Aviation compass. Aviation magnetic compasses and their applications. Determining magnetic course using a deviation direction finder
To understand the principle of operation of a gyromagnetic compass, let’s imagine a gyroscope on the continuation of the outer axis SS 1 suspension of which (Fig. 26) there is an independently suspended arrow N.S. magnetic compass, carrying a contact slider r. On the outer ring NK gyroscope, two insulated contact lamellas are mounted b 1 and b 2 . When the main axis deviates AA 1 from the plane N m 0Z magnetic meridian with which the arrow is aligned N.S. magnetic compass, engine G will come into contact with one of the slats b 1 and b 2 . As a result, through one of the two windings of the electromagnet EM, fixedly mounted on the outer ring NK, electric current will flow.
When the electromagnet windings are connected to the electric current circuit EM a magnetic flux will arise, which, acting on the anchor I, mounted on the axis of the inner ring VC, will create a moment tending to rotate the gyroscope around its axis BB 1 . But, as is known, when exposed to a rapidly rotating around an axis AA 1 When a gyroscope is torqued relative to one of its suspension axes, precessional motion occurs around the second axis. In this case, precessional movement will occur around the axis SS 1 until the main axis LL X is again aligned with the plane N m 0Z magnetic meridian.
At this moment the engine r comes out of contact with the contact lamella and stops powering the electromagnet EM, and, consequently, the influence of an external moment on the gyroscope. Such is the brief outline the fundamental essence of the work of the gyromagnetic compass.
Rice. 27.
In order to eliminate possible shortcomings, they tend to install the magnetic needle on modern aircraft at the greatest possible distance from the engines and the cockpit (at the ends of the wings and the rear fuselage).
The advantage of the device, called a remote gyromagnetic compass, is that the magnetic needle mounted in the rear fuselage is subject to significantly less disturbing moments than those placed directly in the body of the gyroscopic system.
Therefore, driving an aircraft along a given course using a remote gyromagnetic compass will be carried out with greater accuracy than when using a gyromagnetic compass, the needle of which is mounted in close proximity to the gyroscope in one common housing.
To transmit gyroscope readings to the navigator's cabin, and in some cases to the pilot's instrument panel, the remote gyromagnetic compass is equipped with special repeaters P, similar to repeaters used in the navy.
Remote gyromagnetic compasses powered by electric current have become widespread not only in aviation. Small dimensions, ease of maintenance and reliable operation ensured its use on small-tonnage ships.
Fig.28. 1 - gyroscopic unit; 2 - magnetic compass; 3 - navigator repeater; 4 - pilot repeater
Figure 29 shows a set of remote gyromagnetic compass, consisting of a gyroscope, a magnetic system and two repeaters: for the navigator and for the pilot.
The magnetic compass in an airplane determines and maintains the heading of the flight direction. The aircraft heading is the angle between the real longitudinal direction and the aircraft axis along the meridian. It is customary to count the course from the northern direction of the meridian.
From the meridian, the angle is measured clockwise to the longitudinal axis of the aircraft. As we know, the course is possibly magnetic, compass and genuine.
The operating principle 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, the angle to the longitudinal axis of the aircraft is measured using a compass - this is the magnetic heading. It must be emphasized that modern compasses installed in the cockpit are structurally different from field compasses.
In design aviation compasses materials are used that do not exhibit strong magnetic or diamagnetic properties. The main structural parts of an aircraft compass are: bracket, heading line, deviation device, card, bowler.
A cauldron is a vessel made of aluminum or copper and hermetically sealed with a glass lid. The inside of the pot 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 can lead to complete unusability.
The liquid helps as a calmer and dampens the vibrations of the cartridge, in addition, it reduces the pressure of the stud on the firebox.
In the middle of the pot there is a column on which the card 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 lead to deviations from the original values. The upper pairs of magnets have a much larger magnetic moment than the lower ones, in a ratio of 15 CGSm to 12 CGSm. As a result, the total moment should be no lower than 54-56 CGSm. The level of quality of the compass depends on the correct selection of their sizes and magnets.
At the end of the map there is an arrow, which indicates the side of the horizon; it helps to navigate the flight map. The non-specialized magnetic system is calculated for 200 hours of engine operation. A course line is applied to the bowler, which is used as an index when calculating the course.
The airplane compass bowl is filled with liquid; when the temperature changes, its quantity changes, which can lead to an error in the instrument’s 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 mostly in the aggregate of depreciation or the shape of the card. In addition, lighting devices are used to operate in night mode.
The practical use of a compass on an airplane suggests that its use is different for a pilot and a navigator. The pilot uses this device to select the right direction of flight. It is used to identify the accuracy of deviations and analyze the flight from the course.
As for the navigator, he uses a compass to quickly calculate the flight map and to analyze the course. The navigator's compass is usually considered to be the main compass on board an aircraft. Therefore, there are two types of magnetic aviation compasses that are installed on the board of an aircraft - the main one and the travel one.
Aircraft magnetic compass deviation
Even at the dawn of aircraft construction, all aircraft, without exception, were equipped with magnetic compasses, which performed an excellent job of determining the magnetic heading of the aircraft. However, with the upcoming development of multi-engine units with a large part of electronics, serious problems with the operation of compasses have appeared. All electromagnetic vibrations emanating from the second devices significantly affected the accuracy and performance of the instrument.
In some cases, compass readings could differ from the original ones by a dozen degrees, and this is quite a lot to determine the correct direction of flight. During the flight, all compasses experience accelerating and magnetic effects, which lead to deviation.
Magnetic deviation. The totality of each compass takes effect from different magnetic fields of both the Soil itself and other sources of magnetism specifically on board the aircraft. This could be radio systems, electrical wiring and its fields, and the metallic mass of the structure itself.
Therefore, compasses on board an airplane have errors in their readings, which are commonly called magnetic deviation.
This deviation parameter can be calculated at the experimental level; in addition, three subcategories of deviation are distinguished, in particular constant, quarter and semicircular.
The constant 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 semicircular magnetic deviation in the deviation of the compass reading 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 elements and electrical appliances. They have a constant force and direction of action on the compass.
There is also such a thing as inertial deviation, which appears due to bumpiness, 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 calculations and the device for correct direction.
Nevertheless, when manufacturing the airplanes and compasses themselves, the designers take into account all deviations and these influences. To reduce third-party actions on the accuracy of the compass readings, aggregates are used, which can significantly reduce all of the above actions on the accuracy of the readings.
Review of the compass and men and airplanes
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a navigation device for measuring the course of an aircraft. In aviation, astrocompasses (see Celestial navigation systems), gyrocompasses, magnetic compasses, and radio compasses are used. Due to significant measurement errors, magnetic sensors are used only as backup.
View value Aviation Compass in other dictionaries
Aviation- aviation, aviation. Adj. to aviation. Air base.
Ushakov's Explanatory Dictionary
Compass- m. German, Belomorskoe, uterus, magnetic needle on a pin, with a paper card on which the cardinal points or 32 winds are indicated, rumba (arch. strika). The mountain compass serves.........
Dahl's Explanatory Dictionary
Compass- (compass obsolete), compass, m. (Italian compasso) (physical). A physical device for recognizing the cardinal directions, consisting of a magnetized arrow that always points north.
Ushakov's Explanatory Dictionary
Aviation Adj.— 1. Correlative in meaning. with noun: aviation, associated with it. 2. Characteristic of aviation, characteristic of it.
Explanatory Dictionary by 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. transfer decomposition The one who determines the direction........
Explanatory Dictionary by Efremova
Aviation- oh, oh. to Aviation. Ah industry. A devices. A reconnaissance (carried out by aviation means). A. sport (a combination of aircraft modeling, parachute, gliding,........
Kuznetsov's Explanatory Dictionary
Compass- -A; (in the speech of sailors) compass, -a; m. [ital. compasso] A device for determining the cardinal directions, having a magnetized needle that always points north. Seascape. Follow the compass.........
Kuznetsov's Explanatory Dictionary
Compass— conclusion of marketing research, giving recommendations to the manufacturer or seller on behavior in the market.
Economic dictionary
Aviation Personnel— - persons who have special training and carry out activities to ensure flight safety aircraft and aviation security, organizations,........
Legal Dictionary
Compass— Borrowing either from German (Kompass) or from Italian, where compasso is “compass”. The transition of value is explained by the action of a magnetic needle, which rotates freely........
Krylov's etymological dictionary
Aviation Hospital— G., intended for treatment and military medical examination of flight and flight technical personnel of the Air Force.
Large medical dictionary
Aviation Sports- collective name aviation types sports. See Model aircraft sport, Parachuting sport, Gliding sport, Airplane sport.
Aviation Transport— see Transport.
Large encyclopedic dictionary
Compass- a device for orientation to the cardinal directions, which also serves to indicate the direction of the magnetic field. Consists of a horizontally located, movable fixed........
Scientific and technical encyclopedic dictionary
Gyromagnetic Compass- a gyroscopic device for determining the course of an aircraft or ship relative to the magnetic meridian. The action of the gyromagnetic compass is based on correction........
Large encyclopedic dictionary
— founded in 1932. Trains engineering personnel in the main specialties of aviation mechanical and instrument engineering, radio engineering, etc. In 1991, approx. 9 thousand students.
Large encyclopedic dictionary
Compass- (German Kompass) - a device indicating the direction of the geographic or magnetic meridian; serves for orientation relative to the sides of the horizon. There are magnetic,......
Large encyclopedic dictionary
— (Mai Technical University since 1993), founded in 1930. It trains engineering personnel in the specialties of aircraft and helicopter engineering, economics and organization of aircraft production........
Large encyclopedic dictionary
Moscow Aviation Technological University (MATU)— has been leading the history since 1932. Trains engineering personnel in the specialties of the aviation industry, materials science, instrument engineering, economics and management, in the field of security........
Large encyclopedic dictionary
Compass- a compass device for determining the sides of the horizon and measuring magnetic azimuths on the ground, for example. when moving along the route. Basic parts of the compass – magnetic needle,........
Geographical encyclopedia
Compass— - a device indicating the direction of the geographic or magnetic meridian, used for orientation relative to the sides of the horizon. In a broad sense, this is the right direction.
Historical Dictionary
COMPASS- COMPASS, -a (sailors have a compass, -a), m. A device for determining the cardinal points (sides of the horizon). Magnetic card (with a magnetized arrow that always points north). || adj.........
Ozhegov's Explanatory Dictionary