RU2710955C1 - Ignoring turbulence aircraft and aircraft attack angle change sensor - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: group of inventions relates to aircrafts made according to aerodynamic schemes "duck" or "tandem". Aircraft comprises interconnected front and rear bearing surfaces equipped with lifting force control devices functionally dependent on aircraft attack angle variation. Derivative of lift factor by aircraft angle of attack is positive for rear surface and negative for front. Aircraft attack angle variation sensor comprises front and rear surfaces with fastening hinge between them. Derivative with respect to the angle of attack of the coefficient of lift of the rear surface exceeds the derivative of the front surface by not less than one and a half times.

EFFECT: group of inventions is aimed at providing longitudinal stability of aircraft by reducing influence of horizontal gusts on aircraft lifting force.

6 cl, 4 dwg

Description

Technical field

This group of inventions relates to aeronautical engineering, and more specifically to apparatuses heavier than air, namely, to duck or tandem aerodynamic designs, it can be used in the construction of aircraft, mainly for transport purposes.

State of the art

Known ignoring turbulence aircraft containing interconnected front and rear bearing surfaces, equipped with means for regulating the lifting force, functionally dependent on changes in the angle of attack of the aircraft - RF patent No. 2666094. The prototype of the invention according to paragraphs. 1-3 of the formula is an airplane ignoring turbulence, containing front and rear bearing surfaces connected to each other, equipped with means for controlling the lifting force, functionally dependent on changes in the angle of attack of the aircraft according to RF patent No. 2609644, p. 11, lines 33-48. The wing of this aircraft, as it should be for the "duck", located behind the center of mass, is equipped with means for regulating the lifting force, which is functionally dependent on the change in the angle of attack of the aircraft. In this case, the increment of the wing lift with a random change in the angle of attack of the aircraft is leveled by the oppositely directed change in the lift due to the deviation of the means of its regulation. Front horizontal plumage (PGO) is made in the vane version. This embodiment of the bearing surfaces reduces their derivatives of the coefficient of lift in the angle of attack of the aircraft to values close to zero. It is assumed that as a result, the aircraft will not respond to random changes in the angle of attack and will ignore the vertical flows of air masses.

In the future, for brevity, the derivative of the surface lift coefficient with respect to the angle of attack will be called simply the derivative.

The increase in wing lift due to a change in the angle of attack of the aircraft occurs in focus along the angle of attack, and the change in lift due to a deviation of the means for regulating lift (for example, flaperon) occurs in focus according to its angle of deviation. These tricks are located at a distance of approximately equal to a quarter of the average aerodynamic chord of the wing. As a result, there arises a pitching moment leading to longitudinal instability of the aircraft, which has a rather substantial value, which the vane VGE with a derivative close to zero cannot compensate for. This circumstance leads to a deterioration in the operational characteristics of the aircraft.

A known sensor for changing the angle of attack of an aircraft containing a monoplane surface (see RF patent No. 2666094), in this capacity, a servo wheel acts, turning the vane front horizontal plumage when changing the angle of attack of the aircraft. The prototype of the invention according to paragraphs. 4-6 of the formula is a sensor for changing the angle of attack of an aircraft containing a polyplane surface (see RF patent No. 2651958), in this capacity is a polyplane servo wheel that turns the vane front horizontal tail when the angle of attack of the aircraft changes.

Known sensors have a significant drawback, namely, that for a positive increment of the lifting force of the surface under their control, it is necessary that a negative increment of the lifting force occurs on them, i.e. they reduce the effectiveness of the controllable surface. This circumstance leads to a deterioration in the operational characteristics of the aircraft.

The technical problem solved by this group of inventions is to create such an aircraft with two bearing surfaces, which would have static stability and as a result, as well as due to the improvement of the angle of attack sensor, the aircraft would have improved performance.

Disclosure of the invention

This problem is solved in that in an airplane containing front and rear bearing surfaces connected to each other, equipped with lift control means that are functionally dependent on changes in the angle of attack of the aircraft, the derivative of the lift coefficient with respect to the angle of attack of the aircraft is positive for the rear surface and negative for the front.

In addition, the front bearing surface is made in the form of a fully rotatable front horizontal tail, pivotally connected to the rear bearing surface.

In addition, the front bearing surface is made in the form of a front horizontal tail, rigidly connected with the rear bearing surface.

The task is also solved by the fact that in the sensor for changing the angle of attack of the aircraft containing the front and rear surfaces with a mounting hinge between them, the derivative with respect to the angle of attack of the coefficient of lift of the rear surface exceeds the corresponding derivative of the front surface by at least one and a half times.

In addition, in the sensor, the rear surface is monoplane, and the front surface is polyplane.

In addition, the sensor is also a sensor for changing the speed of the oncoming air flow.

This allows you to reliably ensure the longitudinal stability of the aircraft and thereby improve its operational characteristics.

Brief Description of the Drawings

Details, features, and advantages of this group of inventions follow from the following description of embodiments of the claimed aircraft using the drawings, in which:

FIG. 1 is a diagram of the lifting forces acting on an aircraft with a fully rotatable front horizontal tail with a random increase in the angle of attack;

FIG. 2 is a diagram of the lifting forces acting on an aircraft with a classic front horizontal tail, rigidly connected to the fuselage, with a random increase in the angle of attack;

in FIG. 3 shows a sensor for changing the angle of attack of an aircraft in a position corresponding to the cruising flight mode of the aircraft;

in FIG. 4 shows a sensor for changing the angle of attack of an aircraft in a position corresponding to the landing mode of flight of the aircraft;

The implementation of the invention

The inventive aircraft is made according to the aerodynamic scheme "duck", it contains a rear bearing surface in the form of a wing, which consists of two consoles 1 (see Fig. 1), rigidly connected with the fuselage 2. The console 1 is equipped with a pivotally connected lifting force control means in the form of a flaperon 3, which has the ability to deviate under the influence of aerodynamic forces, as a result of the deflection of the servomotor 4. The front bearing surface in the form of an all-inclined front horizontal tail unit (CPGO) 5 is pivotally placed on the fuselage along the O axis About ¹ , perpendicular to the plane of symmetry of the aircraft. Since the wing, consisting of two consoles 1, is rigidly connected with the fuselage 2, the front bearing surface in the form of a central heating element 5 through the fuselage 2 is pivotally connected to the rear bearing surface. The means of regulating the lifting force in the form of a servo wheel 6 is used to change the angle of attack of the CPGO 5 and thereby provides the ability to change its lifting force. Propeller installation 7 provides the movement of the aircraft.

The longitudinal stability of the aircraft is ensured as follows.

In order to prevent vertical flows of air masses from acting on the plane, which randomly change the angle of attack of the aircraft, flaperon 3 deviates upward with a random increase in the angle of attack and downward with its decrease. In this case, the change in the lifting force ΔU of the wing console 1 due to a change in the angle of attack Δα of the aircraft is leveled by the corresponding change in the lifting force ΔT of the console 1 due to the deviation of the flaperon 3 by the angle δ. The deviation of the flaperon 3 is due to the action of aerodynamic forces as a result of the deviation of the servo wheel 4 functionally dependent on the sensor described below changes in the angle of attack of the aircraft. In this case, the deviation of the sensor that occurs when the angle of attack of the aircraft changes is kinematically converted into deviations of the servo wheels 4 and 6. Another option is to service each surface with its own sensor.

The force ΔY is applied at the focus F ^α _{cr of the} wing along the angle of attack, and the force ΔT is applied at the focus F ^δ _{cr of the} wing along the deflection angle of the flap, spaced apart from each other at a distance f _cr approximately equal to a quarter of the average aerodynamic wing chord (SAX). These forces create a fairly significant pitch moment that violates the longitudinal stability of the aircraft. This moment can be compensated by the action of CPGO 5. Since the compensating moment of CPGO should be opposite in sign to the arising moment of the wing due to a random increment of the angle of attack of the aircraft, the derivative of the lifting coefficient of CPGO with respect to the angle of attack of the aircraft should be negative. Those. with a positive increment of the angle of attack Δα of the aircraft, the increment of the lifting force Δt of the CPSC should be negative. Due to the fact that a negative increment Δt of the lifting force occurs on the CPSC, the compensatory effect of the flaperon 3 should be reduced, i.e. the value of ΔT modulo must be less than the value of ΔU per module of Δt. That is, with a positive increment of the angle of attack Δα, the resulting increment of the lift of the wing ΔU + ΔT is also positive.

As a result, it can be stated that in an aircraft ignoring turbulence, the derivative of the lift coefficient with respect to the angle of attack of the aircraft is positive for the rear bearing surface and negative for the front.

где:To determine the angle Δδ of the deflection of the flaperon 3 and the angle Δγ of the deflection of the CPGO 5, at which the action of random changes in the angle of attack Δα of the aircraft is completely reduced, we formulate the following conditions: 1 - a random change in the angle of attack Δα does not lead to a change in the lift of the aircraft; 2 - a random change in the angle of attack Δα generates a stabilizing pitch moment proportional to

Where:

- производная по углу атаки коэффициента подъемной силы крыла;

- wing angle derivative of the angle of attack;

σ is the stability margin equal to the distance between the focus F in the angle of attack of the aircraft and its center of mass G.

As a result of consideration of these conditions, we obtain:

Where:

- производная по углу отклонения закрылка коэффициента подъемной силы крыла;

- derivative with respect to the angle of deflection of the flap of the wing lift coefficient;

L is the distance between the foci along the angle of attack of the wing and TsSPGO 5 (interfocal distance - MPF);

f _cr - the distance between the focus of the wing in the angle of attack and the focus of the wing in the angle of deviation of the flap;

- производная коэффициента подъемной силы ЦПГО 5 по его углу атаки γ;

- derivative of the coefficient of lift of the central strength of civil defense 5 on its angle of attack γ;

- отношение площади ЦПГО 5 к площади крыла - двойной площади консоли 1.

- the ratio of the area of the center 5 to the area of the wing - the double area of the console 1.

In FIG. 2 shows an airplane ignoring turbulence, in which the classic front horizontal tail unit (PGO) 8, rigidly connected with the fuselage, is used as the front bearing surface; it is equipped with a means of regulating the lifting force in the form of a rudder 9 of height, the deviation of which is carried out by aerodynamic forces acting upon deflection servo steering 10, functionally dependent on the sensor changes the angle of attack of the aircraft. In this case, the deviation of the sensor changes the angle of attack of the aircraft, kinematically converted into deviations of the servo wheels 4 and 10.

Here the difference lies in the fact that the deviation Δθ of the elevator 9 should compensate not only for the destabilizing moment of the wing pitch caused by a random change in the angle of attack Δα of the aircraft, but also the increment caused by it Δ Hugo lifting force of the ASE 8. Based on this, the sensor should deflect flaperon 3 and the rudder 9 heights at angles, the values of which satisfy the following conditions:

Where:

f _th - the distance between the focus of the PGO on the angle of attack and the focus of the PGO on the angle of deviation of the elevator;

- производная коэффициента подъемной силы ПГО 8 по углу атаки α;

- derivative of the lift coefficient of the PGO 8 with respect to the angle of attack α;

- производная коэффициента подъемной силы ПГО 8 по углу θ отклонения руля 9 высоты;

- the derivative of the lift coefficient of the PGO 8 with respect to the angle θ of the deviation of the elevator 9;

- отношение площади ПГО 8 к площади крыла - двойной площади консоли 1.

- the ratio of the area of PGO 8 to the area of the wing - double the area of the console 1.

In the case in which both bearing surfaces are the same, the last formulas will take a simpler form:

All the above formulas need to be refined, taking into account the influence of the front surface on the bevel and the decrease in the air flow rate behind it.

When using the electronic remote control system (EMDS), the deviation of the sensor that occurs when the angle of attack of the aircraft is converted by the encoder into an electrical signal, processed by the EMDS and not fed to the servos 4, 6, 10, but to the drives of the flaperon 3, elevator 9 and the central control center 5 .

The technical result of the invention according to claims 1-3 formulas is to ensure the longitudinal stability of the aircraft, while the aircraft ignores the turbulence of the atmosphere. In addition, since with a random increase in the angle of attack of the aircraft, the profile of the bearing surfaces decreases its curvature, the probability of the bearing surfaces reaching the critical angle of attack due to the influence of the atmosphere is almost completely eliminated. Additionally, the resistance of the aircraft is reduced due to the fact that the lifting force of the bearing surfaces of the aircraft does not exceed its gravity. As a result, the operational characteristics of the aircraft improve.

In FIG. 3 shows a sensor for changing the angle of attack of an aircraft, it contains a front polyplane surface formed by two identical plans 11 and 12, rigidly interconnected by a stand 13. A polyplane surface 11, 12 with a stand 13 is strengthened on the basis of 14 using a spring 15 having a very small stroke - about 10 degrees. The base 14 by means of a hinge 16 is connected with the front end of the beam 17. At the rear end of the beam 17 there is a rigidly connected rear monoplane surface 18. A beam 17 also has a rigidly connected lever 19 with a hinge 20 at its end. To change the angle of attack of a polyplane surface 11, 12, a lever 21 with a hinge 22 at its end and a rod 23 with a hinge 24 are used. The rod 25 is connected with a wing mechanization control system not shown in the drawing. Thrust 26 is associated with a servo-wheel of the wing lift control means not shown in the drawing. To place the sensor on the structure (glider) of the aircraft is a mounting hinge 27.

Plans 11, 12 are performed with low elongation - not more than three. The elongation of the surface 18 must be at least eight. The distance between plans 11 and 12 is 100-125% of the chord of plans. Such parameters of the sensor surfaces provide the maximum approximation of the focus by the angle of attack of the system of sensor surfaces to the rear surface 18.

The areas of the front 11, 12, and rear 18 surfaces are equal to each other, and their total area is 10-20% higher than the doubled area of the servo wheel 4 of flaperon 3. Moreover, the distances from the mounting hinge 27 to the foci of the front and rear surfaces are equal.

The ability of the sensor to track changes in the angle of attack of the aircraft is ensured by the fact that the derivative with respect to the angle of attack of the lift coefficient of its rear monoplane surface 18 is significantly higher than the same derivative of the front biplane surface 11, 12. This is a consequence of the large difference in the elongations of these surfaces, as well as a significant decrease in the value of the derivative of the polyplan surface compared to monoplane.

As a result, the focus on the angle of attack of the system of surfaces 11, 12, 18 of the sensor is significantly behind the hinge 27, which serves to mount the sensor on the aircraft structure. This provides weathervane properties of the sensor, i.e. its ability to orient itself along the stream. Effective operation of the sensor is possible with a difference in the derivatives of the rear and front surfaces of the sensor not less than one and a half times.

With a random increase in the angle of attack of the aircraft, for example, when it enters the upward flow, the beam 17 with the lever 19 deviates counterclockwise. The position of the surfaces and the sensor beams in the described situation is represented in the drawing by dashed lines. For clarity, the deviation angles are conditionally exaggerated.

The hang of the flaperon 3 is controlled by horizontal displacement of the thrust 25 with the hinge 24, as a result of which there is a rotation on the hinge 16 of the base 14 and the biplane surface 11, 12 attached to it, which leads to a change in the angle of attack of the plans 11 and 12. This causes a rotation on the hinge 27 beams 17 with lever 19 and followed by the deflection of the flaperon. The rotation control of the sensor is possible due to the fact that the range of working angles of attack of the front surface is much wider than the range of the rear surface. And at the edges of these ranges, i.e. at the maximum possible deviation of the sensor from the direction of flow, the lifting forces and moments of both surfaces are maximum and equal, while both surfaces are at their critical angles of attack.

The sensor connections described here with the means for regulating the lifting force of the front and rear surfaces can be performed both by means of the hard wiring presented here and by the cable.

When using an EMF, the sensor is equipped with an encoder, the signal from which, after processing, is fed to the drives of the means for controlling the lifting force of the front and rear surfaces.

In order for the sensor to respond not only to vertical, but also to horizontal air flows, a spring 15 serves (see Fig. 4). Let the sensor be installed at a certain angle of attack to the oncoming flow, for example, in a position corresponding to the landing stage. An increase in the oncoming flow velocity leads to an increase in the load on the spring 15, as a result of which plans 11, 12 will slightly decrease the angle of attack, which is reflected by dashed lines. At the same time, surface 18 will retain its angle of attack.

This will lead to a counterclockwise deflection of the beam 17 with the lever 19 and a corresponding upward deflection of the flaperon. As a result, an increase in the lifting force of the wing console due to an increase in the velocity head is leveled out by a decrease in the lifting force due to the upward deflection of the flaperon.

Thus, there is a weakening of the dependence of the lifting force of the aircraft on the change in speed of the oncoming air flow.

As can be seen, for a positive increment of the lifting force of the bearing surface, the sensor must rotate so that its surfaces increase their angle of attack, i.e. the increment of the lifting forces of the sensor surfaces must also be positive.

The technical result of the invention according to paragraphs. 4-6 formulas is to eliminate loss of lift on the sensor. In addition, the improvement of the sensor can significantly reduce the dependence of the aircraft lifting force on horizontal gusts (shear) of wind.

Additional advantages of the entire group of inventions include the creation of the possibility of reducing the weight of the airframe, since the bearing surfaces are not subject to fatigue wear and can be counted on the load experienced by the aircraft when touching the runway. As a result, the operational characteristics of the aircraft improve.

Claims (6)

1. Aircraft containing interconnected front and rear bearing surfaces, equipped with means of regulating the lifting force, functionally dependent on changes in the angle of attack of the aircraft, characterized in that the derivative of the coefficient of lift in the angle of attack of the aircraft is positive for the rear surface and negative for the front. 2. Aircraft under item 1, characterized in that the front bearing surface is made in the form of a fully rotatable front horizontal tail, pivotally connected to the rear bearing surface. 3. The aircraft under item 1, characterized in that the front bearing surface is made in the form of a front horizontal tail, rigidly connected with the rear bearing surface. 4. The sensor changes the angle of attack of the aircraft, containing the front and rear surfaces with a mounting hinge between them, characterized in that the derivative with respect to the angle of attack of the coefficient of lift of the rear surface exceeds the similar derivative of the front surface by at least one and a half times. 5. The sensor according to claim 4, characterized in that the rear surface is monoplane and the front surface is polyplane. 6. The sensor according to claim 4, characterized in that it is simultaneously a sensor for changing the speed of the oncoming air flow.

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