New thrust vectoring stealth hovercraft with reverse thrust function

Abstract

The present invention discloses a new type of thrust vector stealth hovercraft with reverse thrust function, comprising a hull, a bottom air cushion skirt and a propulsion system; the four sides of the hull are connected to the bottom air cushion skirt through inclined hull side walls, and two lift-enhancing surfaces are symmetrically arranged on both sides of the top of the hull along the length extension direction of the hull; the area of ​​the hull between the two lift-enhancing surfaces is a deck; there are two sets of propulsion systems, which are connected to the tail ends of the two lift-enhancing surfaces in a one-to-one correspondence, including an S-bend air inlet and a thrust vector propulsion engine; the air inlet of the S-bend air inlet is connected to the external environment, and the air outlet of the S-bend air inlet is connected to the air inlet of the thrust vector propulsion engine; the thrust vector propulsion engine includes an engine body and a thrust vector nozzle with reverse thrust function. It can be seen that the present invention comprehensively improves the stealth, maneuverability and carrying capacity of the hovercraft, and meets the needs of future military scenarios for a new generation of hovercraft.

Description

Technical Field

[0001] The present invention designs a novel thrust vector stealth hovercraft with reverse thrust function, belonging to the technical field of advanced new concept hovercraft. Background Art

[0002] A hovercraft is a high-speed vessel that utilizes the surface effect principle, relying on air at higher pressure than atmospheric pressure to create a cushion between the hull and a supporting surface (water or ground), allowing the hull to sail fully or partially free of the supporting surface. Based on the method used to generate the air cushion, hovercraft can be categorized as full-lift and sidewall-type. Common hovercraft are equipped with engines, typically piston engines or gas turbines, to generate the air cushion and propel the craft forward. High-pressure air generated by the piston engine or gas turbine is piped into an air chamber within the bottom cavity of the vessel, forming a cushion that lifts the hull. The engine then drives the propeller (usually a propulsion fan) to propel the hovercraft close to the supporting surface. Hovercraft can reach speeds of up to 60 to 80 km / h, but resistance at high speeds is a limiting factor in their ability to increase further.

[0003] Looking at the hovercraft currently in service, their most significant advantage is their ability to travel close to the water surface at high speeds while carrying a large payload. Therefore, they are often used in scenarios requiring rapid payload delivery, such as material transport and beach landings. However, numerous disadvantages have also limited their development. Chief among these is their ambiguous attitude control during high-speed travel. Because the hovercraft floats on a supporting surface, the support has little effect on the craft. Furthermore, their heavy weight and high inertia make the conventional method of using propellers to move the rudders difficult to achieve agile maneuvers. Furthermore, after landing on a beach, a hovercraft faces difficulties in rapidly retreating from a narrow shoal. Common methods of retreating hovercraft include turning around by using propellers to move the rudders, or by varying the pitch of the propeller fans to generate reverse thrust. However, both approaches have different drawbacks: turning around is difficult and time-consuming. While the variable pitch approach can generate reverse thrust, the blades operate at an off-design point after the fan pitch is changed, resulting in low efficiency, limited reverse thrust, and slow retreat speed. Of course, further increasing load capacity and reducing resistance for potential practical applications, as well as considering possible military scenarios and improving stealth capabilities through comprehensive design, are also urgent requirements for the future design and use of hovercraft. Summary of the Invention

[0004] Purpose of the Invention: To overcome the shortcomings of the prior art, the present invention describes a new type of thrust-vectoring stealth hovercraft with reverse thrust. Based on the operating principle of conventional hovercraft, this invention utilizes a thrust-vectoring propulsion engine with reverse thrust to provide the hovercraft with course control and reverse thrust for rapid retreat. A specially designed lift-enhancing surface on the hull, combined with the suction effect of the downstream air intake and engine, achieves efficient, low-resistance navigation and increased payload capacity. Furthermore, an S-bend air intake is provided in front of the thrust-vectoring propulsion engine, partially embedding the lift fan air intake within the S-bend air intake, and using the inclined hull sidewalls to reduce the hovercraft's radar cross-sectional area in all directions, achieving stealth. This design comprehensively improves the hovercraft's stealth, maneuverability, and carrying capacity, meeting the needs of future military applications for a new generation of hovercraft.

[0005] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A new type of thrust vectoring stealth hovercraft with reverse thrust function comprises a hull, a bottom air cushion skirt, and a propulsion system. The bottom air cushion skirt is arranged on the bottom surface of the hull, and a plurality of lift fans are arranged inside the hull. The four sides of the hull are connected to the bottom air cushion skirt through inclined hull sidewalls, and two lift-enhancing surfaces are symmetrically arranged on both sides of the top of the hull along the length of the hull. The area of ​​the hull between the two lift-enhancing surfaces is the deck, and the front end of the deck is provided with a front ramp, and the rear end of the deck is provided with a rear ramp.

[0007] There are two propulsion systems, which are connected one by one to the tail ends of the two lift-enhancing surfaces, including S-curved air inlets and thrust vectoring propulsion engines; the air inlet of the S-curved air inlet is connected to the external environment, while the air outlet of the S-curved air inlet is connected to the air inlet of the thrust vectoring propulsion engine; the thrust vectoring propulsion engine includes an engine body and a thrust vectoring nozzle with reverse thrust function connected to the exhaust port of the engine body.

[0008] Preferably, the lower edge of the air inlet of the S-curved air inlet is higher than the upper edge of the thrust vectoring engine in the vertical direction, and at the same time, the upper edge of the air inlet of the S-curved air inlet is lower than the highest point of the lift-enhancing surface in the vertical direction.

[0009] Preferably, the thrust vector nozzle with reverse thrust function is a binary mechanical thrust vector nozzle with reverse thrust function or an aerodynamic thrust vector nozzle with reverse thrust function.

[0010] Preferably, the engine body is a turbofan engine, a turbojet engine, a gas turbine driven fan or a piston engine driven fan.

[0011] Preferably, the lift-enhancing surface is designed using boundary layer suction technology.

[0012] Preferably, the centerline of the single-sided S-bend air inlet is tilted toward both sides from near the center of the hovercraft, and the air inlet and the air outlet of the S-bend air inlet are offset in both the horizontal and vertical directions.

[0013] Preferably, the lift-enhancing profile is formed by increasing the profile angle of attack based on the profile of a typical asymmetric low-speed wing airfoil, and the increased profile angle of attack is 2°-5°.

[0014] Preferably, the air inlet area of ​​the S-curved air inlet is larger than the sum of the inlet areas of the thrust vector propulsion engine and a single lift fan.

[0015] Preferably, the air inlet area of ​​the S-curve inlet should be 130%-170% of the sum of the inlet areas of the thrust vector propulsion engine and a single lift fan.

[0016] Preferably, the angle between the initial position of the lift-enhancing profile on the top of the hull and the horizontal direction is α, the angle between the front ramp and the horizontal plane is β, α+β≤70°, β≤60°, and α≤20°.

[0017] Beneficial effects: Compared with the existing technology, it has the following advantages:

[0018] (1) The present invention replaces the rudder behind the propulsion fan of a traditional hovercraft with a nozzle with thrust vectoring function, which has high aerodynamic efficiency, rapid response, and flexible maneuverability. Combined with a series of designs such as the S-bend air inlet, the hovercraft has fewer exposed parts and greatly improved stealth performance.

[0019] (2) The present invention uses a thrust vectoring nozzle with reverse thrust function to replace the traditional hovercraft's variable pitch reverse propeller or in-situ differential U-turn reversing method, which allows for rapid retreat and can further accurately control the reversing direction by controlling the nozzle, resulting in high safety in use;

[0020] (3) The comprehensive use of inclined walls, S-bend air inlets, etc. has greatly improved the stealth of the hovercraft, reduced the probability of being discovered, and improved battlefield survivability.

[0021] Therefore, the new thrust vectoring stealth hovercraft with reverse thrust function provided by the present invention, based on the working principle of traditional hovercraft, uses a thrust vectoring propulsion engine with reverse thrust function to generate reverse thrust function for the hovercraft to control the course and quickly retreat. Through the specially designed lift-enhancing surface on the hull, combined with the suction effect of the downstream air inlet and the engine, the hovercraft can achieve high-efficiency, low-resistance navigation and increased load capacity. By providing an S-bend air inlet in front of the thrust vectoring propulsion engine, burying part of the lift fan air inlet in the S-bend air inlet, and tilting the hull side wall, the radar cross-sectional area of ​​the hovercraft in all directions is reduced, thereby achieving stealth function. Through the above design, the stealth, maneuverability and carrying capacity of the hovercraft are comprehensively improved, meeting the needs of future military scenarios for a new generation of hovercraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the main view of a new type of thrust vectoring stealth hovercraft with reverse thrust function;

[0023] Figure 2 This is a top view of the AA section of a new type of thrust vectoring stealth hovercraft with reverse thrust function;

[0024] Figure 3 A top view of a new type of thrust vectoring stealth hovercraft with reverse thrust function;

[0025] Figure 4 This is the main view of the BB section of a new type of thrust vectoring stealth hovercraft with reverse thrust function;

[0026] Figure 5 A top-down perspective view of a new type of thrust-vectoring stealth hovercraft with reverse thrust capability;

[0027] Figure 6 Comparison of numerical simulation flow field calculations of a conventional hovercraft and a typical configuration of the present invention, wherein: (a) shows the numerical simulation velocity cloud diagram of the symmetry plane of the conventional hovercraft; (b) shows the numerical simulation velocity cloud diagram of the symmetry plane of the stealth hovercraft according to the present invention;

[0028] Figure 7 This is a partial schematic diagram of the head of a new type of thrust vectoring stealth hovercraft with reverse thrust function;

[0029] The figure includes: 1. air cushion skirt at the bottom of the ship, 2. hull, 3. propulsion system;

[0030] Among them: 2.1, front ramp, 2.2, cargo deck, 2.3, lift fan, 2.4, rear ramp, 2.5, lift-enhancing surface; 3.1, thrust vectoring engine, 3.2, S-curve air inlet. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] like Figures 1 to 5 As shown, the novel hovercraft described in the present invention mainly includes a bottom air cushion skirt 1, a hull 2 ​​and a propulsion system 3.

[0033] The top of the hull 2 ​​is raised above the bottom air cushion skirt 1 through four side surfaces. A lift-enhancing surface 2.5 is provided on the top of the hull 2, and the four side surfaces are all inclined hull side walls, corresponding to the front hull side wall, the rear hull side wall, the left hull side wall, and the right hull side wall. A front ramp 2.1 is provided on the front hull side wall, and a rear ramp 2.4 is provided on the rear hull side wall. Loads such as vehicles can enter the interior of the hovercraft through the front and rear ramps 2.4 and be moored on the deck 2.2. Several lift fans 2.3 are also provided inside the hull 2 ​​to draw air from the top of the hovercraft into the bottom air cushion skirt 1 and blow it out from the bottom of the bottom air cushion skirt 1, allowing the hovercraft to float on the water surface, lawn, mud, etc. The principle of the lift fans 2.3 is consistent with that of traditional active hovercraft, and the common number is 4-8.

[0034] A propulsion system 3 is located near the top and rear end of the hull 2. It consists of an S-shaped air inlet 3.2, a thrust vectoring engine 3.1, and its accessories. The S-shaped air inlet 3.2 allows for efficient air intake and delivery to the thrust vectoring engine 3.1. Preferably, there are two propulsion systems 3, symmetrically arranged on the left and right sides of the hovercraft. The core power source of the thrust vectoring engine 3.1 is a turbofan engine, a turbojet engine, or a fan driven by a gas turbine, or a fan driven by a piston engine. The high-speed jet from the turbofan or turbojet engine outlet, or the high-speed jet downstream of the fan, enters a thrust vectoring nozzle with reverse thrust capability. This nozzle redirects the airflow to generate thrust vectoring and reverse thrust. This nozzle can be a dual mechanical thrust vectoring nozzle with reverse thrust capability, or an aerodynamic thrust vectoring nozzle with reverse thrust capability (such as the bypass-type passive dual-throat vectoring nozzle with reverse thrust capability, as described in ZL 201510140955.1). When sailing forward at high speed, the nozzle can deflect the airflow to the left, right, or not deflect it, which is used for the hovercraft's heading control and reducing the attitude control ambiguity caused by inertia of the hovercraft; after the beach landing is completed, the thrust vectoring nozzle can be adjusted to the reverse thrust function, and the airflow is ejected obliquely forward along the left and right sides of the thrust vectoring propulsion engine 3.1, which is used for high-speed reversing and rapid retreat, avoiding the traditional hovercraft from staying in the war zone for a long time during the most dangerous time of beach landing.

[0035] In order to achieve a better stealth effect, the present invention not only requires that the four sides of the hull 2 ​​are inclined hull sidewalls, but also has certain requirements for the S-curved air inlet 3.2, at least to meet the requirement that in the vertical direction, the lower edge of the inlet of the S-curved air inlet 3.2 is higher than the upper edge of the thrust vectoring propulsion engine 3.1; preferably, in addition to meeting the aforementioned geometric constraints, it is also necessary to meet the requirement that in the vertical direction, the upper edge of the inlet of the S-curved air inlet 3.2 is lower than the highest point of the lift-enhancing surface 2.5 on the top of the hull 2.

[0036] Furthermore, considering the overall layout and design of the present invention, the inlet of the partial lift fan 2.3 should be arranged in the S-bend air inlet 3.2, that is, the partial lift fan 2.3 should share the S-bend air inlet 3.2 with the thrust vectoring propulsion engine 3.1.

[0037] Furthermore, the top of the hull 2 ​​is a lift-enhancing surface 2.5, a special surface designed using boundary layer suction technology. Its downstream is connected to the inlet of the S-bend air inlet 3.2. Through the suction effect of the thrust vectoring propulsion engine 3.1, the flow separation of the airflow when flowing over the lift-enhancing surface 2.5 is reduced, and at the same time, the boundary layer thickness and the flow resistance of the airflow are expected to be reduced. Furthermore, through the suction effect of the thrust vectoring propulsion engine 3.1, the atmospheric pressure acting on the lift-enhancing surface 2.5 is reduced, thereby improving the load capacity of the hovercraft. The optimized configuration is expected to increase the load capacity of the hovercraft by more than 5% and reduce the maximum drag by more than 10%.

[0038] Furthermore, to optimize the hovercraft's aerodynamic performance, the design of the S-curve inlet 3.2 should be considered alongside the design of the lift-enhancing surface 2.5 and the inlet of the lift fan 2.3. An optimal design would be for the inlet width of the S-curve inlet 3.2 to be identical to the width of the lift-enhancing surface 2.5. That is, the centerline of the single-sided S-curve inlet 3.2 should be angled away from the center of the hovercraft, with its inlet and outlet offset both horizontally and vertically.

[0039] Furthermore, the design of the lift-enhancing profile 2.5 can be based on a typical asymmetric low-speed wing airfoil. By selecting its upper surface and increasing the profile's angle of attack by 2°-5°, the overall hovercraft design can be developed. This is then combined with the S-curve inlet 3.2 and the lift fan 2.3 intake, leading to a three-dimensional, multi-objective, and multi-variable integrated design and optimization. Typical airfoil profiles are those suitable for use at speeds around 30 m / s, such as the NACA 4418.

[0040] Furthermore, the design of the hovercraft must take into account the needs of high-speed forward travel and rapid reverse travel. Therefore, when viewed from behind, the two thrust vectoring engines 3.1 are arranged high on either side of the hovercraft, sharing a common reverse airflow channel in the middle, forming a "concave" shape to minimize negative interference from the reverse airflow during rapid reverse travel.

[0041] Figure 6 This figure compares the numerically simulated flow field calculations of a conventional hovercraft and a typical configuration of the present invention, showing the numerically simulated velocity contours for the symmetry planes. (a) shows the numerically simulated velocity contour for the symmetry plane of the conventional hovercraft; (b) shows the numerically simulated velocity contour for the symmetry plane of the stealth hovercraft described in the present invention. Comparing the two, it can be seen that the flow field of the present invention is more uniform, with a smaller separation zone.

[0042] Considering the practical application of the present invention, the inlet flow rate of the S-curve inlet 3.2 must meet the air flow requirements of the propulsion system 3 and a set of lift fans 2.3. Considering the actual operating speed of the present invention, which is 60-100 km / h, and the various losses caused by flow, the inlet area of ​​the S-curve inlet 3.2 should generally be larger than the sum of the inlet areas of the thrust vectoring propulsion engine 3.1 and a single lift fan 2.3 to ensure flow conservation. Preferably, the inlet area of ​​the S-curve inlet 3.2 should be 130%-170% of the inlet area of ​​the thrust vectoring propulsion engine 3.1 and a single lift fan 2.3.

[0043] To optimize aerodynamic performance and stealth, the bow of the hovercraft described herein should be as pointed as possible. However, an overly pointed bow will alter the weight distribution of the hovercraft, affecting maneuverability and navigation. Therefore, there is an optimal range of angles for the bow angle of the hovercraft. Let α be the initial angle between the top lift surface 2.5 of the hovercraft hull 2 ​​and the horizontal, and β be the angle between the bow (front ramp 2.1) and the horizontal. Generally, the sum of these two angles should be less than 90°. If α is too large and β is too small, the front ramp's height angle and opening will be too small, hindering the passage of vehicles, especially large ones. Conversely, if α is too small and β is too large, the aerodynamic performance of the lift surface will be limited, hindering low-drag navigation. Preferably, these two angles should fall within a certain range: α + β ≤ 70°, β ≤ 60°, and α ≤ 20°.

[0044] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A new type of thrust vectoring stealth hovercraft with reverse thrust function, comprising a hull, a bottom air cushion skirt, and a propulsion system; the bottom air cushion skirt is arranged on the bottom surface of the hull, and a plurality of lift fans are arranged inside the hull; the characteristics are: The four sides of the hull are connected to the bottom air cushion skirt through inclined hull sidewalls, and two lift-enhancing surfaces are symmetrically arranged on both sides of the top of the hull along the length extension direction of the hull; the area of ​​the hull between the two lift-enhancing surfaces is the deck, and the front end of the deck is provided with a front ramp, and the rear end of the deck is provided with a rear ramp; There are two propulsion systems, which are connected one by one to the tail ends of the two lift-enhancing surfaces, including S-curved air inlets and thrust vectoring propulsion engines; the air inlet of the S-curved air inlet is connected to the external environment, while the air outlet of the S-curved air inlet is connected to the air inlet of the thrust vectoring propulsion engine; the thrust vectoring propulsion engine includes an engine body and a thrust vectoring nozzle with reverse thrust function connected to the exhaust port of the engine body.

2. The novel thrust vector stealth hovercraft with reverse thrust function according to claim 1 is characterized in that: The lower edge of the air inlet of the S-curve air inlet is higher than the upper edge of the thrust vectoring propulsion engine in the vertical direction. At the same time, the upper edge of the air inlet of the S-curve air inlet is lower than the highest point of the lift-enhancing surface in the vertical direction.

3. The novel thrust vector stealth hovercraft with reverse thrust function according to claim 1 is characterized in that: The thrust vector nozzle with reverse thrust function is a binary mechanical thrust vector nozzle with reverse thrust function or an aerodynamic thrust vector nozzle with reverse thrust function.

4. The novel thrust vector stealth hovercraft with reverse thrust function according to claim 1 is characterized in that: The engine body is a turbofan engine, a turbojet engine, a gas turbine driven fan or a piston engine driven fan.

5. The novel thrust vector stealth hovercraft with reverse thrust function according to claim 1 is characterized in that: The lift-enhancing surface is designed using boundary layer suction technology.

6. The novel thrust vector stealth hovercraft with reverse thrust function according to claim 1 is characterized in that: The centerline of the single-sided S-bend air inlet deviates from the center of the hovercraft to both sides, and the air inlet and outlet of the S-bend air inlet are offset in the horizontal and vertical directions.

7. The novel thrust vector stealth hovercraft with reverse thrust function according to claim 1 is characterized in that: The lift-enhancing profile is formed by increasing the profile angle of attack of a typical asymmetric low-speed wing airfoil profile, and the increased profile angle of attack is 2°-5°.

8. The novel thrust vector stealth hovercraft with reverse thrust function according to claim 1 is characterized in that: The inlet of a lift fan is arranged at the location of the S-curve air inlet; the air inlet area of ​​the S-curve air inlet is larger than the sum of the inlet areas of the thrust vector propulsion engine and a single lift fan.

9. The novel thrust vector stealth hovercraft with reverse thrust function according to claim 7 is characterized in that: The air inlet area of ​​the S-curve inlet should be 130%-170% of the sum of the inlet areas of the thrust vectoring propulsion engine and a single lift fan.

10. The novel thrust vector stealth hovercraft with reverse thrust function according to claim 1, characterized in that: The initial position of the lift-enhancing surface on the top of the hull includes an angle α with the horizontal direction, and the angle between the front ramp and the horizontal plane is β, α+β≤70°, β≤60°, and α≤20°.

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