RU2410286C2 - Canard control (versions) - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: proposed aircraft control system comprises elevator articulated with feathering surface that permanently tends to get arranged parallel with flow for elevator to follow it. Articulation is configured so that varying pitch causes change in elevator position relative to feather. In compliance with regression version, elevator turns through greater angle compared with feather to lessen control effect in increase in vertical slip. Invention covers also versions of mechanic, hydraulic and electric linkage.

EFFECT: ruling out elevator stall.

16 cl, 11 dwg

Description

The invention relates to aviation and is intended to control the aircraft by pitch and, subject to separate control of the left and right elevators / mechanism "scissors" elevators / - roll.

Known aircraft according to the scheme "duck" see US Pat. 2087067 or 2090446.

Their disadvantages are self-increase of the control action with increasing pitch and, as a result, an early stall of the flow on the rudders.

The proposed control "duck" consists of a fully rotary rudders / rudder / height, located in front of the wing / wings /. The rudders kinematically, for example mechanically, hydraulically or electrically, are connected with the weathervane surface / surfaces / / hereinafter referred to as the “weathervane” /, which in flight tends to fly longitudinally under the influence of the incoming air flow.

In this case, the rudders in the general case can rotate by 560 °, and when using mechanical kinematic coupling, the rudders can rotate completely freely around their axis.

The essence of the invention is that the position of the rudders does not depend directly on the controls of the aircraft, but correlates with the position of the weather vane, but may differ by ± a control angle that is set by the pilot. Since the weather vane tends to settle longitudinally to the flow, it turns the rudder by this angle relative to the flow / and not relative to the fuselage /. That is, the steering wheel is always at a given angle to the flow, regardless of the vertical sliding of the fuselage. In this case, when a command is given to change the pitch, the control action does not increase itself, it remains constant.

Or, if the deviation of the wind vane from the longitudinal axis of the aircraft increases, more precisely - from the calculated position corresponding to horizontal flight, the control angle set by the pilot can automatically decrease due to the provided features of the kinematic connection of the rudders with the weather vane / "Regressive" option /. That is, when you turn the weather vane to the sliding angle, the steering wheel will turn at an angle slightly larger than this. In this case, when the pitch changes, the control action will self-decrease. That is, the control characteristics will be similar to the aerodynamic design with tail elevators.

At the same time, all the advantages of the duck control are retained: positive lifting force on the steering wheels / i.e. smaller wing area by twice the area of the rudders /, the absence of "drawdown" during control / increases the accuracy of control and accelerates its reaction to the actions of the pilot /, and the absence of "shading" of the rudders / good controllability in supercritical modes /.

In particular, the consequence of the above will be a quick exit from the stall position. If the tail control at the same time pushes the plane up, turning the kinetic energy into potential / i.e. reducing the already insufficient speed /, then the proposed control for any sliding and pitch immediately lowers the nose of the aircraft down, contributing to an increase in speed and transition to a stable horizontal flight.

Moreover, the control acquires new qualities: firstly, it remains effective in any direction of the incoming flow, in particular when moving the tail forward after cabling and in a flat corkscrew. Secondly, such a control system gives the aircraft one more property - it becomes less sensitive to the so-called "air holes", i.e. to ascending and descending flows, since when an unplanned vertical slip occurs, the rudders turn in the same direction without changing the lifting force on them, or with a decrease during regress. variant, and the subsequent effect of sliding on the wing immediately leads to a change in pitch, aimed at reducing the perturbation.

Since rudders create lift with such a control scheme, their relative area can be greater than with tail control, and the offset of the center of gravity of the aircraft relative to the center of the wing's lift can be greater, which will give the aircraft good anti-tearing properties.

The most appropriate arrangement of rudders and weathercocks on one axis perpendicular to the longitudinal plane of the aircraft, in which case they can be driven by a single control mechanism. However, variants are possible when the axes have a forward or reverse sweep, as well as a forward or reverse V-shaped.

Weathercocks can be located on the rudders coaxially or out of alignment with them / at the end, in the root part or in the middle of the length of the steering console /, i.e. be as if external trimmers. Or can be located separately and, preferably, in front of the rudders.

When applying mechanical kinematic communication (mainly for light-engine aircraft and gliders), it is necessary that the center of aerodynamic forces (hereinafter CAC) is located behind the rudder rotation. However, the location of the CAC exactly behind the axis of rotation of the steering wheel in some cases can lead to spurious self-oscillations of the steering-vane-mechanism system. To exclude the possibility of such self-oscillations, the axis of rotation of the steering wheel may be located in front-above or in front-below the CAC. Perhaps the use of dampers.

For hydraulic and electrical control systems, this condition is less significant, since they imply a large self-extinguishing or even self-braking of the executive machine.

When applying mechanical kinematic coupling, weight balancing of rudders and weathercocks is also mandatory. Although a small conscious unbalance with a shift in the center of gravity below the axis of rotation of the steering wheel is possible. This can be done so that in the parking position the rudders and weathercocks occupy a horizontal position that is safe for them and for staff and that they do not swing under the influence of wind.

For the same purpose, rudders and weathercocks may have small torsion springs, centering them in a horizontal position. Or have small parking brakes, in particular removable.

If the brake is provided for by the aircraft’s design, then it must first exclude spontaneous operation / for example, operate from the pneumatic cylinder when pressure is applied /; secondly, his effort should be small, so that in flight it only complicates, but does not exclude the possibility of control; and thirdly, it should have dual control - i.e. if the pilot forgets to turn it off, it will turn off automatically when a certain speed is set.

For hydraulic and electrical control systems, weight balancing and parking aids are optional.

Several dozen variants of the mechanical kinematic connection of the weather vane with the rudder are possible, especially with a limited range of rudder movement relative to the fuselage. Consider three such options.

The first mechanical option is the simplest structurally, but provides an operating range of approximately 150 / ± 75 in figure 3 and +50 - -100 in figure 4 /. Therefore, the weather vane should have a margin of safety in case of movement of the tail forward. In Fig.3 shows an aerodynamic sub-variant with a spaced arrangement of the steering wheel and weather vane, and in Fig.4 - with coaxial / as in Fig.1, 2 /.

Both sub-options of this option consist of oppositely directed levers located on the axis of the steering wheel and weather vane, which are pivotally connected by rods to the ends of the rocker arm / direct two-arm lever of the first kind /. The axis of rotation of the rocker arm is fixed with the possibility of longitudinal movement to / from / the axis of the steering wheel / for example along guides or in an arc, i.e. on another, preferably larger, lever.

If the steering lever is shorter than the weather vane lever, or the rocker arm connected to the steering wheel is longer than the weather vane arm, then when sliding / when the wind vane is deflected, the steering wheel will move to a larger angle than the weather vane. And the angle of attack of the steering wheel to the flow will decrease / Regressive version of figure 4 /.

The second mechanical version of the kinematic connection is coaxially located steering shaft and weather vane, made like a pipe in a pipe / Fig.5a /. One of the pipes has a longitudinal slot, and the second has a screw slot with a large pitch. Or on pipes there are two oppositely directed screw slots. A pin fixed to the control sliding sleeve with flanges enters the intersection of the slots. The sleeve is located on the outer pipe and is controlled by a fork or lever from an airplane control / not shown /. Moreover, the pin to reduce friction may have two rollers / Fig.5v / or two sliders made of antifriction material / Fig.5c /.

For greater control accuracy in horizontal flight mode, the screw slot / s / can have a larger step in the middle than at the ends. That is, the gear ratio in the middle part is less than at the edges.

The regression option can be implemented as follows: the flanges on the control sleeve form a helical groove in the working range, which then closes to itself. The inclination of the helical groove is selected so that when the positive or negative slip increases, the control action decreases.

The third mechanical option is also coaxially located steering shaft and weather vane, made as a pipe in a pipe, and a control sleeve with flanges on the outer pipe. But the coupling is located on it not slidingly, but on the slots, the role of which can be played by a longitudinal groove or slot in the pipe and the roller in it / Fig.6a /. In the outer pipe there is a slot through which a lever mounted on the inner pipe passes. The lever is connected by a rod located obliquely to the pipe axis with two ball joints with a spline control clutch. The axial movement of the coupling leads to the angular movement of the inner pipe relative to the outer.

For greater linearity of movement, the lever of the inner pipe can be connected to the control sleeve with two such rods through an intermediate single-arm or two-arm lever mounted on the outer pipe.

The variant on figa has one feature - when the rudders turn in one direction, the gear ratio increases, and in the other it decreases. The latter is best chosen for diving / choosing the direction of the draft /.

To obtain a regressive version, as in the second embodiment, a screw groove on the coupling can be applied.

The hydraulic version of the kinematic connection consists of oppositely directed levers located on the shafts of the steering wheel and weather vane. The levers are connected by rods to the ends of the beam, the axis of which is fixed at the end of the second beam / possible unification /. The axis of the second beam is connected to the spool rod / thrust or mounted directly on it /, and the second end of the second beam is connected to the control. The spool controls the rudder drive hydraulic cylinder. /cm. Fig.7 /.

To obtain a regressive version, as in the first mechanical version, the steering lever must be shorter, or the rocker arm connected to it must be longer.

This option has a rudder deflection range of approximately 150 °, for example - 100 ° - + 50 °.

The electrical version of the kinematic connection consists of vertical sliding sensors, rudder position sensors and a control element position sensor. Sensor signals are fed to an amplifier, where they are algebraically summed and, after amplification, are fed to an executive machine.

To obtain a regressive version, the sensor of the control element can be connected to the amplifier through a divider controlled by the signal of the slip sensor. The divider can be disabled, i.e. to shunt.

With the hydraulic control option, the size of the wind vane and its rod can be several times smaller than with a mechanical one. And with the electric version, the weather vane is a slip sensor, which can be arbitrarily small.

Figure 1, 2 shows the proposed control, where: 1 - the fuselage, 2 - elevator, 3 - weather vane, 4 - weather vane, 5 - counterweight.

Figure 3, 4 shows the first mechanical version of the kinematic connection, where: 6 is the weathervane lever, 7 is the steering lever, 8 is the rocker arm, 9 is the link rod, point 0 is the axis of rotation of the rocker arm, which can be controlled to move left and right in the drawing in guides or on a lever of sufficient length / not shown /.

On figa, b, c, the section shows a second mechanical version of the kinematic connection, where: 10 - the inner pipe with a slot 11, 12 - the outer pipe with a slot 13, a pin 14 entering the slots with rollers 15 or sliders 16. The pin is radially -inside mounted in the coupling 17 with the flanges 18.

On figa, b, c, the third mechanical version of the kinematic connection is shown, where: 19 is a lever on the inner pipe, 20 is a rod with ball joints at the ends, 21 is a one-arm lever, 22 is a two-arm lever.

7 shows the hydraulic control option, shows the aerodynamic sub-variant of the separate placement of the steering wheel and the weather vane on the fuselage, where: 8 - the first rocker, 9 - thrust, 23 - the second rocker, 24 - the spool, 25 - the steering cylinder / the connection of the hydraulic cylinder with the steering wheel is not shown.

On Fig, 9 shows the electrical control options / Fig - regressive option / where: - slip sensor, steering wheel. - steering wheel position sensor, Ex. - position sensor of the control. Us. - amplifier, I.M. - executive machine, D - divider.

Figure 10 shows a possible device for the divider in the form of an electric variable resistor with three fixed and one movable / from the slip sensor / contact. 11 shows an exemplary characteristic of such a divider, where: ± α is the deflection angle of the slip sensor, K is the gear ratio of the divider. The divider can be switched off by the VK switch.

The control in FIGS. 1, 2 works as follows: the control elements specify a change in the relative position of the rudders and weathercocks. The weather vane in the stream almost does not change its position, at least this movement can be neglected to a first approximation. That is, when changing the relative position, only the steering wheel deviates, say + 10 °, with the toe up.

Suppose the rudder's efficiency is such that there is an increase in pitch by + 6 °. In normal duck control, the rudder angle with the flow would be + 16 °. In the proposed control, the weather vane with an increase in pitch deviates with respect to the fuselage with its toe down by 6 °, causing the steering wheel to deviate relative to the fuselage with its toe down by 6 °. And the steering angle with the fuselage will be + 4 °, and with the flow still + 10 °.

In the regressive version of the control with an equivalent gear ratio of 1.5, the steering wheel will deviate downward by 9 ° / 6 × 1.5 /, and the angle of deviation of the steering wheel relative to the fuselage will become + 1 °, and relative to the flow 7 °. And the effort on the steering wheel will decrease.

The mechanical control in Fig. 3 works as follows: by moving the axis 0, the angle of deviation of the rudder 2 is set, for example, by the same + 10 °. When the pitch increases, the weather vane 9 will deviate with the toe down, turning the lever 6 to the left. That through the rod 9 will turn the beam 8 counterclockwise, and the beam through the second rod 9 will deflect the lever 7 to the right, turning the steering wheel 2 with the toe down at the same 6 °.

The control in Fig. 4 works similarly, but since the lever 7 is shorter than the lever 6, and the rocker arms are the same, when the wind vane 3 is rotated 6 °, the steering wheel will turn 9 °.

The control in Fig. 5a works as follows: by the force from the control element we shift the coupling 17 / for example, with a single-tooth fork - not shown / left or right. In this case, the pin 14 wedges the intersecting grooves 11 and 13, which will cause mutual rotation of the pipes 10 and 12. That is, the rotation of the steering wheel.

Changing the slip will lead to the simultaneous rotation of both pipes and the coupling without changing the relative position of all three.

In the regression variant, the flanges 18 form a helical groove on the coupling, and the said rotation will be non-synchronous, because when the position of the single-tooth fork is not changed / not shown / the rotation of the coupling will cause its axial displacement, and therefore a change in the relative position of the pipes.

The control in Fig. 6a works as follows: when the spline sleeve 17 is shifted left or right, the rod 20 pulls or pushes the lever 19, and therefore changes the relative position of the two pipes. When the slip changes, both pipes and the coupling synchronously rotate.

The control in FIGS. 6c, 6c works similarly, but the rod 20 connected with the clutch first acts on the intermediate lever 21 or 22, and through the second same rod it acts on the lever 19.

The control in Fig. 7 works as follows: with a controlled movement of the upper end of the second rocker arm 23, its axis 0 ₂ acts through the rod 9 on the spool 24, which drives the hydraulic cylinder 25 and causes the rudder 2 to move.

When the slip changes, the lever 6 through the rod 9 moves the axis 0 _{1 of the} first beam 8. The beam 8 is fixed or connected / dotted / to the lower end of the second beam 23, and this movement will cause the movement of the axis 0 ₂ , which acts on the spool 24. The steering wheel rotates weather vane. The regression option is shown - lever 7 is shorter than lever 6.

The control in Fig. 8, 9 works as follows: the control action through the sensor Ex. fed to the amplifier Us., which supplies energy to the Executive machine IM. The steering wheel rotates until the signal from the steering wheel sensor / other polarity / compensates for the Ex.

The appearance of a slip leads to the appearance of a signal at the Skl sensor, which leads to the appearance of a mismatch signal at the input to the amplifier, and through the IGL it turns the steering wheel in the same direction as the Skl sensor / signals must be of different polarity /.

In Fig.9, in addition, the signal from the sensor activates the divider D., which in a certain range weakens the control signal from the sensor Management becomes regressive.

The divider in Fig. 10 works as follows: the slider of the variable resistor, shifting within the resistor, reduces the transmitted signal in this range. Then shifting to the sliding contacts to the left and to the right of the resistor / shown by the dotted line /, the divider restores full control in supercritical flight modes. See the graph in FIG. 11.

When performing aerobatics, it may be appropriate to turn off the divider with a VK switch.

Claims (16)

1. The control system for an aircraft of the type "duck", including all-turning elevators with a control element, characterized in that it is equipped with weathercocks, each of which is kinematically, hydraulically or electrically connected to the corresponding elevator with the possibility of the pilot setting the angle between the weather vane and elevator through the governing body. 2. The system according to claim 1, characterized in that the gear ratio of the steering angle and the angle between the wind vane and the steering wheel in the middle of the control range is less than at the edges. 3. The control system according to claim 1, characterized in that each weather vane is located separately from the rudders. 4. The control system according to claim 1, characterized in that each weather vane is located on the corresponding steering wheel. 5. The control system according to claim 1, characterized in that it is equipped with torsion springs designed to center the rudders and weathercocks in a horizontal position. 6. The control system according to claim 1, characterized in that the rudders and weathercocks are equipped with parking brakes. 7. The control system according to claim 1, characterized in that the corresponding rudders and weathercocks have a mechanical kinematic connection, consisting of oppositely directed levers located on the axis of the steering wheel and weather vane, which are pivotally connected by rods to the beam, the axis of rotation of which is fixed with the ability to move from the steering axis. 8. The control system according to claim 1, characterized in that the respective rudders and weathercocks have axles made like a pipe in a pipe and are arranged coaxially. 9. The control system of claim 8, characterized in that in one of the pipes there is a longitudinal slot, and in the other there is a screw slot. 10. The control system of claim 8, characterized in that the pipes have two opposite-screw slots and a pin is included in the slot, mounted on a control sliding sleeve located on the outer pipe. 11. The control system according to claim 9, characterized in that at least one screw slot to the ends has a smaller pitch than in the middle. 12. The control system according to claim 1, characterized in that the axis of the steering wheel and the weather vane are made like a pipe in a pipe, in the outer pipe there is a slot through which a lever located on the inner pipe passes, and the lever is connected obliquely to the pipe axis with two ball joints hinges and with a spline control sleeve located on the outer pipe. 13. The control system according to claim 1, characterized in that the axis of the steering wheel and the weather vane are made like a pipe in a pipe, in the outer pipe there is a slot through which a lever located on the inner pipe passes, and the lever is connected by two such rods located on the outer pipe spline control coupling through an intermediate single-arm or two-arm lever. 14. The control system according to claim 12, characterized in that the flanges are made on the control sleeve, which form a helical groove in the working range of the steering angle, which then closes to itself. 15. The control system according to claim 7, characterized in that the weather vane lever is longer than the steering lever and / or the arm of the rocker arm to which the steering rod is attached is longer than the second arm of this rocker arm. 16. The control system according to claim 1, characterized in that the electrical kinematic connection consists of vertical sliding sensors, rudder position sensors and a position sensor of the control element, the signals of which are fed to the amplifier and from it to the executive machine, while the sensor of the control element is connected to amplifier through a divider controlled by the signal of the slip sensor.

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