Aviation gyromagnetic compass. aircraft compass

AIRCRAFT MAGNETIC COMPASS AND THEIR APPLICATIONS

Aircraft heading

The course of the aircraft is the angle in the horizontal plane between the direction taken as the reference point and the longitudinal axis of the aircraft. Depending on the meridian, relative to which they are counting, there are true, magnetic, compass and conditional courses ( Rice. one).

The true heading of the IR is the angle enclosed between the north direction of the true meridian and the longitudinal axis of the aircraft; counted clockwise from 0 to 360°.

The magnetic heading of the MC is the angle enclosed between the northern direction of the magnetic meridian and the longitudinal axis of the aircraft; counted clockwise from 0 to 360°.

The compass course KK is the angle enclosed between the north direction of the compass meridian and the longitudinal axis of the aircraft; counted clockwise from 0 to 360°.

The conditional course of the UK is the angle between the conditional direction (meridian) and the longitudinal axis of the aircraft.

True, magnetic, compass and conditional courses are related by the relations:

IC = MK + (± D m); MK = KK + (± D to);

IC = QC + (± D ) = KK + (± D j) + (± D m);

UK = IR + (± D but).

Magnetic declination D m is the angle enclosed between the north direction of the true and magnetic meridians. It is considered positive if the magnetic meridian is deviated to the east (to the right), and negative if the magnetic meridian is deviated to the west (to the left) of the true meridian.

Azimuthal correction D a is the angle between the conditional and true meridian. It is counted from the conditional meridian clockwise with a plus sign, counterclockwise with a minus sign.

Deviation D to is the angle enclosed between the northern direction of the magnetic and compass meridians. It is considered positive if the compass meridian is deviated to the east (to the right) and negative if the compass meridian is deviated to the west (to the left) of the magnetic meridian.

Variation D is the angle enclosed between the north direction of the true and compass meridians. It is equal to the algebraic sum of magnetic declination and deviation and is considered positive if the compass meridian is deviated to the east (to the right), and negative if the compass meridian is deviated to the west (to the left) of the true meridian.

D = (± D m) + (± D to).

Brief information about terrestrial magnetism

To determine and maintain the course of the aircraft, the most widely used are magnetic compasses, the principle of which is based on the use of the Earth's magnetic field.

The earth is a natural magnet around which there is a magnetic field. The magnetic poles of the Earth do not coincide with the geographic ones and are located not on the surface of the Earth, but at some depth. It is conditionally accepted that the north magnetic pole, located in the northern part of Canada, has southern magnetism, that is, it attracts the northern end of the magnetic needle, and the south magnetic pole, located in Antarctica, has northern magnetism, i.e. attracts south end magnetic needle. A freely suspended magnetic needle is installed along the magnetic lines of force.

The Earth's magnetic field at each point is characterized by the intensity vector NT measured in oersteds, inclination J and declension D m which are measured in degrees.

The total magnetic field strength can be decomposed into its components: vertical Z , directed towards the center of the earth, and horizontal H , located in the plane of the true horizon ( Rice. 2). Strength H is directed along the horizon along the meridian and is the only force holding the magnetic needle in the direction of the magnetic meridian.

With increasing latitude, the vertical component Z . varies from zero (at the equator) to a maximum value (at the pole), and the horizontal component H accordingly changes from the maximum value to zero. Therefore, in the polar regions, magnetic compasses are unstable, which limits, and sometimes even excludes their use.

Angle between horizontal plane and vector H T is called the magnetic inclination and is denoted by the letter J . The magnetic inclination changes from 0 to ±90°. The inclination is considered positive if.vector NT , directed downward from the horizon.

Purpose, principle of operation and device of aviation compasses

The magnetic compass uses the property of a freely suspended magnetic needle to be installed in the plane of the magnetic meridian. Compasses are divided into combined and remote.

For combined magnetic compasses, the course reference scale and the sensitive element (magnetic system) are rigidly fixed on a movable base - a card. Currently, aircraft, helicopters and gliders are equipped with combined magnetic compasses of the type KI (KI-11, KI-12, KI-13), they serve as the pilot's steering compasses and as supplementary compasses in the event of heading instrument failure.

The main advantages of combined compasses are: simplicity of design, reliability of operation, low weight and dimensions, ease of maintenance. On the Rice. 3 shows a cross-section of a magnetic liquid compass of the type KI-12. The main parts of the compass are: sensitive element (card) .7 (compass magnetic system), column 2, course line 3, body 4, diaphragm 5 and deviation device 6 .

A column is placed in the center of the body 2 with a thrust bearing 7. A spring washer is used to limit the vertical movement of the column 8. In the sleeve 9 cartridges pressed core 10, which it rests on the thrust bearing 7. The sleeve has a spring ring 11, protecting the card from jumping off the column when the compass is turned over. The column has a spring cushioning that softens the effect of vertical shocks.

The scale of the card is uniform, with a division value of 5 ° and digitization every 30 °. - The card is painted black, and the numbers and elongated divisions of the scale are covered with a luminous mass.

A holder with two magnets is mounted on the sleeve 12 . The axes of the magnets are parallel to the line C - Yu of the scale.

The deviation device, which serves to eliminate semicircular deviation, is installed in the upper part of the housing. The deviation device consists of two longitudinal and two transverse rollers into which permanent magnets are pressed.


Rice.3 . Compass section KI-12	Rice.4 Appearance compass KI-13

The rollers are connected in pairs with each other by means of gearing and are driven by elongated rollers with splines.

The compass cover has two holes marked C - Yu and B - 3, through which you can rotate the rollers with a screwdriver. When the longitudinal rollers with magnets rotate, an additional magnetic field is created, directed across the aircraft, and when the transverse rollers rotate, a longitudinal magnetic field is created.

Naphtha is poured into the compass case, which provides damping of the vibrations of the card.

The compass has a membrane to compensate for changes in fluid volume as temperature changes. 5, communicating with the body with a special hole.

A light bulb is installed at the bottom of the compass. The light from the bulb through a slot in the case falls on the end of the sight glass, scatters and illuminates the compass scale.

Compass KI-13 (Rice. 4) unlike the KI-12 compass, it has smaller dimensions and weight, as well as a spherical body, which provides good observation of the instrument scale. At the top of the compass there is a diversion chamber to compensate for changes in compass fluid volume. The compass deviation device is designed similarly to the KI-12 compass deviation device, but there is no individual illumination.

Remote compasses are called, in which readings are transmitted to a special pointer installed at some distance from the magnetic system.

The GIK-1 gyro-induction compass is installed on airplanes and helicopters; it serves to indicate the magnetic course and measure the aircraft's turn angles. When working together with an automatic radio compass, on the scale of the gyromagnetic heading indicator and UGR-1 radio bearings, it is possible to read the heading angles of radio stations and the magnetic bearings of radio stations and aircraft.

The principle of operation of the GIK-1 compass is based on the property of an inductive sensing element to determine the direction of the Earth's magnetic field and the property of the gyro-semi-compass to indicate the relative flight course of the aircraft.

Included GIK-1 includes: ID-2 induction sensor, KM correction mechanism, G-ZM gyroscopic unit, UGR-1i pointers UGR-2, amplifier U-6M.

The inductive sensor measures the direction of the horizontal component of the Earth's magnetic field vector. For this purpose, the sensor uses a system of three identical induction-type sensitive elements located in a horizontal plane along the sides of an equilateral triangle of sensitive elements.

The magnetizing windings of the triangle of sensitive elements are fed with alternating current with a frequency of 400 Hz and a voltage of 1.7 V from a step-down transformer located in the SC junction box. .

Rice. 5. Construction of the inductive sensor

1 - core of the sensitive element; 2 - magnetization coil; 3 - signal coil; 4-plastic platform of sensitive elements; 5-inner cardan ring;. 6-hollow cardan axis; 7-cork; 8-float; 9 - deviation device; 10 - clamping ring; // - clamp; 12 - cover; 13-seal gasket; 14-outer cardan ring; 15 - sensor housing; 16, - the hollow axis of the cardan; 17- cup; 18-cargo

Rice. 6, Adjustment mechanism design

1-stator winding of the synchro-receiver; 2- rotor winding of the synchro-receiver; 3-brushes of potentiometers; 4 - base; 5 - curved tape; 6 - head of the deviation screw; 7 - scale 8 - arrow 9 - deviation screw 10 - roller; 11 - swinging lever; 12 - flexible tape! 13 - development engine DID-0.5,

The signal windings are connected to the stator windings of the synchro-receiver of the KM correction mechanism.

The design of the inductive sensor is shown in Fig. five.

The KM correction mechanism is designed to connect the induction sensor with the gyro unit and to eliminate the residual deviation and instrumental errors of the system.

The design of the correction mechanism is shown in Fig. 6.

Pointer UGR-1 (Fig. 7) shows the magnetic heading and angles of the aircraft turn on the heading scale 1 relative to the fixed index 2. The bearings of radio stations and aircraft are determined by the position of the radio compass needle 5 relative to the scale 1. The heading angle of the radio station is measured on a scale of 7 and an arrow 5.

Rice. 7. Pointer UGR-1

Triangular indexes are used to perform 90° turns. Heading arrow 3 installed with a chimney handle 4. The axis of the arrow of the radio compass is rotated by the synchro-receiver, which is connected to the synchro-sensor of the frame of the automatic radio compass. The error of remote transmission from the gyro unit to the UGR-1 pointer is eliminated with the help of a pattern device.

The GIK-1 gyro-induction compass makes it possible to read the aircraft's magnetic heading according to the UGR-1 pointer with an error of ±1.5°. The magnetic bearing of the radio station is determined with an accuracy of ± 3.5 °. The post-turn error of the GIK-1 for 1 minute of turn is 1°.

On modern aircraft, centralized devices are installed that rationally combine gyroscopic, magnetic, astronomical and radio engineering means of determining the course. This allows the use of the same combined pointers and increases the reliability and accuracy of heading measurements. Such devices are called course systems. The heading system typically includes an induction-type magnetic heading sensor, a gyro heading sensor, an astronomical heading sensor, and a radio compass. With the help of these devices, each of which can be used both independently and in combination with each other, the course is determined and maintained in any flight conditions. Such a set of heading instruments makes it possible to determine the values of the true, magnetic, conditional (gyro-semi-compass) and orthodromic courses, the corresponding angles of the radio station and the angles of the aircraft turn, on the pointers, giving out any of these values to consumers if necessary.

The basis of the heading system is a heading gyro sensor - a heading gyroscope, the periodic correction of the readings of which is carried out using a magnetic or astronomical heading sensor (corrector).

To reduce errors in course measurement caused by rolls, the heading gyroscope is connected to the central vertical gyro; to reduce errors in the course due to accelerations, it receives signals from the correction switch, and in order to eliminate the error due to the rotation of the Earth, a signal proportional to the geographical latitude of the aircraft's location is manually entered into it.

Depending on the tasks to be solved, the heading system can operate in one of three modes: gyro-semi-compass, magnetic correction, astronomical correction. The main mode of operation of the course system of any type is the gyro-semi-compass mode.

Course system GMK-1A

The heading system GMK-1A is installed on sports aircraft and helicopters and is designed to measure and indicate the course and turn angles of an aircraft (helicopter). When working in conjunction with the ARK-9 and ARK-15 radio compasses, the GMK-1A allows you to count the heading angle of the radio station and the radio bearing.

Basic data GMK-1a
DC supply voltage
AC supply voltage
AC frequency
Permissible error in determining the IC
Permissible error in determining the CSD

The GA-6 gyro unit is the main unit of the heading system, from the selsyn stator of which the signals of the orthodromic, true and magnetic headings are taken.

The ID-3 induction sensor is a sensitive element of the azimuthal magnetic correction of the gyroscope. The sensor determines the direction of the horizontal component of the Earth's magnetic field vector. To mount the sensor on an airplane (helicopter), there are three oval holes in the base of the housing, next to which divisions are applied on the base of the housing, allowing you to read the sensor installation angle in the range of ±20° (division 2°).

The correction mechanism KM-8 is an intermediate unit in the communication line of the induction sensor with the gyro unit and is designed to compensate for the course system deviation and instrumental errors, enter the magnetic declination, indicate the compass heading and monitor the performance of the course system by comparing the readings of the KM-8i UGR-4UK.

Automatic matching AS-1 is an intermediate unit in the communication line of the correction mechanism with the gyro unit. It is designed to amplify electrical signals proportional to magnetic or true headings, disable azimuth, magnetic and horizontal corrections, and limit the duration of the start of the heading system.

The UGR-4UK pointer is a combined instrument designed to indicate the orthodromic (in the GPK mode), magnetic or true (in the MK mode) aircraft headings, turn angles and radio bearing or heading angle of the radio station.

The control panel serves to control the operation of the MMC-1 AI and allows you to: select the operating mode of the exchange rate system; input of azimuth latitude correction of the gyroscope; error compensation from gyroscope deviations in azimuth (from imbalance); setting the course scale of the UGR-4UK pointer to a given course; enable fast gyroscope matching speed; signaling blockage of the gyroscope of the gyro unit; monitoring the performance of the course system.

The heading system GMK-1A can operate in two modes: in the gyro-semi-compass (GPC) mode and in the magnetic gyroscope correction (MC) mode. Mode GIC is the main operating mode of the system. Mode MK used during the initial "a coordination of the course system after its inclusion, as well as periodically during its operation in flight.

Magnetic compass deviation

The magnetic compass error caused by the aircraft's own magnetic field is called deviation .

The magnetic field of the aircraft is created by the ferromagnetic parts of the aircraft: both aircraft equipment and direct currents in the networks of electrical and radio equipment of the aircraft. .

The dependence of the deviation on the magnetic heading of the aircraft in level flight without acceleration is expressed by the approximate formula:

D k \u003d A + B sin MK+S co s MK+ D sin 2MK+ cos E cos MK,

where A - constant deviation;

B and FROM- approximate coefficients of semicircular deviation;

D and E- approximate coefficients of quarter deviation.

In order to improve the accuracy of heading measurements on aircraft, deviation works are periodically carried out, during which the constant and semicircular deviation are compensated and the quarter deviation is written off.

Permanent deviation, together with the installation error, is eliminated by turning the remote compass sensor and turning the body of the combined compass.

Semi-circular deviation is compensated on four main courses (0°, 90°, 180° and 270°) using a magnetic deviation device mounted on the compass body (inductive sensor). With the help of magnets placed in the deviation device in close proximity to the sensitive element of the compass, forces are created that are equal in magnitude and opposite in direction to those forces that cause semicircular deviation (B "and C").

Quarterly deviation is caused by the alternating magnetic field of the aircraft (forces D " and E") , therefore, it cannot be compensated by the permanent magnets of the deviation device. Quarter deviation together with instrumental errors in remote compasses (GIK-1) is compensated using a mechanical compensator of deviation of the curved type.

In combined magnetic compasses, quarter deviation is not eliminated, its value is determined on eight courses (0e, 45°, 90°, 135°, 180°, 225°, 270° and 315°) and residual deviation graphs are drawn up based on the values found.

Roll deviation is the additional deviation that occurs when the aircraft rolls, climbs or descends as a result of a change in the position of aircraft parts with magnetic properties relative to the magnetic system of the compass.

With transverse rolls, the maximum deviation will be on courses of 0 and 180 ° , and the minimum - on courses 90 and 270 °. With longitudinal rolls on courses 0 and 180 ° it is equal to zero and reaches its maximum value at courses 90 and 270 °. The heel deviation reaches its greatest value during longitudinal rolls (climb and descent).

Aircraft compasses do not have special devices to eliminate roll deviation, however, during a long climb (descent) on magnetic courses close to 90 ° (270 °), the influence of roll deviation is significant, therefore the determination and maintenance of the course must be carried out using a gyro semi-compass or astro compass.

Turning error . The essence of the turning error lies in the fact that when the aircraft turns, the compass card receives almost the same roll as the aircraft. Consequently, the card is influenced not only by the horizontal, but also by the vertical component of the force of terrestrial magnetism.

As a result, the cartouche during a turn makes movements that depend on the magnetic inclination and the bank angle of the aircraft. The movement of the card is so vigorous that the use of the compass is almost impossible. This error is most pronounced on the northern courses, so it is called the northern one.

In practice, the rotational deviation is taken into account as follows. When turning on northern courses, the aircraft is taken out of the turn, not reaching the set course by 30 °, and on the south - after passing 30 ° according to the magnetic compass. Then, with small adjustments, the aircraft is brought to a predetermined course.

If turns are performed on courses close to 90 or 270 °, the aircraft must be taken out of the turn on a given course, since the turning deviation on these courses is 0.

Performance of deviation works

Deviation work on airplanes, helicopters and gliders is performed by specialists of the aviation engineering service in order to determine and compensate for errors in magnetic compasses (IAS) together with the crew of the aircraft (helicopter, glider) under the leadership of the navigator of the aviation organization.

Deviation work is performed at least once a year, as well as in the following cases:

If the crew has doubts about the correctness of the compass readings and if an error in the compass readings is more than 3 °;

When replacing the sensor or individual units of the course system that affect the deviation;

In preparation for the performance of particularly responsible tasks;

When relocating aircraft from middle latitudes to high latitudes.

When performing deviation work, a deviation work protocol is drawn up, which is signed by the navigator and the IAS specialist who performed the deviation work. The protocol is stored together with the aircraft (helicopter, glider) form until the next write-off of the deviation. According to the protocol, deviation graphs are drawn up, which are placed in the cockpits of the aircraft.

To perform deviation work at the aerodrome, a site is selected that is at least 200 m away from the parking lots of aircraft and other equipment, as well as from metal and reinforced concrete structures.

From the center of the selected site, using a deviation direction finder, measure the magnetic bearings of one or two landmarks that are at least 3-5 km away from the site .

Determining the magnetic heading using a deviation direction finder

Deviation device DP-1 (Fig. 10) consists of the following parts:

azimuth limb 1 with two scales (internal and external); scale range from 0 to 360°, division value 1°, digitization is done every 10°;

magnetic needle 2;

sighting frame with two diopters: eye 3 - with a slot and subject 4 - with a thread;

two screws for fixing the target frame;

spherical level 5;

course marker "MK" 6,

ball joint 7 with clamp;

screw 8 fastening the azimuthal limb;

bracket 9.

For storage, the deviation direction finder has a special box, and for work - a tripod.

The magnetic heading of an aircraft using a deviation direction finder can be determined in two ways:

1. According to the heading angle of the remote landmark.

2. Direction finding of the alignment of the longitudinal axis of the aircraft.

To determine the magnetic heading of an aircraft from the heading angle of a remote landmark, it is necessary to first measure the magnetic bearing of the landmark (MPO) using a deviation direction finder, then place the aircraft at the point from which the bearing of the landmark was measured, install the direction finder on the aircraft and measure the heading angle of the landmark (KRO). The aircraft magnetic heading (MK) is defined as the difference between the magnetic bearing and the heading angle of the landmark ( Rice. nine):

MK = MPO - KUO.

Rice. 10. Deviation direction finder

1 - azimuthal limb; 2 - magnetic needle; 3 - eye diopter; 4 - subject diopter; 5 - spherical level; 6 - course marker MK; 7 - ball joint; 8 - limb mounting screw; 9 - bracket.

To determine the magnetic course direction finding of the alignment of the longitudinal axis of the aircraft it is necessary to set the direction finder exactly in the alignment of the longitudinal axis of the aircraft and measure the magnetic bearing of the alignment of the longitudinal axis of the aircraft.

To determine the magnetic bearing of the MPO reference point (alignment of the longitudinal axis of the aircraft), you need:

install a tripod in the center of the site where the deviation will be written off;

fix the direction finder on a tripod and set it to a horizontal position according to the level;

unlock the limbus and magnetic needle;

by rotating the dial, align the “O” of the scale of the dial with the north direction of the magnetic needle, then fix the dial;

unfolding the sighting frame and observing through the slit of the eye diopter, direct the thread of the subject diopter to the selected landmark (in line with the axis of the aircraft);

against the risks of the object diopter on the scale of the limb, count the MPO, equal to the magnetic heading of the aircraft.

Setting the aircraft on a given magnetic course

To set the aircraft on a magnetic heading heading angle of remote landmark necessary:

determine the magnetic bearing of the remote landmark from the center of the selected site;

set the aircraft to the place where the bearing was taken, and the direction finder to the aircraft (line 0-180° along the longitudinal axis of the aircraft);

turn the aircraft to align the line of sight with the selected landmark. After setting the aircraft on a given course, it is necessary to bring the index "MK" of the course marker to the value of the given magnetic course and fix it in this position.

In order to set the aircraft on a different magnetic course (MK2), you need to unstop the dial, bring it under the index "MK" course marker value MK2 and lock it. By turning the aircraft, align the line of sight with the landmark.

To set the aircraft on a magnetic heading direction finding of the longitudinal axis of the aircraft follows (Fig. 9):

Turn the aircraft to a given magnetic course according to the course indicator;

Set the direction finder 30-50 m ahead or behind the aircraft in the direction of the longitudinal axis - the aircraft;

Adjust the direction finder according to the level and align the 0-180° line with the magnetic needle;

Expand the target frame (alidade) so that

The line of sight coincided with the longitudinal axis of the aircraft;

Against the index of the sighting frame on the scale of the limb, count the magnetic course.

The installation of the direction finder on the aircraft must be carried out so that the line 0-180° of the limb is parallel to the longitudinal axis of the aircraft, and the 0° limb is directed towards the nose of the aircraft.

When the direction finder is installed in the center of the canopy of the aircraft cabin, the orientation of the direction finder limb along the longitudinal axis of the aircraft is carried out by direction finding of the aircraft keel.

For this you need:

fix the direction finder in the center of the cabin canopy and adjust it according to the levels;

set the eye diopter of the direction finder to readout along the limb equal to 0°;

by turning the dial of the direction finder, align the line of sight with the keel of the aircraft and fix the dial in this position (the line 0-180° of the dial will be parallel to the longitudinal axis of the aircraft).

heading navigation instrument aircraft. In aviation, astrocompasses are used (see Astronavigation systems), gyrocompasses, magnetic compasses, and radio compasses. Due to significant measurement errors, magnetic transformers are used only as backup.

Watch value Compass Aviation in other dictionaries

Aviation- aviation, aviation. App. to aviation. Air base.
Explanatory Dictionary of Ushakov

Compass- m. German, White Sea, uterus, magnetic needle on a hairpin, with a paper card, on which the cardinal points or 32 winds are marked, rumba (architectural strika). The mountain compass serves ........
Dahl's Explanatory Dictionary

Compass- (compass obsolete), compass, m. (it. compasso) (physical). A physical device for recognizing the countries of the world, consisting of a magnetized needle that always points north.
Explanatory Dictionary of Ushakov

Aviation App.- 1. Corresponding in value. with noun: aviation associated with it. 2. Characteristic of aviation, characteristic of it.
Explanatory Dictionary of Efremova

Compass M.- 1. A device for orientation relative to the sides of the horizon, indicating the direction of the geographic or magnetic meridian. 2. trans. unfold The one who determines the direction ........
Explanatory Dictionary of Efremova

Aviation— oh, oh. to Aviation. Ah industry. Ah devices. A-th reconnaissance (carried out by means of aviation). A. sports (a combination of aircraft modeling, parachuting, gliding, ........
Explanatory Dictionary of Kuznetsov

Compass- -but; (in the speech of sailors) compass, -a; m. [ital. compasso] An instrument for determining the countries of the world, having a magnetized needle that always points north. Sea to. Follow the compass .........
Explanatory Dictionary of Kuznetsov

Compass- output marketing research, giving recommendations to the manufacturer or seller on the behavior in the market.
Economic dictionary

Aviation Personnel- - persons with special training and carrying out activities to ensure flight safety aircraft And aviation security, organizations, ........
Law Dictionary

Compass- Borrowing either from German (Kompass), or from Italian, where compasso is "compass". The change in value is explained by the action of the magnetic needle, which rotates freely........
Etymological Dictionary of Krylov

Hospital Aviation- G., intended for the treatment and military medical examination of the flight and flight technical staff of the Air Force.
Big Medical Dictionary

Aviation Sports- the collective name of aviation sports. See Aeromodelling, Parachuting, Gliding, Aircraft.

Aviation Transport- see Transport.
Big encyclopedic dictionary

Compass- , a device for orientation to the cardinal points, which also serves to indicate the direction of the magnetic field. It consists of a horizontally located, movable fixed ........
Scientific and technical encyclopedic dictionary

Gyromagnetic Compass- a gyroscopic device for determining the course of an aircraft, a vessel relative to the magnetic meridian. The action of the gyromagnetic compass is based on the correction of ........
Big encyclopedic dictionary

- founded in 1932. Trains engineering personnel in the main specialties of aviation machine and instrument making, radio engineering, etc. In 1991, approx. 9 thousand students.
Big encyclopedic dictionary

Compass- (German Kompass) - a device indicating the direction of the geographic or magnetic meridian; serves to orient relative to the sides of the horizon. Distinguish magnetic, ........
Big encyclopedic dictionary

- (Mai Technical University since 1993), founded in 1930. Trains engineering personnel in the specialties of aircraft and helicopter construction, economics and organization of the production of aircraft ........
Big encyclopedic dictionary

Moscow Aviation Technological University (Matu)- has been conducting history since 1932. Trains engineering personnel in the specialties of the aviation industry, materials science, instrument making, economics and management, in the field of security ........
Big encyclopedic dictionary

Compass- a compass device for determining the sides of the horizon and measuring magnetic azimuths on the ground, for example. while moving along the route. Main parts of the compass - magnetic needle, ........
Geographic Encyclopedia

Compass- - a device that indicates the direction of the geographic or magnetic meridian, serves for orientation relative to the sides of the horizon. In a broad sense - the right direction.
Historical dictionary

COMPASS- KOMPAS, -a (sailors have a compass, -a), m. A device for determining the cardinal points (sides of the horizon). Magnetic to. (with a magnetized arrow, always pointing to the north). || adj.........
Explanatory dictionary of Ozhegov

AVIATION COMPASS

compass, an aeronautical device that indicates to the pilot the course of the aircraft relative to the magnetic meridian (magnetic compass, gyromagnetic compass), given direction(gyro semi-compass) or directions to a radio beacon (radio compass, radio semi-compass) and relative to any celestial body (astronomical compass).

Great Soviet Encyclopedia, TSB. 2012

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 used by the pilot to take into account the correction when reading the helicopter's magnetic heading using 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 heading 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.