on Venetian Canals.
Dispatches state that an international aeroplane contest will take place at Venice during October. Prizes amounting to $5,000 will be available.
INTERNATIONAL AERONAUTICAL CONGRESS.
President: Professor Willis L. Moore. Secretary: Dr. Albert Francis Zahm. Chairman Gen'l Committee: Wm. J. Hammer. Chairman Executive Com.: Augustus Post. Sec'y Committees: Ernest La Rue Jones.
The addresses, papers and discussions presented to the Congress will be published serially in this magazine, and at the earliest date possible, bound volumes will be distributed without charge to those holding membership cards in the Congress. Others may purchase the volume at a consistent price when ready or may take advantage of immediate publication by subscribing to this magazine at the regular rate.
In accordance with the program as published in the November number, the informal addresses of the Gordon Bennett contestants and others were concluded before entering upon the printing of the formal papers and discussions.
The eighth and ninth, papers are presented in this issue.
EQUILIBRIUM AND CONTROL OF AEROPLANES.
By L. J. Lesh.
There is a certain problem in the theory and practice of aeronautics which has been rather neglected by the majority of recent dynamic experimenters, generally with disastrous results.
I refer to the balance and steering of aeroplanes, a subject which must be absolutely mastered by the experimenter who hopes to develop a flying machine of any type. Unfortunately, previous investigators have failed to give any precepts or data concerning this problem, either because they had none to give or because they thought their secrets too valuable to make public.
To me, this latter excuse seems unnecessary for it is highly improbable that any experimenter could get ahead by following up the ideas of a man who had the advantage of several years experience. Of course there are exceptions, such as the case of the French aviators who imitate in appearance but not in success, the machines of Professor Langley and the Wright brothers, but even the Frenchmen begin to see that they are on the wrong track.
As one close observer has put it, "there are two ways to learn to ride a balky horse: by working out on paper-just what moves a man would have to make to get the best of him (data obtained by observing his antics from a safe distance), or by getting into the saddle and finding out by experience."
. Substanially the same thing is true concerning aviation, and a very brief glance at the history of aeronautics reveals which method has given the best results. Laboratory data are valuable only when based on information gained in actual field experiments and mathematicians desiring to contribute their calculations concerning mechanical flight would do well to learn the practical side of the proposition so as to produce more useful material.
An aeroplane moving" freely through the air is in a state of equilibrium when its center of pressure coincides with the center of gravity. Unfortunately this state of things exists only when the machine flies in perfectly still air, and even in a calm some defect in the construction or adjustment of the apparatus may cause a disturbance in the equilibrium.
Projected forward in a wind, a machine must be cleverly designed and adjusted indeed to preserve inherent stability and beyond certain limits it will not fly at all unless the controlling agent is human intelligence.
Although "model flight" is a rather uninteresting proposition to the would-be aviator, sound in mind and bod}", 1 should commend a series of experiments of this kind preparatory to work with a full sized aeroplane. By flying small
paper models the investigator becomes acquainted with the merits of variously shaped wings and the travel of the center of pressure under various conditions.
The experimenter 'learns that in arrangement of supporting wings, aeroplanes follow two general svstems :
GLIDER NO. 2 OF I.. J. I.ESH.
the single support type having; the center (or centers) of pressure approximately on the same vertical straight line; and the type having two or more centers of support placed consecutively from front to rear.
The Lilienthal. Pilchcr and Channte gliders are examples of the first class of machine and the Pangley, Wright and Dumont flyers will serve as illustrations of the second type. A careful study of the design of these six machines representing the various, types of successful flyer, leads one to some interesting conclusions.
The Pilienthal and Pilcher machines possessed very little inherent stability, required remarkable agility on the part of the aviator, who steered and balanced the apparatus bv shifting his .weight, and were unsuited for dvnamic flight.
The explanation of these difficulties is found in the arrangement of surfaces, which consisted of two large and wide supporting wings arched from front to rear and tilted laterally at a dihedral angle (forming an unstable craft in a gusty side wind) a tail tilted steeply upward, placed at the rear of the main surfaces, its object being to prevent the wings from tipping over frontwards, and a vertical fin which prevented the apparatus from swerving unduly to one side.
This arrangement is about as unstable as one could wish and its management makes one think of that circus feat which consists in riding a one-wheel cycle. Indeed the two devices are quite similar in reference to the principles of equilibrium concerned—for in one the trick consists in keeping the center of gravity over the center of the pressures exerted on two large artificial wings, while in the other success depends on the rider keeping himself directly over the point of contact of his wheel.
Chanute's machine, although it was also of the "single support" type, embodied some changes in construction and design which were a distinct improvement over former practice. He ingeniously applied the principles of bridge design to the construction of his gliding machines and overcame, in part, the difficulties of balancing, by the use of semi-flexible or pivoted wings and rudders.
The second or "double support" type mentioned in my classification of flyers might be subdivided again into the Langiey type of machine, consisting of two consecutive supporting surfaces with the center of gravity placed between; and the Wright type consisting of a single main support practically coincident with the center of gravity, and a forward rudder which lifts slightly and therefore forms a second center of pressure.
Bleriot's recent flights have demonstrated the inherent stability of the Langiey type of machine which, having two centers of support, is more stable than the single support type for the same reason that a conveyance having two wheels is steadier than a monocycle.
The arrangement of supporting surfaces used in the Langiey type of machine puts it at a material disadvantage, however, for the front wing cutting the wind into eddies as it passes, interferes with the action of the next following surfaces. This has been termed "interference."
Bleriot has effected a considerable improvement over the Langiey design by placing the rudder at the front of the aeroplane instead of at the rear, but the principal defect, "interference," has not been eliminated and the machine is still relatively inefficient.
Apparently, experimenters have not yet arrived at the most efficient system of aeroplane surfaces: for in one case "interference" has been practically eliminated (with a resulting loss of stability), while in the other, excellent equilibrium is assured but the surfaces lose their efficiency.
It is probable that the best arrangement would be a system of surfaces providing two centers of stipport with the weight of motor, operator, etc., located between them. In order to reduce the "interference" and improve the control of the machine it would be desirable to place the controlling surface in a position where it would support a part of the weight and assure a positive control. This could be made possible only by the use of a rudder placed in advance of the main wings.
To obtain this arrangement with the rear supporting surfaces curved to the arc of a circle or with their curvature forward of their center of figure, would necessitate (unless the forward surface be prohibitively small), the weights being placed somewhat in advance of the rear center of pressure and this would introduce new and objectionable complications of construction.
After arriving at these conclusions 1 proceeded to undertake a series of -experiments with models, in hopes that some satisfactory arrangement would be evolved. As the work proceeded T became convinced that in order to province a practical "two support" machine it would be necessary to design the main supporting surface in such a way that its center of pressure would be near the rear edge of the wing.
The answer to these vexing problems came when it was found that a supporting surface curved slightly downwards at its rear edge possessed ■excellent stability when balanced by a forward rudder, and permitted the placing of the weight between the two centers of support thus formed. My recent experiments with this system applied to a full-sized man-carrying aeroplane have proved it to be practical and efficient.
After the working efficiency and inherent stability of a flying machine are satisfactory, the problem of manipulating the surfaces to produce horizontal and vertical changes in the direction of flight may be taken up.
Since steering is largely a matter of skill, and skill in managing an aeroplane can only be acquired by actual practice, the problem will require but little treatment here.
The efficiency and versatility of the system of control will depend on the balancing of the rudders and arrangement of the controlling ropes or levers.
The horizontal rudder should be so balanced that it will return to a horizontal position when not under the control of the operator and the vertical rudder should move freely in its sockets, assuring" positive action.
The arrangement of devices for moving the rudders will obviously depend on the position of the aviator in the machine. If the operator assumes a horizontal position in flight, the surfaces may be manipulated to the best advantage by controlling cords passing within easy reach, while if he assumes a sitting posture or hangs suspended by his arms, levers will generally be found most convenient.
I have found that an aeroplane ma}- be steered to good advantage by the use of a "Chanute type" rear rudder connected to the main wings by a single spar and universal j6int, the steering being done by controlling lines passing in front of the aviator. 1 found it necessary, however, to shift my weight when quartering into the wind Avith this arrangement, for side gusts caused a lateral oscillation of the surfaces which could not be overcome by the rudders without changing the direction of flight.
It occurred to me that these troubles could be overcome by the use of two individual horizontal rudders, and the arrangement was accordingly installed in my experimental machine. The tests demonstrated that with the new device it was possible to quarter into the wind with the wings parallel to the ground, the control being effected by the use of the two horizontal rudders alone.
I believe this system of control to be efficient and hope in the near future to install it in a motor aeroplane. Its most valuable feature will be its abilicy to overcome the torque of the propeller if a single screw is used for propulsion.
CONSTRUCTION AND EQUIPMENT OF WIND-TUNNELS.
By Dr. A. F. Zahm.
(As Dr. Zahm 7vas unable to write out his paper, he made an impromptu address which is here published from the stenographic reports of the Congress).
In determining the atmospheric resistance of bodies there are two general methods that may be followed. One is to propel the bodies against still air, the other is to drive the air in a uniform current against the bodies. By uniform I mean constant in velocity and direction. These two methods should give identical results. I take this as a self-evident proposition.
The first method has been quite generally used for several generations. Originally the bodies were dropped from high places. Sir Isaac Newton determined the resistance of a sphere by dropping it from the dome of St. Paul's cathedral. Others later determined the resistance by placing the wind objects on the end of a long arm of a whirling table. And others again on a car running on a rectilinear track.
These methods have furnished useful data, but they present difficulties. If the bodies fall vertically the speed is not constant and the resistance of the air exceeds that for steady motion. The objection to the whirling table, if the experiment be made in doors, and drift wind be generated, is that all the air of the room circulates with the arm of the whirling table and, therefore, it is impossible to say what the true velociy of the bod}' is with reference to the air. If made out of doors there are almost always some wind currents that mar the accuracy. If the experiments be made on a rectilinear track, which is an ideal method, they must be made out of doors, or in a large building. Professor Langley was very much annoyed by wind currents and finally decided to try in doors, and he found a building suitable for that purpose, about fourteen hundred feet in length. He proposed to place a car on a rectilinear track,
in this building', place the bodies on the car, and have them moved at a regular speed.
A method that .has come into use quite generally in recent years is to drive the air against the body. If it were possible to find a uniform current of air out of doors, we will say blowing" over an extended tract of water or a level surface of the earth, these experiments might be made in the natural wind. 1 would ask our meteorological friends what they think of that proposition. What kind of winds can we find in the most favorable localities? How much do they vary during the time necessary to take careful observations? That is to say, one minute. If the velocity be constant for one minute to within one or two or three per cent., such a wind would be very useful for measuring the resistance of many shapes important in engineering. But in the laboratories I speak of winds are generated artificially.
A very small wind tunnel was built by Professor Marey in Paris. The tunnel was vertical, had a netting" for fine mesh closing" its top and a suction fan at its bottom. The suction fan drew the air through the screen-closed mouth of the tunnel, then passed it through the tunnel in uniform straight lines. By this simple device he was able both to measure the resistance of the bodies and to determine the action of the air as it flowed about the bodies. For instance, he would place a sphere in this current and observe the streamlines as they flowed around it. This could be done by allowing fine particles, or fine threads, to float in the current, but very much more satisfactorily by means of a great many fine streams of smoke. Across the tunnel he constructed a large comb with hollow teeth. Smoke was admitted into the body of the comb and came out of the ends of the teeth, and these smoke streams moved in parallel lines till they came to the object, and then passed gracefully around, if the shape was "easy," but broke into eddies if the body was blunt. Around the front of a sphere they would bend very smoothly, but towards its rear they would break into eddies and then there would be a long wake below the sphere. In the case of a wing surface, the inclination being comparatively small, the stream-lines would begin to bend a short distance in advance of the forward edge of the wing. Part of the stream-lines would bend gracefully over the top of the wing-surface and smoothly close at the rear of the surface and unite with those which passed underneath. Of those that passed underneath, some were bent smoothly and others were disturbed, broken into eddies.
I have observed some of Professor Marev's photographs. I must mention that these stream-lines were photographed by an instantaneous process. The photographs show the stream-lines very clearly, where they bend smoothly, and where they are broken into eddies. In addition to that, the stream-lines will give the actual velocity, because he made the comb vibrate. An electric motor caused the comb to vibrate 10 times a second regularly. That caused all the stream-lines to have a wavy form. Looking at the photographs, you observe the stream-lines beginning at the comb with all the waves parallel. Then, as they approach the wind body, some move more rapidly than others. By counting the number of these waves along each inch of the photograph, you can tell the velocity of each part of the current.
I might say a word as to how the velocity is commonly measured in other wind-tunnels. In the wind-tunnel of the National Physical Laboratory of England, the Pitot tube is used. In my tunnel the Pitot tube is used. In the laboratory of Koutchino, a very different method is employed. The velocity of the wind in the tunnel is directly proportional to the fan speed, so that, when the fan speed is known, the velocity inside the tunnel may be read off from a table, providing the wind object in the tunnel is not very large. If the Pitot tube is used to measure the wind speed, it is necessary so to construct its static orifice that it will not disturb the stream-lines. I will make
a picture to illustrate. Let us suppose that the wind is blowing directly into the mouth of a tube connected with an anemometer. Then the impact of the wind will generate a pressure in this tube. If we know the static pressure in the undisturbed stream, we can immediately compute the velocity of the wind. In order to determine that static pressure, it is necesary to have the air enter another tube undisturbed. The other tube may be co-axial with the first tube mentioned. If a hole is made on the convex surface at some distance from the end of this co-axial outer tube, air will flow into it undisturbed. The stream-lines of the air will be undisturbed as they pass that orifice, and the pressure of the air inside the outer co-axial tube will be the same as in the unchecked, undisturbed stream in the tunnel. Xow, if the pressure in the two tubes is observed in a manometer, and the difference between those two pressures taken, the velocity of the air may be read proportionally to the square root of this differential pressure.
Alany engineers have used the Pitot tubes and have applied the impact at the mouth correctly, but have not used the proper precaution in getting the static pressure. For example, one method is to erect a tube at right angles to the wind current and take the pressure that exists at the mouth of such an orifice. The results are unreliable, because the stream of air bends around the mouth, and a partial vacuum is created. The stream-lines are disturbed; therefore, the static pressure inside the tube is not the same as the static pressure in the unchecked stream.
Two Italians, Dr. G. Fin zi and Dr. X. Soldati, have investigated this subject, and find that the true static pressure in a current may be determined very accurately by using a thin disc. A thin metal sheet placed over the static orifice will prevent the disturbance of the stream-lines, so that the air will flow in a uniform stream, unbent, undisturbed. And, therefore, the pressure obtained at the static mouth is the true pressure in the unchecked stream.
Of course, there are other methods of measuring the wind velocity which are familiar to every one here. Having obtained a wind of uniform velocity and direction, the wind objects are supported inside the wind tunnel on a balance, and the pressures of the air are measured just as one weighs off sugar in a balance.
Mr. Herring: You said that the pressure is measured off directly in the tube; but aren't the effects of pressure of a moving stream on any body composed of pressure in the front and suction in the back? That would give a different value from the direct impact of the air itself.
Dr. Zahm: .That is a very important consideration when you are determining the wind pressure at a particular point about a model. What I am attempting to do in this case is to measure the velocity of the unchecked wind current in the tunnel before it reaches the body.
Mr. Herring: Measure its velocity instead of its wind pressure?"
Dr. Zahm: I am merely describing an anemometer now. I am very glad of this suggestion, because the Italians to whom I have referred have written a very valuable document, in which they have shown how to determine the actual pressure of the air at every point of a surface of any form. They have investigated, for example, the unit wind pressure all over the surface of a torpedo shape, and they have reached the remarkable result that the resultant pressure on the torpedo-shaped body is zero. The pressure in front is just balanced by the pressure of the stream-lines closing in the rear, pushing the torpedo forward. It has been known for a ling time that when a torpedo-shaped body, or a sphere, or any form, passes through a frictionless liquid the resistance is zero when the velocity is unifom. Professor Langley assumed this to be true for the hull of a flying machine moving through the air, because at that time he was not aware of the effect of viscosity and skin-
friction. The experiments of Finzi and Soldati bear out Langley's assumption. Lang'ley assumed that a fish-shaped body moving through the air has a resultant pressure, which is zero, the pressure on the rear balancing the pressure on the front. When such a body is placed on the balance in a wind current, it is found to have a finite.resistance. It may be a considerable resistance. I should judge, then, comparing the results of' Finzi and Soldati with the actual total resistance, that this resistance must be largely frictional. Of course, since I have measured the absolute skin-friction in my wind tunnel at Washington, I can state absolutely and positively that there is such a thing as skin-friction, and I can give its law, and the magnitude for any velocity; and so it is possible to explain the existance of a resultant force on a wind object, even if we assume the aggregated pressure all over the surface balanced and neutralized.
To answer Mr. Herring's question more fully, I would say that, while the static and impulsive pressures at the nozzle of the Pitot tube are used to compute the wind speed at a point well away from the model, the resultant wind force on the model itself is measured, in my tunnel, by means of a bell-crank balance. The knife edges and horizontal graduated arm of the balance are above the ceiling of the tunnel, on the outside; the vertical arm runs through the ceiling into the tunnel (being protected from the wind by a surrounding tube fastened to the ceiling of the tunnel) and supports the wind model at its lower end. The resultant wind pressure on the model is determined by sliding weights on the horizontal graduated beam outside.
Thus by means of the two instruments—the Pitot tube and the bell-crank balance,—the velocity of the undisturbed air, and the resultant wind thrust on the model are measured, but nothing is revealed as to the unit pressure at each point of the model's surface. To determine this latter, one may use the manometric method of Drs. Finzi and Soldati, just referred to. In other words, my balance gives the resultant wind thrust, including skin-friction ; their manometer gives the unit pressure at each part of the model, but ignores the skin-friction. A combination of the two devices would give the unit pressure at every part of the model, the resultant pressure and the resultant skin-friction, but not the unit skin-friction at each point. This latter quantity, so far as I am aware, has never been measured directlv.
THE NEW BALDWIN DIRIGIBLE.
Captain Thomas S. Baldwin, who has the contract to build the Government dirigible, is busily engaged in constructing an experimental airship which will be thoroughly tested out before work is started on the one to be supplied to the Signal Corps. A great deal is expected of the twin propellers, and special work is now being conducted for the purpose of testing the efficiency of certain new shapes. The material of which the bag is to be made is altogether new. Between two layers of silk is a thin composition layer. The effect of the sun's rays, which are so detrimental to rubber, will be made nil in this new fabric. The specifications of this trial airship are as follows:
Gas Bag—Form, ogival; double-wall cemented silk with a breaking strain of 75 x 75 pounds per inch width. Length, 58 feet. Greatest diameter, 16 feet; smallest diameter, 14 feet. Capacity, about 8,000 cubic feet. Envelope with 3 layers of material fore and aft with reinforcements where required. Twelve-inch plunger valve at the top. Ten-inch pressure valve at bottom. Inflating neck, 6 inches. Ripping strip, 5 feet.
Netting—Entire envelope encased in square mesh linen netting, with a working strain of 9,000 pounds. Invented by Captain Thomas S. Baldwin; application filed November 21, 1904, No. 851,481. Netting suspension is so arranged that when on an even keel the forward end will have an upward tendency, causing the pressure of the gas to be strongest where it is met with the greatest resistance. The under part of the gas bag, where the suspension cords leave the netting, is covered with elastic bands to take a portion equal to the displacement of a balloonet, and holds the gas bag tight
at all times. The netting is so adjusted that in case of collapse it would form a parachute and permit a safe descent. Attachment of the gas bag and the frame is the "three-way suspension," which holds the gas bag and frame absolutely rigid.
Frame—Square cross-section of spruce, x i^-inch, bolted together with ^ x J^-inch strips. Operator's section is 3 x 3 x 6 feet. Frame is built in convenient lengths for shipment.
Propellers, Planes and Rudder—The twin screw propellers are placed forward and have a diameter of 8 feet, with a pitch slightly less than the diameter. They drive in
opposite directions on the same shaft at a speed of about 250 r. p. m. The shaft is of Shelby steel tubing mounted on ball and roller bearings. There will be four planes 3 x 3 feet for regulating the ascent and descent, and keeping the ship on an even keel, worked in unison from the operator's section. The rudder, propellers and planes will be of tubing, spruce, bamboo and silk.
M>tor—The motor will be a specially-designed Cnrtiss of 20 horsepower, 4-cycle, 4-cylinder (vertical), air-cooled, magneto-ignition, cast-iron cylinders. The crank case will be of McAdamite. The shaft is a four-throw, hollow vanadium steel, with Parsons' "white brass" bearings. The weight is approximately 200 pounds. Enough fuel will be carried for a two hours' flight.
HYDROGEN AT LOW COST TO ADVANCE BUILDING OF DIRIGIBLES.
By Albert C. Triaca, General Director International School of Aeronautics-.
Up to the present time the inflation of spherical balloons with hydrogen has not been practically realized on account of the high cost of this gas, which has never been less than 20 cents, in France, the cubic metre,'while the price of coal gas is 3 cents per cubic metre.
If one could produce hydrogen at a moderate price, equal, if possible, to the cost of coal gas, he would render an immense service to aeronauts in giving them a gas lifting from 11 to 12 hundred grams per cubic metre.
Using hydrogen we can have smaller balloons. This means the lessening of the expense for fabrics, the cost of the journey back home, and greater facility in handling. Of course, gas holders for hydrogen must be stronger and will be somewhat more expensive, but they will give greater service and by holding the gas for a longer time enable the aeronauts to make longer trips.
Cheap hydrogen will aid greatly in the development of dirigibles for pleasure use instead of being used by Governments for war purposes only. Perhaps next Summer we can have a great number of small private dirigibles, with contests between them.
It was to the realization of the production of hydrogen at low cost that Mr. Howard Lane applied himself, and these are the results of his researches.
Hydrogen is prepared from the decomposition of water through iron in presence of sulphuric acid; from the decomposition of steam through iron or coal at high temperature; and chiefly by electrolysis, which furnishes a gas chemically pure, but at a cost price of nearly 2 francs per cubic metre.
It is the industrial application of the decomposition of steam through red hot iron that is the basis of the Lane process, and it is that which has been able to accomplish the manufacture of hydrogen gas at a cost of 1 franc (19.3c.) per 10 cubic metres (353.14 cu. ft.).
This apparatus has already proven its excellence, since it has been adopted by the Russian Government, which has successively ordered two plants capable of producing respectively 200 cubic metres (7062.80 cu. ft.) per hour.
The English Government has also installed at one of its aerostatic parks, South Farnborough, an apparatus of the same capacity. The officers who have experimented with it there, and who were present at the long trials, are unanimous in declaring that the gas thus obtained is of as good quality as that from the electrolytic process, reaching a degree of purity of 97 per cent. The Royal Batallion of the Prussian aeronauts has asked the Minister of War for a plant of the size above mentioned.
The installation realized by Mr. Lane is essentially composed of an oven in which are three series of retorts; of a special generator, high grade (AA); and of a generator of the Wilson type (BB). Besides the oven with retorts and generators, and a small steam boiler, there are also other accessories and mechanical parts of which it i* not necessary here to give a description.
In order to well understand the work of this installation we will give some explanation about the two generators just mentioned.
The high-grade generator is an apparatus capable of producing, with ordinary combustibles, and even with bituminous coals, a gas of a very high quality and of a high calorific power. This gas, accordiug_to the combustibles used for its production, has a richness in hydrogen varying from 40 to 48 per cent.
*High Grade - Wih-on
C = Boiler D -= Retorts
The Wilson type generator recalls the old Siemens oven, which worked by natural draught without the use of steam and which rendered great service for the heating of ovens. With the Lane apparatus one can use not only ordinary coals and cokes, but also wood and inferior combustibles. The gas produced in this apparatus is sent directly, in a hot state, through special pipes to the parts which arc to be heated. The retorts in the oven mentioned above contain pieces of iron.
These are the three principal organs of the installation. We will see now how it works and how one can obtain hydrogen of a good quality.
The retorts are heated red hot with the gas produced by the Wilson type generator. Then a draught of steam is made to go through the iron contained in the retorts for each one of the series contained in the oven. The steam is decomposed and hydrogen is formed until the complete oxidation of the iron. When this oxidation is accounted for. the same operation is gone through for the other series of retorts. During this new operation a current of gas coming from the high-grade generator is introduced into the series of retorts where the oxidation is produced. This gas has the virtue of combining itself with the oxygen of the magnetic oxide of iron remaining in the retorts and to revivify the iron, at the same time obtaining some steam and carbonic acid. This iron can again be utilized for producing hydrogen as soon as the iron contained in the series of retorts will be completely exhausted. During the new production of hydrogen the revivification will be made.
These operations can be repeated indefinitely and can be summed up in the following chemical equations:
3 Fe + 4 H20 = Fe30' -f- 8 H. Fe304 + 2 CO + 4 H = 3 Fe + 2 CO2 + 2 H20. The hydrogen thus produced in the retorts is sent to a special washer, then in a purifier and from there to its utilization. The analysis of the gas thus obtained is as follows:
Hydrogen (H4) .......................................... 97-20
Formene (C114) ......................................... i.So
Azote (Az) .............................................. i.oo
Finally, it is interesting to establish the cost price. First, 30 kilos of coal at 12 francs a ton (in England) produce 10 cubic meters of gas; second, an apparatus able to produce 200 cubic meters per hour is worked by four men earning each a maximum of 1 franc per hour; third, one can allow a loss of 30 centimes per 10 cubic meters.
One will then have:
Coal (30 kilos at 12 fr. a ton).........................0 fr. 36c.
1 X 4 X 10
Labor - ..................................o fr. 20c.
Loss .................................................0 fr- 30c.
Unforeseen ...........................................0 fr. 14c.
Per 10 cubic meters...............................1 fr. 00c.
1000 cubic meters (35,000 ft.)..............................$19.30
Such in brief, are the advantages resulting from the use of the Lane system for manufacturing hydrogen at low cost.
I believe that because of the geographical position of New York, it is not an easy matter to take balloon trips, by reason of the nearness of the water and the strong winds which frequently prevail. It would be very interesting to have a factory for producing hydrogen at low cost. The time is coming when you can build an airship at a less cost than a 24 horsepower automobile. This is a question of only a few months. In France there was organized two weeks ago a Company especially for the construction of airships. In this company are interested AI. Maurice Mallet, the well-known aeronaut. Count de la Vaulx and M. Schelcher of the Panhard-Lcvavasseur firm. Certainly hydrogen at a low price is the greatest aid to the development of dirigibles. On account of high winds you cannot return with your airship to the starting point. It will be an easy and not very expensive matter to use the ripping cord in your dirigible as in any ordinary spherical balloon. The Aero Club of France will have this Spring the Lane hydrogen system installed at its own park at St. Cloud, Paris.
I believe it is not very far distant when we can have dirigible races from New York to San Francisco. As we now have gasoline stations, we can have hydrogen stations in all parts of the country, and travelling with an airship will be more easy than with automobiles, without danger of collision, without the annoyance of customs houses and without the traps and fines of the police
Note: The information about the Lane system is taken from Aerophile of July, 1907.
BALLOON SPEED RECORDS. Carl E. Myers.
Under this head a recent balloon voyage from Pittstield, Mass., to Hampton Falls, N. H., 130 miles in 3 hours time, or 43 1/3 miles per hour, is thought "possibly better than has been made anywhere," and better than made by the same party last fall from Pittsheld to Short Beach, Conn., a distance of 84 miles, in two and one-half hours, at a rate of 33 1/5 miles per hour.
Prof. John Wise exceeded this nearly 49 years ago when in July, 1859, he made a balloon trip from St. Louis, Mo., with three companions, nearly 1200 miles in length of course, and over 8co miles in air line in about 18 hours, or at a rate of about 45 miles per hour.
In Sept., 1886, Mrs. Carl Myers of Frankfort, N. Y., made a balloon journey from Franklin, Pa., to Kinzua Bridge, a distance of 90 miles in 90 minutes, at a speed of 60 miles per hour, which so far as known is the world's record. Her balloon arose to over 4 miles elevation, the highest record in America, and is notable also as being the first made with natural gas from the earth. Thus the work of a woman is the aeronautic record today. The natural gas on this occasion arose from the wells at a pressure of 700 pounds to the square inch, and was brought through pipes thirty miles to the place of ascension.
Mar. 9.—A. Holland Forbes (A. C. A.) alone from North Adams in the "Stevens 22" (22,500 cu. ft.) at 11:25 <i- landing half-way between Wilbraham and Monson, Mass., at 1:02 p. m. Distance, 58 miles. The ascension was made with the idea of qualifying in this respect for a pilot's license. The start was made in a strong wind which continued throughout the trip. Taking the times noted by observers at various villages, the balloon was travelling 40 miles in 50 minutes during part of the journey. The clouds hung low and the balloon disappeared as it cleared Hoosac Mt. The landing was beautifully made at the exact spot picked out some distance ahead. A very heavy wind was blowing, which necessitated quick work with the rip cord.
Mar. 11.—A. Leo Stevens and William F. Whitehouse (A. C. A.) from Pittsfield in the "Stevens 21" at 11:07, landing near Hampton Beach, N. H., at 2:00 p. m., a distance of about 130 miles air line. Based on this distance, the mean speed by air line would be 45 miles per hour. There was little wind on the ground at the start, but increased rapidly until it was found to be strongest at an altitude of 2,000 feet. The notes of Mr. Whitehouse read: "Pittsfield 11:07, Shelburne Falls 12:00, Turners Falls 12:10; cross Connecticut River 12:15, South Royalston 12:42; crossed Merrimac River at Nashua 1:20, Haverhill 1:45, Hampton Falls 2:00. Landed in a tree with the car about 90 feet from the ground. The tree was about a mile from the sea. It was never cold, except, before the start at Pittsfield, there was a small but driving sleet storm."'
In checking up the distances on a large scale road map they are found to be as noted on the diagram. Using the time table given by Mr. Whitehouse most surprising speeds result. Even allowing for small inaccuracies in measuring and the indefinite exact spot of landing, which lias been ascertained within about half a mile, the mean speed by path, 49 m.p.h. (adding together the speeds between points and dividing), is indeed curious from a meteorological standpoint.
The records of the Concord, N. H.,-Weather Bureau, show "that the wind blew about 2 m.p.h. till noon; after which time it began to increase, averaging about 12
m.p.h. until 8 p. m., and reaching a maximum velocity of 22 miles from the southwest at 5:17 p. m. Low currents were from a northeasterly direction in the forenoon and southwest to west in the afternoon."
A postal card was dropped at Haverhill and was returned with the "following notations—evidently the finder looked up his map:
"Haverhill, Mar. 11, 1908.
"Yours just received, at 1:50 p. m. Wish you good luck. Think you are going to Hampton Beach, where we spend our Summers. If you come our way drop down to see us. Respectfully,
"C. R. Newcomb, 776 Main St."
There can be no doubt of the approximate times as noted by Mr. Whitehouse and the only error is in the mileage. We do not know of any case in which the speed between Haverhill and the landing place has been exceeded. The total distance by path is 131 miles. Mr. Stevens stated that the drag rope at times hung almost horizontal with the car.
Mar. 20.—A. Holland Forbes (A. C. A.) and N. H. Arnold (N. A. A. C.) in the "North Adams 1" (35,000 cu. ft.) from North Adams at 11:02 a. m., landing in Wilbra-ham, Mass., at 1:30 p. m., a distance of 55 miles. The highest altitude was 7,800 feet. This makes five trips for Mr. Forbes and two for Mr. Arnold. It was also the initial trip of the "North Adams 1," formerly the "Stevens 21." It is interesting to note that out of the five ascensions made by Mr. Forbes from North Adams, three landings were made within a few miles of the same spot, Palmer, Mass.
Mar. 25.—Second ascension under the auspices of the N. A. A. C. A. Holland Forbes (A. C. A.). A. W. Chippendale and N. H. Arnold (N. A. A. C.) in the "North Adams 1" from North Adams at 10:20 a. m., landing in Chesterfield, Mass., about 12 miles northwest of Northampton, at 11:45 a. m. Distance. 27 miles. This was Mr. Chippendale's initial flight. Highest elevation, 6,500 feet.
Mar. 31.—A. Holland Forbes (A. C. A.), N. H. Arnold and Roswell Gardner (N. A. A. C.) in the "North Adams 1" from North Adams at 9:25 a. m., landing at Chester, Vt., at 11:50, a distance of 46 miles.
ON THE USE OF LIQUID HYDROGEN AND HYDROGEN-CONTAINING-COMPOUNDS IN LONG DISTANCE BALLOON FLIGHTS.
In Three Parts—Part II.
By Darwin Lyon.
The first instalment, published in the March issue, dealt with the various hydrogen compounds and considered the adaptations of such compounds to an aeronautic use.
For the benefit of those who are unacquainted with the difficulties met with when we attempt to preserve in the liquid state a fluid with a boiling point of minus 253 deg. Centigrade,* considerable must be said: we will also touch upon the various kinds of flasks and receptacles used for holding such a fluid. Incidentally, a few things will be said concerning its nature, properties and production.
Liquid hydrogen is simply hydrogen so cold that it has assumed the liquid state. Matter is usually considered as existing in three forms: the solid, the liquid and the gaseous. Many authorities state that there is a fourth state—the ultra-gaseous or radiant state—and some physicists say that matter in the crystalline form should be considered as a separate "state" of matter.
This is rather off the topic in hand, and I state it merely because so many people entertain an erroneous conception as regards the true nature of a gas in the liquid condition. They either think it a certain "preparation" of the gas or a "solution" of the gas in water. It is because of a want of a correct understanding of such things as these that there so often results an obscurity of ideas bordering upon complete bewilderment.
This want of a correct understanding concerning the true nature of matter is generally accompanied by ideas that are not onbr untrue, but that lead to a confusion and complication of things otherwise simple. Thus, moist air is considered by most people
* Authorities differ greatly on the boiling point of hydrogen: some stating it to be as high as minus 238 deg. C. (—396 deg. F.), while others state it as low as minus 253 deg. C. (—423 deg. F.). The latter is now considered to be correct, although it is one degree lower than that observed by Dewar in 1899, using a hydrogen thermometer under reduced pressure and held as accurate.
to be heavier than dry air—considered to be heavier for much the same reason that they consider a wet sponge to be heavier than a dry one. They compare a saturated atmosphere with a saturated sponge. Not only is their comparison wrong—and thus their reasoning—but they are wrong as a matter of fact. Damp air is lighter than dry air, for damp air contains water not in the state of "water," but as gaseous water or "steam," and the specific gravity of water in the gaseous condition is much less than that of air. Thus it is that a balloon rises better on a dry day than on a damp one, for, to say nothing of the bag and cordage being dry, the air itself is heavier. For similar reasons, a balloon rises easier on a cold day than on a warm one. * * * *
The reduction of a gas to the liquid state is, with few exceptions, accompanied by a reduction of volume. A cubic foot of steam condenses to a cubic inch of water—or, in other words—a cubic inch of water will give a cubic foot of steam. A cubic inch of liquid air will give 800 cubic inches of air at ordinary temperatures. At the sea-level with a temperature of 27 deg. C. (80 deg. F.) a cubic inch of liquid hydrogen will give nearly 900 cubic inches of hydrogen gas.
Now the volume of a gas varies with the temperature. When the temperature is raised one degree Centigrade, the volume of the gas is increased 1/273 Pai't of the volume occupied at O deg. If, therefore, the volume of a gas at O deg. C. is V, at t deg. its volume v will be
The volume of a gas also varies according to the pressure.
When the pressure is doubled the. volume is decreased to one-half; and when the pressure is decreased to one-half the volume is doubled. Increase the pressure two, three or four times and the volume becomes one-half, one-third or one-fourth, and vice versa. In other words, the volume of a gas varies inversely as the pressure.
If at the pressure P the gas has the volume V, and at the pressure p the volume v, we see that our formula for pressure will be
Experiment proves that this law holds true for gases not too near their point of condensation. But as far as the aeronaut is concerned the law is exact: for, though it is only with those gases that under severe pressure become liquefied that departures in the law occur, the departure is only apparent when near the point of liquefaction.*
By reading the barometer and thermometer, and using the two formulae given above, the aeronaut can always tell the exact volume of hydrogen gas that will be given off by, say, a cubic inch of liquid hydrogen. The ratio of liquid hydrogen and gaseous hydrogen under standard conditions of temperature and pressure is about 1:820. Suppose we wish to measure the volume of gas that will be given off by a cubic inch of liquid hydrogen at the sea level at a temperature of 20 deg. C. (68 deg. F.).
At the sea-level the atmosphere exerts a pressure equal to that of a column of mercury 30 inches high; or, in other words, equal to 14.7 pounds per square inch. At a temperature of 20 deg. C. and with the barometer reading 30 inches, we have figured that a cubic inch of liquid hydrogen would yield 880 cubic inches of gas. We have already seen that the volume of a gas varies inversely as the pressure. Thus, at a height of 19,500 feet, the aeronaut would get 1,760 cubic inches of gas from each cubic inch of hydrogen, for at this height the pressure of the atmosphere is just one-half of what it is at the sea-level, the barometer reading only 15 inches. Taking both temperature and pressure into consideration, the most convenient ratio for the aeronaut to use in computing the amount of gas he is going to obtain from his liquid hydrogen, would be 1:1000.
When the aeronaut has ascended to a height of 19,500 feet, or a little less than 2>va miles, he may assume that he has lost one-half of the gas with which he started. As a matter of fact, the pressure at a height of 19,500 feet is generally more or less than one-half, for the pressure of the atmosphere varies somewhat from day to day, from
* The departure from the law is wider the more nearly the point of liquefaction is approached, the diminution of volume then being more than proportionate to the increase in pressure.
PV = pv
the formula: v=M\ 1 -|--1 , we proceed thus:
hour to hour, and with latitude and longitude, but for our purposes it is near enough.
If the atmosphere were everywhere of the same density we would have no difficulty in calculating its height. We would only have to divide the pressure upon one square inch of the earth's surface by the weight of a cubic inch of air, and the quotient would be the height of the atmosphere in inches. Thus a cubic inch of air at o deg. C. at a pressure of 14.7 pounds (235.8 ounces) to the square inch, weighs 0.000749 of an ounce. Dividing 235.8 by 0.000749 we get 314,000, which (were our atmosphere homogenous and of uniform density) would be the height of the atmosphere in inches— 314,000 inches or 4.97 miles. If we turn from this problem to the more important and difficult one of finding the height to which the atmosphere really does extend, we find that no such definite and satisfactory results can be given. We know that at a height of 5 miles, the atmosphere is so attenuated that it barely supports human life; and that at 6 miles it will not support life. We know from the phenomena of twilight that at a height greater than 45 miles it is too attenuated to reflect the light of the sun; but from the combustion of shooting stars we know that an appreciable atmosphere exists as high as 200 miles. As we ascend the strata become rarer and rarer, for the reason that the lower layers are weighed down and compressed by those above, and at increasing heights there is less and less air above to exert this compression. Thus the further we go the more and more attenuated the atmosphere becomes, until at last, by insensible gradations, we reach a perfect vacuum. In the famous balloon ascension of Glaisher and Coxwell, on Sept. 5, 1862, these gentlemen attained a height of almost 5^ miles—a point at which the barometer reads only gj/2 inches.
We computed above that at 20 deg. C. and at a height of 3?4 miles, a cubic inch of liquid hydrogen would yield 1760 cubic inches of gas. At the height attained by Glaisher and Coxwell this would have increased to 2589 cubic inches.
With the exception of helium, hydrogen is the most difficult of all the gases to liquefy, and was the last to withstand the efforts of James Dewar. Its liquefaction in bulk was unknown ten years ago, and hence our rather incomplete data concerning it. In 189T Professor Ramsay wrote as follows: "It [hydrogen] has never been condensed to the solid or liquid state. Cailletet, and also Pictet, who claim to have condensed it by cooling it to a very low temperature and at the same time strongly compressing it, had in their hands impure gas. Its critical temperature, above which it cannot appear as a liquid, is probably not above minus 230 deg."
One of the advantages in the use of liquid hydrogen to the aeronaut is that the gas given off is pure hydrogen—an article almost unknown to balloonists, though many appreciate its value. For it should be borne in mind that air is 14^ times as heavy as hydrogen, and therefore at this rate 7 per cent, of air by volume in hydrogen, means 51.4 per cent, by weight of the mixed gases—over 50 per cent.!
Hydrogen cooled to minus 195 deg. (78 deg. absolute temp.) is still at a temperature that is just twice its critical temperature (—234 deg. or 39 deg. absolute), using the "absolute" degree as a unit. Minus 195 deg. is approximately the boiling point of nitrogen, the boiling point of air being a degree or two higher. The direct liquefaction of hydrogen at minus 195 deg. would be comparable to liquefying air at a temperature of 59 deg.—obviously impossible. In other words, it is more difficult to liquefy hydrogen at the temperature of boiling air, than it is to liquefy air at ordinary temperatures. However, these difficulties have been overcome and liquid hydrogen can now be made in bulk almost as easily as was liquid air twenty years ago. Its production in bulk, though still expensive, has of late been greatly reduced. With the apparatus and methods in use five years ago, it is doubtful if it could have been made at any price in quantities larger than a litre. The amount of hydrogen gas allowed to escape in the cooling process was enormous, sometimes running as high as 20 cubic feet per minute. The liquefying apparatus used by Dewar at the Royal Institute allowed hydrogen to escape continuously from the nozzle of the coil pipe at the rate of 12 cubic feet a minute. With the improved apparatus uoav in use liquid gases can be made both cheaper and easier. The liquid air plant at Washington, D. C, is one of the finest in the country. The apparatus is not modeled after the designs of AI. Pictet or of AI. Cailletet, but was worked out by the makers themselves. The hydrogen circuit is quite distinct from the air circuit. The actual electrical power input to drive shafting, compressors, etc., in making liquid hydrogen with the apparatus in use at Washington is approximately eight kilowatts. In addition, a quantity of liquid air is consumed as a precooling agent, and in making a short run this quantity varies through a comparatively wide range, according to the conditions of starting, stopping, etc. I have no very good data on which to base an estimate, but think it would be safe to say that not less than ten liters of liquid air are expended in producing one liter of hydrogen. With certain modifications of the apparatus the amount of liquid air used could probably be greatly reduced. The plant at Washington produces the liquid hydrogen at the rate of little over a liter an hour. Specifications are now being made for a plant to be in-
stalled in one of our larger universities that, it is claimed, will be able to produce liquid hydrogen at the rate of two or three liters per hour, and at a cost of not more than two dollars per liter when large quantities are to be made and when a chemically pure product is not required. Even with the modifications now in view of the plant at Washington the price per liter would be considerably more than that stated above— just how much I have been unable to determine. It is safe to say, however, that were there a sufficient demand, 140 liters, or 5 cu. ft. (enough to produce 5000 cubic feet of hydrogen gas) could be made for two or three hundred dollars. * * *
If a few drops of water are put in a clean, smooth spoon that has been heated in the fire, they will gather into a globule which will dart around over the spoon's surface. The water has assumed what is known as the "spheroidal state*' and is at a temperature below its boiling point. The globule rests upon a cushion of steam, which prevents it from coming into direct contact with the metal. A liquid so situated that it could touch no other liquid or solid would assume the "spheroidal" state. The importance of the spheroidal state with reference to the liquefaction of gases can hardly be overestimated. But for the spheroidal state not only would it be next to impossible to manipulate liquid gases as we now do, but the dangers in such manipulation would be increased a hundred fold. However, owing to the fact that liquid gases do assume the spheroidal state, we are able to handle them in much the same fashion as we do water, although theoretically it is the same as though we kept the water in red hot vessels. This, as can be proven by experiment, can easily be done, but it is still easier to keep liquid air or hydrogen in vessels at room temperature, for the reason that such a temperature is, as compared with liquid air, "more than red hot," and they are maintained at this "red hot" temperature without having to depend on artificial heat.
Thanks to the "spheroidal state," if liquid hydrogen is accidentally spilled on the hand no injury results. In fact, the hand may be immersed in it with safety, for the heat of the hand causes an extremely thin layer of gas to be formed between the surface of the skin and the liquid hydrogen. Thus this layer of gas keeps the liquid gas from coming in direct contact with the skin and protects it for a short time. Should good contact take place, as may happen if the hand is very dry and chapped, the result is a severe sore similar in nature to a burn.
The reason liquid air does not immediately "flash into air" when poured into a tin cup is again because of this protecting cushion. If left in the open air in ordinary vessels, liquid gases evaporate rapidly—for our purpose altogether too rapidly. The reason liquefied gases volatilise and disappear is that they receive heat from surrounding matter—from the containing vessel, and from the atmosphere.
Early in his scientific work Dewar recognized that it might be possible to make this loss considerably less by utilizing a vacuum as a non-conductor of heat, and that in handling liquid gases the greatest desideratum would be some kind of a vessel that would hold them without the rapid absorption of heat experienced under ordinary conditions. After much labor and many failures he devised the vessel bearing his name. The Dewar vacuum flask, or "Dewar-bulb," as it is more commonly known, consists, in its simplest form, of an inner flask sealed into the neck of a larger one. The space between the two flasks is made as perfect a vacuum as possible. A triple walled flask is still better, as this gives two vacuum spaces. The only ways by which the liquid hydrogen contained in the inner flask can gain heat are, by conduction through the glass where the vessels are joined, and by direct radiation. The first is small; for the walls of the vessels are thin and glass is a poor conductor of heat. The liquid receives practically no heat by conduction from the air above it, for it is protected by a layer or "pad" or gas almost as cold as the liquid itself. The greater part of the heat that is received is imparted by the ether waves as radiant heat. This is further reduced by the device of placing in the vacuum space a small amount of mercury: in the vacuum, this mercury evaporates, and when the flask is filled, the mercury vapor condenses and freezes upon the outer wall of the inner flask. There is thus formed a very perfect mirror which reflects the greater part of the radiant heat striking it. By all these devices the liquid hydrogen is so protected from its heated environment that its boiling is scarcely perceptible: in fact, but for the loss by evaporation, we would not know that it was boiling.
The more perfect the vacuum, the less the heat conducted. A good exhaustion cuts off four-fifths of the heat that would be conveyed were the space filled with air. The mercury mirror reduces the influx of heat to one-sixth of the amount entering without the metallic mirror. With the most perfect flasks obtainable the total effect of vacuum and mirror is to reduce the ingoing heat to one-fortieth part. It has sometimes been said that the metallic mirror does but little or no good, for the reason that all kinds and forms of matter become transparent to radiant heat at low temperatures, but experiments have proven that thTs assumption is unwarranted. In a vessel con-
structed with three separate vacuum spaces 60 per cent, of the influx heat is cut off, as against 96 per cent, in a single walled but silvered vessel. For some reason, vacuum vessels deteriorate—just why we have been unable to discover, but it is certain that many of those on the market are next to worthless. In this country probably the best obtainable are those sold by Eimer & Amend, New York. However, for our purposes, no bulb yet made would suffice, and one much larger than any now in existence, would
have to be made to order. In fact, even if only 19 or 20 liters of liquid hydrogen were to be carried, the bulb, if only one were used, would have to be so large that it is a question as to whether the vacuum flask would, for our purposes, be after all the best; and whether the light tin buckets, to be described later, would not be better. For, as can be seen by the diagram, the inner flask of a triple walled Dewar-bulb is very small as compared with the size of the outermost flask; so that the size of a triple walled Dewar bulb capable of holding 5 gallons (approximately 19 liters) would be very large, to say nothing of its weight and cost. A triple walled Dewar-bulb capable of holding one gallon weighs about 2^ pounds. The sheet-iron case, lined with felt, used for holding the bulb and protecting it during transportation, weighs about 15 pounds. For our purpose one of about one-fourth this weight would suffice. But even supposing that the entire receptacle weighed only seven pounds, this seems too great a weight for the carrying of only one-half a pound of liquid hydrogen, for this would mean the carrying of a weight of 6 pounds for each one-half pound (one gallon) of liquid hydrogen. One-half pound and one gallon! The reader may wonder at the comparison, for at first thought it seems scarcely possible that one gallon of a liquid can weigh only one-half a pound. But this seeming discrepancy is cleared up when we state that the specific gravity of liquid hydrogen is only 0.07, only one-fourteenth that of water. This brings us to another important question—Irrespective of the nature of the container, how shall we carry, fix and support this container?*
As before said, it is only of late that we have been able to manufacture liquid hydrogen in bulk. To calculate its rate of evaporation by comparison with liquid air (though theoretically possible) is difficult, for many things have to be taken into consideration, and at present it is impossible to make any definite statement except as a result of observation on the particular container in question.t Even then a great difference is found depending upon the method used to reduce the convection currents in the gas above the liquid. With the Dewar bulb something depends (for hydrogen we cannot yet say exactly how much) on the degree of exhaustion of the bulb and the perfection of the silvering. A great deal more depends on the shape and size of the flask, since, as before said, with a good vacuum and small convection, the chief source of heat is by conduction through the inner glass wall. This will obviously be smaller when the flask is not agitated and when the neck is kept as cold as possible by the gas that escapes.
(To be continued.)
* This question with a more detailed description of the tin buckets used by Tripler for transporting liquid air, the various kinds of wrappings used, and a comparison of the Tripler buckets with the Dewar bulbs will be treated by Air. Lyon in the May number.—Ed.
t This will be more fully discussed in the May number.
A Park of Sports at Brussels.
There has just been formed a company having a capitalization of 125,000 francs for the purpose of conducting a sporting park in that city. It is expected that aerial contests will be among those held.
North Adams Aero Club.
At a meeting held on March 9th, the North Adams Aero Club was duly organized with Colonel Frank S. Richardson, President; John H. Waterhouse, Vice President; Arthur W. Chippendale, Treasurer and N. FI. Arnold, Secretary. The Executive Committee is composed of Messrs. George A. Macdonald, Roswell A. Gardner and W. H. Pritchard. The other charter members are: Arthur D Potter of Greenfield; E. C. Peebles, R. J. Stratton, Dr. R. D. Randall, I. D. Curtiss, J. D. Hunter, Archer H. Barber, Harry Hewat, Hugh P. Drysdale, all of North Adams; A. Holland Forbes and Aeronaut Leo Stevens, of New York.
The new club has purchased the "Stevens 21," which will be known hereafter as the "North Adams No. 1," and will rent the balloon to its members and supply a qualified pilot at a nominal rate. With the two old balloons of the Aero Club of America out of commission, this will be the only club in this country maintaining a balloon for the use of its members—a great credit to the enterprise of North Adams, but rather the opposite for America in general.
The Berkshire Club gave a "balloon smoker" in the club rooms Thursday evening, March 19, to members of the North Adams Aero Club and invited guests, who included 20 members of the Massachusetts Legislature, who were in the city, having come a day earlier in order to attend the smoker and ascension, than was their intention.
About 200 in all were present, and President A. H. Barber of the Berkshire Club, and also a charter member of the North Adams Aero Club, presided. The speakers included President Frank S. Richardson of the Aero Club; Mr. A. Holland Forbes of the Aero Club of America and the North Adams Aero Club, who piloted the first trip of the "North Adams No. 1" the following morning; President Luke J. Minahan of the Aero Club of Piltsfield; Superintendent E. C. Peebles of the North Adams Gas Light Company, and who is responsible for the excellent quality of gas provided for ballooning purposes at North Adams and is a charter member of the Aero Club; Senator C. Q. Richmond of North Adams; Senator Grimes of Reading and N. H. Arnold, Secretary of the North Adams Aero Club, who was Mr. Forbes' companion on the first trip of the balloon. The aneroid barometer and statoscope were explained and exhibited by Mr. Forbes in the course of his talk to the audience. During the evening-substantial refreshments were served.
On Friday morning, March 20, after the balloon had been inflated and was ready for flight, it was christened by Miss Elizabeth B. Chippendale, daughter of Treasurer A. W. Chippendale of the Aero Club, who broke a bottle of champagne on the anchor. A crowd estimated at over 3,000 and including many from other towns and cities, was present.
The start was made at 11.02 to the accompaniment of the shrieking of mill and factory whistles and the cheers of the crowd. The balloon traveled slowly first to the south and then to the southeast, attaining a height of 5500 feet in 15 minutes. The winds were light and variable, and the sun and clouds bothered a good deal, so that finally after having crossed the Connecticut River at a height of 6400 feet and ascended soon after to 7800, the highest mark, it was decided to descend. The landing was perfect, on property of Mr. Seymour Holland in Wilbraham at 1.30, about two and one-half hours after the start. Distance traveled, about 60 miles. Owing to the stiff ground breeze it was necessary to use the rip cord to prevent damage to the balloon after effecting the landing.
Mr. Arnold proposes to qualify at once as a balloon pilot. He has already made two ascensions.
Aero Club of Ohio.
The A. C. O. seems to be in difficulty. The club is trying to secure McKinley Park for an ascension ground, but President Sherrick wishes nine trees cut down, and serious objection was made to this by the authorities. According to the Canton News the President said:
"If the Aero Club cannot secure the McKinley Park grounds for the purpose of making that the starting place for the ascensions, I will give up the enterprise. We will not use the park unless the nine trees that make the ascensions dangerous are removed. The trees that must be cut down are full of snags, with the exception of two near the center of the park, which are good trees. The others would make the sport too dangerous and the club would not authorize nor permit any trips unless they are out of the way. It would be too bad if the enterprise would have to be dropped on account of the threaten-ed injunction. We would bring thousands of people to Canton by having the ascensions. Supposing we would advertise a balloon ascension for Saturday afternoon. People would come to this city from all directions
on the steam and electric roads to witness it. In that way the merchants would be benefited and the city would be in the public eye all season. We must not give up the sport under any consideration, as it means too much for the city."
Milwaukee Aero Club.
At a meeting of the charter members of the Milwaukee Aero Club, held March 16th, at the offices of the Merchants & Manufacturers" Association, the following officers were elected: Directors—Win. Woods Plankinton, John H. Moss, J. H. Kop-meier, Wm. Geo. Bruce, R. B. Watrous, A. O. Smith, Major Henr}r B. Hersey, Sheldon J. Glass, 11. P. Vilas.
The following named gentlemen were elected officers to serve one }'ear as follows: President, John H. Moss; First Vice-President, J. PI. Kopmeier; Second Vice-President, Commodore Vilas; Secretary, R. B. Watrous; Treasurer, Oliver Clyde Fuller; Consulting Engineer and Assistant Secretary, Dr. A. Rudolph Silverston.
The following named gentlemen comprise the charter members: W. H. Whiteside, President Allis-Chalmers Co.; John 1. Beggs, President The Milwaukee Electric Railway & Light Co. and President of the St. Louis Street Car Co.; Col. Gustave Pabst, President Pabst Brewing Co.; Oliver Clyde Fuller, President Wisconsin Trust Co.; E. P. Vilas, Commodore Milwaukee Yacht Club; Sheldon J. Glass, President and Manager Milwaukee Gas Light Co.; Wm. Woods Plankinton, Capitalist; John H. Kopmeier, President Wisconsin Lakes lee Co. and President Citizens' Business League; John H. Moss, President Rockwell Manufacturing Co. and President Merchants & Manufacturers' Association; A. O. Smith, President A. O. Smith Manufacturing Co.; Major Henry B. Hersey, Inspector United States Weather Bureau; Dr. Louis Fuldner, President Milwaukee Automobile Club; Wm. Geo. Bruce, Secretary Merchants & Manufacturers' Association; R. B. Watrous, Secretary Citizens' Business League; Chas. F. Pfister, Capitalist; Dr. A. Rudolph Silverston; the best men of the State, all enthusiastic sportsmen, and willing to give their time and energetic attention to the affairs of the club.
Aero Club of the United Kingdom.
The English club has made an arrangement with the Hurlingham Club by which a 12-inch pipe will deliver to the grounds 100,000 cubic feet per hour of pure coal gas.
Aero Club of St. Louis.
An aeronautic "carnival" is planned fur October. A. B. Lambert, a member of the committee on arrangements, is now abroad, and while no report has been rendered the directors, a national or an international balloon race will be one of the features. There will be also, it is expected, a contest for dirigibles. Perhaps we can have aeroplane races by that time!
New Aero Clubs.
It is reported that the Philadelphia Aeronautical Recreation Society is being formed, and that Samuel A. King is making a 50,000-cubie foot balloon for the society. "The new society will be composed entirely of amateurs and its sole object will be aerial recreation. It is not meant to be a society for the study of the subject of aeronautics or advancement of science, but a social organization entirely. Its organizers are Dr. Thomas E. Eldridge and Dr. George H. Simmerman, both members of the Ben Franklin Aeronautical Society of the United States and the Balloon Association. Women will be admitted to membership, and before long it is expected that a club house will be purchased."
The Aero Club of Frankfort has been formed and has ordered a 2200 c. b. m. balloon. It already owns the "Ziegler" for the scientific ascensions of the Physikalischer Verein.
The Aero Club de l'Ouest has been formed at Angers. The club already possesses a balloon, l'Ouest, of 800 cubic metres' capacity, built by M. Emile Carton, which recently made its first trip, starting from the enclosure of the present association of the Aero Club de France at Saint-Cloud. The club has leased an enclosure near the Angers gas works, and arrangements will be made for the prompt inflation of balloons. M. Rene Gasnier, who was one of the French competitors at St. Louis, who resides close to Angers, has also promised to give the new club his support and help.
An Aeronautic Section of the Automobile Club of Milan has been formed. Among the members are Engineer Forlalili. Captain Frassinetti. Messrs. Usuelli and Crespi, the renowned Italian aeronauts.
Balloon Farm Notes.
Prof. Carl E. Myers, of the "Balloon Farm," Frankfort, N. Y., announces "that he is constructing for western parties the largest airship yet built by himself or any one else in this country. It is of his well-known spindle shape, and has a circumference and length of 84 feet, and a buoyancy of 1700 pounds. This will be finished in two weeks, when he will begin the construction of a still larger airship on the lines of the Government specifications, but twice the dimensions of the late accepted bid. Within the past five days he has wholly constructed two captive hydrogen gas balloons and nets for the United States Government. This speed is only made possible by use of ready machine-varnished hydrogen proof fabrics originated by him and in use exclusively during thirty years, and from which he has already built 150 hydrogen balloons for the War and Weather Departments of the United States. Ordinarily by the usual systems it requires from thirty to sixty days to completely varnish a hydrogen tight balloon."
France and Her Experimental Field.
The Minister of War has given the Aero Club of France the use of a large field adjoining Issy les Moulineaux. Space will be provided for those aviators who will build garages for their apparatus. The field will be surrounded by a fence and properly policed, so that experimentors can make flights at any time whenever the soldiers are not using the held. Bleriot, Farman and Voisin have already applied for their spaces.
The prizes have been announced for the aviation contests of the Aero Club de Belgique at Spa, July 12, 19 and 26. $11,100 will be distributed in prizes during the three days: $2400 as first prize the first day, $3000 the second day, and $4000 the third clay. Second prizes of $300 each will be distributed on the three days. On the 12th and 19th there will be duration contests, with two prizes of $600 and $200 respectively. In addition to these, an indemnity of $100 will be granted to all competitors not winning prizes, providing that they compete on all three days and make in one of these three at least 100 metres from the point of departure or that their home club, if affiliated, will certify that flights of that length have been made by them.
The competitions are open to any type of aeronefs. The entrance fee is 80 cents for each horsepower. In the contest for duration the one who stays in the air the longest time wins, and an indemnity of $40 will be allowed to any competitor who stays in the air 5 minutes or whose club will certify that he has done so at some other place.
The Aeroplane Ellehammer.
The aeroplane of the Danish experimentor, Herr Ellehammer, has made two hundred flights, of which the best was that on February 13th, 1908, when he achieved a flight of 300 meters. The machine has gone through three forms; monoplane, biplane and triplane. As noted in the July, 1907,1 issue of AERONAUTICS, with a biplane machine of the "Wright type" he made a flight in January, 1906, of 162 feet against the wind. The motor was then stopped and an easy descent made. On January 14th, 1908, he progressed to 175 meters at a height of 5 meters from the ground, with remarkable steadiness. The confined space did not admit of a longer flight. He has been practicing curves and has succeeded in executing an "S" at a speed of 11 meters a second.
Cost of British Military Airships.
According to figures taken from the English Army statistics for 1906-7 the expenditures on "Nulli Secundus" up to March 31, 1907, were, roughly, $33,395. $45,000 represents the "value of articles manufactured and services performed at the balloon factory;" and the United States Government is spending what?
The International School of Aeronautics has removed to 2 East 29th Street, directly opposite the "Little Church Around the Corner." Two entire floors are devoted to the school. Models of the "Ville de Paris" and the "Farman I," besides other valuable additions, are expected within the week. Weekly bulletins from abroad will be posted on the bulletin board. The students thus receive the latest detailed news items two weeks or more before it can be printed in the foreign journals and read here.
A TABLE FOR FINDING THE ASCENSIONAL FORCE OF GASES. By Charles DeF. Chandler, Captain, Signal Corps, U. S. Army.
All persons interested in aerial navigation frequently have occasion to use in computations, figures showing the ascensional force of gases, and, in calculations for dynamic flying machines, it is necessary to know the weight of a certain volume of air. No accurate answer can be given to inquiries concerning the weight of air or the ascensional force of gases, without knowing the temperature and pressure of the atmosphere. A casual inspection of the table shown herewith illustrates the great difference in weight of equal volumes of air when there is a change, either in barometric pressure or temperature.
The weight of one thousand cubic feet of air can be found by an inspection of this table, without any computation, when the temperature in degrees Fahrenheit and barometer in inches of mercury are known, by simply following the horizontal line representing degrees Fahrenheit until it intersects the vertical line corresponding to the barometric reading. At the point of intersection of these two lines, note the figures indicated on the nearest diagonal line.
TABLE FOR FINDING THE ASCENSIONAL FORCE OF GASES
The weight ofoir per 1000 cu ft ot various tempcrotures and pressures may be found by inspection of this table
lb find the weight of on equol volume of any gas, multiply the neightofoir by the specific gravity ot the gas. Hydrogen specgrav 0.0693 (purtj. To fma'the ascensionalforce ofany gas. subtractthe neight ol gos from the weight ot oir - -
This table is sufficient^accurate, for prvcUcal ballooning. Fa extreme ocuirocy. correcUons~inast be^opplied for force. 61 gr.jvltyot lob'tude andetevouori^-thermal expansion at bans scale and glass tut* of thermometer and barometer ond difference in coefficient of expansion of air and hydrogen.
The above is a practical example of finding the ascensional force of a gas having a specific gravity of .40, the barometer reading 30 inches and the thermometer 70 degrees Fahrenheit. By inspection of the table, the lines for 70 degrees Fahrenheit and 30 inches barometer intersect near the diagonal line marked 75. The figure 75 is the weight of 1,000 cubic feet of air. Multiply 75 by .4, which result is 30, the weight of 1,000 cubic feet of the gas. Subtracting 30 from 75 gives 45 pounds as the ascensional force per thousand cubic feet of the gas.
U. S. AERONAUTIC PATENTS, JULY TO DECEMBER, 1907.
Aerial navigator, F. M. Mahan, 861,133; aerial vessel, G. Halliday, 873,542; aerial machine, B. Connolly, 870,936; airship, L. Haines, 859,765; airship, C. McCormick, 864,672; airship, \V. S. Miecarek, 865,415; airship, T. Cornbrodt, 866,665; airship, A. G. Russell, 867,083; airship, M. Schiavone, 868,223; airship, A. \V. H. Griepe, 869,238;
airship, A. C. Ellsworth, 871,164; airship, G. W. Lane, 871,710; airship, Fadda & Di Lorenzo, 872,334; airship attachment, A. Mathews, 870,448; air motor, P. Kiefer, 868,868; air wheel, H. A. Lockwood. 864,317; balloon inflator, F. J. Creque, 874,166; balloon, car suspension for, A. von Parseval, 872,539; balloon captive, II. A. Herve, 870,430; flying machine, J. H. Wilson, 859,274; flying machine, W. Ft. Cook, 860,447; flying machine, F. M. La Penotiere, 861,740; flying machine, A. O'Brate, 867,525; flying machine, mechanism for, J. U. de Uherkocz. 868,038; flying machine, steering gear for, J. U. de Uherkocz, 868,039; flying machine, J. D. Pursell, 869,019; flying machine propeller, L. Gathmann, 871,926; kite, H. Lurz, 859,395.
McADAMITE: A NEW ALLOY HAVING NEARLY THE STRENGTH OF STEEL AND THE LIGHTNESS OF ALUMINUM.
A new aluminum alloy called McAdamite, which is now being manufactured by the United States McAdamite Metal Company, of Brooklyn, is a metal that should have a very wide application and be most useful in the flying machine industry. Most of the best alloys heretofore produced had only some 16,000 pounds compression strength, while McAdamite has 126,000 pounds per square inch. Where the elastic limit was extremely low, the new metal has more than most others, or 84,000 pounds before the yielding point is reached when under compression. Where the very best of the bronzes could barely claim 38,000 pounds per square inch torsional strength, this alloy has 60,000 pounds, or nearly as much as steel, which has 66,000 pounds.
In cast metals it is well known that the tensile strength is low, but even here this new metal is very strong, as it will stand nearly 45,000 pounds per square inch. The elastic limit or yield point of the cast alloy under a tension test is practically the same as the breaking point. A rod 5 inches long and 0.76 inch in diameter separated under a pulling strain of 20,000 pounds with an ultimate elongation of only 0.1 inch in 1 inch of length, or 10 per cent., and a reduction of area from 0.4525 per square inch to 0.442 per square inch, or 2^2 per cent. The tensile strength of this piece figures out at 44,250 pounds per square inch, but the real tensile strength of the cast metal is probably somewhat greater, as the sample used had been turned down, thus removing the tough outer surface, which is the strongest part of all. This material, however, was sound and homogeneous throughout where the fracture occurred, which was at the centre of the rod. v
The specific gravity of cast McAdamite is 3.20, as against 2.56 for aluminum and 2.89 for partinium. There is a shrinkage in casting it of 12 to 14 per cent. Its melting point is 977 deg. Fahr. as against 1,830 deg. Fahr. for brass; but, roughly speaking, it has nearly three times the strength in any direction, and three times the volume or one-third the weight of brass. Various degrees of strength and hardness are obtained by the mode of casting. So homogeneous is this metal and so free from gas that extremely intricate and delicate castings can be made. Very thin strips of the metal, when cast, are much stronger in proportion to their cross-sectional area than are pieces of larger size, as the rapid cooling and consequent hardening takes place from the surface inward, and are more complete with a thin piece than with a thick one.
When a piece of this new metal is broken, it shows a fine grain similar to steel; and if a bar of it be struck by a hammer, it will ring with a clear and resonant tone.
While heretofore it would have been out of the question to make long slender screws, for example, out of any of the aluminum alloys, with this new alloy it is quite possible and almost all of the moving parts of machinery, such as gears, levers, screws, cams, frames, etc., can be made from it. It can be machined with the greatest ease; the chips peel off in long curls, and fine screw threads are cut in it without the aid of oil, turpentine, etc. Although comparatively soft, it is an exceedingly tough metal, retaining all the beautiful qualities of aluminum and removing the weak ones. It gives to aluminum color, strength, tooling, density, fluidity; removes its dryness; and protects it from the attack of salt. It is the first commercially practical metal of great strength and little weight for common every-day use—a metal that may even partially displace cast iron as it grows cheaper, which it will do in time.
Among its many qualities is its freedom from occluded gases and viscousness, which gives it fluidity; and to-day gears and many things are being cast finished. The machine shop is no longer needed to cut the teeth in gears; they are cast cut, so to speak.
One of the heavy costs of work executed with the common metals is the finishing of the castings after they have been, obtained. The surface must be removed by filing, grinding, turning, buffing, etc. With McAdamite only a slight buffing is needed at the most, for the pieces are cast with a bright, silver-white surface.
Its characteristics are similar to those of cast steel, and weight for weight it has equal strength in tension and greater in compression. In resisting tensile stresses, it
bears a very favorable comparison with the usual grades of mild steel even when equal volumes are compared. Thus it will be seen to have a great superiority in weight. Its toughness and elasticity arc quite unusual for a cast metal, and it far outranks all metals classed as alloys in this respect. The fact that the elastic limit when under compression runs so high, gives it a wide application in the arts, and with its other qualities, puts it in a class by itself when compared with any other known alloy, its principal field being largely wherever brass and bronze are used and where extreme strength with minimum weight is required.
McAdamite has already been employed for aeronautical purposes and has been found most satisfactory.
March.—Balloon race organized by the Aero Club of Nice. Distance race at Verona, Italy, on the 19th.
April.—Balloon race of the Aero Club of France on the 15th.
May.—Aero Club of France balloon race on the 16th. International balloon race of the Aero Club of the United Kingdom. International Aeronautic Congress of the F.A.I, at London, on the 30th. Distance balloon race at Barcelona, Spain, on the 17th; $2900 in prizes and gas free. Grand Prix of the Aero Club of France on the 24th. Aeronef contests at Munich.
June.—Aero Club of France balloon race on the nth. Balloon race at Tours on the 21st.
July.—Balloon race at Brussels on the 19th. Flying machine contests at Spa, on the 12th, 19th and 26th.
September.—Grand Prix of the A. C. F. Aeroplane contests at Vichy.
October.—Distance contests and contests for prearranged objective point at Berlin on the 10th. Gordon Bennett International Race on the nth. International aeroplane contests at Venice for $5000 in prizes.
1911.—International assembly of dirigibles in Italy under the auspices of the Societa Aeronautica Italiana.
COMMUNICATIONS. National Airship Co.
To the Editor:
I notice a mention of the National Airship Company of San Francisco, in February AERONAUTICS under the head of "Notes."
Although I am not connected with the Company other than a small stockholder, I am anxious with other stockholders to see our Company a success. And such misleading articles tend to militate against the best interests of the Company.
Your correspondent states that all the officials connected with the concern have disappeared, and with them what is left of the stock sales, amounting to more than a quarter of a million dollars.
After I heard of the trouble I went over to San Francisco and found Mr. Morrell in the office working at a typewriter. He said he had been in the office every day, notwithstanding the report that he had absconded with the funds. He says he has paid out twenty-seven thousand dollars more than received for the sale of stock; never sold a share of personal stock and never accepted a dollar for personal services, and has worked more than fourteen hours per day during three years since the Company was organized. He says the Ariel, will be built, if he is let alone, and do all that he has ever claimed for it. Where the malicious articles claim that the federal officers were asked to investigate on the complaint of hundreds of stockholders, Mr. Morrell says that only two stockholders have made any complaint, and these two are connected with other airship companies, and have an interest to down him.
I do not pretend to say how this trouble will come out. But there are certainly misstatements abroad concerning the Airship Company that should be corrected.
Very truly yours,
Berkeley, Cal., Feb. 28, 1908. W. S. HASKELL.
The Engineers' Corps have finished the project for constructing a dirigible like Patrie, capable of carrying five passengers. It will be built with Russian workmen and with Russian material. The motor is already completed. It will be ready in September.
AERONAUTIC BOOKS FOR SALE.
This magazine will publish each month a list of such rare and contemporaneous books relating to aeronautics as it is able to secure. If you desire any of those listed, kindly send check with your order for the amount stated. Should the book ordered be sold previous to the receipt of your order, the money will be promptly returned.
History and Practice of Aeronautics (John Wise). Illustrated. Svo., cloth, Phila.,
Travels in The Air (James Glaisher). Illustrated. 8vo., cloth, London, 1871...... 10.00
Flying and No Failure, or Aerial Transit Accomplished More than a Century Ago.
(Rev. Ralph Morris). Very rare reprint on Private Press of London, 1751.. 3.00
My Airships (Santos Dumont). Illustrated. Crown Svo., cloth.................. 1.40
Travels in Space (Valentine and Tomlinson). Introduction by Sir Hiram Maxim.
61 plates, 8vo., cloth, London. 1902........................................ 2.00
Conquest of the Air (John Alexander). 12mo., cloth, London, 1902................ 2.00
The Dominion of the Air (J. M. Bacon). Story of aerial navigation. Illustrated.
Crown, 8vo., cloth, London, n. d............................................ 2.50
Resistance of Air and the Question of Flying (Arnold Samuelson). Illustrated.
12mo., 42 pp., paper........................................................85
Flight Velocity (Arnold Samuelson). Illustrated. 45 pp., 12mo., paper.............85
Flying Machines, Past, Present and Future (A. W. Marshall and H. Greenly). Illustrated ..................................................................60
Paradoxes of Nature and Science (W. Hampson). Illustrated. Two chapters on balloons as airships and bird flight. Svo., cloth, N. Y., 1907................... 1.50
Aerial Navigation (Van Salberda). Translated from the Dutch by Geo. E. Waring,
By Land and Sky (J. M. Bacon). Illustrated. 8vo., cloth, London, 1900.......... 2.50
A Balloon Ascension at Midnight (G. E. Hall). Illustrated in color. Limited edition published. Very rare. Svo., paper, San Francisco, 1902................ 2.50,
Andree's Balloon Expedition (Lachambre—Machuron). Illustrated. 12mo., cloth,
New York, 1898........................................................... 1.00
Parakites (G. Woglom). Illustrated. 8vo., cloth, New York, 1896.................75
The Problem of Flight (Herbert Chatley, B. Sc.) A new textbook of aerial engineering both aerostation and aviation. Illustrated. 8vo., cloth, 1908............ 3.50
Pocket Book of Aeronautics (Maj. H. W. L. Moedebeck). A manual of aviation and
aerostation. Illustrated. Cloth, 496 pages, London, 1907.........••________ 3.25
Ballooning as a Sport (Maj. B. Baden Powell). Illustrated. London, 1907......... 1.10
Navigating the Air (Members Aero Club of America). Illustrated. 8vo., cloth, New
York, 1907................................................................ 1.65
L'Omnibus Aerien (Bourget). A musical piece sung by Mile. Flore. Has a
picture of flying omnibus on front. Is extremely rare. Paris, 1840.....-.':. . 7.00
Keely and His Discoveries, Aerial Navigation (Mrs. B. Moore). 8vo. cloth,
London, 1893 ...........................................................'.' 3.00
St. Louis Gordon Bennett race views in an album, full set........................ 3.00
Narrative of the Ascent and First Voyage of the Aerial Steamer (George Aire,
F. A. S., A. L. C, etc.). Paper, 76 pp., ill., London, 1843. Rare............. 2.30
Accounts of Three Aerial Voyages (Mr. Sadler). Small 8vo., boards, autograph of
"Mr. Sadler," London, 1810-17. Very rare.................................. 5.00
Aeronautical Annual (Edited by James Means). Svo., cloth, ill., 176 pp., Boston,
1897 .................................................................... 1.75
Aeronautical Annual (Edited by James Means). 8vo., cloth, ill., 158 pp., Boston,
1896 .................................................................... 1.75
History & Practice of Aeronautics (John Wise). Illustrated, 8vo., cloth, 310 pp..
Phila., 1S50 ............................................................. 9.00
Looking Forward; Aerial Navigation (Dr. A. De Bausset). Paper pamphlet, 48
pp., Boston, 1889......................................................... 1.50
Aerial Navigation (Arthur De Bausset, M. D.). Paper pamphlet, 48 pp., Chicago,
1887 .................................................................... 1.50
Sounding the Ocean of Air (A. Lawrence Rotch, ,S. B., A. M.). 12mo, cloth, ill.,
London, 1900 ............................................................ 1.00
Scientific Experiments in Balloons (James Glaisher, F. R. S.). A lecture before
the Y. M. C. A., 1862-3. Cloth, 8vo., London, 1863......................... 3.00
Proceedings International Conference on Aerial Navigation, Chicago, 1893, cloth,
8vo., ill., New York, 1894................................................ 4.50
Ballooning (G. May). Small 8vo., cloth, ill. Rare.............................. 2.50
Account of the Late Aeronautical Expedition from London to Weilburg (Monck
Mason). Paper pamphlet, 35 pp., N. Y., 1837.............................. 3.50
Airships Past and Present, by Captain A. Hildebrandt; translated by W. H. Story (D.
Van Nostrand Co., 33 Murray St., New York ;)................................ 3.50
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