265results about "Seaplanes" patented technology

A craft comprises at least one hull, a main wing coupled to the hull and configured to facilitate airborne operations of the craft, a plurality of propellers that include one or more electric motor propellers and one or more combustion motor propellers arranged along each of a port side and a starboard side of the main wing and configured to generate lift on the craft by blowing air over the main wing, and a control system. The control system comprises data storage having instruction code stored thereon that, when executed by one or more processors of the control system, causes the control system to: after receiving a takeoff indication, increase thrust generated by the electric motor propellers to cause the craft to transition from a hull-borne mode of operation to an airborne mode of operation, and after a thrust adjustment condition occurs, increase thrust generated by the combustion motor propellers.

A craft includes a hull, a wing, a hydrofoil, and a control system. The wing is configured to generate upwards aero lift as air flows past the wing to facilitate wing-borne flight of the craft. The hydrofoil is configured to generate upwards hydrofoil lift during a first mode of operation as water flows past the hydrofoil to facilitate hydrofoil-borne movement of the craft through the water. While the craft is hydrofoil-borne, the control system is configured to determine the upwards aero lift generated by the wing. The control system is further configured to control the hydrofoil to generate downwards hydrofoil lift to counteract the upwards aero lift generated by the wing that maintains the hydrofoil at least partially submerged in the water while the determined upwards aero lift is below a threshold lift.

To provide an autonomously flying unmanned aircraft freely landing on and leaving the water and its floats that can realize acoustic positioning by SBL by dispersively arranging a plurality of hydrophones in a limited space of the unmanned aircraft.SOLUTION: Lower portions of six arms 11 extending radially from a fuselage of a water-air combination drone 1 are respectively provided with float parts 14 via connectors 16. The float parts 14 sink under the water surface when the water-air combination drone 1 lands on the water surface to generate buoyancy in the water-air combination drone 1 so that the water-air combination drone 1 stays on the water surface. The float part 14 is composed of a columnar main body part 14a and a cap-like or conical projection part 14b extended downward from the main body part, and a hydrophone 20 is mounted inside the projection part 14b. The hydrophone 20 is fixed at a position and in such a posture that a pressure sensor 20a attached to an end portion of the hydrophone 20 can detect a sound wave in the water when the aerial combination drone 1 / aerial drone 1A lands on the water.SELECTED DRAWING: Figure 3

The invention provides a tailstock type tailless layout amphibious aircraft adopting foldable wings and a design method, and relates to the field of amphibious aircraft design. According to the invention, aiming at a tailless-layout tailstock-type amphibious aircraft, by designing a foldable wing mechanism, the wings are unfolded to keep a high aspect ratio layout during air cruise, and the wings are folded to form an envelope layout for a fuselage during water surface dwelling and stopping; therefore, the aerodynamic performance requirement of the tailless layout tailstock type amphibious aircraft in an air cruising mode and the requirement of the tailless layout tailstock type amphibious aircraft in a water surface dwelling mode for the gravity center stabilizing distance and the floating stability are met, and the tailless layout tailstock type amphibious aircraft can take off quickly under the high sea condition. The problems that the relative positions of the gravity center, the pneumatic focus and the stable center of a traditional tailstock type fixed wing aircraft in the water surface floating state and the air cruising flight state are difficult to design, and the stability of the aircraft in the water surface floating state is difficult to guarantee through a traditional layout design are solved.

In crafts that have a hydrofoil, a locking mechanism can be used to lock the hydrofoil in place (e.g., in a retracted position or in a deployed position). However, the forces experienced by the hydrofoil, especially when in the deployed position, can cause strain on the locking mechanism, which can lead to jamming or failure. The embodiments presented herein provide a locking mechanism that can be used to avoid this problem. In one embodiment, the locking mechanism uses a pin that is movable along a single axis for engaging / disengaging a. portion in a catch that is shaped to receive the pin. In another embodiment, a rear strut of the craft is rotatable, allowing the rear strut to both support the rear hydrofoil and act as a. rudder of the craft when in water.

The invention relates to an active lift augmentation tandem wing type ground effect aircraft, and relates to the field of ground effect aircrafts. The defects that a stable take-off environment is needed, take-off time is long, and operation is complex are overcome. An active lift-increasing tandem wing type ground effect aircraft comprises a machine body, a cockpit is formed in the middle of the top of the machine body, connecting pieces symmetrically arranged in the direction of the machine body are fixedly installed on the front side and the rear side of the machine body correspondingly, and wing structures are fixedly connected to the connecting pieces on the front side and the connecting pieces on the rear side correspondingly; the inclination angle between the wing structures fixed to the connecting pieces on the front side of the aircraft body and the ground, the inclination angle between the wing structures fixed to the connecting pieces on the rear side of the aircraft body and the ground and the inclination angle between the wing structures fixed to the connecting pieces on the rear side of the aircraft body are larger than the inclination angle of the front-side wings. By means of the tandem wing type layout, the inclination angles of the paddles, the front wing structure and the rear wing structure relative to the ground are increased, and when the aircraft runs, the aircraft can obtain the maximum lift force compensation under the influence of the ground effect.

The invention discloses an amphibious aircraft alarm database design method, an alarm system and an alarm method. Determining the alarm demand of each alarm demand side based on scenarized demand capture and confirmation; converting each alarm demand into an alarm entry with an alarm attribute, wherein each alarm entry is in a decoupling state; and finally, constructing an alarm database through the alarm entries. According to the invention, the alarm demand conversion efficiency and the alarm realization accuracy of the airplane can be improved.

The invention provides a trigger type folding-stretching linkage wing structure for a seaplane. The trigger type folding-stretching linkage wing structure comprises a wing assembly, a driving assembly, a linkage assembly and a limiting assembly. The wing assembly comprises a wing seat, two wing groups and two guide units, the wing groups can stretch out and draw back, the two ends of each wing group are connected with an inner connecting plate and an outer connecting plate correspondingly, and the inner connecting plates are rotationally installed on the wing seat; the guide unit comprises a telescopic rod and a reset spring, the two ends of the telescopic rod are connected with the inner connecting plate and the outer connecting plate correspondingly, and the telescopic rod is sleeved with the reset spring. The driving assembly comprises a first sliding block and a connecting rod; two ends of the connecting rod are respectively hinged with the first slide block and one end of the wing group close to the wing seat; the linkage assembly comprises a traction rope and a pulley block; the limiting assembly comprises a first limiting unit and a second limiting unit. The first sliding block moves in the direction away from the wing base, sweepback and contraction of the wing set are synchronously achieved, the cross sectional area and the wetted area of the wing can be reduced at the same time during underwater navigation, and fluid resistance is remarkably reduced.

The present invention relates to a vertical take-off and landing (VTOL) aircraft featuring a central fuselage and at least two power units. Each power unit is connected to at least two separate lifting rotors via transmission lines, ensuring that each power unit is linked to at least two rotors diametrically opposed relative to the centre of gravity of the aircraft. The lifting rotors might be driven by power transmission lines of hydrostatic type. The power units on either side might be housed in separate pods which might be incorporated into the main fuselage or arranged as separate pods. These separate pods might also function as floats / pontoons for the aircraft to land, take-off and manoeuvre on water.

The invention belongs to the technical field of amphibious aircraft flight control, and discloses an amphibious aircraft fly-by-wire flight control system and a working method, a cockpit control device is connected with and controls a normal instruction sensor and a backup instruction sensor, the normal instruction sensor transmits a signal to an actuator control electron, and the backup instruction sensor transmits a signal to the actuator control electron; the actuator control electronics and the flight control computer transmit signals mutually, the actuator control electronics and the actuator control module transmit signals mutually, and the actuator control electronics further receive signals of the external signal sensor, the direct angular rate sensor, the flap position sensor and the flight control mode switch; the backup command sensor transmits the signal to the backup flight control computer, and the backup flight control computer transmits the signal to the actuator control module; the actuator control module is connected with and controls the actuator, and the angular displacement sensor is arranged on the actuator and transmits collected signals to the actuator control module. The problem that a current fly-by-wire flight control system is not matched with amphibious aircraft cross-medium application is solved.

An aerial and preferably marine vehicle intended to operate in its principal mode near the surface of water or land employing the Wing-in-Ground Effect (WIG) and capable to take-off and land vertically (VTOL) by means of thrust vectoring, which vehicle has a wing arranged at the lowermost part of the fuselage, propulsion units comprising four rotatable pylons extending transversely in pairs on both sides of the upper part of the fuselage, four elongated nacelles mounted on the outer tips of said pylons, which nacelles contain electric motors (E) and provided with propellers at their extremities, so that the rotation of the pylons results in turning the nacelles and thrust of propellers from substantially vertical, ensuring take-off and landing, to substantially horizontal providing a flight mode, retractable hydroskis for emergency landing on water, while said propulsion units and said wing are spaced apart vertically and horizontally and do not overlap.

The invention belongs to the technical field of unmanned aerial vehicles, and particularly relates to a tailstock type overwater vertical take-off and landing fixed-wing unmanned aerial vehicle which can float and park on the water surface, can vertically take off to leave the water and is switched into a fixed-wing mode for cruising and level flight. The unmanned aerial vehicle comprises a four-rotor support buoy and a wing body fusion body fixed to the upper portion of the four-rotor support buoy, small wing type buoys are arranged on wing tips of the two sides of the wing body fusion body respectively, and lifting ailerons capable of deflecting up and down are arranged on the rear edges of wings on the two sides of the wing body fusion body respectively. And four motor rotor propeller propelling devices are uniformly arranged at the tip part of the four-rotor bracket buoy.

A craft is provided with a lever that can control the power / speed of the craft and semi-automatically transition the craft in various modes of operation. This makes control of the craft somewhat similar to control of a boat, thereby bringing a maritime flight control experience to a wing-in-ground effect vehicles, hydrofoiling vessels, seagliders, and seaplanes. Further, various audio, visual, and / or haptic devices in the cockpit can provide alerts / feedback to the operator on the use of the lever and mode transitions.

The invention discloses a fixed wing type cross-domain aircraft capable of realizing self-adaptive load replacement, belongs to the technical field of cross-domain aircrafts, and is used for a water-air double-domain operation cross-domain aircraft. Comprising an aircraft body, a main wing, an aileron, a tail assembly, a vertical take-off and landing support, a vertical take-off and landing rotor wing, a fixed wing propeller, an underwater propeller, a load replacement device and a control module. The control module comprises a decision making system, a telemetering communication system, a state sensing system, an underwater water surface load replacement system, a water surface four-rotor vertical take-off and landing control system, an air fixed-wing cruise control system and an underwater vehicle control system. According to the fixed wing type cross-domain aircraft, through collaborative innovation of a multi-mode power system and self-adaptive buoyancy control, the dynamic characteristic adaptation problem in cross-domain navigation is solved, and the fixed wing type cross-domain aircraft has the vertical take-off and landing capacity, the air cruising capacity and the underwater maneuvering capacity.

The invention relates to a sea-land-air triphibian aircraft which is composed of an aircraft head, an aircraft body and foldable wings, each wing comprises a fixing part, a folding part and a driving part, and unfolding and folding of the wings are controlled through hydraulic jacks. The aircraft is provided with a propeller engine and a propeller thruster which provide lift force and propulsive force respectively, and air flight, underwater navigation and land advancing are achieved. The driving system assembly comprises a submarine engine and an aircraft star-shaped engine, and the submarine engine is connected with and drives propellers to rotate through gears to provide power; the aircraft star-shaped engine is mainly used for air flight. The triphibian aircraft has multifunctionality, high flexibility and wide applicability, and is suitable for various scenes such as emergency rescue, military reconnaissance and environment monitoring. Special materials and design endow the robot with concealment and maneuverability, the robot can quickly respond and avoid potential threats during task execution, and the robot shows powerful comprehensive performance and wide application potential.

The water-air amphibious unmanned aerial vehicle comprises an unmanned aerial vehicle main body, two main body arms, a left tilting part, a right tilting part, a left rotor wing panel, a right rotor wing panel and four stable empennages, and the two main body arms are arranged on the two sides of the unmanned aerial vehicle main body and are symmetrical about the axis of the unmanned aerial vehicle main body; the left tilting part and the right tilting part are arranged at the ends, away from the unmanned aerial vehicle main body, of the two main body arms in a one-to-one correspondence mode, and the tilting angle of the left tilting part and the tilting angle of the right tilting part are adjusted by being arranged on a motor; the left rotor wing and the right rotor wing are arranged at the ends, away from the two main body arms, of the left tilting part and the right tilting part respectively in a one-to-one correspondence mode, and the stable empennage is installed at the tail of the unmanned aerial vehicle body in a mode of being symmetric about the axis of the unmanned aerial vehicle body. By means of the brand new structural design, the water-air amphibious unmanned aerial vehicle can keep good air flying capacity, and meanwhile the water-air amphibious unmanned aerial vehicle can better sail underwater.

The invention discloses a large seaplane integrated with a distributed electric propulsion technology and a propulsion method, and relates to the technical field of seaplane. Comprising a fuselage, a left wing and a right wing are arranged on the two sides of the fuselage respectively, and a V-shaped hull is arranged at the lower end of the fuselage; and a T-shaped empennage is arranged at the tail part of the fuselage. Through the synergistic effect of the design of the V-shaped ship body and the distributed propulsion system, the whole ship body makes contact with the water surface to provide sufficient buoyancy at the low speed, only the main sliding face makes contact with the ship body to form an air layer at the high speed, and the air film drag reduction effect of a propeller at the bottom of the ship body is matched, so that the water resistance is reduced by 35%-50%, and the draft is reduced by 40%-60% along with speed increase; the problems that a traditional seaplane is large in water resistance and difficult to leave water are effectively solved, meanwhile, the left buoy and the right buoy are in linkage with the attitude control system, wave disturbance can be counteracted in real time, the transverse inclination angle is controlled within 1 degree, the wave resistance is improved to be capable of coping with waves with the height of 1.5 m, and the defects that a traditional seaplane is poor in wave resistance and has strict requirements for taking-off and landing water areas are overcome.

The invention relates to a method, a device and equipment for controlling a water-air cross-medium robot, and aims to design a special control distribution algorithm aiming at the possible contradiction among a plurality of control targets in the sliding process, such as the possible demand conflict between depth keeping and speed adjusting. A plurality of control targets are decomposed into specific tasks and are distributed to different actuators (such as tail vanes or side wings) for execution, so that effective cooperative control of depth, speed and attitude is realized.

A craft comprises a hull, a wing, a hydrofoil, and a control system. The wing is configured to generate upwards aero lift as air flows past the wing to facilitate wing-borne flight of the craft. The hydrofoil is configured to generate upwards hydrofoil lift during a first mode of operation as water flows past the hydrofoil to facilitate hydrofoil-borne movement of the craft through the water. While the craft is hydrofoil-borne, the control system is configured to determine the upwards aero lift generated by the wing. The control system is further configured to control the hydrofoil to generate downwards hydrofoil lift to counteract the upwards aero lift generated by the wing that maintains the hydrofoil at least partially submerged in the water while the determined upwards aero lift is below a threshold lift.

The invention discloses a cross-medium aircraft and belongs to the technical field of aircrafts. Comprising a power propulsion system which provides a power hybrid control system for an aircraft body and is used for realizing data acquisition and operation and accurate control of the power propulsion system, a navigation system and a sinking and floating system; the navigation system is used for providing navigation support for the vehicle body; the gradient skin is composed of multiple gradient materials and covers the outer surface of the aircraft body, and the sinking and floating system is used for controlling floating and diving of the aircraft body. According to the invention, the vehicle can obtain the optimal pneumatic / hydrodynamic performance in the air and seawater medium navigation state; according to the power propulsion system, the requirements of high speed, long distance and high thrust of the aircraft are met; a distributed network and a visual navigation system meet the navigation requirements of the cross-medium aircraft in the air, on the water surface and under the water and the combined combat; the hybrid control system is used for accurately controlling the aircraft; the aircraft application material can complete deformation adaptive to the changed environment.

The invention relates to a water rescue system and method based on combination of a wing-in-ground-effect ship and an unmanned ship, and belongs to the technical field of water rescue. The unmanned surface vehicle and materials are remotely conveyed to a rescue area at a high speed through the wing-in-ground-effect vehicle; the unmanned ship arrives at the drowning person to execute accurate rescue, and the unmanned ship further has the manned capacity; wherein the unmanned ship and the wing-in-ground-effect ship are linked through a communication system, the wing-in-ground-effect ship airdropped lifesaving equipment, and the unmanned ship completes target salvage and returns. According to the invention, the rescue response efficiency can be improved, and the problems of slow response, poor environmental adaptability and insufficient accuracy of water rescue are systematically solved.

A craft comprises at least one hull; at least one wing configured to generate upwards aero lift as air flows past the at least one wing to facilitate wing-borne flight of the craft; a front hydrofoil connected to the at least one hull via a front hydrofoil strut and configured to generate upward hydrofoil lift as water flows past the front hydrofoil to facilitate hydrofoil-borne movement of the craft through the water; a rear hydrofoil connected to the at least one hull via a rear hydrofoil strut and configured to generate upward hydrofoil lift as water flows past the rear hydrofoil to facilitate hydrofoil-borne movement of the craft through the water; and a control system. While the craft is hydrofoil-borne, the control system is configured to facilitate transition of the craft from hydrofoil-borne operation to wing-borne operation via a process comprising: while the upwards aero lift generated by the at least one wing is below a threshold lift, controlling one or both of the front hydrofoil and the rear hydrofoil to generate a downward hydrofoil lift that causes the front hydrofoil and the rear hydrofoil to remain at least partially submerged in the water; and after the upwards aero lift generated by the at least one wing has increased above the threshold lift, transitioning the craft from hydrofoil-borne operation to wing-borne operation at least in part by controlling one or both of the front hydrofoil and the rear hydrofoil to switch from (a) generating the downward hydrofoil lift to (b) generating an upward hydrofoil lift that pushes the craft up and out of the water.

A craft comprises at least one hull, at least one wing configured to generate upwards acro lift as air flows past the at least one wing to facilitate wing-borne flight of the craft, at least one retractable hydrofoil configured to generate upwards hydrofoil lift during a first mode of operation as water flows past the at least one hydrofoil to facilitate hydrofoil-borne movement of the craft through the water, and a control system that comprises data storage having instruction code stored thereon that causes the control system to during a takeoff operation when the craft is accelerating through the water and is supported by the at least one hydrofoil, control the at least one hydrofoil to generate downwards hydrofoil lift that maintains the at least one hydrofoil submerged at a predetermined hydrofoil depth threshold below the water surface; and when the craft reaches a takeoff condition, cause the least one retractable hydrofoil to release the craft from the water to facilitate wing-borne flight of the craft.

The invention relates to the technical field of aircrafts, and discloses a triphibian aircraft and a triphibian form switching method thereof. Comprising an aircraft main body, a left auxiliary body and a right auxiliary body, retractable wings are arranged between the aircraft main body and the left auxiliary body and the right auxiliary body, sliding wheel assemblies are arranged at the bottoms of the three bodies respectively, foldable rotor wing mechanisms are arranged at the tops of the left auxiliary body and the right auxiliary body, a propeller is arranged at the tail of the aircraft main body, and foldable small wings are arranged on the outer sides of the left auxiliary body and the right auxiliary body. During take-off, the wings and the winglets are unfolded, the rotor mechanisms are started, and rising is achieved; during air cruise, the sliding wheel assemblies and the rotor mechanisms are stored, the propellers are started, and smooth flight is ensured; when the unmanned aerial vehicle runs on land, the sliding wheel assemblies are opened, the rotor mechanisms are stored, the wings and the winglets are folded, wind resistance is reduced, and the propellers are started to run; when sailing on the water, the three-body structure ensures buoyancy, and the propeller is pushed to move forwards; through the three-body structure, seamless switching of air, land and water triphibian scenes is achieved, the system adapts to multiple environments, the use flexibility is improved, and the application range is widened.

The invention belongs to the field of cross-medium unmanned aerial vehicles, and particularly relates to a hydrofoil device, a hydrofoil sliding control method and a cross-medium unmanned aerial vehicle, and a hydrofoil comprises a vertical plate, a bottom plate, a hydrofoil, an underwater propeller and a depth gauge; the other end of the vertical plate is fixedly connected with the bottom plate; hydrofoils are rotationally arranged on the two sides of the bottom plate, underwater propellers are fixedly arranged on the hydrofoils, the propelling direction of the underwater propellers faces the downstream of the hydrofoils, and the underwater propeller further comprises a hydrofoil angle adjusting mechanism used for driving the hydrofoils to deflect. The hydrofoil has the water-air medium-crossing capacity, and by means of the high-efficiency control capacity of the hydrofoil propelled by the depth meter and the differential vector, the hydrofoil can keep a certain underwater immersion depth, and the unmanned aerial vehicle connected with the hydrofoil can slide at a high speed across the medium on the water surface.

The utility model discloses a telescopic variable-pitch cross-medium propeller mechanism which comprises a vane seat shell, a supporting frame is arranged in the vane seat shell, an electric telescopic rod assembly is arranged on the supporting frame, vane assemblies are connected to the left end and the right end of the electric telescopic rod assembly in a threaded mode, each vane assembly is formed by sleeving a plurality of multi-section vanes, and the vanes are arranged on the vane seat shell. The front end of the electric telescopic rod assembly is connected with a wing piece at the foremost end of the wing piece assembly, and the wing piece assembly is driven by the electric telescopic rod assembly to stretch and retract. Proper lift force is provided for the cross-medium aircraft or the aircraft, modular design is adopted, the wing panel serialization design can be carried out according to the load requirement of the cross-medium aircraft or the aircraft, the wing panel extends into a large wingspan during air flight, the wing panel contracts into a small wingspan during underwater navigation, and the screw pitch of the propeller is increased.

The invention discloses a variable-structure unmanned ship and a simulation verification method, belongs to the field of water surface robots, and aims to solve the problem that an existing unmanned ship cannot realize cross-medium sailing to cope with complex sea conditions. Two foldable wings are arranged on the two sides of a main boat body respectively, each foldable wing can be turned over up and down, an underwater propeller is arranged on each foldable wing, and the underwater propellers are close to wing tips of the foldable wings and used for water surface and underwater sailing of the variable-structure unmanned boat; the air propeller is arranged at the stern of the main boat body, can turn over up and down and is used for sailing the variable-structure unmanned boat in the air or on the water surface; the number of the sliding wheels is three, and the three sliding wheels are arranged below the main boat body, can be retracted into the main boat body and are used for sliding, taking off and landing of the variable-structure unmanned boat on the land. The variable-structure unmanned ship can be transformed into a ground-effect wing ship mode, a small-waterplane-area triple-hulled ship mode or an underwater glider mode under the overturning of the foldable wings and the air propellers. The method is mainly used for task execution under complex sea conditions.

The invention provides a cross-medium coaxial double-rotor unmanned aerial vehicle with foldable propellers and a control method of the cross-medium coaxial double-rotor unmanned aerial vehicle. The unmanned aerial vehicle comprises a main fuselage module, a vector motor base module, a coaxial propeller power module, a foldable propeller module, a waterproof sealing module and electronic equipment. According to the cross-medium power system, by folding the propellers, the effective area of the propellers is reduced, the influence of different working media of the cross-medium unmanned aerial vehicle on the efficiency of the propellers is fundamentally reduced, the capacity loss is reduced, and the endurance time is prolonged; the number of actuators is reduced, a complex gear structure is omitted, the weight of the unmanned aerial vehicle is reduced, the reliability of the unmanned aerial vehicle is improved, finally, control codes suitable for the cross-medium coaxial double-rotor unmanned aerial vehicle are designed, and automatic control over the rotating speed of motors and folding of propellers of the unmanned aerial vehicle under different working media are achieved. And the power distribution of the unmanned aerial vehicle in the cross-medium task is more reasonable.

The invention discloses a water-air cross-medium amphibious robot based on a controllable attack angle hydrofoil, and relates to the technical field of robots, the water-air cross-medium amphibious robot comprises a fuselage, a power device and the hydrofoil, the fuselage comprises a front wing and an empennage, the fuselage is symmetrically arranged, the front wing is provided with a rear side edge opposite to the front end of the fuselage, and the symmetry axis of the fuselage passes through the front end of the fuselage and is perpendicular to the rear side edge; the front wing is fixedly connected with the empennage; the power device is connected to the front wing; the hydrofoil is connected to the bottom wall of the front wing and comprises a main hydrofoil, the main hydrofoil comprises a first rotating plate, the first rotating plate is rotationally connected to the bottom wall of the front wing around an axis parallel to the rear side edge, and the first rotating plate is connected with the rotating output end of a first rotating device; the first rotating device rotates to drive the first rotating plate to rotate to change the attack angle of the main hydrofoil. The water-air cross-medium amphibious robot based on the controllable attack angle hydrofoil can be higher in effective load capacity and higher in efficiency of taking off from the water surface.

The invention discloses a multi-mode propulsion system of a water-air cross-domain aircraft and a water-air amphibious aircraft. The multi-mode propulsion system of the water-air cross-domain aircraft comprises a brushless motor. The water-air force transmission system comprises a high-speed output transmission set and a low-speed output transmission set, and the input end of the water-air force transmission system is connected with an output shaft of the brushless motor; the output end of the water-air force transfer system is connected with the variable-pitch propeller assembly; when the rotating speed of the brushless motor is lower than or equal to a preset threshold value, a low-speed output transmission set of the water-air force transmission system provides driving force for the variable-pitch propeller assembly. When the rotating speed of the brushless motor is higher than a preset threshold value, a high-speed output transmission set of the water-air force transmission system provides driving force for the variable-pitch propeller assembly. According to the power transmission mechanism, the transmission shaft can be switched to different rotating speed positions, and rotating speed and torque parameter matching of power transmitted to the propeller is achieved.