RU94346U1 - HELICOPTER SMALL AIR SPEED MEASUREMENT SYSTEM - Google Patents

Abstract

 1. A system for measuring low air speeds of a helicopter comprising a multichannel aerometric receiver mounted on the fuselage in the area of the rotor vortex column, pneumoelectric transducers whose outputs are connected through a series-connected multiplexer and analog-to-digital converter to a microprocessor, the output of which is the system output according to the parameters of the true vector helicopter airspeed, characterized in that the aerometric receiver is made in the form of a spherical body, the axis of which o is directed upward in a plane parallel to the plane of symmetry of the helicopter, holes are made on the top surface of this spherical body on the axis of symmetry, which are receivers for taking the total pressure of the resulting incident air flow of the vortex column symmetrically with respect to the axis of symmetry of the spherical body in planes parallel to the plane of symmetry of the helicopter and orthogonal to it, holes are made that are receivers for collecting pressures that determine the angular position of the vortex column Along the axis of symmetry of the spherical body in the above orthogonal planes, in the plane orthogonal to the two indicated planes, holes are made on the surface of the spherical body that are receivers for collecting the static pressure of the resulting incident air flow of the vortex column, while the receivers for collecting the total pressure are connected by flowing pneumatic channels to receivers for taking pressure determining the angular position of the vortex column relative to the axis of symmetry of the spherical body in

Description

The utility model relates to devices for measuring altitude and speed parameters of a helicopter.

Known devices for measuring the altitude-speed parameters of the aircraft that implement the aerometric method of measurement. In such devices, an air pressure receiver installed in the air stream rushing onto the aircraft senses the static and total pressure of the air flow, which determine the barometric altitude, indicator (instrument) and, using information about the outside temperature, the true air speed (D. Braslavsky A. Instruments and sensors of aircraft. M: Mechanical Engineering, 1970, 392 p.) - [1]. Using receivers installed in the oncoming flow, pressure is also perceived, which determines the angular position of the true airspeed vector in a connected velocity coordinate system — the angles of attack and slip (Petunii A.N. Methods and techniques for measuring gas flow parameters. M .: Mechanical Engineering, 1972 , 392 p.) - [2]. However, the use of such devices in a helicopter makes it possible to accurately measure the barometric altitude and airspeed only at flight speeds of more than 70 ... 90 km / h, when the flow receivers go beyond the vortex columns created by the rotor of the helicopter and when noise-tolerant perception and conversion of perceived air pressures is provided . The range of measurement of the angles of attack and slip of these devices is also limited to ± 30 °, while for a helicopter the workers are flying back and forth, left and right, in another other direction in the yaw and pitch planes, as well as flights in the region of small and near-zero speeds, and even in hover mode.

To obtain information about the altitude and speed parameters in the region of low helicopter flight speeds in the known air signal systems (SHS), several flow-through pressure receivers are used located in the nose of the fuselage symmetrically with respect to the longitudinal axis of the helicopter (Kozitsin V.K., Makarov N.N. , Porunov A.A., Soldatkin V.M.Analysis of the principles of constructing helicopter airborne signal systems // Aerospace Instrumentation, 2003, No. 10, C.2-13) - [3]. Experimental studies of such a SHS developed by the Voskhod MPKB showed that at flight speeds of less than 30 km / h the error in measuring the slip angle reaches about ± 2 °, and at speeds of more than 70 km / h, when the nose of the helicopter fuselage, where the flow receivers, leaves the zone of the vortex column, the error decreases to values of ± 0.4 °, acceptable for solving control and piloting problems. However, one of the main disadvantages of such SHS and the method implemented in it is the limited range of measurement by the slip angle with β = ± 20 ° - [1].

A known system of air signals, which allows you to obtain information about the parameters of the vector of the airspeed of the helicopter and at flight speeds less than 30 ... 70 km / h. Known SHS helicopters such as Lassie, KhM-143 and SHS-B1 - [3] contain a freely-oriented air pressure receiver, which at low flight speeds is located in the alignment of the vortex column and is oriented using a spatial weather vane in the direction of the vector the resulting airflow running onto a freely oriented receiver. Vector is, the sum of the vector air speed due to the translational movement of the helicopter, and the vector Inductive air velocity generated by the rotor of a helicopter. In this case, the system of equations by which the components V _x , V _y , V _z of the true air velocity vector are determined , the angles of attack α and glide β of the helicopter have the form (VK Kozitsin. Algorithmic support of helicopter air signal systems based on a freely oriented pressure receiver // Izv. Vyssh. Aviation Engineering. 2004. No. 4. P.52-57) - [ four]:

where i _x , i _z are the angles of inclination of the plane of the rotor disk; α _BK and β _BK are the bevel angles of the vortex column air flow relative to the axes of the coupled (speed) coordinate system.

However, a system based on a freely oriented receiver has significant errors in determining the parameters V _x , V _y , V _z , α and β of the true airspeed vector of the helicopter in the region of low and especially near-zero velocities due to errors in recording angles α _BK , β _BK position vortex columns due to the small weathering moment created by the spatial weather vane, due to the presence of friction in the cardan suspension and loading of the moving system of a freely oriented receiver. It also limits the value of the minimum operating flight speed, which provides a stable measurement of the parameters of the true airspeed vector of the helicopter. Due to the necessity of transmitting perceived air pressures and converting the orientation angles of the movable receiver using a pneumatic manifold and synchro transducers, the design of the system becomes more complicated and its reliability decreases, especially with possible sharp aerodynamic disturbances of the incoming air flow during firing of small arms and jet weapons.

The prototype is a helicopter air signal measurement system (Patent for the invention No. 2307357 dated December 7, 2005 - [4]), in which two fixed orthogonally located aerometric sensors, tubes are used to register the angles α _BK and β _{BK of the} rotor column of the rotor of the helicopter full pressure and static pressure throttling cavities which are connected to pneumatic-electric converters, the outputs of which are connected to a microprocessor through a multiplexer and an analog-to-digital converter, in which the steam is calculated meters of the true airspeed vector of the helicopter in the low-velocity region according to equations of the form

where a _β and a _α are the coupling coefficients of the lateral V _z and longitudinal V _x components of the vector the airspeed of the helicopter with bevel angles β _BK and α _{BK of the} vortex column of the rotor of the helicopter in the yaw plane and the plane orthogonal to it; a _P is the coupling coefficient of the vertical velocity V _y with the rate of change of the throttled static pressure.

Figure 1 shows the layout of the aerometric unit of two fixed orthogonally located multi-channel aerometric sensors of the system - a prototype that is mounted on the fuselage of the helicopter in the area of the rotor vortex column.

Figure 2 shows the structural-functional diagram of the prototype system.

During operation of the system, a fixed flow multichannel aerometric receiver (Fig. 1) in the yaw plane emits a plane-parallel air stream in the incoming stream of the vortex column air stream, in which it generates pressures proportional to the throttled static pressure P _st and pressure P _i characterizing the bevel angle plane-parallel air stream (flow). Using pneumoelectric, for example, _hot-wire anemometric transducers and circuits, the perceived pressures P _Art and P _{i are} converted into electrical signals U _i , which are introduced into the microprocessor through a multiplexer and an analog-to-digital converter. A flow-through multichannel aerometric receiver emits a plane-parallel air stream in the plane of the plane orthogonal to the yaw plane in the incoming air stream of the vortex column in which the pressure corresponding to the throttled static pressure P _Art and pressure P _i characterizing the bevel angle are generated and converted into electric signals orthogonal plane-parallel air stream, which through the multiplexer and analog-to-digital Converter (figure 2) is introduced into the microprocessor. The microprocessor processes the introduced electrical signals according to the developed algorithms, determines the angles of position (slanting) of the vortex column, which calculates the components of the airspeed vector and determines the altitude and speed parameters of the helicopter.

When installing an aerometric unit made in the form of two orthogonally located flow-through multichannel aerometric sensors, two characteristic regimes of the flow around the incoming air flow take place in the nose of the helicopter fuselage.

At flight speeds of more than 70 ... 90 km / h, when the aerometric unit is located outside the rotor vortex column, the components of the airspeed vector on the axis of the associated velocity coordinate system are determined in accordance with a system of equations of the form

where: β = ψ _β and α = ψ _α are the glide and attack angles of the helicopter equal to the bevel angles of the plane-parallel air stream in the yaw plane ψ _β and the air stream in the plane ψ _α orthogonal to it.

The module (value) of the true airspeed vector determined by the ratio

The barometric height H is determined up to the information on the value of the throttled static pressure P _Art.t obtained from multichannel aerometric _sensors , according to the ratio

where: R is the gas constant of air; T = T ₀ + τH is the outdoor temperature; τ is the altitude temperature gradient; P ₀ and T ₀ - static pressure and temperature at ground level.

In the region of low flight speeds, when the aerometric unit with flow multichannel aerometric sensors is in the alignment of the rotor column of the rotor of the helicopter, the angular position of the rotor column of the rotor of the rotor of the helicopter, determined by the bevel angles β = ψ _β and α = ψ _α , which are recorded by orthogonally located flow multichannel receivers and are determined in accordance with equations of the form (2).

As studies have shown (Kaletka J. Evaluation of the Helicopter Low Airspeed System Lassie. // Jornal of American Helicopter Society, 1983, No. 4. pp35-43) - [5], the angular position of the vortex column of a helicopter when flying at low speeds can present as

Where , and a _α , a _β are functions and coefficients determined by the results of flight tests of this type of helicopter.

Thus for each value of α _BK, located in the vortex zone of the column, it is possible to determine two values of β _{BK max} and β _{BK min,} defining the boundaries of the angular position of the vortex column in the orthogonal plane. Therefore, for the criterion for the location of the aerometric block in the vortex column zone, for each α _BK value, the condition

Subject to this condition, i.e. when flying a helicopter at low speeds, the algorithms for determining the altitude and speed parameters of the helicopter have the form

where a _P is the coupling coefficient of the vertical velocity with the rate of change of static pressure.

In case of failure to fulfill condition (7), the vortex column does not cover the helicopter glider and the flight is carried out in the mode when the aerometric unit with multi-channel airborne receivers has gone beyond the vortex column.

The selection using two orthogonal flow multichannel aerometric sensors of two plane-parallel air jets in the yaw plane and in the plane orthogonal to it, the formation of pressures characterizing the throttled static pressure in the jets, and the pressure characterizing their bevel angles, converting the pressure into electrical signals using pneumoelectric , for example, hot-wire transducers and sequential determination of the angular position (bevel angles) of a vortex count nna rotor and more vector parameters of the true airspeed of the helicopter and other overhead signals improves the accuracy of the measurement of altitude and speed parameters to extend operating ranges of the angle of attack and in the low flight speeds and near-zero velocity.

However, the disadvantages of the considered system for measuring low airspeed of a helicopter is a significant complication of the design, an increase in the mass and dimensions of the aerometric unit with receivers, and an increase in the cost of the whole system.

The technical result, which is claimed by the claimed utility model, is to simplify the design, reduce the mass and dimensions of the air pressure receiver, reduce the cost of the system for measuring low air speed of the helicopter by using one air pressure sensor, reduce the number of pneumoelectric converters, simplify the structural-functional and electrical system circuits.

Using the proposed system for measuring low air speeds of a helicopter can improve flight safety and improve the efficiency of solving problems of piloting and combat use, for example, accuracy of shooting and bombing, by improving the reliability of the system, including in the conditions of possible sharp disturbances of the aerodynamic field of the helicopter, and ensuring high accuracy of measuring the parameters of the true airspeed vector of the helicopter in the region of low and near-zero flight speeds.

The technical result is achieved by the fact that:

1. In the system for measuring low air speeds of a helicopter containing

- mounted on the fuselage in the area of the rotor column of the rotor of the rotor multichannel aerometric receiver,

- pneumoelectric converters, the outputs of which are connected through a multiplexer and an analog-to-digital converter to a microprocessor,

- the output of which is the output of the system according to the parameters of the vector of the true air speed of the helicopter,

new is that

- the aerometric receiver is made in the form of a spherical body, the axis of which is directed upward in a plane parallel to the plane of symmetry of the helicopter,

- holes are made on the upper surface of this spherical body on the axis of symmetry, which are receivers for taking the total pressure of the resulting incident air flow of the vortex column,

- symmetrically with respect to the axis of symmetry of the spherical body in planes parallel to the plane of symmetry of the helicopter and orthogonal to it, holes are made that are receivers for pressure collection that determine the angular position of the vortex column relative to the axis of symmetry of the spherical body in the above orthogonal planes,

- in the plane orthogonal to the two indicated planes, holes are made on the surface of the spherical body, which are receivers for taking the static pressure of the resulting incident air flow of the vortex column,

- at the same time, receivers for sampling the total pressure are connected by flowing pneumatic channels to receivers for collecting pressures that determine the angular position of the vortex column relative to the axis of symmetry of the spherical body in the above orthogonal planes containing pneumoelectric differential pressure transducers whose outputs for pneumatic channels of identical planes are connected differentially.

2. In the system for measuring low air speeds of a helicopter, thermoanemometric transducers are used as pneumoelectric transducers of differential pressure.

3. In the helicopter’s low airspeed measurement system, differential hot-wire anemometric transducers are used as thermoanemometric converters, the common input of which is connected to the pneumatic channel of the receiver of the full pressure of the resulting incident air flow, and the other two inputs are connected to the pneumatic channels of the pressure receivers that determine the angular position of the resulting incident air flow in the corresponding plane, and the outputs of the differential hot-wire anemometric converters are differentially.

4. In the helicopter low airspeed measurement system, the microprocessor calculation algorithm is made according to equations of the form

wherein P _1, P ₂ - Pressure at the symmetric points of the spherical body in a plane parallel to the plane of symmetry of the helicopter; P ₃ , P ₄ - pressure at the symmetric points of the spherical body in the plane orthogonal to the plane of symmetry; P _P∑ - total pressure of the resulting incident air flow of the vortex column; P _CT∑ - static pressure of the resulting incident flow of the vortex column of the rotor of the helicopter; T _T∑ is the braking temperature of the resulting incident air flow of the vortex column, sensed by a sensor integrated into the total pressure receiver of the resulting incident air flow of the vortex column.

The essence of the utility model is illustrated in Fig.3-Fig.6.

Figure 3 shows the structural diagram of the aerometric receiver of the proposed system for measuring low air speeds of the helicopter in the form of a spherical body 1, the axis of which is directed upward in a plane parallel to the plane of symmetry of the helicopter. The spherical body 1 is mounted on the rod 11, mounted on the fuselage of the helicopter.

On the upper surface of the spherical body 1 on the axis of symmetry is a hole (receiver) 2 of the total pressure P _{П∑ of the} resulting incident air flow of the rotor column of the rotor of the helicopter. Symmetrically about the axis of symmetry of body 1 in a plane parallel to the plane of symmetry of the helicopter, at an angle φ _{01 there} are openings (receivers) 3 and 4 for taking pressure P ₁ and P ₂ , which determine the angular position φ _{1 of the} vortex column, relative to the axis of symmetry of the spherical body in the plane, parallel to the plane of symmetry of the helicopter. Symmetrically relative to the axis of symmetry of the spherical body 1 in a plane perpendicular to the plane of symmetry of the helicopter, at an angle φ _{02 there} are sampling holes (receivers) of pressure 5 and 6 P ₃ and P ₄ defining the angular position φ _{2 of the} rotor vortex column in a plane perpendicular to the plane symmetry of the helicopter. In the plane orthogonal to the two indicated planes, on the surface of the spherical body 1, circumferential openings for intake (receivers) 7 of throttled static pressure P _{CT∑ of the} resulting incident air flow of the vortex column are arranged in a common channel. The pressure receivers P _P∑ , P ₁ , P ₂ , P ₃ , P ₄ , P _{CT∑ are} connected to the inputs of the pneumatic transducers 8, the outputs of which (Fig. 4) through the multiplexer 12 and the analog-to-digital converter 13 are connected to the microprocessor 14, the output which is the output of the system according to the parameters of the vector true airspeed of the helicopter - components V _x , V _y , V _z , module , angles of attack α and slip β of the helicopter. At the input of the microprocessor 14 through the measuring circuit 10, the multiplexer 12 and the analog-to-digital Converter 13 is connected to the receiver 9 of the braking temperature P _{T∑ of the} resulting incident air flow of the vortex column, which is built into the receiver 2 of the full pressure.

In order to further reduce the number of pneumoelectric converters (Fig. 5), the intake openings (receiver) 2 of the total pressure P _{П∑ are} connected by pneumatic _channels 14 to the intake openings (receivers) 3 and 4, 5 and 6 of the pressures P ₁ and P ₂ , P ₃ and P ₄ defining the angular positions φ ₁ and φ _{2 of the} vortex column in the above orthogonal planes. At the same time, pneumoelectric pressure differential pressure transducers 15 are installed in the pneumatic channels 14, the outputs of which for the pneumatic channels of the same planes are differentially connected, and the difference of their signals through the multiplexer 12 and the analog-to-digital converter 13 is fed to the input of the microprocessor 14.

In order to increase sensitivity and reduce the lower boundary of small operating speeds, the pneumatic channels 14 are made flow-through, and hot-wire anemometric transducers are used as pneumoelectric transducers of differential pressure 15. In order to further increase the sensitivity and lower the lower limit of small working speeds to near zero, as well as to reduce the likelihood of clogging of the intake holes (receivers) of the pressures P ₁ and P ₂ , P ₃ and P ₄ due to the flow of air from them as hot-wire anemometers using hot-wire differential converters 16 (6), the total input of which is connected to the intake vents pnevmokanalu (receiver) _PΣ total pressure P and the other two inputs - pnevmokanalam to the intake vents (n iemnikov) pressures P ₁ and P _2, P ₃ and P _4, which determine the angular φ ₁ and φ ₂ of the resulting oncoming airflow vortex column in the respective planes, and outputs differential thermoanemometric converters are connected differentially, wherein a difference of output signals through multiplexer 12 and An analog-to-digital converter 13 is fed to a microprocessor 14, which calculates the parameters of the true helicopter airspeed vector at low and near-zero flight speeds.

The system for measuring small air speeds of a helicopter operates as follows.

The fixed aerometric receiver, made in the form of a spherical body 1 (Fig. 3), is mounted on a special rod 11 mounted on the fuselage in the area of the rotor column of the rotor of the helicopter. The axis of the spherical body 1 is directed upward in a plane parallel to the plane of symmetry of the helicopter, while the plane passing through the holes for the intake (receivers) of pressure P ₁ and P ₂ parallel to the longitudinal axis of the helicopter. In the plane orthogonal to the plane of the pressure receivers P ₁ and P ₂ , there are openings for the intake (receivers) of the pressures P ₃ and P ₄ .

At low flight speeds, the spherical body 1 is in the alignment of the vortex column of the rotor of the helicopter and perceives the pressure P _P∑ , P ₁ , P ₂ , P ₃ , P ₄ , P _CT∑ and temperature T _T∑ . Moreover, the components of the vector the true air speed of the helicopter is determined by perceiving and recording these parameters and determining the angular position of the resulting incident air stream flowing around the spherical body 1, relative to the coordinate system associated with the helicopter.

Vector the resulting incident air stream flowing around the spherical body 1 is the geometric sum of the vector the speed of the undisturbed air flow due to the translational movement of the helicopter, and the vector rotor inductive flow velocity, i.e. .

For a specific installation site of the aerometric receiver in the form of a spherical body 1 on the helicopter fuselage, the components V _ix , V _iy , V _{iz of the} vector in a connected coordinate system can be described by equations of the form [4]:

where K _ix , K _iy , K _iz are dimensionless coefficients depending on the magnitude (modulus) of the velocity vector undisturbed air flow equal in magnitude V = V _B, as well as the angles of attack α and β sliding helicopter; - vector module speed of inductive flow in hovering mode (V = 0); G is the current weight of the helicopter; - normal overload; ρ _H is the density of the unperturbed air flow at a given height H; F is the area swept by the rotor of the helicopter; χ is the fill factor of the rotor disk; g = 9,80665 - acceleration of gravity.

Velocity V _∑ and density ρ _{∑ of the} resulting incident air flow can be determined from the total P _P∑ and static P _CT∑ pressures and temperature T _{T∑ of the} inhibited resulting air flow sensed by the braking temperature _sensor built into the total pressure receiver using standard dependencies GOST 5212-74 and GOST 4701-81 (GOST 5212-74. Aerodynamic table. Dynamic pressures and braking temperatures of air for speeds from 10 to 4000 km / h. Parameters. M: Publishing House of Standards, 1974. - 239 p. [6] and GOST 4701-81. The atmosphere is standard. Parameters. M: Publishing House of Standards, 1981. - 179 p. [7]):

where the parameters in formulas (11) and (12) have dimensions in units of the SI system.

Using relation (11) from pressures Р _П∑ , Р _CT∑ and temperature T _T∑, it is possible to determine V _∑ and projections of the vector the resulting air flow on the axis of the coordinate system associated with the helicopter as

where φ ₁ and φ ₂ are the angles that determine the position of the vector the resulting incident flow of the vortex column relative to the planes of the pressure receivers P ₁ , P ₂ and P ₃ , P ₄ .

Using the ratios given in [2, p. 122], the relationship of the pressures P ₁ , P ₂ and P ₃ , P ₄ , perceived by the holes for the fence (receivers) 3, 4 and 5, 6 can be represented as

Then the angles φ ₁ and φ ₂ defining the position of the vector the resulting speed of the incident air flow of the vortex column will be determined by the relations

According to the equation , we obtain the equations for the components V _x , V _y , V _{z of the} vector true airspeed helicopter view

wherein V _Σ defined by equation (11), i.e. V _∑ = f ₄ (P _П∑ , P _CT∑ , T _T∑ ).

Studies have shown (see Kozitsin VK. The system of helicopter air signals based on a freely oriented pressure receiver. The dissertation for the degree of candidate of technical sciences. Ulyanovsk. OJSC “Ulyanovsk Instrument Design Bureau. 2006. - 313 p. [8] ), for a specific installation site of an aerometric pressure receiver on a helicopter in each of the flight modes, according to the results of flight tests, it is possible to determine the values of the coefficients K _ix , K _iy , K _iz with sufficient reliability.

Then, according to the pressures P ₁ and P ₂ , P ₃ and P ₄ , P _П∑ and P _CT∑ , and according to the braking temperature T T _{восприним} , perceived by a stationary aerometric receiver in the form of a spherical body after their conversion into electrical signals using pneumoelectric transducers 8 and entering through the multiplexer 12 and the analog-to-digital converter 13 into the microprocessor 14 the parameters of the true airspeed vector of the helicopter in the region of low and near-zero speeds are calculated in accordance with equations of the form

It should be noted that due to the location of the openings for the intake (receivers) of static pressure P _{CT∑ of the} resulting incident flow around the entire circumference of the spherical body, the influence of the angular position of the vortex column is significantly reduced and the pulsations of the resulting incident air flow are averaged.

Thus, the proposed implementation of a stationary aerometric receiver in the form of a spherical body with openings for the intake (receivers) of the total and static pressures of the resulting incident air flow of the vortex column, the receiver of the braking temperature of the resulting stream, the holes for the intake (receivers) of pressure, determining the angular position vortex columns relative to the axes of the associated coordinate system allowed us to significantly simplify the design, reduce the weight and size of the aerome use of a single aerometric receiver, reducing the number of pneumatic-electric converters, simplifying the structural-functional and electrical circuits of the system, increasing the measurement accuracy and expanding the lower boundary of operating speeds to the region of near-zero.

The use of the system for measuring low air speeds on various classes of helicopters can improve flight safety, improve piloting and combat use, increase the reliability of the system in conditions of possible sharp disturbances in the aerodynamic field of the helicopter, increase the accuracy of measuring the parameters of the true air speed of the helicopter in the region of low and near-zero speeds flight.

Claims (4)

1. A system for measuring low air speeds of a helicopter comprising a multichannel aerometric receiver mounted on the fuselage in the area of the rotor vortex column, pneumoelectric transducers whose outputs are connected through a series-connected multiplexer and analog-to-digital converter to a microprocessor, the output of which is the system output according to the parameters of the true vector helicopter airspeed, characterized in that the aerometric receiver is made in the form of a spherical body, the axis of which o is directed upward in a plane parallel to the plane of symmetry of the helicopter, holes are made on the top surface of this spherical body on the axis of symmetry, which are receivers for taking the total pressure of the resulting incident air flow of the vortex column symmetrically with respect to the axis of symmetry of the spherical body in planes parallel to the plane of symmetry of the helicopter and orthogonal to it, holes are made that are receivers for collecting pressures that determine the angular position of the vortex column Along the axis of symmetry of the spherical body in the above orthogonal planes, in the plane orthogonal to the two indicated planes, holes are made on the surface of the spherical body that are receivers for collecting the static pressure of the resulting incident air flow of the vortex column, while the receivers for collecting the full pressure are connected by flowing pneumatic channels to receivers for taking pressure, determining the angular position of the vortex column relative to the axis of symmetry of the spherical body in the indicated above orthogonal planes containing pneumatic-electric pressure differential transducers, the outputs of which for pneumatic channels of identical planes are connected differentially. 2. The system for measuring low air speeds of a helicopter according to claim 1, characterized in that hot-wire anemometric transducers are used as pneumoelectric differential pressure transducers. 3. The helicopter’s low airspeed measuring system according to claim 1, characterized in that differential hot-wire anemometric transducers are used, the common input of which is connected to the pneumatic channel of the total pressure receiver of the resulting incident air flow, and the other two inputs are connected to the pneumatic channels of the pressure receivers, determining the angular position of the resulting incident air flow in the corresponding plane, and the outputs of the differential hot-wire their converters are connected differentially. 4. The system for measuring small air speeds of a helicopter according to claim 1, characterized in that the microprocessor calculation algorithm is made according to equations of the form

;

;

;

;

;

. where P ₁ , P ₂ - pressure at the symmetric points of the spherical body in a plane parallel to the plane of symmetry of the helicopter; P ₃ , P ₄ - pressure at the symmetric points of the spherical body in the plane orthogonal to the plane of symmetry; _PΣ P - total resultant pressure of the oncoming air flow vortex column; P _CT∑ is the static pressure of the resulting incident flow of the rotor column of the rotor of the helicopter; T _T∑ is the braking temperature of the resulting incident air flow of the vortex column, sensed by a sensor integrated into the total pressure receiver of the resulting incident air flow of the vortex column.