Aviation compass. Aircraft compass. Aircraft magnetic compass. Purpose, principle of operation and device of aviation compasses
The concept of terrestrial magnetism
The globe is a large permanent magnet surrounded by the Earth's magnetic field.
Rice. 26. Forces of terrestrial magnetism 27. Magnetic declination
The state of the Earth's magnetic field is characterized by three main parameters: declination, inclination and intensity. At each point on the Earth, the full force of terrestrial magnetism (T) acts at an angle to the horizon (Fig. 26).
The force T can be decomposed into two components: a horizontal force (H) and a vertical force (Z). The horizontal component of the Earth's magnetic field sets the magnetic needle in the N-S direction. The value of the horizontal component is not constant and varies from the maximum value at the equator to zero at the poles.
Rice. 28. Helicopter courses
The magnetic meridians pass through the magnetic poles, they do not coincide with the geographic meridians and are located at some angles with respect to them.
Magnetic declination - the angle enclosed between the magnetic and geographical meridians, measured in the range from 0 to 180 ° and denoted by ∆M (Fig. 27). AM is east and west. The angle that a magnetic needle forms with a horizontal plane is called the angle of magnetic inclination, at the poles it is 90 °.
The phenomenon of terrestrial magnetism is used in aviation magnetic compasses, which make it possible to determine the magnetic flight course of a helicopter (Fig. 28).
Magnetic compass ki-13k
The magnetic liquid aviation compass is designed to measure and maintain the compass heading of a helicopter; is a backup device and is used in conjunction with the GMK-1A heading system and, in case of its failure, the KI-13K is installed on the frame of the cockpit canopy along the longitudinal axis of the helicopter.
The principle of operation of KI-13K is based on using the property of a freely suspended system of magnets to be installed in the plane of the magnetic meridian.
The compass has a sensitive element consisting of two permanent magnets, which are fixed in the card. The scale of the card is uniform in the range from 0 to 360 °, digitization through 30 °, division value 5 0 . To dampen the vibrations of the card and reduce friction when the card is turned, the glass case of the device is filled with naphtha. In the lower part of the housing there is a deviation device to eliminate semicircular deviation. The compass has an individual scale illumination.
Magnetic compass errors
Deviation- the main methodological error of the magnetic compass. The helicopter's own magnetic field causes the compass card to deviate from the magnetic meridian by some angle α. This angle of deviation of the card is called deviation. The compass deviation is measured in degrees and is conventionally denoted as ∆K (Fig. 29).
As a result of the deviation, the magnetic compass measures the compass heading (KK), which differs from the magnetic one by the amount of deviation:
∆K = MK-KK.
The magnetic field of the helicopter, which causes ∆K, is created by the ferromagnetic parts of the helicopter structure and the operation of the electrical and radio equipment. The ferromagnetic parts of the helicopter form "helicopter iron", which is conditionally divided into two groups according to its magnetic properties: solid iron; soft iron.
solid iron, being magnetized, it retains its magnetism for a long time. Solid iron creates a semicircular deviation, which is eliminated by the deviation device of the KI-13K compass on four main points 0°, 90°, 180o, 270°. 
The semicircular deviation during a 360° turn of the helicopter changes its sign twice and comes to zero twice, the change occurs according to a sinusoidal law.
Rice. 29. Deviation
magnetic compass
soft iron is magnetized in proportion to the strength of the magnetic field, and its magnetism is not constant. Soft iron forms a quadruple deviation, which, when turned through 360 °, changes its sign four times. The quarter deviation for the KI-13K compass is not eliminated, but as part of the residual deviation it is written off to the correction chart, which is installed in the cockpit and is used by the pilot to take into account the correction when reading the helicopter's magnetic heading according to the KI-13K.
Permanent deviation (installation error) is compensated by turning the compass at the attachment point. It is determined by algebraic addition of the residual deviation on points 0°, 90°, 180°, 270° and dividing the resulting sum by four. Constant deviation is compensated if ∆Kset is greater than ±2°. Permissible installation error ∆K ±1°.
Other magnetic compass errors
1. North turning error - occurs as a result of the action of the vertical component of the force of terrestrial magnetism on the magnetic system of the compass when the helicopter rolls.
2. Cart entrainment - occurs due to the fact that naphtha additionally unfolds the card when performing a turn due to the presence of friction forces. With long turns, the enthusiasm of the card can reach the speed of the turn.
Cartridge drift greatly distorts the compass readings, so it is very difficult to use the KI-13K during a turn.
After the end of the turn, the card is set within 20-30 seconds, and it is necessary to take the average reading.
Pre-flight preparation of the KI-13K compass and its use in flight
Before the flight, check the device by visual inspection (fastening, cleanliness and level of naphtha). Check if there is a deviation graph in the cockpit.
After taxiing out to the line start, make sure that the MK taken from KI-13K and UGR-4UK corresponds to the direction of the runway axis with an accuracy of ±2°.
KI-13K is used in level flight to duplicate readings of the heading system GMK-1A.
Stable operation of the compass is ensured with helicopter rolls up to 17°, therefore, turns and turns along KI-13K should be performed with rolls of no more than 15°.
In the absence of visual visibility, while climbing or descending, the specified flight course must be maintained according to the indicators of the GMK-1A course system. Deviation work on compasses should be carried out:
if the crew has any comments about the correctness of the course readings;
after installing a new compass;
after replacement of helicopter engines, gearboxes, other massive structural parts;
at least once a year (especially when preparing for important missions and when relocating a helicopter associated with a significant change in latitude.
The deviation work is carried out by the flight navigator (detachment) together with the crew and instrumentation specialists.
The distribution of attention of the helicopter commander during instrument flight should be approximately as follows:
in climb:
AGB-ZK-VR-10, AGB-ZK-UGR-4UK, VD-10, AGB-ZK->US-450 and then in the same order:
in level flight: AGB-ZK->VR-10, AGB-ZK->UGR-4UK-VD-10, AGB-ZK-US-450 and further in the same order with periodic monitoring of the engine operation mode;
when performing turns and turns: AGB-ZK (silhouette of an “airplane” - a ball) -> -VR-10, AGB-ZK->US-450, AGB-ZK->UGR-4UK->VR-10 and further in this the same order;
on landing approach after the 4th turn: AGB-ZK--UGR-4UK--VR-10, AGB-ZK-UGR-4K--VD-10--US-450 and then in the same order.
From the book School of Survival in Accidents and Disasters author Ilyin AndreyAIR TRANSPORT Statistics state that aviation is the safest mode of transport. On average, just over 3,000 people die in aviation accidents worldwide every year. For comparison, I will give all the same statistics of traffic accidents,
From the book All About Everything. Volume 1 the author Likum ArkadyWho Invented the Compass? The simplest form of a compass is a magnetic needle mounted on a rod so that it can rotate freely in all directions. The arrow of such a so-called compass points to "north", which refers to the North magnetic pole
From the book 100 great inventions author Ryzhov Konstantin Vladislavovich21. KOMPAS Compass, like paper, was invented by the Chinese in ancient times. In the III century BC. the Chinese philosopher Hen Fei-tzu described the device of the modern compass as follows: it looked like a pouring spoon made of magnetite with a thin handle and spherical, carefully
From the book Great Soviet Encyclopedia (AS) of the author TSB From the book Great Soviet Encyclopedia (AB) of the author TSB From the book Great Soviet Encyclopedia (YOU) of the author TSB From the book Great Soviet Encyclopedia (GI) of the author TSB From the book Great Soviet Encyclopedia (GO) of the author TSB From the book Great Soviet Encyclopedia (KA) of the author TSB From the book Great Soviet Encyclopedia (KO) of the author TSB From the book Great Soviet Encyclopedia (MO) of the author TSB From the book Great Soviet Encyclopedia (PO) of the author TSB From the book 100 famous inventions author Pristinsky Vladislav Leonidovich From the book Great Encyclopedia of Technology author Team of authors From the author's book From the author's bookAircraft rocket engine Aircraft rocket engine is a direct reaction engine that converts any type of primary energy into the kinetic energy of the working fluid and creates jet thrust. The thrust force is applied directly to the body of the rocket
AVIATION COMPASS
compass, an aeronautical instrument that indicates to the pilot the course of the aircraft relative to the magnetic meridian (magnetic compass, gyromagnetic compass), a given direction (gyro semi-compass) or direction to a radio beacon (radio compass, radio semi-compass) and relative to any celestial body (astronomical compass).
Great Soviet Encyclopedia, TSB.
2012See also interpretations, synonyms, meanings of the word and what is AVIATION COMPASS in Russian in dictionaries, encyclopedias and reference books:
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(lat. Pyxis) the constellation of the Southern ... - COMPASS JOURN. in the Encyclopedic Dictionary of Brockhaus and Euphron:
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[Dutch kompas] a device for orienting relative to the cardinal points on land, at sea and in the air; consists of a magnetic needle rotating ... - COMPASS in the Encyclopedic Dictionary:
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OMPASS (lat. Pyxis), constellation South. … - COMPASS in the Big Russian Encyclopedic Dictionary:
OMPASS (German Kompass), a device indicating the direction of geogr. or magn. meridian; serves for orientation relative to the sides of the horizon. There are magnetic, mechanical. (gyrocompass), ... - AVIATION in the Big Russian Encyclopedic Dictionary:
AIR TRANSPORT, see Transport ... - AVIATION in the Big Russian Encyclopedic Dictionary:
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The magnetic compass in the aircraft determines and maintains the heading of the direction of flight. The heading of the aircraft is the angle between the longitudinal axis of the aircraft and the actual direction along the meridian. It is customary to count the course from the northern direction of the meridian. From the meridian count the angle clockwise to the longitudinal axis of the aircraft. As you know, the course can be magnetic, compass and true.
The principle of operation of each compass is based on the action of a magnetic needle, which is installed in the plane of the magnetic meridian in the north direction. After determining the magnetic meridian with the help of a compass, the angle to the longitudinal axis of the aircraft is measured - this is the magnetic heading. It should be noted that modern compasses installed in the cockpit are structurally different from field compasses. The construction of aviation compasses uses materials that exhibit weak magnetic or diamagnetic properties. The main structural parts of an aircraft compass are: a bracket, a heading line, a deviation device, a card, a bowler hat.
A kettle is a vessel made of aluminum or copper and hermetically sealed with a glass lid. The inside of the kettle is filled with a liquid, usually naphtha or wine alcohol. Replacing or adding liquid significantly impairs the performance of the device and may lead to complete unusability. The liquid serves as a damper and dampens the vibrations of the card, and also reduces the pressure of the pin on the firebox.
In the middle of the pot there is a column on which a potato is attached. A card is a complex of connected magnets, which are directed one to one with the same charged pole. In most cases, aviation compass cards consist of two horizontal and two vertical magnets. The magnets must be positioned with a high degree of accuracy, since the slightest shift can cause the readings to deviate from the true ones. The upper pairs of magnets have a much larger magnetic moment than the lower pairs, at a ratio of 15 CGSm to 12 CGSm. As a result, the total moment should not be lower than 54-56 CGSm. The quality of the compass depends on the correct selection of magnets and their sizes. An arrow is installed at the end of the card, which points to the side of the horizon; it serves to orientate in the flight map. The total magnetic system is calculated for 200 hours of engine operation. Inside the bowler there is a course line, which is used as an index when counting the course.
The aircraft compass bowl is filled with liquid, and when the temperature changes, its volume changes, which can lead to a malfunction in the instrument readings. To avoid this situation, a compensation chamber is installed.
This design is used in all modern aircraft compasses. There are differences, they appear mainly in the depreciation system or the shape of the card. Lighting devices are also used for night operation.
The practical application of the compass on an aircraft shows that its use is different for the navigator and the pilot. The pilot uses this device to select the correct direction of flight. It is used to analyze flight fidelity and detect course deviations. As for the navigator, he uses the compass to quickly calculate the flight map, as well as to analyze the course. The navigator's compass is considered to be the main one on board the aircraft. Because of this, two types of magnetic aviation compasses are distinguished, which are installed on the aircraft's boron - this is the main and directional.
Aircraft magnetic compass deviation
Even at the dawn of the aircraft industry, all aircraft, without exception, were equipped with magnetic compasses, which did an excellent job of determining the magnetic course of the apparatus. Nevertheless, with the further development of multi-engine units with a large part of the electronics, significant problems arose with the operation of compasses. All electromagnetic vibrations emanating from other devices significantly affected the operation and accuracy of the readings of the device. In some cases, the compass readings could differ from the true ones by a dozen degrees, and this is a lot to determine the correct direction of flight. All compasses during flight experience accelerating and magnetic effects that lead to deviation.
Magnetic deviation. The system of each compass receives influence from various magnetic fields both of the Earth itself and other sources of magnetism directly on board the aircraft. These can be radio systems, electrical wiring and its fields, as well as the steel mass of the structure itself. Because of this, the compasses on board the aircraft have errors in their readings, which are commonly called magnetic deviation.
The permanent magnetic deviation on board the aircraft is caused by the inaccuracy of the compass itself. It is characterized by dependence on the magnetic course itself.
The semi-circular magnetic deviation in compass readings can be caused by the so-called hard iron, which has a permanent magnetic charge. Readings are also affected by more permanent sources such as electrical appliances and wiring. They have a constant force and direction of influence on the compass.
There is also such a thing as inertial deviation, which occurs due to chatter, changes in speed, turn, all this creates forces that affect the readings of the magnetic compass on board the aircraft. All this greatly complicates the work with the device and the calculation of the fidelity of the direction.
Nevertheless, in the manufacture of compasses and the aircraft themselves, designers take into account all these effects and deviations. To reduce third-party influences on the accuracy of the compass readings, systems are used that can significantly reduce all of the above impacts on the accuracy of the readings.
The magnetic compass in the aircraft determines and maintains the heading of the direction of flight. The course of the aircraft is the angle between the longitudinal real direction and the axis of the aircraft along the meridian. It is customary to count the course from the northern direction of the meridian.
From the meridian count the angle clockwise to the longitudinal axis of the aircraft. As we know, the course is possibly magnetic, compass and authentic.
The principle of operation of each compass is based on the action of a magnetic needle, which is installed in the plane of the magnetic meridian in the north direction. At the end of the determination of the magnetic meridian, the angle to the longitudinal axis of the aircraft is measured using a compass - this is the magnetic heading. It should be emphasized that modern compasses installed in the cockpit are structurally different from field compasses.
The design of aviation compasses uses materials that exhibit weak magnetic or diamagnetic features. The main structural parts of an aircraft compass are: a bracket, a heading line, a deviation device, a card, a bowler hat.
A kettle is a vessel made of aluminum or copper and hermetically sealed with a glass lid. The inside of the kettle is filled with liquid, in most cases, it is naphtha or ethyl alcohol. Replacing or adding fluid significantly impairs the operation of the device and may lead to complete unsuitability.
The liquid helps as a dampener and dampens the vibrations of the card, in addition, it reduces the pressure of the pin on the firebox.
In the middle of the pot there is a column on which a potato is attached. A card is a complex of connected magnets, which are directed one to one with the same charged pole. As a rule, aviation compass cards are made up of two horizontal and two vertical magnets.
The magnets must be positioned with a high degree of accuracy, because the slightest shift can cause the readings to deviate from the true ones. The top pairs of magnets have a much larger magnetic moment than the bottom pairs, at a ratio of 15 CGSm to 12 CGSm. As a result, the total moment should not be lower than 54-56 CGSm. The level of quality of the compass depends on the correct selection of their sizes and magnets.
An arrow is set at the finish of the card, which indicates the side of the horizon, it helps to orientate in the flight map. Non-specialized magnetic assembly is calculated for 200 hours of engine operation. The bowler has a course line, which is used as an index when counting the course.
The aircraft compass bowl is filled with liquid; when the temperature changes, its amount changes, which can lead to a malfunction in the instrument readings. In order to avoid a similar situation, a compensation chamber is installed.
This design is used in all modern aircraft compasses. There are differences, they appear for the most part in the aggregate depreciation or the shape of the card. In addition, lighting devices are used to work at night.
The practical use of the compass on an airplane suggests that its use for the pilot and navigator is different. The pilot uses this device to select the correct direction of flight. It is used to determine the accuracy of deviations and analyze the flight from the course.
As for the navigator, he uses the compass to quickly calculate the flight map, and to analyze the course. It is customary to calculate the navigator's compass as the main one on board the aircraft. Therefore, there are two types of magnetic aviation compasses, which are installed on the aircraft's boron, - this is the main and travel.
Aircraft magnetic compass deviation
Even at the dawn of the aircraft industry, all aircraft, without exception, were equipped with magnetic compasses, which perfectly coped with the task of determining the magnetic course of the apparatus. Nevertheless, with the upcoming development of multi-engine units with a large part of the electronics, serious troubles appeared with the operation of compasses. All electromagnetic oscillations emanating from the second devices had a significant impact on the accuracy and operation of the instrument readings.
In some cases, the compass readings could differ from the true ones by a dozen degrees, and this is quite a lot to determine the correct direction of flight. All compasses during the flight experience accelerating and magnetic actions, which lead to deviation.
Magnetic deviation. The totality of each compass acquires action from different magnetic fields of both the Earth itself and other sources of magnetism specifically on board the aircraft. These can be radio systems, electrical wiring and its fields, and the metal mass of the structure itself.
Therefore, the compasses on board the aircraft have errors in their own readings, which are usually called magnetic deviation.
This deviation parameter can be calculated at the experimental level, along with this, there are three subcategories of deviation, in particular, constant, quarter and semicircular.
The permanent magnetic deviation on board the aircraft is caused by the inaccuracy of the compass itself. It is characterized by dependence on the magnetic course itself.
The semi-circular magnetic deviation in compass readings is possibly caused by the so-called hard iron, which has a permanent magnetic charge. In addition, readings are affected by more permanent sources such as wiring and electrical appliances. They have a constant strength and direction of action on the compass.
There is also such a thing as inertial deviation, which appears due to chatter, speed transformation, turn, all this forms forces that affect the readings of the magnetic compass on board the aircraft. All this significantly complicates the work with the calculation and the device of the fidelity of the direction.
Nevertheless, in the manufacture of the aircraft themselves and compasses, designers take into account all deviations and these effects. To reduce third-party actions on the accuracy of the compass readings, sets are used that allow you to significantly reduce all of the above actions on the accuracy of the readings.
Overview of the compass and little men and planes
