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HISTORY OF TECHNOLOGY, TECHNOLOGY, OBJECTS AROUND US
Airplane. History of invention and production
Directory / The history of technology, technology, objects around us The idea of aviation is one of the most ancient in the history of mankind. In myths, legends, historical chronicles, one can find evidence of the many attempts made in different centuries by a person to fulfill his old dream to take to the air and fly like a bird. But all these were amateurish undertakings, in which one could see more enthusiasm than calculation, and therefore they invariably ended in failure. It wasn't until the last quarter of the XNUMXth century that the first evidence appeared that heavier-than-air flight might someday become a reality. Why did this art remain an unattainable dream for a person for so long? The fact is that, unlike a balloon, an airplane does not float through the air, but relies on it during flight, obeying complex aerodynamic laws. The correct explanation of the phenomenon of flight was given already in the 1738th-XNUMXth centuries, but the science of the art of flying - aerodynamics - arose only in the first decades of the XNUMXth century. Why do birds, although they are heavier than air, not fall to the ground? The fact is that in the air, the so-called lift force acts on the lower surface of their wings, which exceeds the force of gravity acting in the opposite direction. Where does this force come from, the famous mathematician and physicist Bernoulli explained back in the first half of the XNUMXth century. In XNUMX, in his major work Hydrodynamics, he deduced the law that now bears his name.
The essence of Bernoulli's law (formulated by him for liquids, but also valid for gases) is that with an increase in the flow rate, its pressure on the walls of the vessel decreases. The action of Bernoulli's law is very easy to observe in experience. Let's take, for example, a piece of paper and blow on it - the far edge of the sheet will immediately rise up, as if something is pushing it from below. This "something" is the already mentioned lifting force. It arose due to the fact that the air above the surface of the sheet moves much faster than what is under it. Consequently, the pressure on the sheet from above is noticeably less than the atmospheric pressure that presses on it from below. If the lifting force is greater than the force of gravity, the leaf rises. However, the situation of our experience is not so easy to replicate in a real setting. In order to raise the edge of the sheet, we intentionally blown it in the way that was convenient for us. And how to make some winged apparatus that is in a real air flow rise up? Obviously, the wing of this apparatus should not be flat, like a sheet, but should be shaped so that the speed of flow around it from above and below is not the same - from below it is slower than from above. Then the pressure on the surface of the wing from above will be less than from below. The lift force can be adjusted by changing the angle of attack of the wing (this is the name of the angle between the plane of the wing and the air flow). The greater the angle of attack, the greater the lift. But taking off is not enough - you must be able to keep the airplane in the air. After all, the lifting force is maintained only as long as the bearing surface of the wing is correctly oriented relative to the air flow. Orientation will be violated - the lifting force will disappear, and the airplane will crash to the ground, as if falling into a hole. Stability is a major issue for any heavier-than-air flying machine. If it does not have a mechanism that provides stability, then it turns into a toy of the insidious wind. Dangers lie in wait for such a car at every turn. Any gust of wind or incorrect pilot maneuver can cause the airplane to roll over on its side or nose, roll over and fall. Fortunately, the first aviators had a vague but true idea of the dangers that awaited them and were able to prepare themselves to some extent for them. The first step into the sky was made with the help of models. The direct predecessors of all modern airplanes should probably be considered Peno's toy airplanes, which he built from 1871 and launched with the help of rubber motors. Weighing a few grams, they flew for several tens of seconds. These models, one might say, were the first visible evidence that vehicles heavier than air were capable of flying at all. In 1872, Peno came to the extremely important conclusion that for the stable flight of an airplane, it needs a tail. Soon he managed to give his devices good stability with respect to all three axes.
However, this was only the beginning. Thirty years passed before it was possible to create an aircraft capable of lifting a person into the sky. At the end of the 1894th century, several attempts were made in different countries to build large airplanes with powerful engines. In 31, the famous inventor Hiram Maxim tried to lift a huge plane with a wingspan) of 5 m and weighing about 3 tons into the air. But on the first try, the car crashed. Maxim, having spent £5 on his experience, never returned to aircraft construction. The famous American astronomer Samuel Langley, having received $20 from the US government, built several large aircraft in the early 50s, which invariably crashed every time they tried to take to the air. In France, the engineer Clement Ader was engaged in similar experiments with the same success in the late 1900s. Having spent about 90 thousand francs on his devices, the French government refused the inventor further subsidies. In general, the path chosen by Maxim, Langley, Ader, and some other inventors turned out to be a dead end. The development of aviation took a different path, which was indicated by the German inventor Otto Lilienthal. While others devoted all their attention to "motor flight", Lilienthal set himself another goal - to comprehend, first of all, the secret of non-motorized soaring flight. Instead of expensive machines, he built light gliders and worked hard to improve them. It seems that the idea of a glider is the first thing that aviators should have thought of, but in reality it was different. Until the XNUMXth century, inventors imitated the rowing flight of a bird in their attempts to get off the ground. Because of this persistent effort to follow nature, man mastered gliding flight relatively late. Meanwhile, the technical capabilities for the implementation of such a flight were already in antiquity. The common misconception was that for flight, in addition to the wings, they also assumed the presence of some kind of mechanical force. It was on this point that all the efforts of the inventors were concentrated. For the first time, instant photography attracted attention to soaring flight. The well-known German photographer Ottomar Anschütz, mentioned in one of the previous chapters, took a series of photographs of the flight of a stork. They say that these pictures fell into the eyes of Otto Lilienthal in 1890 and pushed him to the idea of building a glider. Indeed, Anschütz's photographs undeniably testified that such a flight is possible in the air, in which the work necessary for the movement and lifting of the aircraft is carried out not by itself, but by air. Several photographs depicted storks soaring, which were lifted up by a gust of wind. Lilienthal's first glider consisted of a willow, fabric-covered frame, forming rounded, concave bird-like wings in two tiers with a small tail at the back. The entire apparatus weighed only 20 kg. Lilienthal hung up to him, passing his hands through two straps attached under the wings, and ran down the hill towards the wind. At first, he kept his wings inclined with the leading edge down, and then exposed their lower surface to the wind and, raising his wings, glided along the ascending stream. Balance was maintained by balancing the body forward, backward and sideways. Initially, the flights were very short - 15 meters and were made from a small sandy hill. Then they became longer and took place from a hill 30 m high.
From 1891 to 1896, Lilienthal made over 2000 successful gliding flights. In the end, he could fly over 100 m while in the air for up to 30 seconds. Thus, Lilienthal was the first to prove the possibility of gliding flight and the first to correctly approach the study of the aerodynamic forces acting on the wing. Lilienthal's experiments attracted attention in many countries. Soon he had followers. But in August 1896, during one of his flights, picked up by a sharp gust of wind, Lilienthal fell from a height of 15 m and broke his spine. On the same day he died. In the future, the experiments of the American Octave Chanyuta had a great influence on the development of aircraft. His first gliders were modeled after Lilienthal's gliders. Then Chanute began to make various changes to them and eventually created a biplane with an even wing. He also paid great attention to the design of the tail unit, placing movable elevators and rudders there. This glider became a landmark design in the history of aviation. Simple, rational, light, but at the same time durable, it was the best aircraft of its time. Its most striking feature - the design of the wing with horizontal outlines - later became generally accepted. Chanute was the first to stop slavishly imitating the shape of a bird's wing. However, the alignment of the glider remained the same as that of Lilienthal - the pilot hung from below on the belts and, balancing with his body, maintained the stability of the apparatus. However, Chanute remained a rare guest in the sky. The duration of its flights was calculated in seconds, and the range - tens of meters.
The art of flying in the true sense of the word was first mastered by the brothers Wilber and Orville Wright, owners of a bicycle workshop in the small American town of Dayton. They began their experiments at a time when a dull period of calm was established in aviation: the flying machines of Ader and Maxim, which cost a lot of money, did not fly, the brave glider pilot Lilienthal crashed. The immediate goal set by the Wrights was to achieve a stable and controlled flight. In 1899, they made their first (and, as it turned out, most remarkable) discovery - they found that in order to ensure the lateral stability of an airplane, it is necessary to warp the ends of its wings. The thought came to Wilber Wright. One day, while bending a cardboard box, he suddenly thought that in the same way it is possible to bend the ends of the wings of an airplane - one up, the other down - and thereby save it from falling to the side. After that, Wright began to think over the structure of his first glider and chose the scheme created by Chanute - a biplane with two supporting surfaces located one below the other. The brothers built their first glider in 1900. He accurately reproduced Chanute's devices and only greatly surpassed them in size. But there were also some differences. The Wrights abandoned the tail, which they said "was more of a nuisance than a help." They also abandoned the regulation of stability by moving the center of gravity and provided their apparatus with real rudders. Ahead of the airframe, they placed a horizontal surface - the so-called "elevator". By tilting this surface up and down, it was possible to equalize all oscillations of the apparatus in the direction of flight (longitudinal stability). Lateral stability was provided by warping the wings. It was the first glider in history that confidently obeyed the helm. He perfectly passed the test - not only easily soared into the air, but also lifted a person. The pilot was not hung here on belts from the bottom of the apparatus, as was the case with other designers before, but lay like on a skid. In 1901, Wright built a second glider similar to the first, but larger. Testing these devices, they were convinced that they lacked theoretical knowledge of aerodynamics. However, at that time this science was in its infancy. After collecting all the books on the description of the flight of bodies that they could get, the Wrights were convinced that they could not fly far with such luggage. They decided to compile the missing tables on their own. Measurement of the resistance forces of bodies moving in air can be done in two ways: either move the body at a certain speed through calm air, or blow around a stationary body, directing air at a certain speed at it. Langley and Maxim carried out their experiments exclusively in the first way, rotating objects or models by hand through the air. With this method, it was very difficult to measure at what angle the rotated plane or model was at one time or another. In addition, the test results were distorted by the influence of centrifugal force. Not surprisingly, they were inconsistent and inaccurate. Wright chose the second way. In the same year, they built a "wind tunnel" - a wind tunnel into which air was forced by a fan. For its time, this was a remarkable invention that immediately gave them a huge advantage over other designers and quickly advanced them to the goal. In their pipe, the brothers tested more than 200 models of various profile shapes. They were made of sheet iron so that they could be bent in various ways. Such a systematic measurement of the resistance values of various surfaces and wing profiles at various angles of attack in a wind tunnel had never before been made before the Wright brothers. It is not surprising that the results of these stubborn systematic experiments were decisive for their further success. The main result of all these experiments was the determination of the so-called center of pressure, that is, the resultant of all pressure forces on the wing at different angles of attack. The value of the position of the resultant, or center of pressure, is absolutely necessary in the design of airplanes and in calculating their stability. Another important result was the determination of the wing lift and drag force at different speeds. The brothers systematized the results of their research in special tables, which then served as a pocket guide for them. After that, already taking into account aerodynamic surveys, they set about designing a new airframe. The third glider of 1902, unlike the first two, had a vertical tail. The pilot lay down here in a special cradle between the cut of the lower plane and, rising on his elbows, controlled the front elevator with his hands, and by moving his body sideways, beveled the ends of the wings with wire ropes. Launching the glider, two people ran with him from a high mountain against the wind. The tail was arranged due to the fact that the two previous gliders had a tendency to rotate around a horizontal axis and could roll over during the warping of the wings. Wright realized that it was impossible to achieve good controllability of the glider by only warping the wings. At first, the vertical rudder was fixed, but then, when it was discovered that the glider ceased to obey the rudder when tilted sideways, Orville Wright suggested making the vertical rudder movable. Then, by turning it towards the opposite wing, it was possible to restore the transverse balance. Thus, the difference in the resistance of the lowered and raised wings was to be compensated. Wilber agreed with his brother and supplemented his idea with a significant improvement: since the vertical rudder must be turned at the moment when the ends of the wings warp, it is better to connect the rudder and wings with wire ropes in order to act on them simultaneously. After that, the movement of one lever became possible to control the lateral stability. Thus, for the first time in the history of aviation, the Wright brothers used a movable vertical rudder. This was their second remarkable discovery on the way to mastering the air element. When Wright needed to make a left turn, he turned the swing arm; at the same time, by means of wire rods, the trailing edges of the right wing (that is, outside the turn) were lowered. Thus, the right wing, bent somewhat steeper and raking in more air, was directed upward. At the same time, the left wing inside the turn went down. As a result, the airplane as a whole banked inside the curve. The right steering lever a, which served to turn, had a double movement. Directing it forward (pushing it away), the pilot acted on the two-arm lever K in such a way that the steering rods shifted the steering wheel to the left. Pulling this steering lever back (toward yourself) caused the steering wheel to shift to the right. On the other hand, the deviation of the lever a to the left imparted the same movement to the rod C, warping the wings by means of the thrust e: right - down, left - up. Warping of the bearing surfaces by tilting the lever to the right and left could be done both independently of the warping of the rudder (by moving the lever back and forth), and together with it.
The warping of the bearing surfaces also contributed to the preservation of lateral stability during gusts of wind. When a gust of wind tilted the airplane to one side, the pilot immediately picked up the steeper descended wing, simultaneously reducing the meeting angle (the angle of the bearing surface to the direction of movement; the larger it is, the greater the resistance, and hence the lift) in the raised wing. Thus, the airplane corrected the roll, fending off a gust of wind. For such counteraction to the wind, only the movement of the lever a to the right or left was required. Such a transformation of the wings from a plane to a helical surface had, however, an undesirable consequence - the entire airframe turned somewhat around its axis, just as a propeller begins to rotate during translational motion. In order to equalize this unwanted rotation, front vertical crescent surfaces v and w were used, fixed between the surfaces of the elevator, which rotated in the direction opposite to the movement of the rotary rudder. The second steering lever controlled the flight altitude. When pressed forward, the control surfaces became flatter, and the glider lowered its nose down. Testing the airframe with the newly installed vertical rudder immediately gave good results. The glider obeyed the helm well and soared in the air sometimes for a whole minute. At that time, no one in the world could boast of such excellent results. We can say that even then the glider of the Wright brothers was the most advanced aircraft on Earth. It already possessed all the distinguishing features of an airplane: it had two aerodynamically correctly calculated wings, a horizontal elevator in front and a vertical rudder in the rear, warping of the ends of the wings for lateral stability (ailerons). The glider was quite manageable - it went up and down, turned right and left without losing stability. In order to become an airplane, the glider lacked only one thing - a motor with a propeller. Wright began to create it in early 1903. They calculated that they needed a very light and small gasoline engine with at least 8 hp to fly. Despite their best efforts, they were unable to purchase a finished engine. Then they decided to make it themselves and sat down for the calculations. Soon a project for a four-cylinder engine weighing about 90 kg with water cooling and electric ignition was ready. The aluminum case was made in a local forge. All other parts were made by the brothers themselves in their workshop. Despite the fact that this work was completely new to them, the engine started working immediately after assembly, and the brothers saw this as a guarantee of future success. Another problem was the manufacture of the propellers. Of course, there were no theoretical calculations for the propeller then. After much experimentation and heated debate, Wright made two wooden propellers from pieces of Canadian pine. Each had two blades and was mounted on an iron axle. They rotated towards each other and were placed behind (and not in front, as was customary later) each wing. The transmission was carried out with the help of chains. With the engine, propellers, and transmission ready, Wright set about building the airplane itself. Its design was exactly the same as that of the glider of 1902, but it was made more durable. The pilot, as before, was in a supine position. The first airplane was tested on the ocean at Kitty Hawk (where the brothers tested all their gliders). Here, on December 14, 1903, Wilber Wright made the first motorized flight - it lasted 3 seconds. Having flown 5 m, the airplane crashed. After several attempts on December 32, Wilber made a longer flight: the airplane was in the air for 17 seconds and flew 59 m. Due to strong winds, further flights this year had to be stopped. The brothers returned to Dayton very pleased with the results they had achieved. At first glance, the flight, which lasted only 260 seconds, may seem like an insignificant achievement, but for that time it was a huge victory. Before the Wright brothers, not a single device heavier than air could not only fly a hundred or two meters, but simply rise into the air. Wright immediately began to build a second airplane, which was completed in April 1904, and made a new 16 hp engine for it. Airplane tests were carried out right in Dayton, using a large pasture as an airfield. To rise into the air, they came up with a special device, which was a tower, to the top of which a load weighing about half a ton was hung. The cargo was connected to the aircraft with the help of cables and, during its fall, created a force that accelerated the takeoff. The brothers learned to fly with extreme caution. As at first, mastering the glider, they did a lot of takeoffs and landings. At the slightest suspicion of danger, they put the car on the field. Flights for a long time passed in a circle at a low altitude (about 3 m). Gradually, the duration of the flight increased. In November, an airplane could already stay in the air for about 5 minutes and fly up to 5 km. In the winter of 1905, a third airplane with a 20-horsepower engine was built. In the fall, having mastered all the secrets of control, Wright began long flights. On October 5, the airplane was in the air until it ran out of gasoline - 38 minutes, and during this time it flew in a circle of 39 km. However, these records have not received any recognition in the United States and have remained almost unknown. Moreover, all attempts by inventors to interest the government in their airplane were unsuccessful. This is explained, however, very simply - the attention of all journalists and officials at that time was drawn to Langley's experiments. After Langley suffered a complete failure, the creation of an airplane seemed like an impossible dream. Reports that two self-taught mechanics assembled an aircraft from improvised means capable of staying in the air for tens of minutes seemed complete nonsense. The issuance of a patent also dragged on for several years. Only in the spring of 1906, after long delays, the patent was finally received. Meanwhile, the construction of airplanes turned out to be an unbearable burden for the Wright workshop. In 1905, they were forced to stop their flights due to financial difficulties. For three years no one remembered their invention. Only in 1907 did the hype raised in France by rumors of their success finally draw the attention of local officials to them. In the same year, they received an order for an aircraft from the US War Department, which paid them $100 for it. The 1908 airplane already had two seats for a pilot and a passenger. In this regard, the control levers were redone. In the same year, the new airplane was demonstrated in France and made a splash in Europe. Wilber Wright jokingly broke all the records that French pilots and designers had managed to set by this time. On October 21, he set an absolute record, staying in the air for 1 hours, and on December 5 he broke it with a result of 31 hours and 2 minutes. This was the time of Wright's triumph. Each of their flights attracted thousands of spectators. With bated breath, people were ready for hours to follow the airplane, which described one regular circle after another over the field. The most famous people wanted to meet the brothers. Orders for airplanes rained down on them from all sides. The Wright Aircraft Company was founded in New York with a capital of $20 million. Wilber Wright was elected its chairman. The first airplane factory was built in Dayton.
But the influence of Wright's design ideas on the European continent was not as significant as one might initially expect. Although the "rights" received some distribution at first, the scheme of their device was soon recognized as insufficiently perfect. It took great skill to manage them. Due to the lack of a tail, these airplanes had a dangerous tendency to nod off. Several disasters in 1909 on the "rights" clearly demonstrated this. The reason for them was obvious - Wright's planes did not have the very "Fenot tail" that French aircraft designers always supplied their cars with. The role of this tail was played in Wright's airplane by the front elevator, controlled by hand. Therefore, the slightest delay in the operation of this steering wheel or a malfunction in the steering wheel itself and the drives to it always threatened with a loss of balance and a catastrophe, while the “Peno tail” acted automatically in these cases. By the time the Wrights arrived in France, an established aviation school already existed here - several dozen aircraft were built and several high-profile records were set. True, these machines could not really fly yet and rather made long jumps. In order to become perfect aircraft, European airplanes lacked two things - a device for warping the wings and a propeller that was perfect in shape. The greatest success was achieved by the French designer Voisin. The Farman-1907 airplane, built by him in 1 by order of the racing driver Farman, was considered the best before the appearance of the Wright brothers. On this plane, Farman set a flight distance record in the same year - 771 m and for the first time managed to fly in a circle. Farman's biplane, unlike the Wright brothers' airplane, had tail surfaces for longitudinal stability according to the Peno system. The tail greatly facilitated the control of the aircraft. In addition, Farman's aircraft was equipped with a landing gear, with the help of which he took off into the wind. After the French borrowed the wing warping system and propeller shape from Wright, their aircraft began to surpass their overseas counterparts in all respects. This became evident already at the international competitions of 1909. In general, this year was the year of the general triumph of airplanes. The outstanding French aviator Blériot flew across the English Channel in his Blériot-11 airplane. At the same time, Farman created his wonderful airplane "Farman-3" - durable, stable, obedient in control. This aircraft became the main training machine of that time - thousands of pilots from many countries took a course on it - and one of the first airplanes that began to be mass-produced. Author: Ryzhov K.V.
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