RU2723104C1 - Convertible aircraft - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: invention relates to aircraft engineering, particularly, to vertical take-off and landing aircraft. Convertible aircraft comprises fuselage, tail unit, wing, cruise power plant with propellers installed on wing. Lifting EPC (engine-propeller groups) arranged symmetrically on both sides of the wing on extending pylons in fairings at vertical take-off and landing, create a vertical tie-rod. Lifting EPC are retracted inside fairing located at wing ends, due to their rotation through angle of ~180° relative to axes passing through attachment assemblies to wing power elements. Note here that two-blade rotor of engine-propeller groups are additionally folded by turning one blade to another one by 180 degrees, arranged in pairs and parallel in folded position in one fairing. Fairing has sliding and turning flaps, which allow it to open and close during cleaning EPC inside and further release during landing.

EFFECT: eliminated probability of separation flow on stopped lifting screws, uncontrolled moments and flutter.

3 cl, 5 dwg

Description

The present invention relates to aircraft. The invention can be used in the development of aircraft (LA), in particular vertical take-off and landing.

Convertible aircraft, made according to the classical structural and power scheme, combine the advantages of vertical take-off - landing and cruising, in which the creation of lifting aerodynamic force occurs on the wing. Such aircraft are capable of solving the problems of developing an aerodrome network for hard-to-reach areas of our country, where there is no possibility of using alternative modes of transport, and thereby would have received wide practical application.

The use of a multi-rotor circuit, in particular with electric motors, solves the problem of safety in the event of failure and allows the use of motors without gearboxes, which reduces weight and simplifies the design.

Analogs are convertible aircraft, the design solutions of which are described in US patents No. US 20150274290 A1, EU No. EP2669195 A1, RF No. 2635431.

In the first of the above (US 20150274290 A1, IPC В64С 27/50, В64С 27/52 2015), the lifting screws, located in the engine nacelles at the ends of the wing, rotate together with the engines 90 ° during the transition mode, after which the screw stops and its blades fold along the axis of the motor shaft downstream. In the second (EP 2669195 A1, IPC В64С 27/22, В64С 27/30, В64С 29/00, В64С 39/02, 2013), part of the propeller-motor groups (VMGs) are transiently removed inside the fuselage by turning or folding the pylon , on which they are mounted, and the rest are rotated 90 ° together with the pylon and operate as cruising VMGs in cruising mode.

The disadvantage of such aircraft concepts is the need for a vertical rotation system for the VMG. The use of such a system significantly increases the weight of the aircraft, and the folded lifting VMGs in the cruise flight mode are in the stream and create additional resistance in the case of the apparatus presented in US patent No. US 20150274290 A1.

EU Patent No. EP 2669195 A1 proposes 9 layout options for 6 and 4 lift VMGs on a convertible aircraft, some of which are in transition mode - two, three or four are retracted into the fuselage by turning the pylon on which they are mounted, and one or two naval naval ships rotate 90 ° together with the pylon and operate as a cruising naval naval ship. Screws do not fold and do not change geometry.

A tiltrotor is also known (Patent RU No. 2635431, IPC В64С 27/22, В64С 27/30, В64С 37/00, 2017), adopted as a prototype. This solution proposes a tiltrotor equipped with a power plant with three VMGs, including screws, engines and mounting pylons. Two lifting VMGs are equipped with rotary pylons with two degrees of freedom, are fixed symmetrically from the sides in the central part of the fuselage, have the ability to rotate in the horizontal plane for cleaning during horizontal flight forward or backward into the fuselage niches with the possibility of fixing the position, and also the ability to rotate in the vertical plane in transition mode to create a horizontal component of thrust and acceleration of the tiltrotor in transition mode of flight. The lifting screws of the VMG are optimized for hanging mode. The third VMG, located in the rear part of the tiltrotor, also has the ability to rotate in horizontal and vertical planes, on take-off performs the lifting function, and in cruising mode it creates horizontal thrust and has a screw optimized for operation in the cruise flight mode. The ability to rotate relative to the longitudinal axis allows maneuvering in hover mode.

In hover mode (vertical take-off and landing), the screws of all three VMGs create vertical traction. Then, in transition mode, they gradually deviate by a small angle, creating a horizontal thrust component for accelerating the tiltrotor to the speed when the wing begins to create a lift equal to the weight of the tiltrotor. At the end of the transition regime, the aft VMG rotates 90 ° and creates only horizontal traction, and two lifting VMGs are retracted into niches inside the fuselage.

Such a conceptual solution is most applicable to aircraft with the dimension of small unmanned aircraft (take-off weight up to 1000 kg). For unmanned aerial vehicles, the internal volume of the fuselage is used to accommodate special equipment and, as a rule, is not a critical quantity.

For a manned aircraft with a larger dimension and take-off weight, with a specific load on the area swept by lifting propellers in accordance with the requirements of permissible soil erosion, the diameters of the propellers will have to reach significant dimensions commensurate with the half-span of the aircraft wing or with the length of the passenger cabin, which corresponds to the actual dimensions a convertible aircraft with a passenger capacity of 9-19 seats or more. The length of the rotary pylons must be at least the radius of the lifting screws plus the necessary clearance for safety. With such dimensions of the lifting screws, the VMGs removed into the fuselage will occupy a significant amount, which will complicate the layout of the passenger compartment and require a significant increase in the size of the fuselage and its washed surface, and, consequently, the aerodynamic drag of the aircraft as a whole.

The proposed design solution has several advantages compared to the prototype. Compared with other solutions (EU patent No. EP2669195 A1) and prototype, RF patent No. 2635431, where the lifting screws are retracted into the fuselage, the cleaning of the lifting VMGs in the wing fairings located on the wing will provide greater design compactness, and will reduce: the dimensions of the rotary pylons: the total volume of removable carrier system (lifting VMGs): additional washable surface and aerodynamic drag during cruising flight mode.

The objective and technical result of the present invention is the development of a convertible aircraft, which eliminates the likelihood of a tear-off flow on stopped lifting propellers, various uncontrolled moments and flutter, that is, it provides reliability and safety, as well as high speed and economic characteristics, allows to reduce aerodynamic drag on cruising flight mode.

The solution of the problem and the technical result are achieved by the fact that in a convertible aircraft containing the fuselage, wing, mid-flight propeller groups and retractable lifting rotor groups, lifting rotor groups are equipped with folding screws in the plane of rotation, mounted in pairs at both ends of the wing on rotary pylons, retracted when turning into fairings together with propeller groups with previously folded screws. Fairings for cleaning lifting propeller groups are equipped with sliding and / or pivoting flaps. Swivel pylons are made of individual swivel links.

FIG. 1 - Convertible aircraft with folding and retractable wing-mounted wing fairings in take-off and landing configuration.

FIG. 2 - Folding the lifting screws in transition mode convertible aircraft.

FIG. 3 - Cleaning lifting VMG inside the fairing of a convertible aircraft in transition mode.

FIG. 4 - Closure of the flaps of the fairing of a convertible aircraft at the final phase of the transition mode.

FIG. 5 - Convertible aircraft with folding and retractable lifting screws in the wing fairings in the cruise configuration. The proposed solution is that the fixed screws with engines (rotor-motor groups) mounted on rotary pylons are removed inside the special fairing by turning them through an angle of ~ 180 ° relative to the axes passing through the attachment points to the power elements of the wing. At the same time, the two-bladed screws of the propeller-motor groups (VMG) are also preliminarily folded by turning one blade to another 180 degrees, located in pairs and parallel in the folded position in one fairing, which allows for maximum compactness. The fairing has sliding and pivoting flaps, which allow it to open and close during the cleaning of the VMG inward and subsequent release during landing.

The proposed design of a convertible aircraft in the take-off and landing configuration is shown in FIG. 1. The convertible aircraft has a fuselage 1, tail unit 2, wing 3 with mid-flight VMGs, including propellers 4, as well as lift screws 5 driven by electric motors 6, mounted at the ends of the wing in pairs on rotary pylons (cantilever beams) 7, forming aggregates lifting VMG. Fairings 8 have sliding and pivoting flaps that allow cleaning two VMGs inside each fairing 8 in transitional flight modes, and in cruising flight mode they take a streamlined shape. During vertical take-off and landing, the lifting screws 5 placed on the rotary pylons 7 create the vertical thrust necessary for the hovering mode of the converted aircraft. Management on hovering mode, the change in the angles of pitch and pitch of a convertible aircraft is carried out by differentiating the thrust of four lifting VMGs.

At the beginning of the transition mode, the propellers of the 4 mid-flight VMGs begin to create traction, the convertible aircraft increases horizontal speed. When the speed of the convertible aircraft reaches a value at which the wing lift becomes equal to the take-off weight, the thrust of the lift screws 5 decreases to 0. The lift screws 5 stop and fold in the plane of rotation by turning one blade to another, as shown in FIG. 2. Then, the folded blades of the lifting screws 5 are installed along the rotary pylons 7 and are fixed.

In FIG. Figure 3 shows the process of cleaning lifting VMGs with folded rotor blades 5 in the fairing 8. Cleaning is carried out by turning the pylons 7 through an angle of ~ 180 °. The rotation is carried out simultaneously for both pairs of lifting VMGs, but with a given desynchronization in the angular velocity of rotation between the front and rear VMGs in order to avoid a collision between the front and rear lifting VMGs during harvesting. The central wings of the fairing 8 open up and down to move the lifting VMG inside the fairing 8. The turn is completed when the front and rear lifting VMGs are harvested synchronously.

After the cleaning of the lifting VMGs and their fixing inside the fairings 8 are completed, their central wings are closed, and the front and rear wings are moved forward and backward, respectively, as shown in FIG. 4. The transition mode is completed by connecting and fixing the cuspid flaps 8.

In FIG. 5, a convertible aircraft is shown in cruise configuration. The fairing 8 with closed wings has the shape of a streamlined body (teardrop shape) close to the body of revolution.

There is the possibility of embedding an additional turning unit in the rotary pylons 7, breaking it into two structural links or knees, which, when folding the system, will rotate relative to each other. In this case, it is possible to ensure greater compactness of the structure when folding, and the lifting VMGs will perform complex spatial movement close to plane-parallel, since the VMGs with folded screws will not be deployed during cleaning. This version of the system will have advantages in compactness and a reduction in the size of the fairing 8, the pylons will create less resistance and influence on the aerodynamics of the convertible aircraft in transition mode.

The performed calculations confirm that the proposed convertible aircraft eliminates the possibility of creating a separated flow on stopped lifting propellers, various uncontrollable moments and flutter, i.e. will provide the necessary controllability, reliability and safety in all flight modes, as well as high speed and economic characteristics

Convertible aircraft can be effectively used for passenger and cargo transportation on local and regional airlines.

Claims (3)

1. A convertible aircraft containing the fuselage, wing, mid-flight propeller groups and retractable lift propeller groups, characterized in that the lift rotor groups are equipped with folding screws in the plane of rotation, mounted in pairs at both ends of the wing on the rotary pylons, removed when turning into fairings together with propeller groups with pre-folded screws. 2. Convertible aircraft according to claim 1, characterized in that the fairings for cleaning lifting propeller groups are equipped with sliding and / or pivoting flaps. 3. Convertible aircraft according to claim 1, characterized in that the rotary pylons are made of separate rotary links.

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