Report: Jet propulsion in nature and technology. Jet propulsion in nature and technology

Multi-ton spaceships soar into the sky, and sea ​​waters Transparent, gelatinous jellyfish, cuttlefish and octopuses deftly maneuver - what do they have in common? It turns out that in both cases the principle of jet propulsion is used to move. This is the topic that our article today is devoted to.

Let's look into history

The most The first reliable information about rockets dates back to the 13th century. They were used by Indians, Chinese, Arabs and Europeans in combat as combat and signal weapons. Then followed centuries of almost complete oblivion of these devices.

In Russia, the idea of ​​using a jet engine was revived thanks to the work of the revolutionary Nikolai Kibalchich. Sitting in the royal dungeons, he developed a Russian project of a jet engine and an aircraft for people. Kibalchich was executed, and his project long years gathering dust in the archives of the Tsarist secret police.

The basic ideas, drawings and calculations of this talented and courageous man were further developed in the works of K. E. Tsiolkovsky, who proposed using them for interplanetary communications. From 1903 to 1914, he published a number of works in which he convincingly proved the possibility of using jet propulsion for space exploration and justified the feasibility of using multi-stage rockets.

Many of Tsiolkovsky’s scientific developments are still used in rocket science to this day.

Biological missiles

How did it even arise? the idea of ​​moving by pushing off your own jet stream? Perhaps, by closely observing marine life, coastal residents noticed how this happens in the animal world.

For example, scallop moves due to the reactive force of a water jet ejected from the shell during rapid compression of its valves. But he will never keep up with the fastest swimmers - squids.

Their rocket-shaped bodies rush tail first, throwing out stored water from a special funnel. move according to the same principle, squeezing out water by contracting their transparent dome.

Nature has endowed a plant called a “jet engine” "squirting cucumber". When its fruits are fully ripe, in response to the slightest touch, it shoots out the gluten with seeds. The fruit itself is thrown in the opposite direction at a distance of up to 12 m!

Neither sea ​​creatures, nor plants know the physical laws underlying this method of movement. We'll try to figure this out.

Physical basis of the principle of jet propulsion

First, let's turn to the simplest experience. Let's inflate a rubber ball and, without stopping, we will let you fly freely. The rapid movement of the ball will continue as long as the stream of air flowing out of it is strong enough.

To explain the results of this experiment we must turn to the Third Law, which states that two bodies interact with forces equal in magnitude and opposite in direction. Consequently, the force with which the ball acts on the jets of air escaping from it is equal to the force with which the air pushes the ball away from itself.

Let's transfer these arguments to a rocket. These devices eject some of their mass at enormous speed, as a result of which they themselves receive an acceleration of opposite direction.

From a physics point of view, this the process is clearly explained by the law of conservation of momentum. Momentum is the product of a body's mass and its speed (mv). While the rocket is at rest, its speed and momentum are zero. If a jet stream is ejected from it, then the remaining part, according to the law of conservation of momentum, must acquire such a speed that the total impulse is still equal to zero.

Let's look at the formulas:

m g v g + m r v r =0;

m g v g =- m r v r,

Where m g v g the impulse created by the jet of gases, m p v p the impulse received by the rocket.

The minus sign indicates that the direction of movement of the rocket and the jet stream are opposite.

The design and principle of operation of a jet engine

In technology, jet engines propel airplanes, rockets, and launch spacecraft into orbit. Depending on their purpose they have different device. But each of them has a supply of fuel, a chamber for its combustion and a nozzle that accelerates the jet stream.

The interplanetary automatic stations are also equipped with an instrument compartment and cabins with a life support system for astronauts.

Modern space rockets These are complex, multi-stage aircraft using the latest advances in engineering. After launch, the fuel in the lower stage first burns, after which it separates from the rocket, reducing its total mass and increasing speed.

Then the fuel is consumed in the second stage, etc. Finally, the aircraft is launched onto a given trajectory and begins its independent flight.

Let's dream a little

The great dreamer and scientist K. E. Tsiolkovsky gave future generations the confidence that jet engines will allow humanity to escape beyond the Earth’s atmosphere and rush into space. His prediction came true. The Moon and even distant comets are successfully explored by spacecraft.

Liquid jet engines are used in astronautics. Using petroleum products as fuel, but the speeds that can be achieved with their help are insufficient for very long flights.

Perhaps you, our dear readers, you will witness the flights of earthlings to other galaxies on devices with nuclear, thermonuclear or ion jet engines.

If this message was useful to you, I would be glad to see you

Jet propulsion in nature and technology - a very common phenomenon. In nature, it occurs when one part of the body separates at a certain speed from some other part. In this case, the reactive force appears without interaction of the given organism with external bodies.

In order to understand what we're talking about, it is best to refer to examples. in nature and technology are numerous. We will first talk about how animals use it, and then how it is used in technology.

Jellyfish, dragonfly larvae, plankton and mollusks

Many people, while swimming in the sea, came across jellyfish. In the Black Sea, in any case, there are plenty of them. However, not everyone realized that jellyfish move using jet propulsion. The same method is used by dragonfly larvae, as well as some representatives of marine plankton. The efficiency of invertebrate marine animals that use it is often much higher than that of technical inventions.

Many mollusks move in a way that interests us. Examples include cuttlefish, squid, and octopus. In particular, the scallop clam is able to move forward using a jet of water that is ejected from the shell when its valves are sharply compressed.

And these are just a few examples from the life of the animal world that can be cited to expand on the topic: “Jet propulsion in everyday life, nature and technology.”

How does a cuttlefish move?

The cuttlefish is also very interesting in this regard. Like many cephalopods, it moves in water using the following mechanism. Through a special funnel located in front of the body, as well as through a side slit, the cuttlefish takes water into its gill cavity. Then she vigorously throws it through the funnel. The cuttlefish directs the funnel tube back or to the side. The movement can be carried out in different directions.

The method that the salpa uses

The method that the salpa uses is also curious. This is the name of a sea animal that has a transparent body. When moving, the salpa draws in water using the front opening. The water ends up in a wide cavity, and gills are located diagonally inside it. The hole closes when the salpa takes a large sip of water. Its transverse and longitudinal muscles contract, compressing the entire body of the animal. Water is pushed out through the rear hole. The animal moves forward due to the reaction of the flowing jet.

Squids - "living torpedoes"

The greatest interest is, perhaps, the jet engine that the squid has. This animal is considered the most major representative invertebrates that live at great ocean depths. In jet navigation, squids have achieved real perfection. Even the body of these animals resembles a rocket in its external shape. Or rather, this rocket copies the squid, since it is the squid that has the undisputed primacy in this matter. If it needs to move slowly, the animal uses a large diamond-shaped fin for this, which bends from time to time. If a quick throw is needed, a jet engine comes to the rescue.

The mollusk's body is surrounded on all sides by a mantle - muscle tissue. Almost half of the total volume of the animal’s body is the volume of its cavity. The squid uses the mantle cavity to move by sucking water inside it. Then he sharply throws out the collected stream of water through a narrow nozzle. As a result of this, it pushes backwards at high speed. At the same time, the squid folds all 10 tentacles into a knot above its head in order to acquire a streamlined shape. The nozzle contains a special valve, and the animal's muscles can turn it. Thus, the direction of movement changes.

Impressive squid speed

It must be said that the squid engine is very economical. The speed it is capable of reaching can reach 60-70 km/h. Some researchers even believe that it can reach up to 150 km/h. As you can see, the squid is not called the “living torpedo” for nothing. It can turn in the desired direction, bending its tentacles folded in a bundle down, up, left or right.

How does a squid control movement?

Since the steering wheel is very large compared to the size of the animal itself, only a slight movement of the steering wheel is sufficient for the squid to easily avoid a collision with an obstacle, even moving at maximum speed. If you turn it sharply, the animal will immediately rush into reverse side. The squid bends the end of the funnel back and, as a result, can slide head first. If he bends it to the right, he will be thrown to the left by the jet thrust. However, when it is necessary to swim quickly, the funnel is always located directly between the tentacles. In this case, the animal rushes tail first, like the running of a fast-moving crayfish if it had the agility of a racer.

When there is no need to rush, cuttlefish and squid swim, undulating with their fins. Miniature waves run across them from front to back. Squid and cuttlefish glide gracefully. They only push themselves from time to time with a stream of water that shoots out from under their mantle. The individual shocks that the mollusk receives during the eruption of jets of water are clearly visible at such moments.

Flying squid

Some cephalopods are capable of accelerating up to 55 km/h. It seems that no one has made direct measurements, but we can give such a figure based on the range and speed of flying squids. It turns out that there are such people. The Stenoteuthis squid is the best pilot of all mollusks. English sailors call it a flying squid (flying squid). This animal, the photo of which is presented above, has no big sizes, about the size of a herring. It chases fish so quickly that it often jumps out of the water, skimming like an arrow over its surface. He also uses this trick when he is in danger from predators - mackerel and tuna. Having developed maximum jet thrust in the water, the squid launches into the air and then flies more than 50 meters above the waves. When it flies, it is so high that frequent flying squids end up on the decks of ships. A height of 4-5 meters is by no means a record for them. Sometimes flying squids fly even higher.

Dr. Rees, a mollusk researcher from Great Britain, in his scientific article described a representative of these animals, whose body length was only 16 cm. However, he was able to fly a fair distance through the air, after which he landed on the bridge of a yacht. And the height of this bridge was almost 7 meters!

There are times when a ship is attacked by many flying squids at once. Trebius Niger, an ancient writer, once told sad story about a ship that seemed unable to withstand the weight of these sea animals and sank. Interestingly, squids are able to take off even without acceleration.

Flying octopuses

Octopuses also have the ability to fly. Jean Verani, a French naturalist, watched one of them speed up in his aquarium and then suddenly jump out of the water. The animal described an arc of about 5 meters in the air and then plopped down into the aquarium. The octopus, gaining the speed necessary for the jump, moved not only thanks to jet thrust. It also paddled with its tentacles. Octopuses are baggy, so they swim worse than squids, but at critical moments these animals can give a head start to the best sprinters. California Aquarium workers wanted to take a photo of an octopus attacking a crab. However, the octopus, rushing at its prey, developed such a speed that the photographs, even when using a special mode, turned out to be blurred. This means that the throw lasted only a fraction of a second!

However, octopuses usually swim quite slowly. Scientist Joseph Seinl, who studied the migrations of octopuses, found that the octopus, whose size is 0.5 m, swims at an average speed of about 15 km/h. Each jet of water that he throws out of the funnel moves him forward (more precisely, backward, since he swims backwards) by about 2-2.5 m.

"Squirting cucumber"

Reactive movement in nature and technology can be considered using examples from the plant world to illustrate it. One of the most famous is the ripened fruits of the so-called They bounce off the stalk at the slightest touch. Then, from the resulting hole, a special sticky liquid containing the seeds is ejected with great force. The cucumber itself flies in the opposite direction at a distance of up to 12 m.

Law of conservation of momentum

You should definitely talk about it when considering jet motion in nature and technology. Knowledge of the law of conservation of momentum allows us to change, in particular, our own speed of movement if we are in open space. For example, you are sitting in a boat and you have several stones with you. If you throw them in a certain direction, the boat will move in the opposite direction. IN outer space This law also applies. However, for this purpose they use

What other examples of jet propulsion can be noted in nature and technology? Very well illustrated with the example of a gun.

As you know, a shot from it is always accompanied by recoil. Let's say the weight of the bullet was equal to the weight of the gun. In this case, they would fly apart at the same speed. Recoil occurs because a reactive force is created, since there is a thrown mass. Thanks to this force, movement is ensured both in airless space and in the air. The greater the speed and mass of the flowing gases, the greater the recoil force that our shoulder feels. Accordingly, the stronger the reaction of the gun, the higher the reaction force.

Dreams of flying into space

Jet propulsion in nature and technology has been a source of new ideas for scientists for many years. For many centuries, humanity has dreamed of flying into space. The use of jet propulsion in nature and technology, it must be assumed, has by no means exhausted itself.

And it all started with a dream. Science fiction writers several centuries ago offered us various means of how to achieve this desired goal. In the 17th century, Cyrano de Bergerac, a French writer, created a story about a flight to the moon. His hero reached the Earth's satellite using an iron cart. He constantly threw a strong magnet over this structure. The cart, being attracted to him, rose higher and higher above the Earth. Eventually she reached the moon. Another famous character, Baron Munchausen, climbed to the moon using a bean stalk.

Of course, at that time little was known about how the use of jet propulsion in nature and technology could make life easier. But the flight of fancy certainly opened up new horizons.

On the way to an outstanding discovery

In China at the end of the 1st millennium AD. e. invented jet propulsion to power rockets. The latter were simply bamboo tubes that were filled with gunpowder. These rockets were launched for fun. The jet engine was used in one of the first automobile designs. This idea belonged to Newton.

N.I. also thought about how jet motion arises in nature and technology. Kibalchich. This is a Russian revolutionary, the author of the first jet project aircraft, which is designed for human flight. The revolutionary, unfortunately, was executed on April 3, 1881. Kibalchich was accused of participating in the assassination attempt on Alexander II. Already in prison, while awaiting execution of the death sentence, he continued to study such an interesting phenomenon as jet motion in nature and technology, which occurs when part of an object is separated. As a result of these researches, he developed his project. Kibalchich wrote that this idea supports him in his position. He is ready to calmly face his death, knowing that he is so important discovery will not die with him.

Implementation of the idea of ​​space flight

The manifestation of jet propulsion in nature and technology continued to be studied by K. E. Tsiolkovsky (his photo is presented above). At the beginning of the 20th century, this great Russian scientist proposed the idea of ​​​​using rockets for space flights. His article on this issue appeared in 1903. It presented a mathematical equation that became the most important for astronautics. It is known in our time as the “Tsiolkovsky formula”. This equation described the motion of a body having variable mass. In his further works, he presented a diagram rocket engine, running on liquid fuel. Tsiolkovsky, studying the use of jet propulsion in nature and technology, developed a multi-stage rocket design. He also came up with the idea of ​​​​the possibility of creating entire space cities in low-Earth orbit. These are the discoveries the scientist came to while studying jet propulsion in nature and technology. Rockets, as Tsiolkovsky showed, are the only devices that can overcome a rocket. He defined it as a mechanism with a jet engine that uses the fuel and oxidizer located on it. This device transforms the chemical energy of the fuel, which becomes kinetic energy gas jet. The rocket itself begins to move in the opposite direction.

Finally, scientists, having studied the reactive movement of bodies in nature and technology, moved on to practice. A large-scale task lay ahead to realize the long-standing dream of humanity. And a group of Soviet scientists, led by Academician S.P. Korolev, coped with it. She realized Tsiolkovsky's idea. First artificial satellite of our planet was launched in the USSR on October 4, 1957. Naturally, a rocket was used.

Yu. A. Gagarin (pictured above) was the man who had the honor of being the first to fly in outer space. This important event for the world took place on April 12, 1961. Gagarin flew around the entire planet on the Vostok satellite. Earth. The USSR was the first state whose rockets reached the Moon, flew around it and photographed the side invisible from Earth. In addition, it was the Russians who visited Venus for the first time. They brought scientific instruments to the surface of this planet. American astronaut Neil Armstrong is the first person to walk on the surface of the Moon. He landed on it on July 20, 1969. In 1986, Vega 1 and Vega 2 (ships belonging to the USSR) explored at close range Halley's Comet, which approaches the Sun only once every 76 years. Space exploration continues...

As you can see, physics is a very important and useful science. Jet propulsion in nature and technology is just one of interesting questions which are discussed in it. And the achievements of this science are very, very significant.

How jet propulsion is used in nature and technology these days

In physics, particularly important discoveries have been made in the last few centuries. While nature remains virtually unchanged, technology is developing at a rapid pace. Nowadays, the principle of jet propulsion is widely used not only by various animals and plants, but also in astronautics and aviation. In outer space there is no medium that a body could use to interact in order to change the magnitude and direction of its speed. That is why only rockets can be used to fly in airless space.

Today, jet propulsion is actively used in everyday life, nature and technology. It is no longer a mystery as it used to be. However, humanity should not stop there. New horizons are ahead. I would like to believe that the jet movement in nature and technology, briefly described in the article, will inspire someone to make new discoveries.

Among the great technical and scientific achievements XX century one of the first places undoubtedly belongs to rockets and jet propulsion theory. The years of the Second World War (1941-1945) led to an unusually rapid improvement in the design of jet vehicles. Powder rockets reappeared on the battlefields, but using higher-calorie smokeless TNT powder (“Katyusha”). Airbreathing aircraft, unmanned aircraft with pulsating airbreathing engines ("FAU-1"), and ballistic missiles with a range of up to 300 km ("FAU-2") were created.

Rocketry is now becoming a very important and rapidly growing industry. The development of the theory of flight of jet vehicles is one of the pressing problems of modern scientific and technological development.

K. E. Tsiolkovsky did a lot for knowledge fundamentals of the theory of rocket propulsion. He was the first in the history of science to formulate and study the problem of studying rectilinear movements missiles, based on the laws theoretical mechanics. As we indicated, the principle of communication of motion, with the help of the reaction forces of thrown particles, was realized by Tsiolkovsky back in 1883, but his creation of a mathematically rigorous theory of jet propulsion dates back to end of the 19th century centuries.

In one of his works, Tsiolkovsky wrote: “For a long time I looked at the rocket, like everyone else: from the point of view of entertainment and small applications. I don’t remember well how it occurred to me to make calculations related to the rocket. It seems to me that the first seeds of thought were planted by the famous dreamer Jules Verne; it awakened my brain's work known direction. Desires appeared, behind the desires the activity of the mind arose. ...An old piece of paper with the final formulas relating to the jet apparatus is marked with the date August 25, 1898.”

"...I have never claimed complete solution question. First inevitably come: thought, fantasy, fairy tale. Behind them comes scientific calculation. And in the end, execution crowns thought. My works about space travel belong to the middle phase of creativity. More than anyone, I understand the abyss that separates an idea from its implementation, since during my life I not only thought and calculated, but also executed, also working with my hands. However, it is impossible not to have an idea: execution is preceded by thought, precise calculation is preceded by fantasy.”

In 1903, Konstantin Eduardovich’s first article on rocket technology appeared in the journal Scientific Review, which was called “Exploration of world spaces using rocket instruments.” In this work, on the basis of the simplest laws of theoretical mechanics (the law of conservation of momentum and the law of independent action of forces), the theory of rocket flight was given and the possibility of using jet vehicles for interplanetary communications was substantiated (Creation general theory the movement of bodies whose mass changes during movement belongs to Professor I.V. Meshchersky (1859-1935)).

The idea of ​​using a rocket to solve scientific problems, the use of jet engines to create the movement of grandiose interplanetary ships belongs entirely to Tsiolkovsky. He is the founder of modern long-range liquid-propellant rockets, one of the creators new chapter theoretical mechanics.

Classical mechanics, which studies the laws of motion and equilibrium of material bodies, is based on three laws of motion, clearly and strictly formulated by an English scientist back in 1687. These laws were used by many researchers to study the motion of bodies whose mass did not change during movement. Very important cases of motion were considered and a great science was created - mechanics of bodies constant mass. The axioms of the mechanics of bodies of constant mass, or Newton's laws of motion, were a generalization of the entire previous development of mechanics. Currently the basic laws mechanical movement are presented in all physics textbooks for high school. We will give here summary Newton's laws of motion, since the next step in science, which made it possible to study the movement of rockets, was further development methods of classical mechanics.

The law of conservation of momentum is of great importance when considering jet motion.
Under jet propulsion understand the movement of a body that occurs when some part of it separates with a certain speed relative to it, for example, when combustion products flow out of the nozzle of a jet aircraft. In this case, the so-called Reactive force pushing the body.
The peculiarity of the reactive force is that it arises as a result of the interaction between parts of the system itself without any interaction with external bodies.
While the force imparting acceleration, for example, to a pedestrian, a ship or an airplane, arises only due to the interaction of these bodies with the ground, water or air.

Thus, the movement of a body can be obtained as a result of the flow of a stream of liquid or gas.

Jet motion in nature inherent mainly in living organisms living in an aquatic environment.

In technology, jet propulsion is used in river transport (water jet engines), in the automotive industry (racing cars), in military affairs, in aviation and astronautics.
All modern high-speed aircraft are equipped with jet engines, because... they are able to provide the required flight speed.
It is impossible to use engines other than jet engines in outer space, since there is no support there from which acceleration could be achieved.

History of the development of jet technology

The creator of the Russian combat missile was artillery scientist K.I. Konstantinov. Weighing 80 kg, the flight range of Konstantinov’s rocket reached 4 km.

The idea of ​​​​using jet propulsion in an aircraft, the project of a jet aeronautical device, was put forward in 1881 by N.I. Kibalchich.

In 1903, the famous physicist K.E. Tsiolkovsky proved the possibility of flight in interplanetary space and developed a design for the first rocket plane with a liquid-propellant engine.

K.E. Tsiolkovsky designed a space rocket train made up of a number of rockets that operate alternately and fall away as fuel is used up.

Principles of jet engines

The basis of any jet engine is the combustion chamber, in which the combustion of fuel produces gases that have a very high temperature and exert pressure on the walls of the chamber. Gases escape from a narrow rocket nozzle at high speed and create jet thrust. In accordance with the law of conservation of momentum, the rocket acquires speed in the opposite direction.

The momentum of the system (rocket-combustion products) remains equal to zero. Since the mass of the rocket decreases, even with a constant gas flow rate, its speed will increase, gradually reaching its maximum value.
The motion of a rocket is an example of the motion of a body with variable mass. To calculate its speed, the law of conservation of momentum is used.

Jet engines are divided into rocket engines and air-breathing engines.

Rocket engines Available with solid or liquid fuel.
In solid fuel rocket engines, the fuel, which contains both fuel and oxidizer, is trapped inside the engine's combustion chamber.
IN liquid jet engines, intended to run spaceships, fuel and oxidizer are stored separately in special tanks and supplied to the combustion chamber using pumps. They can use kerosene, gasoline, alcohol, liquid hydrogen, etc. as fuel, and liquid oxygen, nitric acid, etc. as the oxidizing agent necessary for combustion.

Modern three-stage space rockets are launched vertically, and after passing through the dense layers of the atmosphere they are transferred to flight in a given direction. Each rocket stage has its own fuel tank and oxidizer tank, as well as its own jet engine. As the fuel burns, the spent rocket stages are discarded.

Jet engines currently used mainly in aircraft. Their main difference from rocket engines is that the oxidizer for fuel combustion is oxygen from the air entering the engine from the atmosphere.
Air-breathing engines include turbocompressor engines with both an axial and a centrifugal compressor.
The air in such engines is sucked in and compressed by a compressor driven by a gas turbine. The gases leaving the combustion chamber create a reactive thrust and rotate the turbine rotor.

At very high flight speeds, compression of gases in the combustion chamber can be achieved due to the oncoming oncoming air flow. There is no need for a compressor.

Jet propulsion in nature and technology

ABSTRACT ON PHYSICS

Jet propulsion- movement that occurs when any part of it is separated from the body at a certain speed.

Reactive force occurs without any interaction with external bodies.

Application of jet propulsion in nature

Many of us in our lives have encountered jellyfish while swimming in the sea. In any case, there are quite enough of them in the Black Sea. But few people thought that jellyfish also use jet propulsion to move. In addition, this is how dragonfly larvae and some species of marine plankton move. And often the efficiency of marine invertebrate animals when using jet propulsion is much higher than that of technological inventions.

Jet propulsion is used by many mollusks - octopuses, squids, cuttlefish. For example, a sea scallop mollusk moves forward due to the reactive force of a stream of water thrown out of the shell during a sharp compression of its valves.

Octopus

Cuttlefish

Cuttlefish, like most cephalopods, moves in water in the following way. She takes water into the gill cavity through a side slit and a special funnel in front of the body, and then energetically throws out a stream of water through the funnel. The cuttlefish directs the funnel tube to the side or back and, quickly squeezing water out of it, can move in different directions.

The salpa is a marine animal with a transparent body; when moving, it receives water through the front opening, and the water enters a wide cavity, inside of which the gills are stretched diagonally. As soon as the animal takes a large sip of water, the hole closes. Then the longitudinal and transverse muscles of the salp contract, the whole body contracts, and water is pushed out through the posterior opening. The reaction of the escaping jet pushes the salpa forward.

The squid's jet engine is of greatest interest. The squid is the largest invertebrate inhabitant of the ocean depths. Squids have reached supreme perfection in reactive navigation. Even their body, with its external forms, copies the rocket (or better said, the rocket copies the squid, since it has indisputable priority in this matter). When moving slowly, the squid uses a large diamond-shaped fin that periodically bends. It uses a jet engine to throw quickly. Muscle tissue - the mantle surrounds the mollusk's body on all sides; the volume of its cavity is almost half the volume of the squid's body. The animal sucks water inside the mantle cavity, and then sharply throws out a stream of water through a narrow nozzle and moves backwards with high speed pushes. At the same time, all ten tentacles of the squid are gathered into a knot above its head, and it takes on a streamlined shape. The nozzle is equipped with a special valve, and the muscles can rotate it, changing the direction of movement. The squid engine is very economical, it is capable of reaching speeds of up to 60 - 70 km/h. (Some researchers believe that even up to 150 km/h!) No wonder the squid is called a “living torpedo.” By bending the bundled tentacles to the right, left, up or down, the squid turns in one direction or another. Since such a steering wheel is very large compared to the animal itself, its slight movement is enough for the squid, even at full speed, to easily dodge a collision with an obstacle. A sharp turn of the steering wheel - and the swimmer rushes in the opposite direction. So he bent the end of the funnel back and now slides head first. He bent it to the right - and the jet push threw him to the left. But when you need to swim quickly, the funnel always sticks out right between the tentacles, and the squid rushes tail first, just as a crayfish would run - a fast walker endowed with the agility of a racer.

If there is no need to rush, squids and cuttlefish swim with undulating fins - miniature waves run over them from front to back, and the animal glides gracefully, occasionally pushing itself also with a stream of water thrown out from under the mantle. Then the individual shocks that the mollusk receives at the moment of eruption of water jets are clearly visible. Some cephalopods can reach speeds of up to fifty-five kilometers per hour. It seems that no one has made direct measurements, but this can be judged by the speed and flight range of flying squids. And it turns out that octopuses have such talents in their family! The best pilot among mollusks is the squid Stenoteuthis. English sailors call it flying squid (“flying squid”). This is a small animal about the size of a herring. It chases fish with such speed that it often jumps out of the water, skimming over its surface like an arrow. He resorts to this trick to save his life from predators - tuna and mackerel. Having developed maximum jet thrust in the water, the pilot squid takes off into the air and flies over the waves for more than fifty meters. The apogee of a living rocket's flight lies so high above the water that flying squids often end up on the decks of ocean-going ships. Four to five meters is not a record height to which squids rise into the sky. Sometimes they fly even higher.

The English mollusk researcher Dr. Rees described in a scientific article a squid (only 16 centimeters long), which, having flown a fair distance through the air, fell on the bridge of a yacht, which rose almost seven meters above the water.

It happens that a lot of flying squids fall on the ship in a sparkling cascade. The ancient writer Trebius Niger once told a sad story about a ship that allegedly sank under the weight of flying squids that fell on its deck. Squids can take off without acceleration.

Octopuses can also fly. French naturalist Jean Verani saw how an ordinary octopus accelerated in an aquarium and suddenly jumped out of the water backwards. Having described an arc about five meters long in the air, he plopped back into the aquarium. When picking up speed to jump, the octopus moved not only due to jet thrust, but also rowed with its tentacles.
Baggy octopuses swim, of course, worse than squids, but at critical moments they can show a record class for the best sprinters. California Aquarium staff tried to photograph an octopus attacking a crab. The octopus rushed at its prey with such speed that the film, even when filming at the highest speeds, always contained grease. This means that the throw lasted hundredths of a second! Typically, octopuses swim relatively slowly. Joseph Seinl, who studied the migrations of octopuses, calculated: an octopus half a meter in size swims through the sea at an average speed of about fifteen kilometers per hour. Each jet of water thrown out of the funnel pushes it forward (or rather, backward, since the octopus swims backwards) two to two and a half meters.

Jet motion can also be found in the plant world. For example, the ripened fruits of the “mad cucumber”, with the slightest touch, bounce off the stalk, and a sticky liquid with seeds is forcefully thrown out of the resulting hole. The cucumber itself flies off in the opposite direction up to 12 m.

Knowing the law of conservation of momentum, you can change your own speed of movement in open space. If you are in a boat and you have several heavy stones, then throwing stones in a certain direction will move you in the opposite direction. The same will happen in outer space, but there they use jet engines for this.

Everyone knows that a shot from a gun is accompanied by recoil. If the weight of the bullet were equal to the weight of the gun, they would fly apart at the same speed. Recoil occurs because the ejected mass of gases creates a reactive force, thanks to which movement can be ensured both in air and in airless space. And the greater the mass and speed of the flowing gases, the greater the recoil force our shoulder feels, the stronger the reaction of the gun, the greater the reactive force.

Application of jet propulsion in technology

For many centuries, humanity has dreamed of space flight. Science fiction writers offered the most different means to achieve this goal. In the 17th century a story appeared French writer Cyrano de Bergerac about the flight to the moon. The hero of this story reached the Moon in an iron cart, over which he constantly threw a strong magnet. Attracted to him, the cart rose higher and higher above the Earth until it reached the Moon. And Baron Munchausen said that he climbed to the moon along a bean stalk.

At the end of the first millennium AD, China invented jet propulsion, which powered rockets - bamboo tubes filled with gunpowder, they were also used as fun. One of the first car projects was also with a jet engine and this project belonged to Newton

The author of the world's first project of a jet aircraft intended for human flight was the Russian revolutionary N.I. Kibalchich. He was executed on April 3, 1881 for his participation in the assassination attempt on Emperor Alexander II. He developed his project in prison after being sentenced to death. Kibalchich wrote: “While in prison, a few days before my death, I am writing this project. I believe in the feasibility of my idea, and this faith supports me in my terrible situation... I will calmly face death, knowing that my idea will not die with me.”

The idea of ​​using rockets for space flights was proposed at the beginning of this century by the Russian scientist Konstantin Eduardovich Tsiolkovsky. In 1903, an article by Kaluga gymnasium teacher K.E. appeared in print. Tsiolkovsky “Exploration of world spaces using reactive instruments.” This work contained the most important mathematical equation for astronautics, now known as the “Tsiolkovsky formula,” which described the motion of a body of variable mass. Subsequently, he developed a design for a liquid-fuel rocket engine, proposed a multi-stage rocket design, and expressed the idea of ​​​​the possibility of creating entire space cities in low-Earth orbit. He showed that the only device capable of overcoming gravity is a rocket, i.e. a device with a jet engine that uses fuel and oxidizer located on the device itself.