Aircraft (la) are heavier than air. "Aircraft heavier than air are impossible!"

Aircraft heavier than air include airplanes; gliders, projectiles, rockets, helicopters, autogyros, ornithopters.

Airplane- an aircraft (LA) heavier than air for flights in the atmosphere with the help of engines and a wing that is fixed relative to other parts of the apparatus. Due to its high speed, payload and range, reliability in operation, high maneuverability, stability and controllability, the aircraft has become the main means of transportation in the air.

The main parts of the aircraft: “snout, fuselage, landing gear, plumage, power plant.

The wing creates lift as the aircraft moves. It is usually fixed on the fuselage, but for some aircraft it can rotate about the transverse axis (for example, for vertical takeoff and landing aircraft) or change its configuration (sweep, span). Roll rudders are installed on the wing - ailerons and wing mechanization elements - devices that can increase the carrying capacity and resistance of the wing during landing, takeoff, maneuver (shields, flaps, slats, etc.).

The fuselage serves to accommodate the crew, passengers, cargo and equipment.

The landing gear is designed to move the aircraft around the airfield, absorb the impact energy during landing, and, as a rule, is equipped with brakes. Landing gears are retractable in flight and non-retractable. Aircraft with retractable landing gear have less drag but are heavier and more complex in design.

The plumage is used to ensure the stability, controllability and balance of the aircraft. Usually it is located in the wing lozad and consists of fixed and movable surfaces. The fixed part of the horizontal tail is called the stabilizer, and the vertical tail is called the keel. The elevator, usually consisting of two halves, is articulated to the stabilizer, and the rudder is attached to the keel. The rudders are deflected using the steering column

to improve flight safety, passenger aircraft are usually controlled by two pilots, and autopilots and on-board computers may be included in the control system. Reducing the loads acting on the control levers when the rudders are deflected is achieved using hydraulic, pneumatic or electric amplifiers, as well as aerodynamic compensation devices. Aircraft control, when the air rudders are not effective (flying in a highly rarefied atmosphere, on vertical takeoff or landing aircraft), is carried out by gas rudders. The control system of the air rudders is called the main one. Auxiliary systems are used to control engines, rudder trims, hatches, landing gear, brakes.

The power plant of an aircraft is necessary to create thrust * It consists of aircraft engines, as well as systems and devices that ensure their operation and change in thrust. On airplanes civil aviation mainly used turbojet and turboprop engines. There are also aircraft with piston engines, in which the thrust force is created by propellers. Turbo jet engines thrust occurs due to the expiration of gases from the jet nozzle at high speed. In turboprop engines, more than 85% of the thrust is created by propellers, and the rest is due to the outflow of gases. Aircraft engines are usually placed in nacelles. The operation of the engines is provided by the following systems: fuel, lubrication (oil), air intake, gases, start-up, control and automated control.

Aircraft equipment consists of instrumentation, radio, electrical equipment, anti-icing devices, high-altitude, airborne and special equipment. Instrumentation, depending on the purpose, is divided into flight and navigation (variometers, speed indicators, artificial horizons, compasses, autopilots, etc.), for monitoring the operation of engines (pressure gauges, tepJ (mometers, flow meters) and auxiliary (for example, ammeters, voltmeters). The electrical equipment of the aircraft ensures the operation of instruments, controls, radio, aircraft engine starting systems, lighting. Radio equipment is a means of radio communication and radio navigation, radar equipment, automatic take-off and landing systems. To ensure the safety and protection of a person when flying at high altitudes, a high-altitude equipment (air conditioning systems, oxygen supply, etc.) Convenience of accommodation for passengers and crew, comfort during the flight are provided by household equipment, Special equipment includes devices for placing and spraying chemicals on agricultural aircraft, for transporting the sick and wounded on aircraft sanitize air force, loading and

securing bulky cargo from cargo aircraft, aerial photography, etc.

Glider- a motionless apparatus heavier than air, the lifting force of which is created by a wing that is stationary relative to the body. The forward motion of the glider is created by the action of the weight component. The glider takes off with the help of a rubber shock absorber, a winch, on the drum of which a cable is attached to the glider, or with the help of a towing aircraft. Flight in a calm atmosphere occurs with a constant descent at a certain angle to the horizon. In the presence of ascending air currents in the atmosphere, flight with a climb is possible. Gliders, as a rule, are single and double. The designers of domestic gliders are O. K. Antonov, B. O. Korvyalis, B. I. Oshkinis, V. F. Spivak, and others. During record flights, the glider gained altitude up to 14 km and flew with a range of over 1000 km. The main flight and technical data of modern gliders are: descent speed 0.4-0.8 m/s, flight speed at maximum lift-to-drag ratio 80-100 km/h, wing span 29 m, wing aspect ratio 20-36, maximum lift-to-drag ratio 40- 53.

Aircraft projectiles and missiles refer to unmanned aerial vehicles heavier than air. Initially, they were created to study the operation of rocket engines and the upper atmosphere. Advances in rocket technology over the past decades have made it possible to create numerous systems of ballistic aircraft, rockets for launching artificial Earth satellites and manned spacecraft.

Helicopter (helicopter) Heavier-than-air aircraft in which the lift and thrust necessary for flight are provided by one or more rotors rotating in a horizontal or near-horizontal plane. The rotors are driven by piston or jet engines through a gearbox and a vertical shaft. Helicopters have been created in which the rotation of the main rotor is carried out from jet engines or nozzles mounted on the blades. The nozzles are supplied with compressed air from the compressor. Helicopters with such a rotor drive are called jet. In contrast to an aircraft, the lift force on the wing of which is created only during translational motion, the main rotor of a helicopter can create lift without the translational movement of the vehicle. The main rotor of a helicopter replaces not only the wing, but also the pulling propeller (jet engine thrust), allowing the device to move forward, backward and to the sides, rise and fall at various angles to the horizon, hang motionless in the air and turn around

vertical axis. This is achieved on

clone of the main rotor thrust in the direction of flight. The main rotor of a helicopter has another exceptional property - in the event of an engine failure in flight, it can create lift by rotating under the action of the oncoming air flow (autorotation). This allows the helicopter to perform a glide or parachute descent and landing. 1.3. Autogyro. Any helicopter design

the schemes form the fuselage, landing gear, main rotor, controls, instrumentation, radio, electrical equipment, power plant with systems that ensure its operation (fuel, oil, air intake, cooling, control, etc.), transmission, including gearboxes , shafts,] transmission clutch, main rotor brake. For uve-; Flight speed options Some helicopters have a small wing that takes the load off the main rotor. Single-rotor helicopters with a mechanical drive of the main rotor, in addition, have a tail! howling screw and control system. Some helicopter designs*! years are equipped with vertical and horizontal plumage.

Vertical takeoff and landing devices (VTOL) are either a combination of an aircraft with a helicopter, or aircraft in which the lifting force during takeoff and landing is created by means of jet engines, called lift. Horizontally; In the long-range flight of such vehicles, the lifting force is created by the wing, and the thrust is created by conventional engines, which are called marching. In other configurations, vertical take-off and landing can1 be accomplished by deflecting the thrust vector, which is achieved either by turning the engines or by deflecting the jet. When designing such devices, the task is to combine the advantages of a helicopter with high speed aircraft. However, the prospect of using such devices, obviously, will completely overestimate economic indicators: more complex and expensive design should have high performance.

Autogyro - an aircraft heavier than air, in which the main bearing surface is a rotor - a rotor rotating under the action of an oncoming air flow. The translational movement of the autogyro is provided, unlike a helicopter, by a conventional propeller rotated by an engine (Fig. 1.3).

Autogyros are not widely used for half a mile because, being significantly inferior to aircraft in flight speed, they cannot take off vertically and carry out vertical landing.

movements can achieve certain successes.

1. aircraft;

2. gliders;

3. aircraft shells;

4. rockets;

5. helicopters;

6. gyroplanes.

1. Planes - la. heavier than air for flight in the atmosphere with the help of engines and a wing that is stationary relative to other parts of the apparatus. Due to its high speed, payload, range, reliability in operation, high maneuverability, stability and controllability, the aircraft has become the main means of transportation in the air. The main parts of the aircraft are the wing, fuselage, landing gear, plumage and power plant.

a) The wing generates lift as the aircraft moves. It is usually fixed on the fuselage, but in some aircraft it can rotate about the transverse axis. Roll rudders and wing mechanization elements are installed on the wing, that is, devices capable of increasing the carrying capacity and drag of the wing during landing, takeoff, and maneuver.

b) The fuselage serves to accommodate the crew, passengers, cargo and equipment.

c) The landing gear is designed to move the aircraft around the aerodrome, absorb the impact energy during landing, and brakes are installed on it. There are retractable and non-retractable chassis. Aircraft with retractable landing gear have less drag but are heavier and more complex in design.

d) the empennage is used to provide stability, controllability and balance of the aircraft. It is usually located behind the wing and consists of movable and fixed surfaces. The fixed part of the horizontal tail is called the stabilizer, and the vertical keel. The elevator, which usually consists of two halves, is hinged to the stabilizer, and the steering wheel to the keel. The rudders are deflected using the steering column or control stick and pedals located in the cockpit. To facilitate piloting and increase flight safety, passenger aircraft are usually controlled by 2 pilots, and autopilots and on-board computers can be included in the control system. Reducing the loads acting on the control levers and steering deflection is achieved using hydraulic pneumatic or electric amplifiers, as well as aerodynamic compensation devices. Aircraft control when the air rudders are not effective (flying heavily discharged in the atmosphere on vertical takeoff or landing aircraft) is carried out by gas rudders. The control system of the air rudders is called the main one. Auxiliary systems are used to control engines, rudder trippers, landing gear hatches and brakes.

e) The aircraft propulsion system is required to generate thrust. It consists of aircraft engines as well as systems and devices that ensure their operation and change in thrust. On civil aviation aircraft, mainly turbojet and turboprop engines are used.

There are also aircraft with piston engines in which the thrust force is created by propellers. In turbojet engines, thrust arises as a result of the outflow of gases from a jet nozzle at high speed. In turboprop engines, more than 85% of the thrust is created by propellers and the rest is due to the outflow of gases. Aircraft engines are usually placed in gandolas, the operation of the engines provide systems for fuel, oil, intake of air and gases, start-up control and automated control.
Aircraft equipment consists of instrumental radio and electrical equipment, anti-icing devices, high-altitude airborne and special. equipment.
Instrumentation, depending on the purpose, is divided into:
- flight navigation (variometers, speed indicators, artificial horizons, autopilots, compasses, etc.) for controlling the operation of engines (pressure gauges, kerometers, flow meters) auxiliary (voltmeters, ammeters)
- the electrical equipment of the aircraft ensures the operation of the instruments of the radio controls of the system for starting aircraft engines and lighting.
- radio equipment is a means of radio communication and radio navigation; radar equipment of an automatic take-off and landing system.
To ensure the safety and protection of a person when flying at high altitudes, high-altitude equipment (air conditioning systems, oxygen supply, etc.) is used. The convenience of accommodating passengers and crew comfort during the flight is provided by household equipment.
Special equipment includes devices for placing and spraying chemicals near agricultural aircraft for transporting the sick and wounded on air ambulance aircraft loading and securing bulky cargo from cargo aircraft and different kinds pickups (Aeroflot survey, magnetic survey, etc.)

2. A glider is a non-motorized device, the lifting force is heavier than air, which is created by a wing that is fixed relative to the body. The forward motion of the glider is created by the action of the weight component. The glider takes off with the help of a rubber armatizer and a winch, on the drum of which a cable is wound, attached to the glider. Flight in a calm atmosphere occurs with a constant decrease at a certain angle to the horizon; in the presence of ascending air currents in the atmosphere, flight with a climb is possible. Gliders, as a rule, are single and double, with record flights the glider gained altitude up to 14 km and flew with a range of over 1000 km.

34. Projectiles and missiles are unmanned aircraft. heavier than air. Initially, they were created to study the operation of rocket engines in the upper atmosphere. Achievements in the field of rocket technology have made it possible to create numerous systems of ballistic la., rockets for launching artificial earth satellites of manned spacecraft.

5. Helicopter (helicopter) - la. heavier than air, in which the lifting force is created by one or more rotors rotating in a horizontal plane. The rotors are driven by piston or jet engines through a gearbox and a vertical shaft. Helicopters have been created in which the rotation of the main rotor is carried out under the action of jet engines or nozzles mounted on the blades, compressed air is supplied to the nozzles from the compressor. Helicopters with such a rotor drive are called jet. Unlike an aircraft, the lift force on the wing of which is created only during translational movement, the main rotor of the helicopter can create lift without the translational movement of the apparatus. The main rotor of the helicopter replaces not only the wing but also the pulling screw, allowing the aircraft to move forward and backward and to the sides, rise and fall at various angles to the horizon, hang motionless in the air and turn around the vertical axis. This is achieved by tilting the main rotor thrust in the direction of flight. The main rotor of a helicopter has another exceptional property in case of engine failure in flight, it can create lift by rotating under the influence of the oncoming air flow, this phenomenon is called autorotation, this allows the helicopter to make a glide or parachute descent and landing. The design of a helicopter of any scheme is formed by:

a) fuselage

b) chassis

c) main rotor

d) governing bodies

e) instrumentation

f) radio

g) electrical equipment

h) power plant with systems that ensure its operation (fuel oil air intake cooling control, etc.)

i) transmission including: gearboxes, shafts, couplings including transmissions and main rotor brake.

To increase the flight speed, some helicopters have a small wing that unloads the main rotor (MI6 helicopter). Single-rotor helicopters with a mechanically driven main rotor have a tail rotor and a tail rotor control system. Some helicopter designs are equipped with vertical and horizontal tails.
Vertical takeoff and landing devices.
They are a combination of a helicopter with an airplane or airplanes in which the lift from the aircraft during takeoff and landing is created using jet engines called lifting. In the horizontal flight of such devices, the lift force is created by the wing and the thrust is created by conventional engines, which are called marshals. In other schemes, vertical takeoff and landing can be performed by deflecting the thrust vector, which is achieved either by turning the engines or by deflecting the jet. When designing such devices, the task is to combine the advantages of a helicopter with the high speed of an aircraft; however, the prospect of using weaving devices depends on economic indicators, that is, a more complex and expensive design should have high performance.

A person had the opportunity to observe and study free-flying "apparatuses" long before the creation of the first aircraft - he always had an example of a flying bird before his eyes. In the legends of any nation can be found fairy tale hero capable of moving through the air, and these methods are extremely diverse.

The ideas about the mechanism of bird flight were just as diverse. It has even been suggested that the lift of the wing is caused by electrical charges arising on the spread feathers when the bird opens its wings.

However, heavier-than-air flight became possible quite recently (by the standards of human history) and more than a hundred years after the first flight on hot-air balloon(aerostat) Montgolfier brothers.

Gliders, or non-powered aircraft

Observations of soaring birds led to experiments using updrafts and the creation gliders. However, a serious drawback of the airframe as vehicle is that it is not capable of taking off on its own.

In 1891, Otto Lilienthal made a glider from wicker twigs covered with fabric. For the period from 1891 to 1896, he made up to 2000 flights. August 9, 1896 Otto Lilienthal died. A copy of his apparatus can be seen in the museum of N. E. Zhukovsky in Moscow on the street. Radio.

Gliding was popular in the 1930s. Most of the well-known aircraft designers, for example, O.K. Antonov, S.P. Korolev, A.S. Yakovlev, started with glider projects. The use of modern materials and aerodynamic forms has led to the fact that in conditions of stable updrafts, for example, in mountainous areas, gliders are able to fly for hours and even days.

The aerodynamic schemes of gliders became the basis for devices heavier than air, driven by the power of human muscles - "muscle planes", as well as other devices with low flight speed.

Descendants of gliders are "hang gliders" and "paragliders". Paragliding is currently extremely popular.

Reduced models of paragliders are used as sports equipment for towing mountain and water skiers. Such a device can be made independently even at home.

Attempts to create an aircraft capable of independently taking off, landing at a given point and taking off again from there ended in failure not only due to lack of knowledge, but also due to the lack of a suitable engine. Equally true is the statement that the advent of a new engine, lighter and more powerful or based on a different principle of creating a driving force, leads to a revolutionary breakthrough in the development of aviation.

The theoretical foundations for the flight of vehicles heavier than air were developed by N. E. Zhukovsky at the beginning of the 20th century. The necessary experimental data were obtained back in the 19th century by A.F. Mozhaisky, O. Lilienthal and others.

Subject: Aircrafts heavier than air. flywheels. Aircraft. The development of military aviation. Civil Aviation.

3.1. Aircraft heavier than air

The first airplane model made its flight in 1647. Its developer was the Italian Burattini. This aircraft had four pairs of wings located along the fuselage and a tail unit. The two middle pairs were motionless, while the movement, according to the principle of an ornithoper, was carried out by means of springs installed on the front and rear pairs of wings.

Here it is necessary to say a few words about the flywheels. Flywheels are heavier-than-air aircraft in which the lifting force arises due to the flapping movements of the wings, like a bird's. Another name for these devices is ornithopers. There are flywheels with a drive due to the muscular strength of a person (musculoletes) and with a mechanical drive from engines of various types: spring, steam, internal combustion engines, etc.

Subsequently, up to 1809, various aircraft projects were created, but before them practical implementation it didn't work out. The founder of the scientific stage in the development of aircraft construction is called the Englishman D. Cayley. His experiments on a rotary machine in 1804 were the first aerodynamic experiments, thanks to which it was possible to accurately determine the lift developed by a small aspect ratio wing at different speeds and angles of impact on it. When testing the airframe model, it was possible to establish the values ​​of the coefficient lifting force, and in 1808 to determine the points of application of this force.

A year later, i.e. in 1809, Cayley created a full-size flying machine with a seat for the pilot, a tail and additional flapping wings. Jogging with gusts of wind allowed him to rise into the air for only a few minutes.

Cayley's "On Air Navigation" was soon published, the first among others. theoretical works on fixed wing flights. The inventor, confident that the muscular strength of a person is not enough to rise into the air, paid great attention to the development of a caloric (use of hot air), a powder engine and an internal combustion engine running on liquid fuel.

The first proposals for the creation of aircraft in Russia date back to the 1860s. Inventor A.V. Ewald presented to the public a description of the “ideal aircraft design”, which included all the elements necessary for flight: an engine, a propeller, a streamlined shape that provides low drag, fragments to achieve stability and steering. Unfortunately, it has not been worked out in detail.

A.F. Mozhaisky said a special word in the field of aircraft construction. It is known that in 1877 he proposed to the Military Ministry of the Russian Empire to build an aircraft. The project he proposed spoke of a monoplane with one pulling and two pushing propellers, with

wing in the form of a plane of slight elongation. Despite financial difficulties, by 1883 a braced monoplane had been created with two steam engines and three propellers (one in front and two on the sides). The fuselage, which housed the steam engines (in the bow and center), the boiler, oil tanks, instruments and crew seats, was a boat with a wooden frame and fabric lining. The rectangular wooden wing of small elongation, made in the "gull" type (slightly arched with a bulge upwards), had a multi-spar structure and silk lining impregnated with varnish to ensure airtightness.

The load-bearing surfaces supported steel braces connected to the masts on the fuselage and to the landing gear. The tail unit consisted of two twisting rudders (Fig. 3.1.).

Rice. 3.1.- Aircraft designed by A.F. Mozhaisky

The plane took off after a long takeoff run on wooden rails. Newspaper notes of that time contain information about the test flight of Mozhaisky's monoplane, which ended in an accident.

An important milestone in the history of aircraft construction is the creation by the German Nikolaus Otto of a four-stroke gas internal combustion engine (1876), which resulted in a qualitative improvement in the characteristics of engines. A few years later, Otto's compatriot, G. Daimler, invented a gasoline-powered engine, which led many designers to think about the problem of using such engines in aircraft construction, especially since by the end of the 19th century, no one had the prospect of using internal combustion engines in aviation. raised doubts.

The Russian scientist K.E. Tsiolkovsky also spoke about this, who in 1894 published a draft of a cantilever monoplane classical scheme with a gasoline internal combustion engine, the material for which was to be aluminum.

In the 90s of the 19th century, for the first time, the idea arose of using a device on an aircraft that ensures automatic stability of the aircraft in the air when flying in a turbulent atmosphere. Attempts to use the pendulum as an autopilot showed its serious drawback - the presence of acceleration forces in flight led to disruption of its operation. And soon the pendulum was replaced by a gyroscopic automaton, which is a small disk rapidly rotating under the influence of an electric current, mounted on axes in such a way that its plane always remains stationary relative to the projectile. It was not until the 1930s that he found a life in aviation.

By 1910, two directions had developed in aircraft construction: two-seat biplanes without a fuselage with a pusher propeller and an elevator located under the wing and single-seat monoplanes with a fuselage, tail

and pull screw. Each of these designs had its own advantages: biplanes were distinguished by their high carrying capacity and the best view for the pilot and passenger, they were often used as training machines, while high-speed monoplanes were more suitable for amateur pilots and athletes. Thus, there were prerequisites for the evolution of aircraft of both types, and for several decades there was a sharp struggle between mono- and biplanes.

AT that period, not only the general designs of aircraft were improved, but also individual systems: control devices, power plants, landing gear. The cockpits were unified: there were pedals connected to the rudder, and a lever that controls the elevator and ailerons. Thus, the pilot could fly the plane with one hand and feet, which was very important for military purposes (shooting, photographing the area and other tasks). The layout, which has become standard, is also used in modern aircraft. In the prewar years, wheeled and wheeled chassis. The most common types of propellers were propellers with solid wood blades and high efficiency for that time. The hull and wings were covered with wood or canvas, steel was used mainly in the chassis structure, wing and fuselage connecting nodes, braces and control wiring. Metal was rarely used as a structural material.

The most typical biplane design was the plane of the Wright brothers,

created by them on the basis of a glider (Fig. 3.2.). It was supplemented by a four-cylinder in-line water-cooled gasoline engine of its own design, with a power of 12 hp. The engine drove two pusher propellers rotating in opposite directions. The pilot controlled the warping of the wing by moving the hips, the levers located in front of him served to turn on the engine and control the elevator. The first flight took place on December 14

Rice. 3.2.- Aircraft designed by the Wright brothers

Further modernization of biplanes contributed to the improvement of their aerodynamic performance: they became quite stable, streamlined and were able to reach high speed. The carrying capacity of these aircraft has also increased. By the beginning of the First World War, fuselage biplanes were replaced by more promising two-winged aircraft (bimonoplanes) with a propeller located in front and a fully sheathed hull.

In the Russian Empire, the first home-made airplanes appeared in 1909. However, the development of domestic aircraft construction was slow for the simple reason that the Russian industry did not produce engines suitable for use on aircraft.

Over time, the government, having assessed the potential of home-made aircraft, became interested in the fate of the domestic aircraft industry. Appropriations were allocated for the construction of experimental machines. Soon, the flight of the Gakkel-3 machine took place, made in the form of a bimonoplane designed by engineer Yakov Gakkel. In 1911, the Gakkel-7 apparatus (Fig. 3.3.) with a powerful engine, aileron control, reinforced structure and increased payload capacity won the First Military Competition for aircraft created in the Russian Empire. This car was the only one that passed all the tests. In 1912, Gakkel-7 received the Big Gold Medal, thereby recognizing the merits of the Russian inventor.

Rice. 3.3.- Airplane "Gakkel-7"

Gakkel's work on the creation of a bimonoplane was continued by Igor Sikorsky. His C-6 plane, with a hull lined with thin, carefully polished and varnished wooden planks, acquired a streamlined shape. Thanks to this, the talented aircraft designer managed to set world speed records: with two passengers on board - 111 km / h, with five - 106 km / h. For two years, Sikorsky's airplanes have won prizes in military aircraft competitions, in no way inferior to the leading European models.

In the meantime, monoplanes in their purest form also received their development. In 1907, the talented French aviator and designer Louis Blériot began to create monoplanes. His aircraft were the first monoplanes with movable surfaces for lateral control: some of his models had rotary wingtips, others had movable rudders on the tail. These innovations allowed the aviator to become the first pilot in the world to master monoplane maneuvering.

His historic flight across the English Channel on July 25, 1909 made his Blériot the most popular model. Since that moment, mankind has ceased to look at the aircraft as a means of entertainment for the public and turned it into one of the most promising species vehicles designed to transport people, goods and conduct combat operations.

An important step towards improving the monoplane was completed project Frenchman E. Nieuport, which was based on "Bleriot-11". Its durable, stable in flight, sensitive to steering deviation and well-planned, the Nieuport-4 soon took its rightful place in the armed forces of France, Russia and Italy.

In 1912, designer and head aviation company A. Duperdussen was the first to use a monocoque design in aircraft construction. The airplane named after him had wood skin that was pressure-glued onto a blank in the shape of a fuselage. After removing the blank, the wooden shell was glued on the outside and inside with a cloth, and then varnished. The case obtained as a result of this procedure with a wall thickness of 4.5-5 mm was distinguished by great rigidity and strength.

Now the designers faced the task of increasing the carrying capacity of aircraft. It was possible to increase it only by increasing the take-off weight, which required an increase in the power of the power plant. And since at that

At that time there were no strong engines, it was supposed to put several engines on the planes.

Indicative in this regard was the creation in Russia of the Grand (Russian Knight) and Ilya Muromets airplanes, the projects of which belonged to Igor Sikorsky. Models had four engines installed on the wing. In front of the fuselage of the Russian Knight there was a glazed cockpit with compartments for the pilot, passengers, a toilet and room for spare parts and tools. There was a small space in front of the cockpit where one could go during the flight. When any of the tandem engines was stopped, the aircraft could continue its flight without hindrance (Fig. 3.4.).

Rice. 3.4.- Aircraft "Grand" ("Russian Knight")

The aircraft "Ilya Muromets", built in October 1913, became the successor to the "Grand". It was a biplane with a strong fuselage, in the bow of which there was a glazed cockpit with electric lighting and heating (Fig. 3.5.). The first time a biplane took off on December 23, 1913. Experiments with two engines turned off and take-offs on skis from the snow turned out to be very successful. World records for carrying capacity, range and flight altitude were set.

Rice. 3.5.- Aircraft "Ilya Muromets"