RU2752104C1 - Short take-off and landing aircraft - Google Patents

Abstract

FIELD: aviation.SUBSTANCE: short take-off and landing aircraft includes a fuselage (1) with a cockpit (2), a propulsion system including one propulsion engine, electric take-off and landing engines equipped with propellers and installed on the leading edge of the wing consoles (3) in areas not blown by the sustainer power plant. The aircraft has a wing (3) of high aspect ratio with developed mechanization, vertical (7) and horizontal (6) tail structures, chassis (8). Developed wing mechanization (3) includes droop noses (4) and multi-slotted flaps (5), having an area of ​​all their aerodynamic elements of at least 25% of the wing area (3) and extending to an angle of up to 90 °С. The total additional power of electric take-off and landing engines (10) is at least 40% of the maximum power of the cruise power plant. A control electric motor (11) with an impeller is provided, located behind the horizontal (6) tail structure. The impeller spinner axis is vertical. The electric take-off and landing engines (10) and the control electric engine (11) are powered by storage batteries.EFFECT: invention is aimed at taking off and landing along a steep trajectory with a take-off and landing distance of not more than 50…60 m while ensuring the safety of take-off and landing of the aircraft.1 cl, 4 dwg

Description

The proposed invention relates to aeronautical engineering and can be used in the development of short takeoff and landing aircraft, namely to provide the possibility of using small airfields with relatively small runways and the use of unprepared sites with a takeoff and landing distance of no more than 50 ... 60 m.

Known aircraft with vertical take-off and landing (patent CN No. 105460215, publ. 04/06/2016), which includes the fuselage, wing and tail. The empennage includes horizontal empennage and vertical empennage. The wing and tail assembly are respectively provided with a plurality of oblique propellers, each of which is connected via a steering gear, and the steering gear may be in a plane parallel to the plane of symmetry of the aircraft. The proposed design makes it possible to obtain a good aerodynamic efficiency of an aircraft wing, that is, to provide a relatively high lift with a relatively small load on the structure. The use of small propellers in the design plus the motor drive mode allows for a low load on each propeller, which makes the console a simpler and lighter design. The use of a large number of small propellers increases safety, since if some propellers fail, this has little effect on the safety of the entire machine.

The closest in technical essence and the achieved result is a short take-off and landing aircraft (RF patent No. 171939, published on 06/21/2017) containing a fuselage, a wing with an auxiliary distributed electric power plant with propellers retractable in cruising flight, a tail unit, and a main (cruising) power plant, while the distributed electric power plant, which is retractable in cruise flight into the wing, can significantly increase the lift of the wing, providing a short take-off and landing mode or / and an increase in cruising flight speed and aerodynamic quality by reducing the wing area. In patrol modes, the distributed power plant allows for minimum patrol speeds.

The known technical solution and the resulting aircraft wing configuration are based on calculating the characteristics of the aircraft in cruise flight and are aimed at improving these characteristics.

However, the known technical solution does not allow taking off and landing along a steep trajectory with a takeoff and landing distance of no more than 50 ... 60 m while ensuring the safety of takeoff and landing of the aircraft.

The technical result of the invention is achieved by the fact that the short take-off and landing aircraft includes a fuselage with a cockpit, a cruise power plant, consisting of at least one cruise engine. The aircraft also has electric takeoff and landing engines equipped with propellers and mounted on the leading edge of the wing consoles in areas not blown by the sustainer power plant, a high aspect ratio wing with advanced mechanization, vertical and horizontal tail and landing gear. According to the invention, developed wing mechanization contains deflectable socks and multi-slotted flaps, having an area of all their aerodynamic elements of at least 25% of the wing area and extending to an angle of up to 90 °.

The choice of the angle depends on the implemented aerodynamic configuration of the wing, taking into account the nature of its blowing by the takeoff and landing engines.

The total additional power of electric takeoff and landing engines is at least 40% of the maximum power of the cruise power plant. The aircraft also contains a control electric motor with an impeller located behind the horizontal tail of the aircraft, and the impeller impeller axis is vertical.

During the take-off and landing phases, the take-off and landing electric motors and the control electric motor are powered by accumulator batteries, which provides an increase in the total power of the entire power plant.

The claimed technical solution makes it possible to create additional power of takeoff and landing electric motors for at least 40% of the maximum power of the sustainer power plant without taking off the power of the sustainer (sustainer) engine to power the electric motors, as well as to use a high aspect ratio wing with high aerodynamic quality to create the necessary lifting force. The necessary lift is created by blowing the wing with a cruise power plant and electric take-off and landing engines at extremely low speeds of horizontal movement of the aircraft during the short take-off and landing stages, with a significant delay in the stall from the upper surface of the wing at critical angles of attack. At the landing stage, there is an increase in the projection of the vector of the total aerodynamic force to the direction opposite to the direction of motion of the center of mass of the aircraft. The claimed technical solution also provides reliable controllability of the aircraft in the longitudinal channel at extremely low speeds of horizontal movement due to the use of a control engine with an impeller.

Numerical aerodynamic calculations performed using the ANSIS CFX software package for the selected configuration and total take-off weight of the aircraft with the task of ensuring the take-off and landing distance of no more than 50 ... 60 m, showed:

1. To ensure takeoff, the required value of the total additional power of electric takeoff and landing engines must be at least 40% of the maximum thrust of the cruise power plant. So with the power of the cruise power plant of 400 kW. and using, for example, eight electric takeoff and landing engines, each electric takeoff and landing engine powered by batteries must have a power of 20 kW, then their total additional power will be 160 kW, i.e. 40% of the power of the cruise power plant.

It is known that the take-off distance is divided into two stages: takeoff run and climb. The shorter the takeoff run, the smaller the trajectory inclination angle is possible to set to achieve a given altitude at the border of a given takeoff distance.

At the lift-off point, the lift is equal to the weight of the aircraft. To reduce the take-off run, it is necessary, on the one hand, to reduce the take-off speed, for which it is necessary to increase the lift coefficient, on the other hand, to increase the acceleration during the take-off run by increasing the thrust of the propellers.

In our case, an obstacle with a height of 15 m is located at a distance of 50 ... 60 m from the starting point.

Hence: the total thrust-to-weight ratio of the aircraft should provide such a ratio of the take-off run (i.e. acceleration) and the trajectory slope (overcoming the gravity component), which in total allow one to be at an altitude of more than 15 m at a distance of 50 ... 60 m.

Accordingly, at a total power of less than 140%, this condition is not fulfilled.

2. The area of all aerodynamic elements of the flaps relative to the wing area, which can provide an increase in lift required for short takeoff and landing, is not less than 25%.

3. The optimal flap deflection angle during landing, which provides the necessary projection of the total aerodynamic force vector to the direction opposite to the direction of motion of the aircraft center of mass while maintaining the continuous flow around the wing, is up to 90 °, depending on the aerodynamic configuration of the wing, taking into account the nature of its takeoff blowing. landing engines.

The propulsion system of the aircraft may comprise a single propulsion engine, which in this case is located at the front of the fuselage, as shown in FIG. one.

The propulsion system of the aircraft may contain two propulsion engines, one of which is mounted on the right wing console, and the other on the left wing console, as shown in FIG. 2.

The propulsion system of the aircraft may contain three propulsion engines, one of which is installed in the front of the fuselage, the second on the right wing console and the third on the left wing console (Fig. 3).

The cockpit has a glazing area that provides visibility during takeoff and landing of the aircraft at high angles of attack.

In the future, the invention is illustrated by an example of a specific implementation and drawings, in which:

Fig. 1 - Configuration of an airplane with one propulsion engine;

FIG. 2 - Airplane configuration with two propulsion engines;

FIG. 3 - Airplane configuration with three propulsion engines;

FIG. 4 - Cruising, takeoff and landing wing configuration.

An example of a specific implementation of the aircraft, according to the claimed technical solution, is given by the example of a glider with two propulsion engines (Fig. 2), which is made according to the normal aerodynamic high-wing configuration and includes a fuselage 1 with a cockpit 2 for the pilot, a wing 3 of high aspect ratio with developed mechanization, namely a deflectable toe 4 and a multi-slotted flap 5 of a large area, a horizontal tail 6 and a vertical tail 7 in the aft fuselage 1 and a tricycle landing gear 8.

In this example, the aircraft contains two propulsion engines 9. The cruise engines 9 can be either piston or turboprop. The aircraft also has electric takeoff and landing engines 10 equipped with propellers and a control electric motor 11 with an impeller. Together, the engines form the power plant.

Electric take-off and landing engines 10 are installed on the leading edge of the wing consoles 3 of the aircraft in areas not blown by the propulsion engines 9, and are configured to create additional total thrust at the take-off stage and additional lift at the take-off and landing stages of the aircraft.

Operation of the proposed short take-off and landing aircraft is carried out as follows.

Fix the brakes of the wheels of the main landing gear 8 and start the cruise engines 9. After warming up the cruise engines 9, the multi-slotted flaps 5 and the deflectable nose 4 are transferred to the takeoff position (Fig. 4b). At the same time, the maximum speed of the propulsion engines 9 and the take-off and landing electric motors 10 are set.

The revolutions of the control electric motor 11 are set in such a way that the amount of thrust created by the impeller corresponds to the condition of balanced horizontal flight.

In this case, all electric motors are powered by storage batteries (not shown in the drawings). The rechargeable batteries are recharged during cruising from the generators of the propulsion engines 9.

To start the movement, the brakes of the wheels of the main landing gear 8 are released. The aircraft performs a short (10 ... 15 meters) take-off run with acceleration up to the take-off speed and further climb at a constant speed along a steep trajectory. The increase in the pitch angle after lift-off is carried out by increasing the speed of the control electric motor 11 and the corresponding movement of the elevator.

Upon reaching a safe altitude, the aircraft's trajectory flattens out to climb to the climb with the electric takeoff and landing engines 10 off. When this speed is reached, all the electric takeoff and landing motors 10 and the control electric motor 11 are turned off.

After turning off the electric takeoff and landing engines 10 and the control electric motor 11, to reduce the resistance, the rotor blades of the electric takeoff and landing engines 10 are folded along the axis of rotation or removed.

When the required speed is reached, the multi-slotted flaps 5 and the deflectable nose 4 are transferred to the flight position (Fig.4a), and when the required altitude and speed are reached, the cruise engines 9 are transferred to the cruising flight mode, during which the batteries are recharged.

During takeoff and landing, in the operating modes of the aircraft with the electric takeoff and landing motors 10 and the electric motor 11 operating, the aircraft is controlled as follows:

- in pitch with the help of the elevator, as well as by changing the thrust of the impeller, that is, to increase the pitch angle, the revolutions of the electric motor 11 increase, to decrease - the revolutions of the electric motor 11 decrease;

- on the roll of the ailerons, blown by the flow from the propellers of the electric takeoff and landing engines 10;

- on the course - differential power control of external electric takeoff and landing engines 10.

In other flight modes, the aircraft is controlled by pitch - by the elevator, roll - by ailerons, heading - by ailerons and rudder.

The flight speed is changed by regulating the speed of the main engines 9.

The aircraft is landed as follows.

The rotations of the main engines 9 are reduced to a value corresponding to the required descent rate. Multi-slotted flaps 5 and deflectable nose 4 are deflected into the landing position (Fig. 4c). Upon reaching a predetermined height, electric takeoff and landing engines 10 and a control electric motor 11 are switched on, and the propulsion engines 9 are brought to full power with a simultaneous increase in the pitch angle to values corresponding to the landing mode.

The increase in the pitch angle is carried out by increasing the speed of the control electric motor 11 and the corresponding movement of the elevator. The plane descends until it touches the ground.

The braking of the aircraft during the run on the ground occurs due to the braking system of the wheels of the main struts.

Thus, the proposed design of an aircraft with the declared power plant, including propulsion piston or turboprop engines, an electric motor control and electric take-off and landing engines, distributed over the entire wing span, which is equipped with tiltable toes and large-area multi-slotted flaps, allows the aircraft to take off and land. with a minimum take-off run and a mileage of up to 50 ... 60 meters, by increasing the power of the power plant during takeoff by using electric motors powered by batteries, additional controlled airflow of the wing to increase its lift during takeoff and landing with a significant delay in the stall from the upper surface wing at critical angles of attack, as well as due to the deviation of the vector of the total aerodynamic force in the direction opposite to the direction of movement of the aircraft to damp the landing speed, while ensuring the safety of takeoff and landing.

Claims (1)

A short take-off and landing aircraft, including a fuselage with a cockpit, a cruise power plant, including at least one propulsion engine, electric takeoff and landing engines equipped with propellers and installed on the leading edge of the wing consoles of the aircraft in areas not blown by the cruise power plant , a wing of high aspect ratio with developed mechanization, vertical and horizontal tail, a landing gear, characterized in that the developed wing mechanization contains deflectable socks and multi-slotted flaps, having an area of all their aerodynamic elements of at least 25% of the wing area and extending to an angle of up to 90 °, with the total additional power of electric takeoff and landing engines is at least 40% of the maximum power of the cruise power plant, the aircraft also contains an electric control motor with an impeller located behind the horizontal tail of the aircraft, with the impeller impeller axis being vertically electric takeoff and landing engines and the control electric motor are powered by rechargeable batteries.

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