OUR BOY FRIEND AND THE SCIENTIST LOOK OVER MODERN AEROPLANES AND FIND GREAT IMPROVEMENTS OVER THOSE OF A FEW YEARS AGO—A MODEL AEROPLANE.

EVERY effort of the aeroplane inventors these days is bent toward making the power flier useful—a faithful servant to man in his day-to-day life—and to this end greater carrying capacity is one of the chief objects," said the scientist one day in answer to a question from his young friend as to what the future of aviation would be.

"No one can tell what the future will bring forth," he continued. "You or one of your friends might invent the ideal aeroplane. There is one way of telling how the wind blows, though, and that is by watching the new developments of aeroplanes very carefully. Let's look at some of them."

Of course it was impossible for the boy to study every improvement or every make of aeroplane, but the scientist pointed out a few examples that served to show how science is trying to improve on aviation as we know it to-day.

The boy's friend said that probably the most wonderful accomplishment in the art of air navigation since power fliers became an accomplished fact was the work of Orville Wright in the fall of 1911 with his new glider, which he tested at the Wright brothers' old experiment station at Kitty Hawk, N. C.

"Never before in the history of aviation, so far as is known," said the scientist, "has man come so near to the true soaring flight which we have seen is the third stage of aeroplaning."

Not only did this wonderful glider sail into the wind and reach an altitude of 200 feet, but, under the control of the pilot, it stayed in the air 10 minutes and 1 second, most of the time hovering over one spot, without the use of any propelling device.

On the day of the great test the glider was taken to the top of Kill Devil Hill, which is 110 feet high, and while the wind was roaring through the canvas at 42 miles an hour the machine was launched. To those unaccustomed to the actions of gliders it would have seemed that the engineless biplane would be blown backward over the edge of the hill. Instead, it shot forward and upward into the teeth of the hurricane. The force of the wind on the planes, which were presented diagonally to it, caused the flier to rise and go ahead by just about the same principle that a ship can sail almost into the teeth of the wind by having her sails set at the proper angle.

When it had reached the altitude of 200 feet it stopped motionless and to those below who saw Orville Wright sitting calmly in the pilot's seat it seemed that some unseen hand was holding him aloft. Suddenly the pilot pressed a lever and the glider darted 250 feet to the left, returned to her original position, sank to within a few feet of the hillside and hovered there for two minutes.

The Wrights had been working on the principles involved for a long time and at the testing grounds were Orville Wright, his brother Loren, who up to that time had not been known to the world of aviation, and Alexander Ogilvy, an English aviator.

After the remarkable test Orville Wright was asked, "Have you solved real bird flight?"

"No," he replied, "but we have learned something about it."

The aviator went on to explain that had he been up 3,000 feet or so, where the wind currents are always strong, he probably could have stayed up there all night, or as long as he cared to.

This greatest of all feats of soaring was accomplished in a glider that looked to the ordinary person very much like the modern Wright biplane without the engine. There were skids but they were very low. In general outline the machine was composed of two main planes, a vertical vane set out in front, two vertical planes at the rear of the tail, and behind these the horizontal plane. The details of the construction of the glider were not made public and only a few persons saw it, but from all accounts the curve of the main planes was much greater than is usual, thus gaining the glider a greater degree of support from the air, and the planes were capable of being warped much more than in the ordinary Wright biplane. The vertical vane in front, which does not appear on any of the Wright power fliers, was a foot wide and five feet tall. It acted as a keel and gave the machine greater side-to-side stability because the wind passing at a high speed to each side of it tended to keep it vertical.

In working out a biplane that could rise from or alight on the water, Glenn Curtiss practically doubled the usefulness of aeroplanes. The experiments, conducted under the auspices of the United States Navy so impressed the officers that several have been added to its equipment. Curtiss has been experimenting with hydro-aeroplanes for several years, but before actually completing one he conducted a number of experiments with ordinary biplanes in the vicinity of Hampton Roads, Va., in 1911, to prove them available for use on battleships. Finally, Lieutenant Ely flew from the deck of the cruiser Birmingham over the water and to a convenient landing spot on land.

Later on Curtiss went to California to perfect his hydro-aeroplane, and while conducting the work Lieutenant Ely made a flight from shore to the deck of the battleship Pennsylvania which was lying in San Francisco Harbour. These two incidents were more in the nature of "stunts" than developments, but they showed what an aeroplane could do if attached to a battleship fleet as a scout.

Even more convincing was the proof when Curtiss finally worked out a form of wooden float which was put between the mounting wheels. The float was flat-bottomed with an upward inclination at the prow so that when skimming over the water the tendency was to rise from the surface rather than to cut through it. Small floats at the outer tips of the lower main plane helped to keep the machine on an even balance while floating at rest upon the water. The wheels served their regular purpose if the machine started from or alighted upon land.

The experiments were conducted on San Diego Bay, and it was only after long and patient labour that the work of Mr. Curtiss and his military associates was rewarded with success. In the course of the experiments he tried a triplane, which had great lifting power, but this later was abandoned in favour of the regular biplane fitted with a float. After the machine had been perfected, Curtiss flew his hydro-aeroplane out into the bay to the cruiser Pennsylvania, upon which Ely had landed a month before, and after landing on the water at the cruiser's side was pulled up to her deck and later was put back into the water from where he sailed to camp. The machine was named the Triad because it had conquered air, land, and water.

Of the machine Curtiss says: "I believe the hydro-aeroplane represents one of the longest and most important strides in aviation. It robs the aeroplane of many of its dangers, and as an engine of warfare widens its scope of utility beyond the bounds of the most vivid imagination. The hydro-aeroplane can fly 60 miles an hour, skim the water at 50 miles and run over the earth at 35 miles."

It was not long after the Curtiss hydro-aeroplane had been successfully demonstrated, before all the other leading makers brought out air craft that could sail from and alight on water as well as on land. The Wright hydro-aeroplane, which is equipped with two long air-tight metal floats instead of one, has achieved great success in the United States. In Europe all the leading biplane types are now made with hydro-aeroplane equipment, and flying over water became as popular last year as flying over land did in 1910.

The first American monoplane to be equipped with the floats of a hydro-plane was shown by the "Queen" company at the New York Aero show in May, 1912. It was called an aero boat as the front part of the fuselage was enclosed like a boat and the operator sat in it, under the wings. The propeller was at the rear and there was a small pontoon at each end of the wings to keep it on an even keel when stationary in the water. A short time after this the Curtiss company turned out the flying boat which was described on page 90.

In general outline the aeroplanes in use to-day differ greatly from those seen several years ago, but the difference is in form rather than in principle. There have been many improvements, of course, in construction, control of the fliers, and in the powerful engines that drive them. In fact the tendency of aeroplane builders has been to adopt the successful devices on other machines rather than to work out original ones.

The most noticeable change in the present-day aeroplanes is the way in which builders nowadays are enclosing the bodies and landing framework in canvas or even light metal, so that they shall offer as little resistance to the air as possible. It gives the machines the appearance of being armoured, as will be noticed from the pictures of the new planes, so the term has come to be used in that sense, although, of course, the covering would not protect them against bullets. This armour has become particularly popular with the designers who are making aeroplanes for the French Army, and at the recent military tests in France most of the machines were covered to some degree, and many of them looked for all the world like great long-bodied gulls or mammoth flying fishes. Several aeroplanes have been equipped with twin motors and double steering systems so that either or both could be used. This, of course, is a great advantage in case one fails. Also designers are figuring on wing surfaces that can be reefed or telescoped for better stability as well as wings that can be folded for easier transportation.

Experts do not agree on the respective merits of the two great general types of aeroplanes—that is, monoplanes and biplanes. Some claim that the monoplane is the best and others that the biplane is the most successful flier. Records show that so far monoplanes are the faster of the two types, but biplanes can be fitted with hydro-aeroplane floats, whereas it is impractical with most monoplanes. Many declare the biplane to have the greater lifting power, but the BlÉriot "Aero-Bus" has carried a jolly family party of eight without difficulty. Each type has its champions as to safety, reliability and endurance, but time will have to decide the question.

First let us look at one of the latest Wright biplanes as it is brought out on the aviation field and is being tuned up by its keen-eyed young American pilot. The description of the 1909 Wright will be remembered. Also it will be remembered how the Wright brothers in 1910 discarded the forward horizontal elevating rudder entirely, and substituted in its place a single elevating rudder at the rear end of the tail, which also served to give fore and aft stability. Also in 1910 the Wright brothers added wheels to the skids that hitherto had been used for starting and alighting. Thus the old system of having the machine skidded along a rail by a falling weight, as previously described, was done away with in favour of its running over the ground on its wheels.

After noting these improvements, we will look at the general outlines of such a Wright racing machine as contested for the James Gordon Bennett Cup in 1910. The two main planes are the smallest yet used on a biplane, being only 21-1/2 feet wide from tip to tip, and only 3-1/2 feet from front to rear. Thus, the aspect ratio, it will be seen is 7. They are the same general shape as the planes on the other Wright machines, and their total area is 145 square feet. The machine is steered up or down by the horizontal elevator rudder in the rear, which is oblong-shaped, 8 by 2 feet. The rudder that steers the machine from right to left is set vertically at the tail and is worked in combination with the levers that work the warping of the tips of the planes. On this little machine the twin-screw propellers, 8-1/2 feet in diameter, sweep practically the whole width of the machine. They are connected by chains to the 60-horsepower 8-cylinder Wright engine (in ordinary biplanes of this type the engine is 30 horsepower) and make 525 revolutions per minute (in ordinary machines of this type they make 450 revolutions per minute). The machine weighs a total of 760 pounds and is capable of more than 60 miles an hour.

The elevation rudder is controlled by a lever set either at the right or left hand of the operator. The direction rudder is controlled by a lever that also controls the warping of the planes, as in turning it is necessary to cant the machine over to the inner side of the curve being made, in order to prevent slipping sidewise through the air. However the handle of the direction and warping lever is so arranged by a clutch system that by moving the lever simply from side to side the direction lever can be worked independently of the warping. The direction and balancing system then, we see, is worked in this manner. Say, while flying, a gust of wind causes the biplane to dip at the right end. The operator quickly moves his warping lever forward. This pulls down the tips of the right planes, and at the same time elevates the tips of the left planes. The change of the angle makes the right side lift to its normal position while it makes the left side drop. Consequently the machine is restored to an even keel and the operator lets the planes spring back to their normal shape.

The large 1911 Wright biplanes, model B, are designed the same as the small racing models except that the wings have a spread of 39 feet, and a depth of 6-1/4 feet—a total area of 440 square feet. The perpendicular triangular surfaces in front like two little jib sails, are a distinguishing feature, although the latest Wright models substitute narrow vertical fins about six feet tall and six inches wide. They are placed immediately in front of the main planes. The hydro-aeroplane substitutes two aluminum floats for the wheels.

The Curtiss biplane, which we have seen has had a great deal to do with the development of aviation, is one of the simplest and most successful machines known to-day. The main planes of the regular-sized machines have a spread of 26-1/2 feet, are set 5 feet apart, and have a depth from front to rear of 4-1/2 feet. The total wing area is 220 feet. The direction rudder is a single vertical vane at the rear, which is turned by the steering wheel connected by cables. The elevation rudder consisting of one horizontal plane 24 square feet in area is at the front and is turned up or down by the pilot as he desires to sail up or down, by means of a long bamboo pole connecting the elevation rudder with his pilot wheel. He pushes the wheel forward or back to rise or descend, while he twists it from right to left to turn in either of those directions. The side-to-side balance was maintained in the early Curtiss machines by flexible wing tips, but these later were replaced by ailerons placed between and at the outer tips of the main planes. Each aileron had an area of 12 square feet and they were operated by a brace fitted to the operator's body. Thus, if the machine tipped to the right, the operator would swing to the left, turn the ailerons, and right the machine. In some later Curtiss biplanes these ailerons were replaced by others, like flaps attached to the rear outer edges of the main planes. By raising the flaps on one side and lowering them on the other the balance was well preserved.

As before stated, these machines are driven by Curtiss engines. In most of them the engines are 4-cylinder, 25-horsepower motors. The cylinders in this type, of course, are stationary, but the engine shaft is directly connected with the 6-foot propeller at the rear, which makes 1,200 revolutions per minute. The pilot sits between the two main planes of his engine. On large Curtiss machines seats for as many as three passengers have been arranged at the sides of the pilot.

The most important work Curtiss has done in the last few years is the development of the hydro-aeroplane, which has been explained.

The next biplane with which we are familiar is the Voisin, which Henri Farman demonstrated as the first really successful aeroplane seen in Europe. This machine was a standard of what was called the cellular type because it was composed of cells, like a box kite. The two main planes, which were the same size, 37 feet by 6-1/2 feet, were connected at the outer edges so as to make the plane a closed cell—i. e., a box with the ends knocked out. Two other vertical surfaces between the main plane gave the machine the appearance of three box kites side by side. The tail out behind was composed of a square cell. In the centre of it was a vertical vane for steering it from right to left, while out in front was a single horizontal rudder for raising or lowering the plane. The control was much the same as in the Curtiss machine. The steering wheel turned the plane from right to left, and was connected by a rod with the elevator, so that by pushing it forward or back, the machine was raised or lowered. There was no device for maintaining a side-to-side balance as the cell formation was supposed to keep the machine on an even keel. The motor drove a propeller at the rear.

The later Bordeaux type of Voisin which was built for military purposes does away with the side curtains and box tail. On the outer rear edge of the upper main plane are ailerons for maintaining the balance, which are operated by foot pedals. The elevator is a single horizontal plane at the rear of the tail, while the direction rudder is a vertical plane beneath it. This machine carries two persons, and is frequently driven by a Gnome engine. Still another and later type of the Voisin Bordeaux is the front control. In this the ailerons are used as previously described, but also there are side curtains enclosing the outer edges of the main planes. Out in front at the end of a long framework or fuselage are the horizontal elevating planes, and the vertical direction planes. Both these machines have double control systems.

Dissatisfied with the work of his first Voisin biplane in the early days of flying Henri Farman designed and built a machine that bore his own name, of which the military type is now looked upon with great favour by many of the European experts.

The two main supporting planes in the regular Farman models were 33 feet by 6-1/2 feet, set 7 feet apart, and with a total area of 430 square feet. These dimensions have been varied slightly in other machines. The elevating rudder, which was set well out in front of the body of the machine, was a horizontal plane controlled by a wire and lever. In the rear was a tail of two parallel surfaces, slightly curved like the main planes of the biplanes. These two surfaces steadied the machine from front to rear. At their two sides were two vertical surfaces, giving the tail the appearance of a box kite, so familiar in the Voisin. These two vertical surfaces, however, comprised the direction rudder, and were turned from side to side by the operator with a foot lever. In some of the later Farman biplanes the two vertical surfaces were done away with in favour of a single one, extending between the centres of the two horizontal surfaces of the tail. The side-to-side balance was maintained by ailerons in the form of wing tips set at the outer rear edges of the main planes. The tips were hinged and connected with wires which led to the lever that worked the elevating rudder. Thus by pulling this lever toward him the operator tilted the rudder up, and the machine rose, and by moving it from side to side the biplane was kept on an even keel. For instance, if the machine were to tip to the right he would move the lever to the left, pulling down the hinged ailerons on the right. The ones on the left would still remain standing straight out at the same angle as the main planes. The increase in the lifting power on the right side would cause that end to rise, righting the machine.

Most Farman biplanes these days are driven by the well known 7-cylinder Gnome rotary air-cooled engines, set at the rear of the main plane. They are directly connected with the single propeller, which is 8-1/2 feet in diameter. The seat for the aviator is in front of the engine at the front edge of the lower plane, and there also frequently are placed seats for two other passengers. The machine is mounted on wheels and skids. The "Farman Militaire" type is one of the largest and heaviest machines made to date, having a total area of supporting plane of 540 square feet. The chief difference is that instead of two direction rudders there are three, and that the lower main plane is set at a dihedral angle. It was on such a machine ("Type Michelin") that Farman flew steadily for eight and a half hours. It also has made remarkable distance, endurance, and weight-carrying records, although it is a slow machine, making but 34 to 35 miles an hour. The "Type Michelin" is distinguished by the fact that the upper main plane has a spread of 49 feet, 3 inches, while the lower plane had a spread of only 36 feet.

Soon after Henri Farman had become famous as an aviator and constructor of aeroplanes, his brother Maurice began to build air craft. The Maurice Farman biplane was the result. After conducting their business separately for several years the brothers consolidated, and each type is known by the name of the brother designing it. The Maurice Farman biplane has some remarkable records, among them the winning of the Michelin prize in 1910 by Tabuteau, who flew 362-1/2 miles in seven and a half hours without stopping.

The main planes have a spread of 36 feet and a depth of 7-1/2 feet. They have not as great a curve or camber as most biplanes, which increases their speed. The tail is of the well-known Farman cell formation—that is, it has four sides. The two vertical surfaces swing on pivots and are controlled by wires connecting with the direction steering wheel. The horizontal surfaces of the tail, except for the tips, are stationary, and steady the machine from front to rear. The rear tips of these two surfaces, however, work on pivots in connection with the main elevating plane which is set out in front. The elevator is a single plane controlled by a rod connected with the steering wheel, while the tips of the horizontal tail surfaces are controlled in unison with the main elevator by wires, also connected with the steering wheel. Ailerons are set into the rear outer tips of the main planes, for the control of the side-to-side balance, and these are worked by foot pedals. In order to give greater safety in case of the breakage of a wire, all the controlling parts in the Maurice Farman machine are duplicate, which is a big step toward the much-desired double controlling system in aeroplanes. The biplane is mounted on both skids and wheels. The operator sits well forward on the lower plane in a comfortable little pit enclosed in canvas. Thus, the Maurice Farman machine was the first to adopt this device for shielding the pilot from the wind. The engine used usually is an 8-cylinder air-cooled Renault, which drives a propeller nearly 10 feet in diameter.

Only slightly known in the United States but well and favourably known in Europe, particularly in France, is the Breguet biplane, which made wonderful records in the French Army tests in 1911. A brief description will show the difference between this machine and others of the biplane type. It has won many prizes for its stability and lifting powers, and also has shown great speed. The framework is mostly metal and is so elastic that it gives under the pulsations for the wind, so that the machine is not so badly strained by gusts as the more rigid kinds. Also it is thought the elasticity increases its lifting capacity. Of the two main planes the upper one spreads 43-1/2 feet, while the lower one spreads 32-1/2 feet. They are 5-1/2 feet deep, and set 7 feet apart. The body and tail of the machine are made on delicate graceful lines, terminating in the elevation and direction rudders at the rear. There are no rudders, vanes, or other rigging out in front. The lateral balance is maintained by warping the planes. The propeller is at the front of the machine, and is of the tractor type, pulling it through the air instead of pushing it. In the latest machines a metallic three-bladed Breguet propeller, the pitch of which is self-adjusting, is used, but in others a two-bladed wooden propeller, such as is familiar in this country. The long body, or fuselage, as the framework of the tail is called, is enclosed on the latest types of Breguets in use by the French Army, greatly adding to its gracefulness, and decreasing the wind pressure.

There are several other makes of biplanes that could be described to advantage but space prevents it, and the descriptions here given serve to illustrate the principle of the biplane type of aeroplane.

The first and probably best known monoplane, the BlÉriot, still holds many records for both speed and endurance. The BlÉriot machines have so many variations that it would be impossible to describe all the types of monoplanes this versatile Frenchman has turned out. We are familiar in a general way with the BlÉriot, the single widespreading main plane, set at a slight dihedral angle, with its long, graceful body out behind terminating in the horizontal elevating and vertical direction rudders, giving it the appearance of a great soaring bird as it sails through the air as steadily as an automobile on a smooth road—much more steadily in fact, for as soon as the wheels of an aeroplane leave the ground all jolting disappears, and not even the vibration of the engine is noticeable, although the roar of its explosions can be heard a great distance. There is nothing but the breeze and the earth streaming along behind you, as if it were moving and you were hovering motionless high up in the sky. In the famous BlÉriot XI, in which the designer made the first trip across the English Channel, the main plane had a spread of a little more than 28 feet and a depth of 6-1/2 feet, a total area of 151 square feet and a low aspect ratio of about 4.6. At the end of the stout wooden framework, that made up the body and tail, was the vertical direction rudder 4-1/2 square feet in area which was turned from right to left by a foot lever. The elevation rudder was divided into two halves, one part being put at each side of the direction rudder. The total area of the elevator was 16 square feet, while the horizontal stabilizing plane to which the elevator was attached was about the same. The balance was maintained by warping the main plane, but instead of warping the tips of the plane, as is done in the Wright biplanes, the two sides of the main plane were warped from the base, so that the operator could change the angle of incidence—that is, the angle at which the planes travel through the air. Thus, if the machine should tip down on the right side, the operator would warp the planes so as to increase the angle of incidence on the right side and lessen it on the left side. In other words, the rear part of the right wing would be bent downward, while on the left side the rear edge would be raised. The forward edge remains stationary. The increase of the angle on the right side would cause an increase of the lifting power on that side and also the decrease of the angle on the left side would lessen the lifting power of the left wing so the right side, which was tipping down, would be lifted, and the machine restored to an even keel. This warping was done by moving from side to side the same lever on which was mounted the steering wheel. The whole machine was mounted on a strong chassis with wheels for starting and alighting. The pilot sat in the framework above the main plane. The monoplane was propelled by a single propeller of the tractor type 6 to 7 feet in diameter, placed at the front of the machine. It was driven in the early BlÉriots by a 23-horsepower Anzani motor, but more lately the BlÉriot machines have carried Gnome motors.

One of the important improvements which appeared on the No. XI bis was the changing of the main plane so that the upper side was curved but the under side was nearly flat. This gave the machine much more speed and the designers found that the flattening out of the curve on the under side did not greatly lessen the lifting power. This same type of machine also was made later to carry three passengers. The machine known as the "Type Militaire" was just about like the others except that the tail instead of being rectangular was fan-shaped. It carried seats for two and was equipped with all the latest aviation accoutrements, such as tachometers, barographs to record altitude, instrument to record inclination, various other gauges, map cases and thermos bottles. The most distinctive feature of the BlÉriot No. XII, which was the first aeroplane to carry three passengers, was the long vertical keel, shaped like the fin of a fish at the top of the framework. The direction rudder was at the rear of this keel, while the elevation rudder was at the rear and a little below it. Immediately below the direction rudder was a small horizontal plane about the size of the elevation rudder which helped to maintain a fore and aft stability.

Then there was the famous BlÉriot aerobus which would carry 8 to 10 people. The machine was very large, the wings having a spread of 39 feet and a total area of 430 square feet. It was driven by a 100-horsepower Gnome motor and a propeller 10 feet in diameter, which was placed at the rear of the main plane. Thus the propeller drove the machine through the air from the rear instead of pulling it from the front as do the tractor propellers on most of the BlÉriot monoplanes. The passengers were seated underneath the main plane on the framework which extended out to the rear. The tail terminated in the vertical direction rudder and a large stationary horizontal surface which gave the necessary front-to-rear stability. The elevating plane of this type was placed out in front.

THE FLYING BOAT STARTING

The latest aeroplane is here seen cutting through the water preparatory to ascending into the air.