Lifting apparatus for aerial vehicle

Abstract

A lift generation apparatus for an aerial vehicle, according to an embodiment of the present invention, comprises: an inlet duct (30) which is provided in an aerial vehicle (1) and which guides the inflow and current of air in the atmosphere; a jet stream generation device (20) for generating a high speed jet stream by using the air flowing in through the inlet duct (30); a duct (10) arranged such that the direction of the jet stream outlet thereof faces the downward direction of the aerial vehicle (1); first vanes (12) provided at the outlet of the duct (10) so as to adjust the spray direction of the jet stream; and a second vane (13) provided at the inlet of the duct (10) so as to assist the jet stream in smoothly flowing along a curved surface at which a centrifugal force is generated.

Description

Lift device of an aircraft

[0001] The present invention relates to a lifting device for an aircraft that generates lift for the aircraft.

[0002] Fixed-wing aircraft generate lift by the difference in static pressure caused by the difference in the speed of the air flowing on the upper and lower surfaces of the airfoil-shaped wings, and require a runway for takeoff.

[0003] Rotary-wing aircraft generate lift through the thrust generated by the flow of air flowing from the upper surface to the lower surface as the airfoil-shaped blades rotate. Rotary-wing aircraft require a tail rotor to offset the torque generated by the rotation of the large blades. Furthermore, the low speed of the air ejected through the blades makes them vulnerable to strong gusts during vertical takeoff and landing, a major cause of crashes.

[0004] In addition, patent document 1 discloses a technology for generating lift by flowing a jet stream using the Coanda effect on the surface of a fuselage or wing.

[0005] As an experiment to verify the practical application of Patent Document 1, when compressed air from an air compressor was flown through a nozzle with a gap of 0.010 mm in a jet stream close to the speed of sound on a curved surface with a diameter of 20 mm as small as possible, it was confirmed that a considerable amount of lift was generated by the centrifugal force generated when the jet stream rotated along the curved surface while flowing on the curved surface without separation.

[0006] However, in order to put Patent Document 1 into practical use, the diameter of the curved surface must be large and the gap of the nozzle must also be large. However, when a jet stream with a high speed close to the speed of sound flows along a curved surface with a large diameter, the centrifugal force increases, and the jet stream flows along the curved surface due to the Coanda effect. The jet stream acts more strongly than the viscous force with the surface of the curved surface, causing a separation phenomenon of the jet stream, which limits its practical use.

[0007] In addition, when analyzing Computational Fluid Dynamics (CFD), there is a problem that when a strong external wind is applied to a jet stream flowing along a curved surface, the jet stream easily separates.

[0008] [Prior Art Literature]

[0009] [Patent Document]

[0010] (Patent Document 1) KR 10-2048412 B1

[0011] (Patent Document 2) EP 2 451 706 B1

[0012] (Patent Document 3) KR 10-2020-0034987 A

[0013] The present invention is intended to solve the above problems, and the purpose of the present invention is to provide a lift device for an aircraft that can dramatically improve the low reliability and safety of helicopters or multicopters using existing vertical takeoff and landing lift generating devices due to the high incidence of accidents caused by unexpected gusts and strong winds during vertical takeoff and landing and transition flight.

[0014] In addition, another object of the present invention is to provide a lifting device for an aircraft that significantly improves the energy efficiency of the entire flight by taking into account the energy efficiency during cruising.

[0015] In addition, another object of the present invention is to provide a VTOL aircraft equipped with a lift generating device that can be a vertical takeoff and landing aircraft that can have the advantages of both existing fixed-wing and rotary-wing aircraft, and to provide a lift device for an aircraft that can stably control attitude during vertical takeoff and landing and transition flight by arranging a number of lift generating devices of various shapes and sizes on the aircraft.

[0016] According to an embodiment of the present invention for achieving the above technical task, a lift generating device for an aircraft includes: an inlet duct (30) installed in an aircraft (1) to guide the inflow and flow of air in the atmosphere; a jet stream generating device (20) for generating a high-velocity jet stream using air introduced through the inlet duct (30); a duct (10) arranged such that the exit direction of the jet stream faces the lower side of the aircraft (1); and a first vane (12) installed at the exit of the duct (10) to adjust the injection direction of the jet stream.

[0017] In addition, the inlet duct (30) of the lift device of the aircraft according to the embodiment of the present invention can allow air in the atmosphere to flow in a vertical downward direction regardless of the angle (a°) formed by the inlet and the outlet.

[0018] In addition, air can be introduced in a vertical downward direction into the atmosphere so that the suction force generated by the difference in static pressure that decreases on the upper surface of the lip (35) of the inlet duct (30) increases the lift.

[0019] In addition, air can be introduced in the horizontal direction in the atmosphere so that the suction force generated by the difference in static pressure lowered on the upper surface of the lip of the inlet duct (30) does not result in a loss of lift.

[0020] In addition, the duct (10) of the lift device of the aircraft according to the embodiment of the present invention may have an angle (a°) formed by the inlet and the outlet of 0° to 180°.

[0021] In addition, in the lift device of the aircraft according to the embodiment of the present invention, a gap (t) is formed at a portion where the inlet of the duct (10) and the jet stream generator (20) are connected, and external air that does not pass through the jet stream generator (20) can be introduced into the duct (10) through the gap (t).

[0022] In addition, the duct (10) of the lift device of the aircraft according to the embodiment of the present invention may have a horseshoe-shaped (∩) cross-section, prevent the jet stream discharged from the jet stream generator (20) from spreading outward, prevent the jet stream from being obstructed by wind and gusts outside the aircraft, and allow outside air to freely flow in according to the Coanda effect.

[0023] In addition, the duct (10) of the lift device of the aircraft according to the embodiment of the present invention is guided by a vane (13) installed so that the jet stream discharged from the stream generating device (20) extends to a position where a large lift component due to centrifugal force acts following a predetermined straight section (15) before flowing along the curved surface, so that the jet stream can smoothly flow along the curved surface where centrifugal force is generated.

[0024] In addition, the lift device of the aircraft according to the embodiment of the present invention has a concave dimple shape having a diameter of 1 mm or less formed on the inner surface of the duct (10) or the inlet duct (30), and the dimple shape can reduce the friction loss between the air or the jet stream and the duct (10) or the inlet duct (30). In addition, preferably, considering the speed of the jet stream reaching 252 km / h to 432 km / h, the dimple size may have a diameter of about 1 to 4 mm, and the dimple may have a depth of about 0.15 mm.

[0025] In addition, the lift device of the aircraft according to the embodiment of the present invention can control the attitude of the aircraft by controlling the output of the jet stream generator (20) or controlling the angle of the first vane (12).

[0026] In addition, the lift device of the aircraft according to the embodiment of the present invention may be configured such that the duct (10) includes a first section (10a) and a second section (10b), the first section (10a) has a shape that is bent with a gentle curvature and has a circular shape with a closed cross-section, and the second section (10b) has a shape that is bent with a gentle curvature and has a cross-section that is open in the lower direction and has a width that increases toward the outlet.

[0027] In addition, the lift device of the aircraft according to the embodiment of the present invention may have a duct (10) whose cross-sectional area gradually increases from the inlet to the outlet and is bent at a gentle curvature to form a spiral shape.

[0028] Specific details of other embodiments are included in the detailed description and drawings.

[0029]

[0030] The lift device of an aircraft according to an embodiment of the present invention is capable of performing vertical takeoff and landing and transition flight of a vertical takeoff and landing aircraft even in situations where there are strong winds and gusts, and by using a fan connected to a BLDC motor or turboshaft engine that rotates at a high speed of about 50,000 RPM as a jet stream generator, the necessary lift can be stably obtained by the centrifugal force generated inside the duct and the thrust of the jet stream discharged at a high speed of about 50 m / s or more from the outlet.

[0031] In addition, the lift device of the aircraft according to the embodiment of the present invention can simultaneously perform attitude control by appropriately arranging a plurality of lift generating devices of various shapes and sizes on the aircraft, and referring to the fact that the World Meteorological Organization defines the average maximum speed of gusts (Term Gusts) as 10 to 15 knots, strong gusts as 15 to 25 knots, and violent gusts as exceeding 25 knots (12.90 m / s), a jet stream ejection speed of 50 m / sec or more at the exit of the duct can stably perform attitude control during vertical takeoff and landing and transition flight even in strong gusts.

[0032] On the one hand, if the jet stream is directed in a vertical descending direction, a vortex ring may be generated, but in the case of the lift device of the aircraft according to the embodiment of the present invention, the positions of the air intake and outlet of the lift generating device are separated, so a vortex ring cannot be generated fundamentally, and there is no need to worry about energy loss due to the vortex ring.

[0033] Through experiments using a commercial EDF (Electric Ducted Fan) and a simple experimental device without an inlet duct, it was found that the lift of the lift device of the aircraft according to the embodiment of the present invention was 1.99 kgf / kw, and considering the improvement of the optimized jet stream generator and the addition of an inlet duct that allows air intake from the top, the expected lift efficiency can be expected to be at least 3.0 kgf / kw or more.

[0034] Referring to the Hover Vertical Lift Efficiency (source: Wilimedia commons), the lift device of the aircraft according to the embodiment of the present invention can obtain an effect that is at least 50% improved over the maximum lift of a conventional lift-fan of 2.1 kgf / kw, and this level of lift is the same level as the lift of a tilt rotor.

[0035] In addition, the lift device of the aircraft according to the embodiment of the present invention, obtained through an experiment using an experimental model without an inlet duct, has a lift of 1.99 kgf / kw, which is lower than that of a conventional helicopter, but considering that there is sufficient room for improvement through improvement of the jet stream generator, addition of an inlet duct to the lift generator, and optimization of the duct design, a lift efficiency of at least 3.0 kgf / kw is expected.

[0036] In addition, the lift device of the aircraft according to the embodiment of the present invention has the effect of relatively small air resistance during cruising flight by having the fan, blades, propeller, etc. required for vertical takeoff and landing not exposed to the outside but installed inside the aircraft.

[0037] In addition, the lift device of the aircraft according to the embodiment of the present invention has a much higher energy efficiency than the existing rotary wing-shaped vertical take-off and landing aircraft, and more specifically, the aircrafts in order of lift efficiency from the smallest to the largest are Direct Lift aircraft, Lift Fan aircraft, Tilt Wing aircraft, Tilt Rotor aircraft, and helicopter, and the aircraft (Lift & Cruise type) equipped with the lift device of the aircraft according to the embodiment of the present invention can be estimated to have the same level as the Tilt Rotor aircraft, and when the energy efficiency during cruising is also taken into consideration, the energy efficiency of the aircraft (Lift & Cruise type) equipped with the lift device of the aircraft according to the embodiment of the present invention will be by far the highest.

[0038] Since the power of the jet stream generator can be used from an electric motor to a turboshaft engine, it can be used as a lift generator for VTOL of small to large vertical take-off and landing aircraft, and can replace the lift generator of existing rotary wing concept VTOL aircraft that have a high accident risk due to their vulnerability to strong winds and gusts during vertical take-off and landing.

[0039] The lift device of an aircraft according to an embodiment of the present invention changes the method of causing a jet stream of less than the speed of sound to flow on a concave surface with an appropriate radius of curvature that can minimize drag, and it was confirmed that the lift is generated by the sum of the vertical component of the difference between the generated centrifugal force and the static pressure inside the lift generating device and the atmospheric pressure outside the duct, and the thrust generated by the action and reaction when the jet stream is vertically ejected from the exit of the lift generating device. At this time, the ejection speed is much higher (approximately 50 m / s or more) than the typically generated strong gust speed (approximately 13 m / s or more), and thus has strong resistance to external disturbances such as strong winds or gusts. Therefore, considering that the existing rotary wing aircraft are very vulnerable to external disturbances during vertical takeoff and landing and transition flight, which is a major cause of accidents, the present lift generating device has the effect of having high reliability and safety.

[0040] In addition, the lift device of the aircraft according to the embodiment of the present invention has confirmed that the suction force at the inlet of the lift generating device is at a level that cannot be ignored compared to the thrust due to the action and reaction at the outlet, so that the inlet of the lift generating device can have the effect of further increasing the lift by installing an inlet duct to minimize friction loss while allowing air to flow in as vertically downward as possible.

[0041] FIGS. 1A to 1J are drawings for explaining a lift device of an aircraft according to an embodiment of the present invention.

[0042] FIG. 2 is a drawing for explaining an example in which a lift device of an aircraft according to an embodiment of the present invention is applied to an aircraft.

[0043] Figure 3 is a table for explaining the operational effects of the lift device of an aircraft according to an embodiment of the present invention.

[0044] Figure 4 is a graph that provides an easy-to-understand view of the table shown in Figure 3.

[0045] Figure 5 is a table for explaining the operational effect of a state in which a gap is formed in a lift device of an aircraft according to an embodiment of the present invention.

[0046] Figure 6 is a graph that provides an easy-to-understand view of the table shown in Figure 5.

[0047] Figures 7 and 8 are figures and tables showing the results of measuring and calculating the change trend of the vertical component lift value reflecting the centrifugal force and the projected area while increasing the rotation angle of the device according to the present invention by 10 to 15 degrees at a 180° rotation angle unit.

[0048] Figure 9 is a drawing for explaining a lift device of an aircraft according to another embodiment of the present invention.

[0049] Figure 10 is a drawing for explaining a lifting device of an aircraft according to another embodiment of the present invention.

[0050] FIGS. 11a and 11b are drawings for explaining the position where the auxiliary lifting device is mounted on the aircraft when used for attitude control during vertical takeoff and landing and transition flight of the aircraft according to an embodiment of the present invention.

[0051] The advantages and features of the present invention and the method for achieving them will become clear with reference to the embodiments described in detail below together with the attached drawings.

[0052] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The embodiments described below are provided by way of example to help understand the present invention, and it should be understood that the present invention can be implemented with various modifications different from the embodiments described herein. However, in describing the present invention, if it is determined that a detailed description of a related known function or component may unnecessarily obscure the gist of the present invention, the detailed description and specific illustration thereof will be omitted. In addition, the attached drawings are not drawn to scale to help understand the invention, and the sizes of some components may be exaggerated.

[0053] On the one hand, the terms described below are terms established in consideration of their functions in the present invention, and thus may vary depending on the intention or custom of the manufacturer. Therefore, their definitions should be made based on the contents throughout this specification.

[0054] Identical reference numerals throughout the specification refer to identical components.

[0055] Hereinafter, a lift device of an aircraft according to an embodiment of the present invention will be described with reference to the drawings. FIGS. 1A to 1J are drawings for explaining a lift device of an aircraft according to an embodiment of the present invention. FIG. 2 is a drawing for explaining an example in which a lift device of an aircraft according to an embodiment of the present invention is applied to an aircraft. FIG. 3 is a table for explaining the operation and effect of a lift generating device of an aircraft according to an embodiment of the present invention. FIG. 4 is a graph for easy understanding of the table shown in FIG. 3.

[0056] [Explanation of symbols]

[0057] 10: Duct

[0058] 12, 13: Bane

[0059] 15: A straight section of a duct (10) installed to reduce the cross-sectional area inside the duct to effectively generate centrifugal force and to maintain the centrifugal force constant.

[0060] 20: Jet stream generator

[0061] 30: Inlet duct

[0062] 35: Lip

[0063] 100: Aircraft

[0064] a°: angle between the inlet and outlet of the jet stream

[0065] R: Radius of the outer inner wall of the duct

[0066] R0: Inner radius of the duct

[0067] H duct : Internal height of the curved part of the duct

[0068] R duct : Inner radius of the curved part of the duct

[0069] W duct : Internal width of the straight portion of the duct

[0070] D fo : Exit diameter of jet stream generator

[0071] t: gap formed between the duct and the air injection device

[0072] P duct : Static pressure inside the duct

[0073] P a : atmospheric pressure

[0074] F suct : Suction force at the inlet duct entrance

[0075] F' suct : Vertical action / reaction force of suction at the inlet duct entrance

[0076] Lift: Total lift

[0077] L duct : Lift generated inside the duct

[0078] Ft : Action / reaction force generated by vertical thrust generated at the duct outlet

[0079] The lift device of an aircraft according to an embodiment of the present invention can be configured to include a duct (10), a jet stream generator (20), and an inlet duct (30).

[0080] The duct (10) is installed in the aircraft (1) to guide the flow of the jet stream, and is arranged so that the exit direction of the jet stream faces the lower side of the aircraft (1).

[0081] A jet stream generator (20) is installed at the inlet of the duct (10) and can inject a high-velocity jet stream into the duct (10) using air introduced through the inlet duct (30).

[0082] The jet stream generator (20) can be configured as a jet fan, and the jet fan can be operated by utilizing the rotational power of an electric motor, an internal combustion engine, or a jet engine, or can be replaced by a method of ejecting compressed air stored in a high-pressure compressed air tank.

[0083] Compressed air tanks can store air by compressing it using an air compressor on the ground before flight, can store air by compressing it using the electric energy generated while the aircraft is flying, or can store air by compressing it using the power of the thrust engine.

[0084] In addition, referring to FIG. 1, the lift device of the aircraft according to the embodiment of the present invention may further include a vane (13). In addition, a straight section (15) may be further provided behind the jet stream generator (20). The air sucked through the vane (13) may pass through the device of the present invention, i.e., the duct (10), while adhering to it. This allows for a stronger centrifugal force and the resulting lift to be obtained. Ultimately, the increase in centrifugal force effectively increases the internal static pressure.

[0085] In addition, referring to FIG. 9, the lift device of the aircraft according to the embodiment of the present invention may be configured to further include a vane (12).

[0086] The vane (12) can be installed at the outlet side of the duct (10). The vane (12) can be adjusted in position to tilt to one side or the opposite side (see b °), and the angle adjustment can be controlled in an automatic control manner.

[0087] The vane (12) can be controlled so that the thrust generated at the outlet of the duct (10) is generated in the vertical direction by artificially adjusting the discharge direction of the jet stream.

[0088] In addition, the vane (12) can be provided as a fixed type considering the characteristics of the duct (10), or can be used to control the attitude of the aircraft by adjusting the angle in an automatic control manner during flight.

[0089] In this way, the vane (12) ensures that the jet stream is discharged in a straight direction intended by the manufacturer of the aircraft without being disturbed at the exit of the duct (10).

[0090] That is, when the jet stream is discharged, the vane (12) causes the jet stream to be discharged straight in the vertical direction without being disturbed at the point of discharge, thereby converting the thrust by the action-reaction into lift, and additionally, by automatically controlling the vane (12), it can be used to control the attitude of the aircraft in the intended direction during vertical takeoff and landing and transition flight.

[0091] On the one hand, increasing the speed of the jet stream can cause energy loss and unacceptably high levels of noise due to shock waves generated inside the lift-generating device, and a jet stream close to the speed of sound can even cause shock waves, so it is desirable to control the speed of the jet stream to a speed much lower than the speed of sound to avoid a decrease in the lift efficiency of the lift-generating device and a decrease in energy efficiency.

[0092] Additionally, the duct (10) can be designed with a radius of curvature that reduces air friction loss, and can be designed to reduce energy loss and increase lift efficiency.

[0093] Also, referring to FIG. 10, the lift device of the aircraft according to the embodiment of the present invention may be provided with a duct (10) in a spiral tube shape.

[0094] The embodiment of the duct (10) shown in Fig. 10 is a shape in which the cross-sectional area gradually increases from the inlet where the jet stream flows in to the outlet where the jet stream is discharged, and has a gently curved shape overall.

[0095] In this way, the duct (10) can be expected to have the effect of increasing the flow rate when the jet stream is discharged from the outlet by taking the form of a body shape that gradually increases.

[0096] In addition, by providing the duct (10) in a spiral shape with a gentle curve, the external size of the duct (10) can be minimized, and there is an effect of occupying a minimum amount of space when installing the duct (10) in an aircraft (100).

[0097]

[0098] In addition, as shown in Fig. 2, the lifting device of the aircraft according to the present invention can be positioned inside the aircraft to block the influence of external wind, etc. Fig. 2 only shows an embodiment of the present invention, and the arrangement of the duct (10) and the inlet duct (20) is not limited thereto.

[0099] An aircraft has a minimum flight speed set to gain lift, and if it flies at a speed similar to or slower than the minimum flight speed, the aircraft will descend, and if it loses lift, it may stall and crash.

[0100] The lift device of an aircraft according to an embodiment of the present invention can operate during vertical takeoff and landing and transition flight of a vertical aircraft, and can also be temporarily used as a lift auxiliary device to prevent a spin from occurring when proceeding at a speed lower than a stall speed in an abnormal situation during cruise flight of a vertical takeoff and landing aircraft of cruise and lift type.

[0101] When the lift device of an aircraft according to an embodiment of the present invention is operated, a jet stream is injected into the duct (10) from a jet stream generator (20) that uses atmospheric air introduced through an inlet duct (30).

[0102] Fig. 1i shows another embodiment of the duct (10), including a drawing showing the overall shape from the direction in which air is injected, a drawing showing the overall shape from the direction in which air is discharged, and a side view showing the overall shape.

[0103] The duct (10) can be configured to include a first section (10a) having a circular cross-sectional shape and a second section (10b) with one end open.

[0104] The first section (10a) of the duct (10) is in the shape of an elbow, as shown in the front view of Fig. 1i, and the cross-section of the first section (10a) is circular, as shown in View A of Fig. 1i.

[0105] In addition, the second section (10b) of the duct (10) has an open bottom as shown in View B to View D of Fig. 1i, and has a shape in which the width becomes wider as it approaches the outlet.

[0106] The lift generating device of the present invention shown in Fig. 1i changes the direction of travel according to the shape of the first section (10a) as the jet stream passes through the first section (10a), and then, as it passes through the second section (10b), the pressure increases and it is discharged in a downward direction.

[0107] In particular, the second section (10b) is provided in an open form at the bottom, so that air other than the jet stream is added, allowing more air to be discharged in the downward direction.

[0108] The total lift of this lift generating device is the vertical component of the centrifugal force (Fc) generated as the jet stream flows along the inside of the curved surface at position R of the duct (10), and the static pressure inside the duct (P duct ) and external atmospheric pressure (P a ) the vertical component of force generated by the difference in the suction force (F') generated at the vertical inlet of the inlet duct (30) suct ), and the outlet of the duct (10) faces the lower direction of the aircraft (100), so it is the sum of the thrust (Ft) generated by the action and reaction of the jet stream discharged in the lower direction of the aircraft (100).

[0109] Referring to Figure 1j, the total lift =

[0110] Centrifugal force (F) generated as the jet stream flows along the inside of the curved surface at position R of the above duct (10) c ) of the vertical component of force +

[0111] Static pressure inside the duct (P duct ) and external atmospheric pressure (P a ) + suction force (F') generated at the vertical inlet of the inlet duct (30) suct ) +

[0112] This is the thrust (Ft) generated by the action and reaction of the jet stream discharged in the downward direction of the aircraft (10).

[0113] On the one hand, the duct (10) can be formed in a gentle curved shape as shown in FIGS. 1A and 1B, or by forming dimples like golf balls on the inside of the curved surface of the duct (10), frictional loss and potential pressure loss can be reduced when the jet stream moves in the duct (10). The dimples may have a diameter of 1 mm or less and a concave shape. In addition, preferably, considering the speed of the jet stream ranging from 252 km / h to 432 km / h, the dimple size may have a diameter of about 1 to 4 mm, and the dimple depth may be formed to be about 0.15 mm.

[0114] In particular, the angle (a°) formed by the inlet and outlet of the duct (10) can be set from 30° to 180°. However, the present invention is not limited thereto.

[0115] The above angle (a°) is explained with reference to FIGS. 3 and 4.

[0116] Fig. 3 is a table showing the lift measured from an experimental lift generator without an inlet duct while changing the angle (a°), and Fig. 4 is a graph showing the lift. More specifically, the electric energy provided to the jet stream generator (20) is measured, and the lift (kgf) generated compared to the power (kW) supplied to the lift generator mounted on the simulated aircraft when the jet stream generator (20) was in operation is measured, and this is expressed as lift efficiency.

[0117] The lift force may be a vertical component of the force generated by the centrifugal force, which is proportional to the mass of the jet stream flowing over the curved surface and the square of the velocity of the jet stream, and inversely proportional to the radius of curvature of the jet stream flowing over the curved surface.

[0118] In addition, the lift generating device of the aircraft according to the embodiment of the present invention can uniquely form the configuration of the duct (10) so as to effectively generate lift.

[0119] The above duct (10) may have a single value of the radius of curvature R, which allows the angular velocity of the jet stream to flow uniformly at the same angle when flowing on a curved surface while the jet stream passes through the duct (10), or may have multiple radii of curvature and centers in an elliptical shape.

[0120] The cross-sectional shape of the duct may be a horseshoe shape (∩) with rounded corners, the inlet may be positioned vertically upward from a horizontal position, and the outlet may be positioned in a vertically downward direction, so that the angle (a°) formed by the inlet and outlet may be determined from 0° to 180°. However, this is not limited thereto.

[0121] In addition, the cross-sectional shape of the inlet duct (30) can be gradually changed to minimize energy loss due to resistance and friction while atmospheric air is introduced through the inlet duct (30) and into the jet stream generating device (10), and it is preferable to form it in a streamlined shape, and it can be designed with care so that centrifugal force in the opposite direction to the lift is not generated.

[0122] The cross-section of the above duct (10) has a horseshoe shape (∩) with one end of the duct (10) open so that external gas that does not pass through the jet stream generator injection device (20) can flow inward according to the Coanda effect when the jet stream flows along the curved surface.

[0123] The inner surface of the duct (10) may be formed with small, concave dimples, like the surface of a golf ball. The dimples can reduce frictional resistance when the jet stream moves in the duct (10).

[0124] In addition, in the lift generating device of the aircraft according to an embodiment of the present invention, a gap (t) is formed at a portion where the inlet of the duct (10) and the airflow injection device (20) are connected, and external gas that does not pass through the jet stream generating device (20) is introduced into the duct (10) through the gap (t) according to the Coanda effect, and the effect of lowering the speed of the high-speed jet stream to an appropriate level can be obtained.

[0125] In addition, the lift generating device of the aircraft according to the embodiment of the present invention may configure a vane (12) to obtain thrust in the vertical direction generated by the action and reaction of a jet stream discharged into the atmosphere in the vertical direction at the outlet side of the duct (10).

[0126] The vane (12) can be arranged to tilt to one side or the other, and can be positionally controlled to change the tilt angle.

[0127] Experiment 1

[0128] Experiment 1 measured the lift efficiency (kgf / kw) by setting the radius (R) of the outer wall of the duct (10) to 120 mm and setting the angle (a°) between the inlet and outlet from 45 degrees to 135 degrees.

[0129] According to the results of Experiment 1, the angle (a°) was found to be good when it was 130° to 135°, and the attitude of the simulated aircraft was stably controlled.

[0130] On the other hand, in Experiment 1, when the angle was less than 130° or greater than 135°, the attitude of the simulated aircraft was shaken or less stable than when the angle (a°) was between 130° and 135°, even though the appropriate lift was measured.

[0131] Experiment 2

[0132] Experiment 2 measured the lift (kgf / kw) by setting the radius (R) of the outer wall of the duct (10) to 190 mm and setting the angle (a°) between the inlet and outlet from 90 degrees to 180 degrees.

[0133] According to the results of Experiment 2, the angle (a°) was found to be good when it was 120° to 135°, and the attitude of the simulated aircraft was stably controlled.

[0134] On the other hand, in Experiment 2, when the angle (a°) was less than 120° or greater than 135°, the attitude of the simulated aircraft was shaken or less stable than when the angle (a°) was between 120° and 135°, even though the appropriate lift was measured.

[0135] Experiment 3

[0136] Experiment 3 was repeated under the same conditions as Experiment 2 and the lift (kgf / kw) was measured.

[0137] According to the results of Experiment 3, as in Experiment 2, the angle (a°) was good when it was 120° to 135°, and the attitude of the simulated aircraft was stably controlled.

[0138] On the other hand, in Experiment 3, when the angle (a°) was less than 120° or greater than 135°, the attitude of the simulated aircraft was shaken or less stable than when the angle (a°) was between 120° and 135°, even though the appropriate lift was measured.

[0139] Experiment 4

[0140] Experiment 4 was conducted by forming the inner wall of the duct at the R position of the duct (10) into an elliptical shape, setting the elliptical shape to have a long axis of 1232 mm and a short axis of 240 mm, and measuring the lift (kgf / kw) by setting the angle (a°) between the inlet and the outlet from 40 degrees to 180 degrees.

[0141] According to the results of Experiment 4, the angle (a°) was found to be good when it was 130° to 135°, and the attitude of the simulated aircraft was stably controlled.

[0142] On the other hand, in Experiment 4, when the angle (a°) was less than 120° or greater than 135°, the attitude of the simulated aircraft was shaken or less stable than when the angle (a°) was between 130° and 135°, even though the appropriate lift was measured.

[0143] Experiment 5

[0144] Experiment 5 was repeated under the same conditions as Experiment 4 and the lift (kgf / kw) was measured.

[0145] According to the results of Experiment 5, as in Experiment 4, the results were good when the angle (a°) was 130° to 135°, and the attitude of the simulated aircraft was stably controlled.

[0146] On the other hand, in Experiment 5, when the angle (a°) was less than 120° or greater than 135°, the attitude of the simulated aircraft was shaken or less stable than when the angle (a°) was between 130° and 135°, even though the appropriate lift was measured.

[0147] Accordingly, it can be seen that the duct (10) above can effectively implement lift and stably control the attitude of the simulated aircraft when the angle (a°) formed by the inlet and outlet is 130° to 135°.

[0148] Meanwhile, the lift device of an aircraft according to an embodiment of the present invention may have a shape in which the gap (t) and the inner curved portion of the duct (10) are open to the atmosphere in order to supply more flow to the duct (10), and the surrounding air is introduced according to the Coanda effect. This will be described with reference to FIGS. 5 and 6. FIG. 5 is a table for explaining the effect of allowing external air to be introduced into the lift device of an aircraft according to an embodiment of the present invention. FIG. 6 is a graph that makes it easy to understand the table shown in FIG. 5.

[0149] The lift device of an aircraft according to an embodiment of the present invention may be formed so that a gap (t) is formed at the part where the inlet of the duct (10) and the jet stream generator (20) are connected, as shown in FIG. 1, and the inside of the duct (10) is opened so that outside air can be introduced.

[0150] External gas that does not pass through the jet stream generator (20) through the above gap (t) and the open curved surface can flow into the duct (10), thereby allowing a gas flow rate greater than the flow rate of the jet stream provided from the jet stream generator (20) to flow inside the duct (10).

[0151] Although the flow rate of the jet stream discharged from the above duct (10) increases, the speed of the jet stream decreases due to air friction caused by the inflow of surrounding air, and there is a secondary effect of overcoming the difference in angular velocity according to the difference in radius at the same angular position, and by allowing the jet stream to smoothly rotate around the curved surface of the above duct (10) at almost the same angular velocity, the effect of increasing centrifugal force can be obtained.

[0152] Experiment 6

[0153] Experiment 6 measured the lift (kgf / kw) by setting the angle (a°) between the inlet and the outlet from 90 degrees to 160 degrees while forming a gap (t) at the point where the inlet of the duct (10) and the air injection device (20) are connected.

[0154] According to the results of Experiment 6, the lift efficiency was similar at all angles (a°), and the attitude of the simulated aircraft was stably controlled.

[0155] Experiment 7

[0156] Experiment 7 was repeated under the same conditions as Experiment 6 to measure lift (kgf / kw).

[0157] According to the results of Experiment 7, the lift was particularly excellent at 135 degrees, and the attitude of the simulated aircraft was stably controlled.

[0158] However, the gap (t) at the part where the inlet of the duct (10) and the jet stream generator (20) are connected can cause the inflow of surrounding air according to the Coanda effect, can see the effect of increasing the flow rate of the jet stream, and can see the phenomenon of the lift efficiency decreasing due to the decrease in the speed of the jet stream. However, based on the experimental results using a convex surface duct, it can be estimated that the lift efficiency can be increased because the speed can be seen to decrease when the jet stream is ejected from the jet stream generator (20) at a pressure higher than the atmospheric pressure and a speed close to the speed of sound. On the other hand, if the inner surface of the R0 position of the duct (10) is opened to facilitate the inflow of outside air, the lift efficiency is well implemented, the flight attitude is stabilized, and in particular, the duct (10) can significantly implement lift and lift efficiency when the angle (a°) formed by the inlet and the outlet is 135°.

[0159] In all the previous experiments, the fact that the lift was relatively higher at a position of about 135° than at a 90° angle can be seen as an increase in centrifugal force as the angle increases, and after that, there is a phenomenon where the lift value decreases for a while and then recovers as the angle approaches 180°.

[0160] The phenomenon of the lift value decreasing for a moment and then recovering was confirmed to be due to the suction force generated at the inlet of the lift generating device reducing the lift, and by adding an inlet duct (30), the lift can be increased by having the outside air flow in vertically downward, or by having the outside air flow in horizontally from the side, an improvement effect can be seen in which the lift reduction effect is eliminated.

[0161] Figures 7 and 8 are figures and tables showing the results of measuring and calculating the change trend of the vertical component lift value reflecting the centrifugal force and the projected area while increasing the rotation angle of the device according to the present invention by 10 to 15 degrees at a 180° rotation angle unit.

[0162] In more detail, Fig. 7 is a table showing the results of measuring the centrifugal force acting on a curved surface with gauge pressure at a position at the corresponding angle from the jet stream inlet and calculating the vertical component of lift when using a lift generation device test kit equipped with an EDF with a maximum output of 1.2 kW and a rotation angle of 180°, a diameter of 380 mm, and a width of 95 mm, and Fig. 8 is a drawing showing the centrifugal force measurement position mentioned in Fig. 7 and the length of the projected area (width 95 mm × projected length) to calculate the vertical component of lift.

[0163] The present invention can be applied to vertical take-off and landing (VTOL) aircraft. More specifically, the present invention is based on the experimental results as of the filing date, which show that the lift is 1.99 kgf / kW using an experimental model of a lift generating device without an inlet duct. Considering that the lift efficiency can be improved by at least 50-100% by adding an inlet duct, improving the jet stream generating device, and improving the duct design, the expected lift is predicted to be 3.0-4.0 kgf / kW.

[0164] In order to operate a small, 4-seater aircraft with a maximum takeoff weight of about 1,600 kg as a vertical takeoff and landing aircraft, a jet stream generator with a high-speed fan attached to an existing 300 HP (223.71 kw) turboshaft engine (each weighing less than 90 kgf) can be used to obtain a lift of 2,013 to 2,684 kgf, which can be used not only for stable vertical takeoff and landing and transition flight, but also for forward propulsion through an additional power transmission device when cruising with the remaining engine thrust.

[0165] Although its energy efficiency is relatively lower than that of a helicopter during vertical takeoff and landing and transition flight, it can be applied as a lift generating device to large vertical takeoff and landing aircraft due to its high stability and reliability that enables vertical takeoff and landing and transition flight even in strong winds and gusts, and if cruise flight is also taken into account, the overall energy efficiency will be much higher than that of a helicopter.

[0166] Figures 11a and 11b are drawings illustrating embodiments to which the present invention is applied. Referring to Figures 11a and 11b, the present invention can be installed as a small lift-generating device at the end of one or more of the fuselage, main wing, or tail of an aircraft for the purpose of controlling the attitude of the aircraft. The red mark may indicate the location where the present invention is installed.

[0167] In more detail, a small lift generating device can be placed in a position where the moment can be increased for attitude control of the aircraft during vertical takeoff and landing or transition flight, and can be used for attitude control. In order to reduce air resistance during cruise flight, it can be hidden inside the fuselage, wings, or tail, and when performing vertical takeoff and landing or transition flight, it can be movably protruded to perform attitude control.

[0168] According to an embodiment of the present invention, in addition to the lift or propulsion force by action and reaction, the lift generated by the centrifugal force that the fluid, i.e., air, receives from the device of the present invention through the Coanda effect can be obtained inside the aircraft, so that the aircraft to which the present invention is applied can have a shape that is resistant to external disturbances and can have more stable flight control.

[0169] In addition, the present invention utilizes the Coanda effect in which a high-speed jet stream discharged from a jet stream generator flows along a curved surface, and utilizes the effect in which surrounding air is drawn in to increase the flow rate.

[0170] According to the present invention, a jet stream discharged from a jet stream generator generates a centrifugal force that is proportional to the mass of the jet stream flowing along a lift-generating curved portion and the square of the velocity of the jet stream and inversely proportional to the radius of curvature due to the increase in flow rate caused by the inflow of surrounding air according to the Coanda effect. The device to which the present invention is applied can be lifted together by the vertical component of this centrifugal force to generate lift.

[0171] In addition, according to an embodiment of the present invention, when a jet stream flows along a curved surface through the Coanda effect, lift is generated by centrifugal force, so that additional lift can be obtained compared to simply directing the jet stream downward.

[0172] Although the embodiments of the present invention have been described with reference to the attached drawings, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical idea or essential features thereof.

[0173] Therefore, the embodiments described above should be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the claims described below, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

[0174] The present invention can be used in future mobility industries, including the aviation industry.

Claims

1. An inlet duct (30) installed in an aircraft (1) to guide the inflow and flow of air in the atmosphere; A jet stream generator (20) that generates a high-speed jet stream by using air introduced through the above inlet duct (30); A duct (10) arranged so that the exit direction of the jet stream faces the lower side of the aircraft (1); and A first vane (12) installed at the outlet of the above duct (10) to adjust the injection direction of the jet stream; A lifting device for an aircraft including:

2. In paragraph 1, The above inlet duct (30) is The air in the atmosphere flows in vertically downward or vertically upward or horizontally from the side or vertically upward, regardless of the angle (a°) formed by the inlet and outlet; A lifting device for an aircraft including:

3. In paragraph 1, A gap (t) is formed at the part where the inlet of the duct (10) and the jet stream generator (20) are connected, and external air that does not pass through the jet stream generator (20) flows into the duct (10) through the gap (t); A lifting device for an aircraft including:

4. In paragraph 1, The above duct (10) is The cross-sectional shape is horseshoe-shaped (∩), Prevents the jet stream discharged from the above jet stream generator (20) from spreading to the outside, To ensure that the jet stream is not disturbed by winds and gusts outside the aircraft, Allowing outside air to flow in freely according to the Coanda effect; A lifting device for an aircraft including:

5. In paragraph 1, The above duct (10) or the above inlet duct (30) has a concave dimple shape formed on the inner surface, The above dimple shape reduces friction loss between the air or jet stream and the duct (10) or the inlet duct (30); Lifting device of an aircraft including 6. In paragraph 1, Controlling the attitude of the aircraft by controlling the output of the jet stream generator (20) or controlling the angle of the first vane (12); A lifting device for an aircraft including:

7. In paragraph 1, A second vane (13) installed on the outlet side of the jet stream generator (20) to adjust the direction of the jet stream; A lifting device for an aircraft including:

8. In paragraph 1, The above duct (10) is configured to include a first section (10a) and a second section (10b), The above first section (10a) is a shape bent with a gentle curvature and has a circular shape with a closed cross-section. The above second section (10b) has a shape that is bent with a gentle curvature, and the cross-section is open in the lower direction and the width becomes wider as it goes toward the exit; A lifting device for an aircraft characterized by:

9. In paragraph 1, The above duct (10) has a cross-sectional area that gradually increases from the inlet to the outlet and is bent at a gentle curvature to form a spiral shape; A lifting device for an aircraft characterized by:

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