Classification of transport aircraft by carrying capacity. Classification by purpose

Schengen

Plan:

1 Aircraft classification
- 1.1 By purpose
- 1.2 Takeoff weight
- 1.3 By type and number of engines
- 1.4 According to the layout
- 1.5 By flight speed
- 1.6 By type of landing organs
- 1.7 Type of takeoff and landing
- 1.8 By type of thrust source
- 1.9 Reliability
- 1.10 By way of management
2 Aircraft design
3 Aircraft history
4 Interesting Facts

Introduction

Airplane(aka airplane) - an aircraft with an aerodynamic method of creating lift using an engine and fixed wings (wings) and used for flights in the Earth's atmosphere. (Later in this article, the term airplane interpreted only in this sense.)

The aircraft is capable of moving at high speeds, using the lift of the wing to keep itself in the air. A fixed wing distinguishes an airplane from an ornithopter (maple) and a helicopter, and the presence of an engine distinguishes it from a glider. An airplane differs from an airship in an aerodynamic way of creating lift - an aircraft wing creates lift in the oncoming air flow.

The above definition is "classic" and relevant for aircraft that existed at the dawn of aviation. In relation to modern and promising developments in aviation technology (integrated and hypersonic aerodynamic layouts, the use of a variable thrust vector, etc.), the concept of "aircraft" requires clarification: Airplane- an aircraft for flights in the atmosphere (and outer space (for example, an orbital aircraft)), using the aerodynamic lift of the airframe to keep itself in the air (when flying within the atmosphere) and the thrust of the power (propulsion) installation for maneuvering and compensating for losses of the full mechanical energy for drag.

1. Aircraft classification

The classification of aircraft can be given according to various criteria - by purpose, by design features, by engine type, by flight performance parameters, etc., etc.

1.1. By appointment

1.2. Takeoff weight

Light aircraft MAI-223

1st class (75 tons and more)
2nd class (from 30 to 75 tons)
3rd class (from 10 to 30 tons)
4th class (up to 10 tons)
light-engine
ultralight (up to 495 kg)

The class of the aircraft is associated with the class of the airfield capable of receiving aircraft of this type.

1.3. By type and number of engines

Cross-sectional radial engine

Turbojet engine compressor (TRD)

By type of power plant:
- piston (PD) (An-2)
- turboprop (TVD) (An-24)
- turbojet (TRD) (Tu-154)
- with rocket engines
- with combined power plant (CPU)
By number of engines:
- single-engine (An-2)
- twin-engine (An-24)
- three-engine (Tu-154)
- four-engine (An-124 "Ruslan")
- five-engine (He-111Z)
- six-engine (An-225 "Mriya")
- seven-engine (K-7)
- eight-engine (ANT-20, Boeing B-52)
- ten-engine (Convair B-36J)
- twelve-engine (Dornier Do X)

1.4. According to the layout

Classification on this basis is the most multivariant). Some of the main options are offered:

By the number of wings:
- monoplanes
- one and a half gliders
- biplanes
- triplanes
- polyplanes
By wing position (for monoplanes):
- high-wingers
- medium plans
- low-wing
- parasol
According to the location of the tail:
- normal aerodynamic configuration (tail plumage at the rear)
- flying wing (tailless)
- tailless
- type "duck" (plumage in front);
By type and dimensions of the fuselage:
- single-body;
  - narrow-body;
  - wide-body;
- two-beam scheme ("frame");
- fuselageless ("flying wing").
- Double-deck aircraft
Chassis type:
- Land;
  - with wheel chassis;
    - with tail support;
    - with front support;
    - bicycle type support;
  - with ski chassis;
  - with caterpillar chassis;
- seaplanes;
  - amphibians;
  - float;
  - "flying boats".

1.5. By flight speed

subsonic (up to Mach 0.7-0.8)
transonic (from 0.7-0.8 to 1.2 M)
supersonic (from 1.2 to 5 M)
hypersonic (over 5 M)

1.6. By type of landing organs

land
shipborne
seaplanes
flying submarine

1.7. Type of takeoff and landing

vertical (GDP)
short (KVP)
normal takeoff and landing

1.8. By type of thrust source

screw
reactive

1.9. Reliability

experimental
experienced
serial

1.10. By way of management

piloted
unmanned

2. Aircraft design

The main elements of the aircraft:

Wing - creates the lift necessary for the flight during the forward movement of the aircraft.
Fuselage - is the "body" of the aircraft.
Plumage - bearing surfaces designed to provide stability, controllability and balance of the aircraft.
Chassis - takeoff and landing device of the aircraft.
Power plants - create the necessary traction.
On-board equipment systems - various equipment that allows you to fly under any conditions.

3. Aircraft history

Viktor Vasnetsov "Flying Carpet", 1880

Vimana aircraft are described in ancient Indian literature. There are also references to aircraft in the folklore of different nations (flying carpet, stupa with Baba Yaga).

The first attempts to build an airplane were made in the 19th century. The first full-size aircraft built in 1882 and patented is the aircraft of Mozhaisky A.F. In addition, Ader and Maxim built aircraft with steam engines. However, none of these structures could take to the air. The reasons for this were: too high take-off weight and low specific power of engines - (steam engines), lack of flight and control theory, theory of strength and aerodynamic calculations. In this regard, the aircraft were built "at random", "by eye", despite the engineering experience of many aviation pioneers.

The first aircraft that was able to independently take off the ground and make a controlled horizontal flight was the Flyer-1, built by the brothers Orville and Wilbur Wright in the USA. The first aircraft flight in history took place on December 17, 1903. The Flyer stayed in the air for 59 seconds and flew 260 meters. The brainchild of the Wrights was officially recognized as the world's first heavier-than-air vehicle, which made a manned flight using an engine.

Their apparatus was a canard-type biplane - the pilot was placed on the lower wing, the rudder at the rear, the elevator at the front. The two-spar wings were sheathed in thin unbleached muslin. The Flyer's engine was a four-stroke, with a starting power of 16 horsepower and weighed only (or whole, if we evaluate from a modern point of view) 80 kilograms.

The apparatus had two wooden propellers. Instead of a wheeled chassis, the Wrights used a launch catapult consisting of a pyramidal turret and a wooden guide rail. The catapult was driven by a falling massive load connected to the aircraft by a cable through a system of special blocks.

In Russia, the practical development of aviation was delayed due to the government's orientation towards the creation of aeronautic aircraft. Based on the example of Germany, the Russian military leadership relied on the development of airships and balloons for the army and did not timely assess the potential of a new invention - an airplane.

The story of V. V. Tatarinov's "Airmobile" also played a negative role in relation to aircraft heavier than air. In 1909, the inventor received 50 thousand rubles from the Ministry of War for the construction of a helicopter. In addition, there were many donations from individuals. Those who could not help with money offered their labor for free to realize the inventor's plan. Russia had high hopes for this domestic invention. But the venture ended in complete failure. The experience and knowledge of Tatarinov did not correspond to the complexity of the task, and a lot of money was thrown to the wind. This case had a negative impact on the fate of many interesting aviation projects - Russian inventors could no longer obtain government subsidies.

In 1909, the Russian government finally showed interest in aircraft. It was decided to reject the offer of the Wright brothers to buy their invention and build aircraft on their own. Aircraft officers M.A. Agapov, B.V. Golubev, B.F. Gebauer and A.I. Shabsky were instructed to design the aircraft. We decided to build three-seater aircraft of various types in order to choose the most successful one later. None of the designers not only did not fly airplanes, but did not even see them in kind. Therefore, it is not surprising that the planes crashed even while running on the ground.

"Kudashev-1" - the first Russian flying aircraft

Winged benz. Russian airplane in the back of a truck on the Caucasian front of the First World War. 1916

The first successes of Russian aviation date back to 1910. June 4 Professor of Kyiv polytechnic institute Prince Alexander Kudashev flew several tens of meters on a biplane of his own design.

On June 16, the young Kyiv aircraft designer Igor Sikorsky for the first time took his plane into the air, and three days later the plane of engineer Yakov Gakkel flew an unusual biplane with a fuselage scheme (bimonoplane) for that time.

4. Interesting facts

In 1901, two professors at one of the US universities "proved" that a heavier-than-air aircraft could never get off the ground, that it was like a "perpetuum mobile". The US Senate banned the Pentagon from funding developments, but three years later the Wright brothers' plane took off, which gave way to aviation developments.
The X-43A hypersonic aircraft is the fastest aircraft in the world. The X-43A recently set a new speed record of 11,230 km/h, exceeding the speed of sound by 9.6 times. For comparison: jet fighters fly at or above twice the speed of sound.

Literature

The history of aircraft designs in the USSR - Vadim Borisovich Shavrov. History of aircraft designs in the USSR 1938-1950 // M. Mashinostroenie, 1994. ISBN 5-217-00477-0.
"THORNY WAY TO ANYWHERE. Notes of an aircraft designer." L.L. Selyakov

AT civil aviation flight vehicles are divided into the following categories:

passenger,

agricultural purpose,

transport,

postal,

experimental

Passenger aircraft

Let's start the review of civil aviation models with them. This type of air Vehicle, as the name implies, is designed to carry passengers. The first serial aircraft carrying civilians is considered to be the same domestic Ilya Muromets, which in the future was converted into a bomber. He made his first flight from St. Petersburg to Kyiv with sixteen passengers back in 1914. The most popular airliner during the existence of aviation is the American device Douglas DC-3,

Douglas DC-3

made the first aviation flight back in 1935. Various modifications of it are still in use today. For example, the Soviet version of this aircraft was the Li-2. The first aircraft have been described above. Names of the main competitors in the modern market passenger aviation— Boeing and Airbus.

Boeing

The Boeing Company was founded in 1916. Since then, it has been producing aircraft, mainly for civil aviation, although there are also military transport models. Most famous titles passenger aircraft this company - Boeing 737, Boeing 747, Boeing 747-8, Boeing 777 and Boeing 787. aircraft classification their types types names.

Boeing 737

The first of the above models was released in 1968, and today it is the most massive of all passenger aircraft. boeing 747,

Boeing 747

produced a year later, is a pioneer among wide-body airliners. The Boeing 747-8 is the longest passenger aircraft. It was released in 2010. Today, the Boeing 777, which has been produced since 1994, has become the most popular in the passenger aviation market.

Boeing 777

The most new model corporations on this moment- Boeing 787 2009 creation.

Boeing 787

"Airbus"

As mentioned earlier, Boeing's main competitor in the global market is the European Airbus headquartered in France. It was founded much later than its American rival - in 1970. The most famous aircraft names of this company are A300, A320, A380 and A350 XWB. Launched in 1972, the A300 is the very first twin-engined wide-body aircraft.

Airbus A300

The A320, manufactured in 1988, was the first in the world to use a fly-by-wire form of control.

Airbus A320

The A380, which first took to the skies in 2005, is the largest in the world.

Airbus A380

He is able to take on board up to 480 passengers. The latest development of the company is the A350 XWB.

A350XWB

Its main task was to compete with the previously released Boeing 787. And this airliner successfully copes with this task, bypassing its rival in terms of efficiency.

Soviet passenger aircraft

The Soviet passenger service was also presented at a decent level. aviation industry. Most of the models are Aeroflot aircraft. The names of the main brands: Tu, Il, An and Yak. The first domestic jet airliner is the Tu-104, released in 1955.

Tu-104

Tu-154, the first takeoff of which was made in 1972, is considered the most massive Soviet passenger aircraft.

Tu-154

The 1968 Tu-144 gained legendary status as the world's first airliner to break the sound barrier.

Tu-144

He could reach speeds of up to 2.5 thousand km / h, and this record has not been broken to our time. At the moment, the latest operating model of an airliner developed by the Tupolev Design Bureau is the Tu-204 aircraft of 1990, as well as its modification Tu-214.

Tu-214

Naturally, in addition to Tu, there are other Aeroflot aircraft. The most popular names are: Il-18, Il-114, Il-103, An-24, An-28, Yak-40 and Yak-42.

IL-114

Yak-40

Airliners of other countries of the world

In addition to the above, there are noteworthy models and other manufacturers of passenger aircraft. The British airliner De Havilland Comet, released in 1949, is the first jet airliner in world history.

De Havilland Comet

The French-British airliner Concorde, developed in 1969, gained wide popularity.

Concorde

He went down in history due to the fact that he is the second successful attempt (after the Tu-144) to create a supersonic passenger aircraft. And so far, these two airliners are unique in this regard, since so far no one else has been able to produce a passenger aircraft suitable for mass operation, capable of moving faster than sound.

Transport workers

The main purpose of transport aircraft is to transport goods over long distances. Among the devices of this type, it is necessary to designate Western models of passenger aircraft modified for transport needs: Douglas MD-11F, Airbus A330-200F, Airbus A300-600ST and Boeing 747-8F.

Douglas MD-11F

But most of all in the production of transport aircraft, the Soviet, and now the Ukrainian design bureau named after Antonov, became famous. It produces aircraft that constantly break world records in terms of carrying capacity: An-22 1965 (carrying capacity - 60 tons), An-124 1984 (carrying capacity - 120 tons), An-225 1988 (takes on board 253, 8 t).

An-225

The latest model holds the hitherto unbroken load capacity record. In addition, they planned to use it to transport the Soviet Buran shuttles, but with the collapse of the USSR, the project remained unrealized. AT Russian Federation with transport aviation, everything is not so rosy. The names of Russian aircraft are as follows: Il-76, Il-112 and Il-214. But the problem is that the currently produced Il-76 was developed back in Soviet times, in 1971, and the rest are planned to be launched only in 2017.

IL-76

Agricultural aircraft

There are aircraft whose tasks include the treatment of fields with pesticides, herbicides and other chemicals. This type of aircraft is called agricultural. Of the Soviet samples of these devices, the U-2 and An-2 are known, which, due to the specifics of their use, were popularly called "maize" by the people.

U-2

The main units of the aircraft

Aircraft belong to aircraft heavier than air, they are characterized by the aerodynamic principle of flight. Airplanes have lift Y is created due to the energy of the air flow washing the bearing surface, which is fixedly fixed relative to the body, and translational motion in a given direction is provided by the thrust of the power plant (PU) of the aircraft.

Different types of aircraft have the same main units (components): wing , vertical (VO) and horizontal (GO) plumage , fuselage , power plant (SU) and chassis (Figure 2.1).

Rice. 2.1. The main structural elements of the aircraft

Aircraft wing1 creates lift and provides lateral stability to the aircraft during its flight.

often the wing is a power base for placing the landing gear, engines, and its internal volumes are used to accommodate fuel, equipment, various components and assemblies of functional systems.

For improvement takeoff and landing characteristics(VPH) of modern aircraft, mechanization equipment is installed on the wing along the leading and trailing edges. On the leading edge of the wing is placed slats , and on the back - flaps10 , spoilers12 and aileron spoilers .

In terms of power, the wing is a beam of complex design, the supports of which are the power frames of the fuselage.

Ailerons11 are cross-government bodies. They provide lateral control of the aircraft.

Depending on the scheme and flight speed, geometric parameters, structural materials and structural power scheme, the mass of the wing can be up to 9 ... 14 % from the takeoff weight of the aircraft.

Fuselage13 combines the main units of the aircraft into a single whole, i.e. provides a circuit for the power circuit of the aircraft.

The internal volume of the fuselage is used to accommodate the crew, passengers, cargo, equipment, mail, baggage, rescue equipment in case of emergencies. in the fuselages cargo aircraft developed loading and unloading systems, devices for fast and reliable cargo mooring are provided.

The function of the fuselage of seaplanes is performed by a boat, which allows you to take off and land on the water.

the fuselage in terms of force is a thin-walled beam, the supports of which are the wing spars, with which it is connected through the nodes of the power frames.

the mass of the fuselage structure is 9…15 % from the takeoff weight of the aircraft.

Vertical plumage5 consists of a fixed part keel4 and rudder (PH) 7 .

Keel 4 provides the aircraft with directional stability in the plane X0Z, and РН - directional controllability about the axis 0y.

Trimmer RN 6 ensures the removal of prolonged loads from the pedals, for example, in the event of an engine failure.

Horizontal tail9 includes a fixed or limited movable part ( stabilizer2 ) and the moving part - elevator (RV) 3 .

Stabilizer 2 gives the aircraft longitudinal stability, and RV 3 - longitudinal controllability. RV can carry a trimmer 8 to unload the steering column.

Weight, structures of GO and VO usually do not exceed 1.3 ... 3 % from the takeoff weight of the aircraft.

Chassis aircraft 16 refers to takeoff and landing devices (TLU), which provide takeoff, takeoff, landing, run and maneuvering of the aircraft when moving on the ground.

The number of supports and their relative position center of gravity (CM) of the aircraft depends on the chassis layouts and the characteristics of the operation of the aircraft.

The landing gear of the aircraft shown in Fig. 2.1 has two main supports16 and one bow support17 . Each support includes a power rack18 and supporting elements wheels15 . Each support can have several racks and several wheels.

Most often, the landing gear of an aircraft is made retractable in flight, therefore, special compartments in the fuselage are provided for its placement. 13. It is possible to clean and place the main landing gear in special gondolas (or engine nacelles), fairings14 .

The chassis ensures the absorption of the kinetic energy of impact during landing and braking energy during the run, taxiing and maneuvering the aircraft on the airfield.

amphibious aircraft can take off and land both from ground airfields and from the water surface.

Fig.2.2. Amphibious aircraft landing gear.

on the body seaplane install a wheeled chassis, and place under the wing floats1 ,2 (fig.2.2).

The relative mass of the chassis is usually 4…6 % from the takeoff weight of the aircraft.

Power point 19 (see Fig. 2.1), provides the creation of aircraft thrust. It consists of engines, as well as systems and devices that ensure their operation in flight and ground operation of the aircraft.

For piston engines, the thrust force is created by a propeller, for turboprops - by a propeller and partly by the reaction of gases, for jet engines - by the reaction of gases.

The CS includes: engine attachment points, nacelle, CS control, engine input and output devices, fuel and oil systems, engine start systems, fire and anti-icing systems.

The relative mass of the control system, depending on the type of engines and their layout on the aircraft, can reach 14 ... 18 % from the takeoff weight of the aircraft.

2.2. Technical, economic and flight technical
aircraft characteristics

The technical and economic characteristics of the aircraft are:

Relative payload mass:

`m mon = m Mon /m 0

where m mon - payload mass;

m 0 - aircraft takeoff weight;

Relative mass of the maximum paid load:

`m knmax = m knmax / m 0

where m knmax mass of maximum payload;

Maximum hourly output:

P h = m knmax ∙ v flight

where v flight - flight speed of the aircraft;

Fuel consumption per unit of productivity q T

The main flight performance characteristics of aircraft include:

Maximum cruising speed v cr.max;

cruising economic speed V to p .ek;

Cruise altitude H to p;

Flight range with maximum paid load L;

Average lift-to-drag ratio To in flight;

rate of climb;

Carrying capacity, which is determined by the mass of passengers, cargo, baggage carried on an aircraft for a given flight mass and fuel supply;

Takeoff and landing characteristics (TLC) of the aircraft.

The main parameters characterizing the airborne landing are the approach speed - V z.p.; landing speed - V P; take-off speed - V omp; takeoff run length l once; landing run length - l np; the maximum value of the lift coefficient in the landing configuration of the wing - With y max n;maximum value of the lift coefficient in the takeoff configuration of the wing With at max vzl

Aircraft classification

Classification of aircraft is carried out according to many criteria.

One of the main criteria for classifying aircraft is appointment criterion . this criterion predetermines the flight performance, geometric parameters, layout and composition of the functional systems of the aircraft.

According to their purpose, aircraft are divided into civil and military . Both the first and second aircraft are classified depending on the type of tasks performed.

The classification of civil aircraft only is considered below.

Civil aircraft designed to transport passengers, mail, cargo, as well as to solve a variety of economic problems.

Aircraft are divided into passenger , cargo , experimental , training , as well as aircraft target national economic purpose .

Passenger aircraft, depending on the flight range and carrying capacity, are divided into:

- long haul aircraft - range of flight L>6000 km;

- medium haul aircraft - 2500 < L < 6000 км;

- short haul aircraft - 1000< L < 2500 км;

- aircraft for local airlines (MVL) - L <1000 км.

long haul aircraft(Fig. 2.3) with a flight range of more than 6000 km, usually equipped with a control system of four turbofan engines or propfan engines, which improves flight safety in the event of failure of one or two engines.

Medium haul aircraft(Fig. 2.4, Fig. 2.5) have a control system of two or three engines.

Short haul aircraft(Fig. 2.6) with a flight range of up to 2500 km, they have a control system of two or three engines.

Aircraft of local airlines (LA) are operated on air routes with a length of less than 1000 km, and their control system can consist of two, three or even four engines. The increase in the number of engines to four is due to the desire to ensure a high level of flight safety with a high intensity of takeoffs and landings, typical for international aircraft.

MVL aircraft include administrative aircraft, which are designed to carry 4 ... 12 passengers.

Cargo aircraft provide transportation of goods. These aircraft, depending on the flight range and carrying capacity, can be subdivided similarly to passenger ones. transportation of goods can be carried out both inside the cargo compartment (Fig. 2.7) and on the external sling of the fuselage (Fig. 2.8).

Training aircraft provide training and training for flight personnel in educational institutions and civil aviation training centers (Fig. 2.9) Such aircraft are often made double (instructor and trainee)

experimental aircraft are created to solve specific scientific problems, to conduct full-scale research directly in flight, when it is necessary to verify hypotheses and constructive solutions.

Aircraft for national economy depending on the intended use, they are divided into agricultural, patrol, observations of oil and gas pipelines, forests, coastal zone, traffic, sanitary, ice reconnaissance, aerial photography, etc.

Along with aircraft specially designed for these purposes, small-capacity MVL aircraft can be re-equipped for specific tasks.

Rice. 2.7. Cargo airplane

Rice. 2.10

Rice. 2.9

Fig.2.8

Rice. 2.8. Transportation of goods on an external sling

Rice. 2.9. Trainer aircraft

Rice. 2.10. Aircraft of national economic purpose

Aerodynamic layout aircraft characterizes the number, external shape of the bearing surfaces and the relative position of the wing, tail and fuselage.

The classification of aerodynamic layouts is based on two features:

- wing shape ;

- plumage arrangement I.

In accordance with the first sign, six types of aerodynamic configurations are distinguished:

- with a straight and trapezoidal wing;

- with swept wing;

- with a delta wing;

- with a straight wing of small elongation;

- with an annular wing;

- with round wing.

For modern civil aircraft, the first two and partly the third type of aerodynamic configurations are practically used.

According to the second type of classification, the following three options for aerodynamic layouts of aircraft are distinguished:

Normal (classical) scheme;

Schemes "duck";

Tailless scheme.

A variation of the "tailless" scheme is the "flying wing" scheme.

Aircraft normal circuit (see fig. 2.5, 2.6) have GO located behind the wing. This scheme has become dominant on civil aviation aircraft.

The main advantages of the normal circuit:

Possibility of effective use of wing mechanization;

Easy balancing of the aircraft with extended flaps;

Reducing the length of the forward fuselage. This improves the pilot's view and reduces the airfoil area, since the shortened forward fuselage causes less destabilizing ground moment;

The possibility of reducing the areas of VO and GO, since the shoulders of GO and VO are much larger than those of other schemes.

disadvantages of the normal scheme:

GO creates negative lift in almost all flight modes. This leads to a decrease in the lift force of the aircraft. Especially in transitional flight conditions during takeoff and landing;

GO is located in the disturbed air flow behind the wing, which adversely affects its operation.

To remove the GO from the "aerodynamic shadow" of the wing or from the "wake" of the flaps in transitional flight modes, it is shifted relative to the wing in height (Fig. 2.11, a), it is carried out to the middle of the keel (Fig. 2.11; b) or to the top of the keel (Fig. 2.11, c).

Rice. 2.12

Rice. 2.11

Rice. 2.11 Horizontal tail layouts

a. VO., offset relative to the wing in height;

b. VO is located in the middle of the keel (cruciform plumage);

in. T-shaped plumage;

g. v - figurative plumage.

In the practice of aircraft construction, there are known cases of using a combined, so-called v-tail (Fig. 2.12). the functions of GO and VO in this case are performed by two surfaces spaced at an angle relative to each other. The rudders placed on these surfaces, with a synchronous up and down deflection, work as a RV, and when one rudder is deflected up and the other down, the aircraft is steered in directional respect.

Quite often, a two-keel and even a three-keel air defense can be used on aircraft.

With the aerodynamic layout of the aircraft according to duck pattern on GO they are placed in front of the wing on the forward part of the fuselage (Fig. 2.13)

The advantages of the "duck" scheme are:

Placement of GO in an undisturbed air flow;

The possibility of reducing the size of the wing, since the GO becomes a carrier, i.e. participates in the creation of the lifting force of the aircraft;

Sufficiently easy parrying of the emerging diving moment when the mechanization of the wing is deflected by the deflection of the GO;

Rice. 2.13 The layout of the aircraft according to the scheme "duck"

An increase in the GO shoulder by more than 30% than in the normal scheme, which makes it possible to reduce the wing area;

When high angles of attack are reached, the flow stall on the GO occurs earlier than on the wing, which practically eliminates the risk of the aircraft reaching supercritical angles of attack and stalling it into a tailspin.

For an aircraft made according to the "duck" scheme, the shift of the focus position back when moving from M<1 к М>1 is less than that of normal aircraft, so the increase in the degree of longitudinal stability is observed to a lesser extent.

The disadvantages of this scheme are:

Reducing the bearing capacity of the wing by 10-15 % due to the bevel of the flow from the GO;

A relatively small arm of the VO, leading to an increase in the area of the VO, and sometimes to the installation of two keels to increase directional stability. This compensates for the destabilizing moment created by the elongated forward fuselage.

Tailless scheme is characterized by the absence of GO (see Fig. 1.13), while the functions of GO are shifted to the wing. Aircraft made according to this scheme may not have a fuselage, in which case they are called a "flying wing". Such aircraft are characterized by minimal drag.

The tailless scheme has the following advantages:

Since triangular wings are used on such aircraft, with large dimensions of the onboard rib, it is possible to reduce the relative thickness of the profile, ensuring the rational use of the wing volume for fuel placement;

The absence of GO loads makes it possible to lighten the tail section of the fuselage;

The cost and weight of the airframe are reduced, since there is no GO, for the same reason, the frictional resistance of the aircraft decreases due to a decrease in the area of the surface streamlined by the air flow;

Significant geometric dimensions of the onboard rib provide the ability to create the effect of "air cushion" in the landing mode of the aircraft;

Since double swept wings are used in the "tailless" scheme, a significant increase in the lift coefficient occurs during takeoff.

Among the shortcomings of this scheme, the most significant are:

Impossibility of full use of the bearing capacity of the wing on landing;

Reducing the aircraft ceiling due to a decrease in aerodynamic quality, which is explained by holding the elevons in the upper deflected position to achieve the highest angle of attack of the wing;

Difficulty, and sometimes the impossibility of balancing the aircraft with the flaps extended;

It is difficult to ensure the directional stability of the aircraft due to the small shoulder of the VO, therefore, sometimes three keels are installed (see Fig. 1.13).

In the practice of experimental aircraft construction, you can find options with a combination of basic schemes in one aircraft.

A variant is possible when two GOs are used on the aircraft - one in front of the wing and the second behind it. When implementing the "tandem" scheme, the aircraft has a wing and GO that are almost commensurate in area. The "tandem" scheme can be considered as an intermediate between the normal scheme and the "duck" scheme, due to which the operational range of balance of balance is expanded with relatively small losses in aerodynamic quality for balancing the aircraft.

The main design features by which aircraft are classified are:

Number and arrangement of wings;

Fuselage type;

Type of engines, number and placement of them on the aircraft;

Chassis scheme, characterized by the number of supports and their relative position relative to the aircraft CM.

Depending on the number of wings, monoplanes and biplanes are distinguished.

Scheme monoplane dominates in aircraft construction, and most aircraft are made according to this scheme, which is due to the lower drag of the monoplane and the possibility of increasing the increase in flight speeds.

Planes scheme "biplane" (Fig. 2.16) are distinguished by high
maneuverability, but they are low-speed, so this scheme is implemented for special-purpose aircraft, for example, for agricultural ones.

Figure 2. 16 Biplane aircraft

According to the location of the wing relative to the fuselage, aircraft can be operated according to the scheme "low-wing" (Fig. 2.17, a), "medium-wing" (Fig. 2.17, b) and "high-wing" (Fig. 2.17, c).

Fig.2.17. Various wing layouts

Scheme "low-wing" the least advantageous in terms of aerodynamics, since in the zone of junction of the wing with the fuselage, the smoothness of the flow is disturbed and additional resistance arises due to the interference of the wing-fuselage system. This disadvantage can be significantly reduced by setting fairings, ensuring the elimination of the diffuser effect.

The placement of the gas turbine engine in the root part of the wing makes it possible to use
ejector effect from the engine jet, which is called active fairing.

The low-wing aircraft has a higher location of the lower fuselage contour above the ground. This is due to the need to prevent the wing tip from touching the runway surface during a rolled landing, as well as to ensure the safe operation of the control system when placing engines on the wing. In this case, the process of unloading and loading cargo, luggage, as well as boarding and disembarking passengers becomes more complicated. This shortcoming can be avoided by equipping the landing gear of the aircraft with a "squat" mechanism.

The "low-wing" scheme is most often used for passenger aircraft, as it provides greater safety compared to other options for emergency landing on soil and water. During an emergency landing on the ground with the landing gear retracted, the wing absorbs the impact energy, protecting the passenger cabin. When landing on water, the aircraft is immersed in water up to the wing, which gives the fuselage additional buoyancy and simplifies the organization of work related to the evacuation of passengers.

An important advantage of the "low-wing" scheme is the smallest mass of the structure, since the main landing gear is most often associated with the wing and their dimensions and weight are less than those of a high-wing. Compared to a high-wing aircraft with a landing gear on the fuselage, a low-wing aircraft has a lower mass, since it does not require weighting of the fuselage associated with attaching the main landing gear to it.

The low-wing aircraft with the placement of the main supports on the wing retains the basic rule: the aircraft is supported by the bearing surface. This rule is maintained in all operational modes, both in flight and during takeoff and landing. The wing in the latter case rests on the chassis during the run and run. Thanks to this, it is possible to unify the power circuit, which determines the ways of transferring maximum loads, and to reduce the weight of the aircraft structure as a whole. The considered advantages have become the reason for the dominant position of the "low-wing" scheme on passenger aircraft.

Scheme "medium plan" (Fig. 2. 17, b) is most often not used for passenger and cargo aircraft, since the wing box (its power section) cannot be placed in the passenger or cargo cabin.

With the growth of take-off masses and aircraft parameters, it becomes possible to bring the wing layout of wide-body aircraft closer to the mid-plane. In this case, the wing is raised to the level of the floor of the passenger cabin or cargo compartment, as is done on the A-300, Boeing-747, Il-96, etc. Thanks to this solution, it is possible to significantly improve aerodynamic characteristics.

In its pure form, the "medium-plan" scheme can be implemented on double-deck aircraft, where the wing practically does not interfere with the use of fuselage volumes for accommodating passenger compartments, cargo spaces and equipment.

The "high-wing" scheme (Fig. 2.17, c) is widely used for cargo aircraft, and also finds application on MVL aircraft. In this case, it is possible to obtain the smallest distance from the lower contour of the fuselage to the runway surface, since the high wing does not affect the choice of the height of the fuselage relative to the ground.

When using schema "high-wing" there is a possibility of free maneuvering of special vehicles during aircraft maintenance.

The transport efficiency of cargo aircraft is increased due to the lowest position of the cargo compartment floor, which allows for quick and easy loading and unloading of bulky cargo, self-propelled equipment, various modules, etc.

The resource of engines increases, since they are located at a considerable distance from the ground and the probability of solid particles from the runway surface entering the air intakes is sharply reduced.

The noted advantages of the high-wing aircraft explain the dominant position that this scheme has taken on transport aircraft in domestic (An-22, An-124, An-225), foreign (C-141, C-5A, C-17 (USA) and others .) practice.

The "high-wing" scheme easily provides a rated safe distance from the runway surface to the end of the propeller blade or the lower contour of the GTE air intake. This explains the rather frequent use of this scheme on MVL passenger aircraft (An-28 (Ukraine), F-27 (Holland), Short-360 (England), ATP 42, ATP-72 (France-Italy)).

The undoubted advantage of the "high-wing" scheme is a higher value With at max due to the preservation of a completely or partially aerodynamically clean upper surface of the wing above the fuselage, greater efficiency of wing mechanization by reducing the end effect on the flaps, since the fuselage side and the engine nacelle play the role of end washers.

However, the large mass of the airframe structure in comparison with other schemes adversely affects either the payload, or the fuel supply and flight range. The weighting of the airframe structure is explained by:

The need to increase the area of VO by 15-20 % due to part of it getting into the shading zone from the wing;

An increase in the mass of the fuselage by 15-20 % due to an increase in the number of reinforced frames in the attachment area of the main landing gear, strengthening the structure of the lower fuselage contour area in case of an emergency landing with the landing gear not extended, and due to hardening of the pressurized cabin.

When attaching the main landing gear to the power base of the fuselage, there are difficulties in providing the required gauge.

The small track of the chassis increases the load on one concrete slab,
which may require a higher aerodrome class to operate the aircraft.

The desire to provide an acceptable gauge often makes it necessary to increase the overall width of the reinforced frames in the area where the main supports are located, to form protruding landing gear nacelles and to increase the midsection of the aircraft, and hence its aerodynamic drag. As statistics show, in this case, the frontal resistance of the chassis nacelles can reach 10-15 % from the total resistance of the fuselage.

The lower safety of a high-wing aircraft during an emergency landing on water and land sometimes makes it impossible to use this scheme on aircraft with a large passenger capacity, since during an emergency landing on the ground, the wing with its mass, together with the engines, tends to crush the fuselage and the passenger cabin. When landing on water, the fuselage sinks to the lower contours of the wing and the passenger cabin may be under water. In this case, the organization of work to rescue passengers is much more complicated and evacuation of people is possible only through emergency hatches in the upper part of the fuselage.

by fuselage type aircraft are divided into conventional ones, i.e. made according to a single-fuselage scheme (Fig. 2.18, a); according to the two-fuselage scheme and the "nacelle" scheme (Fig. 2.18, b).

Rice. 2.18 Classification of airplanes by fuselage type

The most widely used single-fuselage scheme, which allows you to get the most advantageous configuration of the fuselage shape from an aerodynamic point of view, since the drag in this case will be the smallest compared to other types.

When placing the tail of the aircraft not on the fuselage, but on two beams (Fig. 2.18, b) or replacing the fuselage with a gondola, an increase in drag occurs. The "nacelle" scheme (Fig. 2.18, b) is characterized by poor streamlining of the nacelles, which can lead to aircraft instability at high angles of attack. Therefore, the two-beam "nacelle" scheme in the practice of aircraft construction is rarely implemented, mainly on transport aircraft, where issues of transport efficiency become paramount. An example of such a solution is the Argosy cargo aircraft from Hawker Sidley.

Fig. 2.19 Aircraft "Adgie Aircraft"

By engine type distinguish between aircraft with PD, turbojet, TVLD, etc.

By number of engines aircraft are divided into one-, two-, three-, four-, six-engine.

On passenger aircraft, from the condition of ensuring flight safety, the number of engines should not be less than two. An increase in the number of engines over six is unjustified due to the difficulties associated with ensuring the synchronization of the operation of individual control systems and the increase in time and labor intensity of maintenance work.

According to the location of the engines subsonic passenger aircraft can be classified into four main groups: engines - on the wing (Fig. 2.20, a), engines - in the root of the wing, engines - on the rear fuselage (b) and a mixed version (c) of the engine layout.

When choosing a place for installing engines, the features of the general layout of the aircraft, operating conditions and ensuring the maximum engine life are taken into account, they strive to obtain the least frontal resistance of the control system, to minimize air losses in the air intakes.

So, on aircraft with three engines, it is advisable to use a mixed layout option (Fig. 2.20): two engines under the wing and a third one in the rear fuselage or on the keel.

Rice. 2.20 Aircraft engine layouts

On aircraft with two engines, the control system is placed on the wing or on the rear fuselage.

With an increase in the bypass ratio of the engine, its diameter increases. Therefore, when arranging the engines under the wing, it is necessary to increase the height of the chassis to ensure a normalized distance from the bypass of the engine nacelle to the ground. This leads to an increase in the mass of the aircraft structure and creates a number of problems related to passengers, baggage and maintenance. First of all, this applies to MVL aircraft, which are often operated from airfields that do not have special equipment. At the same time, the effect of unloading the wing in flight due to the placement of engines on it is significantly reduced, since with an increase in the bypass ratio, the specific gravity of the turbojet engine decreases.

Figure 2.21 shows two aircraft, the design of which was created on the basis of the same requirements for paid load, range, air-to-air ratio, fuselage midsection, etc. Figure 2.21 shows the difference between the two aircraft in terms of the height of the wing and fuselage relative to the ground.

Fig. 2.21 Effect of bypass engines on aircraft layout

By type of landing gear they are divided into wheeled, ski, float (for seaplanes), caterpillar and hovercraft chassis.

The predominant distribution was received by a wheeled chassis, and quite often a float is used.

According to the chassis diagram aircraft are divided into tricycle and
two-support.

The three-bearing scheme is carried out in two versions: a three-bearing scheme with a nose support and a three-bearing scheme with a tail support. In most cases, aircraft use tricycle with nose support. The second version of this scheme is found on light aircraft.

The two-bearing chassis scheme on civil aircraft is practically not used.

On heavy, especially transport, aircraft, a multi-support chassis scheme has become widespread. For example, on a Boeing-747 aircraft, a five-post landing gear is used, on an An-225 aircraft, a sixteen-post landing gear, and on a passenger Il-86, a four-post landing gear.

2.4. DESIGN REQUIREMENTS
AIRCRAFT

All requirements for the design of aircraft are divided into general , mandatory for all airframe units, and special .

The general requirements include aerodynamic, strength and rigidity, reliability and survivability of aircraft, operational, maintainability, manufacturability of aircraft production, economic and requirements, minimum weight of the airframe structure and functional systems.

Aerodynamic requirements are reduced to ensuring that the influence of the aircraft shape, its geometric and design parameters correspond to the given flight data obtained at the lowest energy costs. The implementation of these requirements provides for ensuring the minimum resistance of the aircraft, the required characteristics of stability and controllability, high air handling characteristics, indicators of the cruising flight mode.

The fulfillment of aerodynamic requirements is achieved by choosing the optimal values of the parameters of individual units (parts) of the aircraft, their rational mutual layout and a high level of specific parameters.

Strength and stiffness requirements are presented to the airframe frame and its skin, which must withstand all types of operational loads without destruction, while deformations should not lead to a change in the aerodynamic properties of the aircraft, dangerous vibrations should not occur, and significant residual deformations should not appear. The fulfillment of these requirements is ensured by the choice of a rational power circuit and cross-sectional areas of power elements, as well as the selection of materials.

Reliability and survivability requirements aircraft provide for the development and implementation of constructive measures aimed at ensuring flight safety.

Aircraft reliability represents the ability of a structure to perform its functions while maintaining operational performance for a specified period of an inter-regulatory period, resource or other unit of measurement of the operating time. Reliability characteristics are flying hours per failure, the number of failures per one flight hour, etc.

The reliability of the aircraft can be increased by selecting reliable structural elements, their duplication (redundancy).

Aircraft survivability is determined by the ability of the structure to perform its functions in the presence of damage. To ensure this requirement, constructive measures are necessary, for example, the use of statically indeterminate power circuits, effective fire protection measures and, mainly, redundancy. These requirements are especially important to ensure a given level flight safety .

Operational Requirements provide for the establishment of such
structures that allow in a short time to provide technical
maintenance of aircraft at minimal material and technical costs.

The implementation of such requirements is possible by providing convenient access to the units, standardization and unification of units, units, parts of the aircraft and connectors, the use of built-in systems for automatic monitoring of the technical condition of aircraft systems and units, effective systems for troubleshooting and troubleshooting, increasing the resource and inter-regulation service life.

Maintainability Requirements predetermine the possibility of a quick and cheap restoration of failed (damaged) parts of the aircraft, operational maintenance of the number of aircraft and engine fleet. The significance of these requirements is increasing due to the constant complication of aircraft and means of

To carry out military air transportation, various transport aircraft and helicopters of military and civil aviation are used.

From the point of view of transportation, transport aircraft and helicopters can be classified according to the purpose, capacity and type of installed engines.

By purpose, transport aircraft (helicopters) are divided into passenger, cargo and cargo-passenger.

Passenger aircraft are designed primarily for the transport of passengers, baggage and mail, for which they have appropriate household equipment that provides convenience and comfort to passengers. Transportation of goods in them can be carried out in small quantities in trunks located under the floor of the passenger cabin.

Passenger airplanes of civil aviation, depending on the passenger capacity, flight range and class of airfields used, are divided into mainline and local airliners.

The main aircraft, in turn, are divided into long-range (DMS), medium (CMC) and short-range (Navy).

The DMS includes: Il-62, Tu-114 and the first supersonic passenger aircraft Tu-144.

To CMC - Tu-154, Tu-104, An-10, Il-18.

To the Navy - Tu-134, Tu-124.

The aircraft of local air lines include: An-24, Yak-40, Be-30, An-2.

Cargo aircraft are designed to transport cargo and equipment, they have special equipment that ensures the loading of cargo and its fastening, as well as the necessary climatic conditions inside the cargo compartment during the flight. If necessary, they can be equipped with removable seats for transporting people.

Cargo aircraft include: An-24t, An-12, An-22 and Mi-4A, Mi-8, Mi-6, Mi-10 helicopters.

Cargo-passenger aircraft are designed to carry passengers and cargo. Passenger-and-freight aircraft have separate rooms for passengers (usually the upper floor) and cargo (usually the lower floor) or the passenger cabin equipment is easily removable, which allows, if necessary, to quickly adapt the aircraft (helicopter) to combined or purely cargo transportation. Aircraft adapted for -quick conversion from a passenger to a cargo version are called convertible aircraft.

By carrying capacity, transport aircraft and helicopters are divided into light, with a normal landing load of up to 11 tons, medium - up to 20 tons and heavy - more than 20 tons.

Light aircraft and helicopters are relatively little used in the work of military communications - only for individual small transportation or in conditions where there are no airfields in the unloading area suitable for landing medium-lift aircraft.

For military transport, medium-sized aircraft are currently most widely used: cargo aircraft of the An-12 type and passenger aircraft of the Il-18, Tu-104, An-10 and Tu-154 types. However, it is known that as the carrying capacity and passenger capacity of aircraft increase, the productivity of air transport workers increases, and the cost of transportation decreases, it becomes possible to carry out a given volume of traffic with a smaller number of aircraft, which helps to reduce the frequency of aircraft movement in airport areas and improves flight safety. Considering the development of military air transport, there is every reason to believe that heavy transport aircraft with a payload capacity of 100 tons or more and passenger or convertible aircraft with a capacity of 300-500 people or more will be increasingly used for their implementation.

According to the type of installed engines, modern transport aircraft and helicopters are divided into those with gas turbine (GTE) and piston (RP) engines.

Aircraft with gas turbine engines, in turn, are divided into those with turbojet engines (TRD) and turboprops (TVD).

Aircraft with turboprop engines have a much lower specific fuel consumption compared to jet ones.

At present, transport aircraft with bypass turbojet engines (DTJD) are becoming more and more common, occupying an intermediate position between the theater and turbojet engines in terms of efficiency.

With a further increase in the speeds of transport aircraft, the most promising are aircraft with compressorless air-jet engines, ramjet engines (ramjet) and pulsed jet engines (puVRJ), which have better operational characteristics compared to the diesel engine at cruising flight speeds corresponding to the number M > 3.

From the point of view of departmental affiliation, transport aircraft (helicopters) are divided into military and civil aviation aircraft (helicopters).

On military aircraft, additional equipment is installed related to the performance of combat missions (weapons, special equipment for parachute landing of troops, equipment and cargo, an in-flight refueling system, etc.).

The main units of the aircraft

Airplanes are heavier than air aircraft, they are characterized by the aerodynamic principle of flight. Airplanes have lift Y is created due to the energy of the air flow washing the bearing surface, which is fixedly fixed relative to the body, and translational motion in a given direction is provided by the thrust of the power plant (PU) of the aircraft.

Rice. 2.1. The main structural elements of the aircraft

Aircraft wing1 creates lift and provides lateral stability to the aircraft during its flight.

often the wing is a power base for placing the landing gear, engines, and its internal volumes are used to accommodate fuel, equipment, various components and assemblies of functional systems.

In terms of power, the wing is a beam of complex design, the supports of which are the power frames of the fuselage.

Ailerons11 are cross-government bodies. They provide lateral control of the aircraft.

Depending on the scheme and flight speed, geometric parameters, structural materials and structural power scheme, the mass of the wing can be up to 9 ... 14 % from the takeoff weight of the aircraft.

Fuselage13 combines the main units of the aircraft into a single whole, i.e. provides a circuit for the power circuit of the aircraft.

The internal volume of the fuselage is used to accommodate the crew, passengers, cargo, equipment, mail, baggage, rescue equipment in case of emergencies. Cargo aircraft fuselages are equipped with advanced loading and unloading systems, devices for fast and reliable cargo mooring.