RU2097229C1 - Wing-in-ground effect craft and method of longitudinal control - Google Patents

Abstract

FIELD: dynamically supported hovering craft. SUBSTANCE: wing-in-ground effect craft includes fuselage, wing, tail unit straightway tunnel open at bow which is formed by wing or by its center section nix and provided with controllable flap fitted at aft extremity of tunnel; it is provided with tunnel bottom profile corrector made in form of front and rear controllable doors articulated together. They are articulated respectively with fore and aft parts of tunnel bottom. Doors of profile corrector may be retracted flush with tunnel bottom and may be differentially extended into flow forming break of aerodynamic profile whose top is located under CG of wing-in-ground effect craft. Method of longitudinal control of wing-in-ground effect craft consists in differentiated throttling of air flow passing through under-wing tunnel both at its outlet and in area of wing-in-ground effect craft CG. EFFECT: enhanced reliability. 3 cl, 6 dwg

Description

 The invention relates to the field of aircraft on a dynamic air cushion, with increased stability along the longitudinal channel, regardless of the distance to the screen.

Known vehicle on a dynamic air cushion containing a fuselage with a tail tail mounted above the supporting wing of an S-shaped profile, equipped with controlled flaps, side skegs [1]
The way to control this vehicle along the longitudinal channel is to regulate the degree of throttling of the tunnel exit area under the lower surface of the wing with a shield located on the aft part of the wing.

Known ekranoplan "Eaglet" containing the fuselage, center wing, wing console, tail, side washers located under the center wing, flaps installed at the aft end of the center wing and wing consoles [2]
The way to control the ekranoplan "Eaglet" in the longitudinal control channel is to throttle the air flow flowing under the wing in the tunnel bounded by the lower surface of the wing center section, the screen surface and the screen washers. Throttling is carried out by a flap located at the exit of the tunnel at the aft end of the wing.

 The ekranoplan "Eaglet" and the longitudinal control method implemented on this ekranoplane, as the closest means of the same purpose in terms of the totality of features to those proposed, are taken as a prototype.

 The disadvantages of the known vehicle on a dynamic air cushion ekranoplan "Eaglet" and the method of longitudinal control of it are their low longitudinal stability and insufficient flight safety.

This is explained by the following:
1. The lack of self-healing by the ekranoplan of the initial balance of moments relative to the center of gravity (CT) after the action of random disturbing factors, that is, the progressive instability of the ekranoplan in the longitudinal control channel.

 In other words, a stable near-screen flight of ekranoplanes can be realized only by manually parrying external disturbing factors (or the consequence of their action) by the crew by correcting the balance of the device by manually deflecting the elevators.

2. The impossibility of a simple and reliable way to bring the ekranoplan from on-screen flight to free flight and the reverse transition from free flight to near-screen flight, which is explained by the fact that to leave the elevator screen create a cabrioque moment so that the ekranoplan goes into climb. As you move away from the screen, the diving moment from the force P _e decreases vigorously, while an uncontrolled increase in the excess of the converting moment from the force P _p can cause a loss of speed, controllability of the ekranoplan and cause an emergency.

 The proposed group of inventions is aimed at solving the problem of improving flight safety and maneuvers, as well as improving the stability of the ekranoplan regardless of the distance to the screen by ensuring self-balancing of the ekranoplan along the longitudinal channel. In other words, the problem is being solved to ensure the suppression of changes in the trajectory of a steady screen flight in the event of and / or after the termination of external disturbances by the ekranoplan itself without crew intervention, as well as to ensure the safety and simplicity of the ekranoplan being taken out of a screen flight into free flight and entered into a screen flight from free flight.

 The result is achieved due to the fact that the ekranoplane containing the fuselage, wing, tail, flowing, open from the nose, formed under the wing or its center wing symmetrical relative to the longitudinal axis of the wing, the tunnel with a controlled shield at the aft end of the wing or its center section, is equipped with a profile shape corrector the bottom and the size of the passage section of the flowing part of the tunnel, made in the form of pivotally connected by one ends to each other, and the other movably with the bow and stern parts of the bottom, respectively, of the front and the rear controlled flaps installed with the possibility of cleaning flush with the bottom of the tunnel and differentiated release into the stream with the formation of a kink in the aerodynamic profile, and the top of the kink is located under the center of gravity of the winged craft.

 This ekranoplan allows you to implement a method of longitudinal control of the ekranoplan, including throttling the air flow at the exit of the underwing tunnel and additional differential throttling of the air flow in the air duct of the tunnel in the center of gravity of the ekranoplan.

где ΔS_iн элемент площади нижней поверхности профиля центроплана от передней кромки до вершины излома корректора профиля;
ΔS_jxb элемент площади нижней поверхности от вершины корректора профиля центроплана до выходной кромки щитка на кормовой оконечности туннеля;
P_iнi, P_jxb местные статические давления на соответствующих i-ых и j-ых участках площади профиля центроплана;
l_iнi, l_jxb расстояния от центра тяжести экраноплана до i-го и j-го элементов площади на днище крыльевого профиля, образующего проточный туннель,
позволяет поместить точку приложения равнодействующей от сил статического давления потока воздуха в проточном туннеле на днище экраноплана также в зону центра тяжести экраноплана.These differences are significant, since additional throttling of the air flow in the flowing part of the tunnel, which is carried out in the center of gravity under the bottom of the winged aircraft, for example, according to the law

where ΔS _{iin is the} element of the area of the lower surface of the center section profile from the leading edge to the top of the break of the profile corrector;
ΔS _jxb element of the lower surface area from the top of the center section profile corrector to the output edge of the shield at the aft end of the tunnel;
_Pini , P _jxb local static pressures in the corresponding i-th and j-th sections of the profile area of the center section;
l i _ni , l _{jxb the} distance from the center of gravity of the winged wing to the i-th and j-th elements of the area on the bottom of the wing profile forming a flow tunnel,
allows you to place the point of application resultant from the forces of static pressure of the air flow in the flow tunnel on the bottom of the winged wing also in the area of the center of gravity of the winged wing.

 In this case, the possibility of rebalancing of the ekranoplan during the action (or after the end of the action) of external disturbing factors is excluded.

 Moreover, the simultaneous differential throttling of the air flow in the zone of the center of gravity and on the trailing edge of the ekranoplan flap allows the process of dynamic self-regulating suppression of external disturbing factors and / or the consequences of their action on the trajectory of a steady steady flight near the screen.

 In addition, a dynamically stable ekranoplane self-regulating in the longitudinal channel can be displayed with a high degree of reliability from screen flight to free flight and transferred from free flight to screen flight, as well as to ensure the safety of maneuvers of the ekranoplan.

 Figure 1 shows an ekranoplane, a side view with the flush removed flush with the wing profile (center section) of the profile corrector and the shield in free flight; in FIG. 2 the same, with issued profile corrector and shield in screen flight; figure 3 the same, with the released profile corrector and the removed shield for leaving the screen in free flight; figure 4 is the same, with the issued profile corrector and the shield at the entry of the winged craft in a screen flight with a decrease with a negative path angle θ; figure 5 is the same with the issued profile corrector and the shield at the entrance to the screen flight with a positive pitch angle + α; figure 6 is a screen, front view.

The ekranoplan contains a fuselage 1, a power plant 2, tail unit with keel 3, rudder 4, stabilizer 5 and elevator 6, wing with center wing 7 and consoles 8. Under the wing or its center wing, screen washers 9 are installed, which together with the wing or its the center section forms a flow-through tunnel 10, symmetrical with respect to the longitudinal axis of the winged wing, at the aft end of which a guided shield 11 is installed to control the area f _{5 of the} output section of the tunnel 10. In the center of gravity center section of the winged wing below the center section a profile shape corrector 12 is installed with the front wing 13 and the rear wing 14. The wing 14 is mounted on the bottom of the wing or center section 7 on the hinge 15. The front wing 13 is hung on the bottom of the center section 7 on the rollers 16 with the possibility of moving the rollers along the rails 17.

 The front wing 13 and the rear wing 14 are interconnected by a hinge 18. The hinge 18 is located under the center of gravity of the winged craft.

 The flaps 13, 14 and the flap 12 can fit flush with the lower aerodynamic surface of the wing profile of the wing or center section 7 or extend beyond the contours of the center section into the flow part of the tunnel 10, partially overlapping its cross section, and the hinge 18 is slightly displaced back from the central assembly at the work of corrector 12 not reflected.

In the released position, the shutters 13, 14 under the center of gravity of the winged wing form a kink (Figs. 2-5) of the aerodynamic wing profile, which can protrude into the flow part of the tunnel 10 and provide the ability to control the passage section of the tunnel f ₂ under the center of gravity of the winged wing.

 The profile corrector 12 and the shield 11 during operation can occupy different positions from the extreme retracted I to the extreme released II, including many combinations of intermediate positions that are needed for each specific case.

WIG operates as follows. Before the start of the take-off, the shield 11 is released to the extreme deflected position, the power plant 2 is switched on for take-off mode and the winged craft is accelerated to a separation speed from the screen surface. As the speed increases during take-off, the profile corrector 12 is smoothly pushed into the flow path of the tunnel’s air path 10, while adjusting the passage section of the path f ₂ so that the winged plane is in the horizontal plane.

 After separation of the winged wing from the screen surface in the flowing part of the underwing tunnel 10, the air flow mode is established, which satisfies the equality / 1 /.

 A sign of a stable steady screen flight in the horizontal plane is the absence of ekranoplan vibrations relative to the center of gravity from bow to stern and from stern to bow.

The air flow in the tunnel 10 is throttled at least two times. The first throttling occurs in section f ₂ at the break point of the profile corrector 12. The second throttling of the flow is carried out at the trailing edge of the shield 11 in section f ₅ . The selection of the cross-sectional areas f ₂ and f ₅ for each speed mode, taking into account the loading of the ekranoplan, ensures the equality of the moments M _1E and M _2E on the bottom of the ekranoplan from the side of the flow tunnel 10 in sections from sections f ₁ to f ₂ and from f ₂ to f _5, respectively.

The point of application resulting from pressure forces on the center wing bottom at the same time passes through the center of gravity of the winged aircraft. The ekranoplan turns out to be dynamically balanced in terms of the dipping M _1E and diving M _2E moments M _1E M _2E , created to ensure longitudinal balancing without deviation of elevators. At the same time, the ekranoplan is able to instantly respond to external disturbing factors, suppressing their effect without crew intervention.

Let, for example, under the action of a disturbance, the nose part of the apparatus be raised (Fig. 5), that is, the cross section f _{2 will} be increased.

In this case, there was a decrease in static pressure in the section of the tunnel from f ₁ to f ₂ and an increase in static pressure in the section from f ₂ to f ₅ . Accordingly, the moment M _1E decreased and the moment M _2E increased. As a result of this, the ekranoplane begins to rotate relative to the CT, bringing the bow to the screen and decreasing the area f ₂ , until the initial relationship between the areas f ₂ and f _{5 is} restored.

 Similarly, the restoration of a stable flight after an accidental impact caused the lowering of the bow of the apparatus (Fig. 4).

In this case, the opening of the area f _{5 of the} tunnel 10 occurs so that most of the differential pressure head is triggered in the section from section f ₁ to section f ₂ and an uncompensated increment of the cabling moment DM _1E appears, which causes the apparatus to rotate for cabling while simultaneously covering the area f ₅ , the appearance and increase in the increment of the diving moment DM _2E to equalize the moments M _1E M _2E .

 From what has been said, it follows that in a steady screen flight, the profile shape corrector 12 and the shield 11 reliably ensure the maintenance of the dynamic balance of the ekranoplan along the longitudinal control channel without crew participation.

 The presence of the corrector of the shape of the profile 12 and the shield 11 also allows you to easily, smoothly without the occurrence of hazardous conditions, remove the device from screen flight to free flight.

To do this, in a steady screen flight with the main ekranoplan configuration of the apparatus (figure 2) move the flap 11 in the direction of the retracted position (figure 3), increasing the area f ₅ and leaving the area f ₂ unchanged.

As a result of this, most of the pressure drop in the tunnel 10 is triggered in the area from f ₁ to f ₂ , creating an excess of uncompensated converging moment D M _1E , under the influence of which the ekranoplan begins rotation relative to the central center to raise the bow, and since the ekranoplan has a translational speed, then he goes into climb. Moreover, as you move away from the screen, the rotation of the device decays vigorously due to the attenuation of the screen effect, and the device goes into a gentle climb. After going to a safe height, the profile shape corrector 12 is removed and the apparatus acquires the aerodynamic contours characteristic of an airplane intended for flying in free space.

 Entering the device in screen flight from free space can be carried out in two fairly effective and safe options. In each of them, before entering the device, a profile shape corrector 12 and a flap 11 are released to the screen in the positions corresponding to the speed (taking into account the load) that the winged aircraft will have after entering the on-screen flight.

The first variant of entering an ekranoplan in an on-screen flight with planning with a negative trajectory angle q. In that case (Fig. 4), the area of the tunnel 10 in section f _{5 is} greater than the area f ₂ .

Therefore, as the ekranoplan approaches the screen surface, the moment M _1E , which is unbalanced relative to the CT, increases in the section of the tunnel 10 from f ₁ to f ₂ and increases all the time. Moment M _1E begins to turn the ekranoplane to raise the bow and lower the tail. In this case, the area f _{5 of the} tunnel 10 is reduced, there is a redistribution of pressure drops along the path of the flow part of the tunnel 10. The converging moment M _1E begins to decrease. At the same time, the dive moment M _2E appears and begins to increase. After their equalization M _1E M _{2E, the} rotation of the ekranoplan to lower the stern is stopped. The regime of dynamic equilibrium of steady screen flight comes.

 The second version of the introduction of the ekranoplan in the screen flight from free flight is carried out by reducing the apparatus with a positive pitch angle + α (Fig. 5).

In this case, the area f _{5 of the} flow tunnel 10 at the entrance to the area of the screen effect is less than the area f ₂ . The throttling of the air flow in the tunnel 10 occurs in section f ₅ . The resultant of the pressure forces on the lower surface of the center wing in this case is applied behind the center point, as a result of which there is an excess of the unbalanced diving moment DM _2E (Fig. 5), which starts to rotate the winged plane relative to the center point toward lowering the bow. Area f _{2 is} throttled. The excess torque DM _2E is reduced.

When D _2E decreases to 0, the moments M _1E and M _2E with respect to the DH equalize. The steady-state mode of dynamic equilibrium screen flight comes.

 U-turns on the proposed ekranoplan are as follows: increase the thrust of the engines of the power plant 2, move the shield 11 in the direction of the retracted position. The profile corrector 12 is left released. The ekranoplan passes, as described earlier, into a climb with a simultaneous increase in speed.

 After gaining a safe height for creating rolls, the device is deployed in an airplane in a climb or, translating it previously into horizontal flight, working with ailerons, rudders and elevators.

 After completing the U-turn, the shield 11 is again released, the excess engine thrust is dumped, the apparatus is lowered, and then it enters into flight flight, as described earlier, according to the first or second embodiment.

 The method of longitudinal control of the ekranoplan by differential throttling of the air flow in the flowing underwing tunnel is implemented as follows.

 Before the start of the take-off run, under its bottom, the shield 11 is released to the extreme deflected position at the aft end of the wing (center section) 7. After that, the power plant 2 is switched on for take-off mode and the winged craft is accelerated to the speed of separation from the screen surface. In the process of acceleration, as the speed increases, under the bottom of the wing profile smoothly differentially to the height of the trailing edge of the shield 11 above the screen, a profile corrector 12 is released into the flowing underwing air tunnel 10.

 In this case, the air tunnel 10 is shaped like a flat venturi with a flat confuser attached to its exit.

 The air flow in the tunnel 10 is thereby subjected to additional throttling in the fracture zone of the lower surface of the wing profile under the center of gravity of the winged craft.

 The differential release of the corrector 12 is performed so that the ekranoplane in acceleration (from separation from the screen surface) and in flight after separation is in a horizontal position.

The absence of ekranoplan fluctuations on the bow or stern after separation from the screen surface means that the throttling of air in the underwing air tunnel 10 in the area of the wing profile kink in section f ₂ and the throttling at the edge of the shield 11 in section f ₅ occur so that the resultant from pressure forces on the lower wing surface of the wing (center section) 7 is applied in the fracture zone of the profile shape corrector 12, that is, under the center of gravity of the winged wing and the winged wing is dynamically stabilized longitudinally stable anal flight over the screen control.

Claims (2)

 1. An ekranoplan containing a fuselage, wing, tail, flowing, open from the nose, formed under the wing or its center wing symmetrical relative to the longitudinal axis of the ekranoplan, a tunnel with a controlled shield on the aft end, characterized in that it is equipped with a corrector profile of the bottom of the tunnel, made in the form pivotally connected by one end to each other, and the other movably with the bow and stern parts of the bottom, respectively, of the front and rear guided flaps installed with the possibility of cleaning flush with the bottom of the tunnel and differential release into the stream with the formation of a kink of the aerodynamic profile, and the top of the kink is placed under the center of gravity of the ekranoplan.  2. A method of longitudinal control of an ekranoplan by throttling a stream of air flowing through an underwing tunnel at the outlet of the latter, characterized in that the stream is additionally differentially throttled in the area of the center of gravity of the ekranoplan.

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