Aircraft interacting with the atmosphere fall into two broad categories: lighter than air and heavier than air. This division is based on different principles of flight. In the first case, to create a lifting force, they use the law of Archimedes, that is, they use the aerostatic principle. In vehicles that are heavier than air, the lifting force arises due to aerodynamic interaction with the atmosphere. We'll look at the first category, lighter-than-air aircraft.
Ascent in the ocean of air
A device that uses Archimedean - buoyant - force to lift, is called a balloon. This is an aircraft equipped with a shell filled with hot air or a gas that has a lower density than the surrounding atmosphere.
The difference in the density of the gas inside and outside the shell causes a pressure difference, due to which there is an aerostatic buoyancy force. This is an example of Archimedes' principle in action.
The lifting ceiling of lighter-than-air aircraft is determined by the volume and elasticity of the shell, the way it is filled andatmospheric factors - primarily a drop in air density with height. The record for a manned ascent to date is 41.4 km, unmanned - 53 km.
General classification
Aerostat is the common name for an entire class of aircraft. First of all, all balloons are divided into uncontrolled (balloons) and controlled (airships). There are also tethered balloons used in various areas for certain special tasks.
1. Balloons. The principle of balloon flight does not imply the possibility of controlling an aircraft in a horizontal plane. The balloon does not have an engine and rudders, therefore, its pilot cannot choose the speed and direction of his flight. On the ball, height regulation is possible with the help of valves and ballast, but otherwise its flight is a drift along air currents. According to the type of filler, there are three types of balloons:
- Hot air balloons.
- Charliers with gas filling. Most often, hydrogen and helium were used (and continue to be used) for these purposes, but both of them have their own drawbacks. Hydrogen is extremely flammable and forms an explosive mixture with air. Helium is too expensive.
- Rosieres are balloons that combine both types of fillings.
2. Airships (French dirigeable - "controlled") are aircraft, the design of which includes a power plant and controls. In turn, airships are classified according to many criteria: by rigidityshells, by the type of power unit and propulsion, by the method of creating a buoyancy force, and so on.
Early history of aeronautics
The very first reliable device that took to the air with the help of Archimedean force should probably be considered a Chinese lantern. The annals mention paper bags rising under the influence of hot air from the lamp. It is known that such lanterns were used in military affairs as a means of signaling as early as the 2nd-3rd centuries; it is possible that they were known before.
Western technical thought came to the idea of the possibility of such devices by the end of the 17th century, realizing the futility of attempts to create muscular flywheel devices for human flight. Thus, the Jesuit Francesco Lana designed an aircraft lifted with the help of evacuated metal balls. However, the technical level of the era in no way allowed this project to be carried out.
In 1709, the priest Lorenzo Guzmao demonstrated to the Portuguese royal court an aircraft, which was a thin shell, the air in which was heated by a brazier suspended from below. The device managed to rise several meters. Unfortunately, nothing is known about Guzmao's further activities.
Beginning of aeronautics
The first aircraft lighter than air, the successful test of which was officially recorded, was the balloon brothers Joseph-Michel and Jacques-Etienne Montgolfier. On June 5, 1783, this balloon flew over the French town of Annone, overcoming2 km in 10 minutes. The maximum lifting height was about 500 meters. The shell of the ball was canvas, pasted over with paper from the inside; as a filler, smoke from the burning of wet wool and straw was used, for a long time after that it was called "hot air balloon gas". The aircraft, respectively, was named "hot air balloon".
Almost simultaneously, on August 27, 1783, a balloon filled with hydrogen, designed by Jacques Charles, soared into the air in Paris. The shell was made of silk impregnated with a solution of rubber in turpentine. Hydrogen was obtained by exposing iron filings to sulfuric acid. A ball with a diameter of 4 meters was filled for several days, having spent more than 200 kilograms of acid and almost half a ton of iron. The first charlier disappeared into the clouds in front of 300,000 spectators. The shell of the balloon, which exploded high in the atmosphere, fell 15 minutes later in the countryside near Paris, where it was destroyed by frightened locals.
First manned flights
The first passengers of the aeronautical apparatus that took off on September 19, 1783 in Versailles were, most likely, nameless. A rooster, a duck and a ram flew in a hot air balloon basket for 10 minutes and a range of 4 km, after which they landed safely.
The flight of people on a hot air balloon for the first time took place on November 21 of the same breakthrough year of 1783. It was made by the physicist Jean-Francois Pilatre de Rozier and two of his comrades. Then, in November, de Rozier consolidated his success with the ballooning enthusiast Marquis François. Laurent d'Arland. Thus, it was proved that the state of free flight is safe for humans (doubts still existed).
December 1, 1983 (a truly significant year for aeronautics!) Charliere also took off, carrying on board the crew, which, in addition to J. Charles himself, included mechanic N. Robert.
In subsequent years, balloon flights of both types were practiced very widely, but gas balloons still had some advantage, since hot air balloons consumed a lot of fuel and developed little lift. Rosiers, on the other hand, are balls of a combined type, which turned out to be too dangerous.
A balloon in service
Balloons very soon began to serve not only entertainment purposes, but also the needs of science and military affairs. Even during the first flight, Charles and Robert were engaged in measuring air temperature and pressure at high altitude. Subsequently, scientific observations were often made from balloons. They were used to study the Earth's atmosphere and geomagnetic field, and later cosmic rays. Balloons are widely used as meteorological probes.
Military balloon service began during the French Revolution, when tethered balloons began to be used to monitor the enemy. Subsequently, such devices were used for high- altitude reconnaissance and fire adjustment not only in the 19th, but also in the first half of the 20th century. During the Great Patriotic War, tethered barrage balloons were an elementAir defense of large cities. During the Cold War era, high- altitude balloons were used by NATO intelligence against the USSR. In addition, long-range communication systems for submarines using tethered balloons have been developed.
Higher and higher
A stratosphere balloon is a balloon of the "charlier" type, capable of rising into the upper rarefied layers of the Earth's atmosphere - the stratosphere, due to the design features. If the flight is manned, such a balloon is filled with helium. In the case of an unmanned flight, it is filled with cheaper hydrogen.
The idea of using a balloon at high altitudes belongs to D. I. Mendeleev and was expressed by him in 1875. The safety of the crew, according to the scientist, was supposed to be provided by a sealed balloon gondola. However, the creation of such an aircraft requires a high technical level, which was achieved only by 1930. Thus, the flight conditions require a special arrangement of a stratospheric balloon, the use of light metals and alloys, the development and implementation of ballast release systems and gondola thermoregulation, and much more.
The first stratospheric balloon FNRS-1 was created by the Swiss scientist and engineer Auguste Picard, who, together with P. Kipfer, first ascended into the stratosphere on May 27, 1931, reaching an altitude of 15,785 m.
The creation of these aircraft was especially developed in the USSR. Many records in flights into the stratosphere were set in the second half of the 1930s by Soviet aeronauts.
In 1985, during the implementation of the Soviet spaceThe Vega project launched two stratospheric balloons filled with helium in the atmosphere of Venus. They worked at an altitude of about 55 km for more than 45 hours.
First airship
Attempts to create a balloon controlled in horizontal flight began to be made almost immediately after the first flights of hot air balloons and charliers. J. Meunier proposed to give the aircraft an ellipsoidal shape, a double shell with a balloonet and equip it with propellers driven by muscle power. However, this idea required the efforts of 80 people…
For many years, due to the lack of a suitable power unit for flight conditions, a controlled balloon remained only a dream. It was possible to carry it out only in 1852 by Henri Giffard, whose car made its first flight on September 24th. Giffard's airship had a rudder and a 3 horsepower steam engine that turned the propeller. The volume of the gas-filled shell was 2500 m3. The soft shell of the airship was subject to collapse with changes in atmospheric pressure and temperature.
For a long time after the flight of the first airship, engineers tried to achieve the optimal combination of engine power and weight, to improve the design of the shell and gondola of the apparatus. In 1884, an electric engine was installed on the airship, and in 1888, a gasoline one. The further success of the airship industry was associated with the development of machines with a rigid shell.
Success and tragedy of the Zeppelins
The breakthrough in the creation of airships is associated with the name of Count Ferdinandvon Zeppelin. The flight of his first machine, built in Germany on Lake Constance, took place on July 2, 1900. Despite a breakdown that resulted in a forced landing on the lake, the design of the rigid airships, after further testing, was considered a success. The design of the machine was improved, and the airship of Ferdinand von Zeppelin was purchased by the German military. In the First World War, zeppelins were already used by all the leading powers.
The rigid shell of the airship consisted of a cigar-shaped metal frame covered with cellon-coated fabric. Gas cylinders filled with hydrogen were attached inside the frame. The aircraft was equipped with stern rudders and stabilizers, had several engines with propellers. Tanks, cargo and engine compartments, passenger decks were located at the bottom of the frame. The volume of the airship could reach 200 m3, the length of the hull was huge. For example, the length of the infamous Hindenburg was 245 m. Driving such a huge machine was extremely difficult.
During the period between the world wars, zeppelins were widely used as a means of transport, including in transatlantic flights. However, a number of disasters, the most famous of which was the collapse of the Hindenburg airship as a result of a fire, and the high cost of these machines did not play in their favor. But the main factor in the curtailment of the airship industry was the upcoming World War II. The nature of the warfare required massive usehigh-speed aviation, and there was no serious place for airships in it. As a result, there was no revival of them as a widely used vehicle after the war.
Balloons and modernity
Despite the development of aviation, airships and balloons did not disappear into oblivion, on the contrary, by the end of the 20th century, interest in them increased again. This is due to advances in the development of high-tech materials and computer control and safety systems, as well as the relative cheapening of helium production. Airships may well be reborn as machines that perform important tasks in some special industries, for example, in the maintenance of oil platforms or in the transportation of bulky cargo in remote areas. The military again began to show some interest in these aircraft.
Miniature airships are also used for various applications, such as filming for television broadcasts.
The public accustomed to airplanes, helicopters and spaceships is again experiencing interest in aeronautics. Balloon festivals in different countries of the world, including Russia, have become a frequent occurrence. Thanks to heat-resistant lightweight materials and special burners powered by gas cylinders, hot air balloons are experiencing a second youth. Solar hot air balloons have also been invented, generally requiring no fuel combustion.
Great interest among athletes and spectators is caused by competitions and enchanting mass starts of many devices held onevery balloon festival. These events have long been an integral part of the entertainment industry.
It is difficult to predict what the future holds for lighter-than-air aircraft. But we can confidently say: they have this future.
