Part 7
The Fort Myer machine had sails of forty feet spread, six and one-half feet deep, with front elevating planes three by sixteen feet. It made about forty miles per hour with two passengers. The apparatus was specified to carry a passenger weight of 350 pounds, with fuel for a 125-mile flight. The main planes were six feet apart. The steering rudder (double) was of planes one foot deep and nearly six feet high. The four-cylinder-four-cycle, water-cooled motor developed twenty-five horse-power at 1400 revolutions. The two propellers, eight and one-half feet in diameter, made 400 revolutions.
The flight by Mr. Wilbur Wright from the Statue of Liberty to the tomb of General Grant, in New York, 1909, and the exploits of his brother in the same year, when a new altitude record of 1600 feet was made and H.R.H. the Crown Prince of Germany was taken up as a passenger, are only specimens of the later work done by these pioneers in aerial navigation.
Like the Wrights, the Voisin firm from the beginning adhered firmly to the biplane type of machine. The sketch gives dimensions of one of the early cellular forms built for H. Farman (see illustration, page 147). The metal screw makes about a thousand revolutions. The wings are of india rubber sheeting on an ash frame, the whole frame and car body being of wood, the latter covered with canvas and thirty inches wide by ten feet long. The engine weighed 175 pounds. The whole weight of this machine was nearly 1200 pounds; that built later for Delagrange was brought under a thousand pounds. The ratio of weight to main surface in the Farman aeroplane was about 2-3/4 to 1.
A modified cellular biplane also built for Farman had a main wing area of 560 square feet, the planes being seventy-nine inches wide and only fifty-nine inches apart. The tail was an open box, seventy-nine inches wide and of about ten feet spread. The cellular partitions in this tail were pivoted along the vertical front edges so as to serve as steering rudders. The elevating rudder was in front. The total weight was about the same as that of the first machine and the usual speed twenty-eight miles per hour.
Henry Farman has been flying publicly since 1907. He made the first circular flight of one kilometer, and attained a speed of about a mile a minute, in the year following. In 1909 he accomplished a trip of nearly 150 miles, remaining four hours in the air. Farman was probably the first man to ascend with two passengers.
The _June Bug_, one of the first Curtiss machines, is shown below. This was one of the lightest of biplanes, having a wing spread of forty-two feet and an area of 370 square feet. The wings were transversely arched, being furthest apart at the center: an arrangement which has not been continued. It had a box tail, with a steering rudder of about six square feet area, _above_ the tail. The horizontal rudder, in front, had a surface of twenty square feet. Four triangular ailerons were used for stability. The machine had a landing frame and wheels, made about forty miles per hour, and weighed, in operation, 650 pounds.
Mr. Curtiss first attained prominence in aviation circles by winning the _Scientific American_ cup by his flight at the speed of fifty-seven miles per hour, in 1908. In the following year he exhibited intricate curved flights at Mineola, and circled Governor's Island in New York harbor. In 1910 he made his famous flight from Albany to New York, stopping _en route_, as prearranged. At Atlantic City he flew fifty miles over salt water. A flight of seventy miles over Lake Erie was accomplished in September of the same year, the return trip being made the following day. On January 26, 1911, Curtiss repeatedly ascended and descended, with the aid of hydroplanes, in San Diego bay, California: perhaps one of the most important of recent achievements. It is understood that Mr. Curtiss is now attempting to duplicate some of these performances under the high-altitude conditions of Great Salt Lake. According to press reports, he has been invited to give a similar demonstration before the German naval authorities at Kiel.
The _aeroscaphe_ of Ravard was a machine designed to move either on water or in air. It was an aeroplane with pontoons or floaters. The supporting surface aggregated 400 square feet, and the gross weight was about 1100 pounds. A fifty horse-power Gnome seven-cylinder motor at 1200 revolutions drove two propellers of eight and ten and one-half feet diameter respectively: the propellers being mounted one behind the other on the same shaft.
Ely's great shore-to-warship flight was made without the aid of the pontoons which he carried. Ropes were stretched across the landing platform, running over sheaves and made fast to heavy sand bags. As a further precaution, a canvas barrier was stretched across the forward end of the platform. The descent brought the machine to the platform at a distance of forty feet from the upper end: grappling hooks hanging from the framework of the aeroplane then caught the weighted ropes, and the speed was checked (within about sixty feet) so gradually that "not a wire or bolt of the biplane was injured."
Recent combinations of aeroplane and automobile, and aeroplane with motor boat, have been exhibited. One of the latter devices is like any monoplane, except that the lower part is a water-tight aluminum boat body carrying three passengers. It is expected to start of itself from the water and to fly at a low height like a flying fish at a speed of about seventy-five miles per hour. Should anything go wrong, it is capable of floating on the water.
In the San Diego Curtiss flights, the machine skimmed along the surface of the bay, then rose to a height of a hundred feet, moved about two miles through the air in a circular course, and finally alighted close to its starting-point in the water. Turns were made in water as well as in air, a speed of forty miles per hour being attained while "skimming." The "hydroplanes" used are rigid flat surfaces which utilize the pressure of the water for sustention, just as the main wings utilize air pressure. On account of the great density of water, no great amount of surface is required: but it must be so distributed as to balance the machine. The use of pontoons makes it possible to rest upon the water and to start from rest. A trip like Ely's could be made without a landing platform, with this type of machine; the aeroplane could either remain alongside the war vessel or be hoisted aboard until ready to venture away again.
There are various other biplanes attracting public attention in this country. In France the tendency is all toward the monoplane form, and many of the "records" have, during the past couple of years, passed from the former to the latter type of machine. The monoplane is simpler and usually cheaper. The biplane may be designed for greater economy in weight and power. Farman has lately experimented with the monoplane type of machine: the large number of French designs in this class discourages any attempt at complete description.
The smallest of aeroplanes is the Santos-Dumont _Demoiselle_. The original machine is said to have supported 260 pounds on 100 square feet of area, making a speed of sixty miles per hour. Its proprietor was the first aviator in Europe of the heavier-than-air class. After having done pioneer work with dirigible balloons, he won the Deutsch prize for a hundred meter aeroplane flight (the first outside of the United States) in 1906; the speed being twenty-three miles per hour. His first flight, of 400 feet, in a monoplane was made in 1907.
The master of the monoplane has been Louis Blériot. Starting in 1907 with short flights in a Langley type of machine, he made his celebrated cross-country run, and the first circling flights ever achieved in a monoplane, the following year. On July 25, 1909, he crossed the British Channel, thirty-two miles, in thirty-seven minutes.
The Channel crossing has become a favorite feat. Mr. Latham, only two days after Blériot, all but completed it in his Antoinette monoplane. De Lesseps, in a Blériot machine, was more fortunate. Sopwith, last year, won the de Forest prize of $20,000 by a flight of 174 miles from England into Belgium. The ill-fated Rolls made the round trip between England and France. Grace, contesting for the same prize, reached Belgium, was driven back to Calais, started on the return voyage, and vanished--all save some few doubtful relics lately found. Moisant reached London from Paris--the first trip on record between these cities without change of conveyance: and one which has just been duplicated by Pierre Prier, who, on April 12, made the London to Paris journey, 290 miles, in 236 minutes, without a stop. This does not, however, make the record for a continuous flight: which was attained by Tabuteau, who at Buc, on Dec. 30, 1910, flew around the aerodrome for 465 minutes at the speed of 48-1/2 miles per hour.
Other famous crossings include those of the Irish Sea, 52 miles, by Loraine; Long Island Sound, 25 miles, by Harmon; and Lake Geneva, 40 miles, by Defaux.
It was just about a century ago that Cayley first described a soaring machine, heavier than air, of a form remarkably similar to that of the modern aeroplane. Aside from Henson's unsuccessful attempt to build such a machine, in 1842, and Wenham's first gliding experiments with a triplane in 1857, soaring flight made no real progress until Langley's experiments. That investigator, with Maxim and others, ascertained those laws of aerial sustention the application of which led to success in 1903.
The eight years since have held the crowded hours of aviation. Before this book is printed, it may be rendered obsolete by new developments. The exploits of Paulhan, of R. E. Peltèrie since 1907, Bell's work with his tetrahedral kites--all have been either stimulating or directly fruitful. Delagrange began to break speed records in 1908. A year later he attained a speed of fifty miles. The first woman to enjoy an aeroplane voyage was Mme. Delagrange, in Turin, in 1908.
The first flight in England by an English-built machine was made in January, 1909. That year, Count de Lambert flew over Paris, and in 1910 Grahame-White circled his machine over the city of Boston. The year 1910 surpassed all its predecessors in increasing the range and control of aeroplanes; over 1500 ascents were made by Wright machines alone; but 1911 promises to show even greater results. Three men made cross-country flights from Belmont Park to the Statue of Liberty and back, in New York;[B] at least five men attained altitudes exceeding 9,000 feet. Hamilton made the run from New York to Philadelphia and return, in June. The unfortunate Chavez all but abolished the fames of Hannibal and Napoleon by crossing the icy barrier of the Alps, from Switzerland to Italy--in forty minutes!
Tabuteau, almost on New Year's eve, broke all distance records by a flight of 363 miles in less than eight hours; while Barrier at Memphis probably reached a speed of eighty-eight miles per hour (timing unofficial). With the new year came reports of inconceivable speeds by a machine skidding along the ice of Lake Erie; the successful receipt by Willard and McCurdy of wireless messages from the earth to their aeroplanes; and the proposal by the United States Signal Corps for the use of flying machines for carrying Alaskan mails.
McCurdy all but succeeded in his attempt to fly from Key West to Havana, surpassing previous records by remaining aloft above salt water while traveling eighty miles. Lieutenant Bague, in March, started from Antibes, near Nice, for Corsica. After a 124-mile flight, breaking all records for sea journeys by air, he reached the islet of Gorgona, near Leghorn, Italy, landing on bad ground and badly damaging his machine. The time of flight was 5-1/2 hours. Bellinger completed the 500-mile "accommodation train" flight from Vincennes to Pau; Vedrine, on April 12, by making the same journey in 415 minutes of actual flying time, won the Béarn prize of $4000; Say attained a speed of 74 miles per hour in circular flights at Issy-les-Moulineaux. Aeroplane flights have been made in Japan, India, Peru, and China.
One of the most spectacular of recent achievements is that of Renaux, competing for the Michelin Grand Prize. A purse of $20,000 was offered in 1909 by M. Michelin, the French tire manufacturer, for the first successful flight from Paris to Clermont-Ferrand--260 miles--in less than six hours. The prize was to stand for ten years. It was prescribed that the aviator must, at the end of the journey, circle the tower of the Cathedral and alight on the summit of the Puy de Dome--elevation 4500 feet--on a landing place measuring only 40 by 100 yards, surrounded by broken and rugged ground and usually obscured by fog.
The flight was attempted last year by Weymann, who fell short of the goal by only a few miles. Leon Morane met with a serious accident, a little later, while attempting the trip with his brother as a passenger. Renaux completed the journey with ease in his Farman biplane, carrying a passenger, his time being 308 minutes.
This Michelin Grand Prize is not to be confused with the Michelin Trophy of $4000 offered yearly for the longest flight in a closed circuit.
Speeds have increased 50% during the past year; even with passengers, machines have moved more than a mile a minute: average motor capacities have been doubled or tripled. The French men and machines hold the records for speed, duration, distance, and (perhaps) altitude. The highest altitude claimed is probably that attained by Garros at Mexico City, early this year--12,052 feet above sea level. The world's speed record for a two-man flight appears to be that of Foulois and Parmalee, made at Laredo, Texas, March 3, 1911: 106 miles, cross-country, in 127 minutes. Three-fourths of all flights made up to this time have been made in France--a fair proportion, however, in American machines.
NOTE
The rapidity with which history is made in aeronautics is forcibly suggested by the revision of text made necessary by recent news. The new _Deutschland_ has met the fate of its predecessors; the Paris-Rome-Turin flight is at this moment under way; and Lieutenant Bayne, attempting once more his France-to-Corsica flight, has--for the time being at least--disappeared.
THE POSSIBILITIES IN AVIATION
Men now fly and will probably keep on flying; but aviation is still too hazardous to become the popular sport of the average man. The overwhelmingly important problem with the aeroplane is that of stability. These machines must have a better lateral balance when turning corners or when subjected to wind gusts: and the balance must be automatically, not manually, produced.
Other necessary improvements are of minor urgency and in some cases will be easy to accomplish. Better mechanical construction, especially in the details of attachments, needs only persistence and common sense. Structural strength will be increased; the wide spread of wing presents difficulties here, which may be solved either by increasing the number of superimposed surfaces, as in triplanes, or in some other manner. Greater carrying capacity--two men instead of one--may be insisted upon: and this leads to the difficult question of motor weights. The revolving air-cooled motor may offer further possibilities: the two-cycle idea will help if a short radius of action is permissible: but a weight of less than two pounds to the horse-power seems to imply, almost essentially, a lack of ruggedness and surety of operation. A promising field for investigation is in the direction of increasing propeller efficiencies. If such an increase can be effected, the whole of the power difficulty will be greatly simplified.
This same motor question controls the proposal for increased speed. The use of a reserve motor would again increase weights; though not necessarily in proportion to the aggregate engine capacity. Perhaps something may be accomplished with a gasoline turbine, when one is developed. In any case, no sudden increase in speeds seems to be probable; any further lightening of motors must be undertaken with deliberation and science. If much higher maximum speeds are attained, there will be an opportunity to vary the speed to suit the requirements. Then clutches, gears, brakes, and speed-changing devices of various sorts will become necessary, and the problem of weights of journal bearings--already no small matter--will be made still more serious. And with variable speed must probably come variable sail area--in preference to tilting--so that the fabric must be reefed on its frame. Certainly two men, it would seem, will be needed!
Better methods for starting are required. The hydroplane idea promises much in this respect. With a better understanding and control of the conditions associated with successful and safe descent--perhaps with improved appliances therefor--the problem of ascent will also be partly solved. If such result can be achieved, these measures of control must be made automatic.
The building of complete aeroplanes to standard designs would be extremely profitable at present prices, which range from $2500 to $5000. Perhaps the most profitable part would be in the building of the motor. The framing and fabric of an ordinary monoplane could easily be constructed at a cost below $300. The propeller may cost $50 more. The expense for wires, ropes, etc., is trifling; and unless special scientific instruments and accessories are required, all of the rest of the value lies in the motor and its accessories. Within reasonable limits, present costs of motors vary about with the horse-power. The amateur designer must therefore be careful to keep down weight and power unless he proposes to spend money quite freely.
The Case of the Dirigible
Not very much is being heard of performances of dirigible balloons just at present. They have shown themselves to be lacking in stanchness and effectiveness under reasonable variations of weather. We must have fabrics that are stronger for their weight and more impervious. Envelopes must be so built structurally as to resist deformation at high speeds, without having any greatly increased weight. A cheap way of preparing pure hydrogen gas is to be desired.
Most important of all, the balloon must have a higher speed, to make it truly dirigible. This, with sufficient steering power, will protect it against the destructive accidents that have terminated so many balloon careers. Here again arises the whole question of power in relation to motor weight, though not as formidably as is the case with the aeroplane. The required higher speeds are possible now, at the cost merely of careful structural design, reduced radius of action, and reduced passenger carrying capacity.
Better altitude control will be attained with better fabrics and the use of plane fin surfaces at high speeds. The employment of a vertically-acting propeller as a somewhat wasteful but perhaps finally necessary measure of safety may also be regarded as probable.
The Orthopter
The _aviplane_, _ornithoptère_ or _orthopter_ is a flying machine with bird-like flapping wings, which has received occasional attention from time to time, as the result of a too blind adherence to Nature's analogies. Every mechanical principle is in favor of the screw as compared with any reciprocating method of propulsion. There have been few actual examples of this type: a model was exhibited at the Grand Central Palace in New York in January of this year.
The mechanism of an orthopter would be relatively complex, and the flapping wings would have to "feather" on their return stroke. The flapping speed would have to be very high or the surface area very great. This last requirement would lead to structural difficulties. Propulsion would not be uniform, unless additional complications were introduced. The machine would be the most difficult of any type to balance. The motion of a bird's wing is extremely complicated in its details--one that it would be as difficult to imitate in a mechanical device as it would be for us to obtain the structural strength of an eagle's wing in fabric and metal, with anything like the same extent of surface and limit of weight. According to Pettigrew, the efficiency of bird and insect flight depends largely upon the elasticity of the wing. Chatley gives the ratio of area to weight as varying from fifty (gnat) to one-half (Australian crane) square feet per pound. The usual ratio in aeroplanes is from one-third to one-half.
About the only advantages perceptible with the orthopter type of machine would be, first, the ability "to start from rest without a preliminary surface glide"; and second, more independence of irregularity in air currents, since the propulsive force is exerted over a greater extent than is that of a screw propeller.
The Helicopter
The _gyroplane_ or _helicopter_ was the type of flying machine regarded by Lord Kelvin as alone likely to survive. It lifts itself by screw propellers acting vertically. This form was suggested in 1852. When only a single screw was used, the whole machine rotated about its vertical axis. It was attempted to offset this by the use of vertical fin-planes: but these led to instability in the presence of irregular air currents. One early form had two oppositely-pitched screws driven by a complete steam engine and boiler plant. One of the Cornu helicopters had adjustable inclined planes under the two large vertically propelling screws. The air which slipped past the screws imposed a pressure on the inclined planes which was utilized to produce horizontal movement in any desired direction--if the wind was not too adverse. A gasoline engine was carried in a sort of well between the screws.