RU2787115C1 - Main rotor capable of folding and unfolding in flight - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: invention relates to aviation engineering, namely, to vertical/short takeoff and landing aerial vehicles, and is intended for convertiplanes equipped with a jet compressor drive of the main rotor. Main rotor capable of folding and unfolding in flight includes variable-pitch blades, a rotor sleeve with horizontal hinges, the main rotor axle of rotation, a swashplate, and cyclic pitch controls. The rotor sleeve is secured on a slider with freedom of movement along the rotor axle of rotation. The swashplate is positioned on the surface of the slider with freedom of movement thereon when the total pitch of the blades is changed using driving rods. Each blade is linked via a synchronising mechanical link with the end of the rotor axle of rotation by means of equal articulated rods. The base of the slider has a power link with the mechanism for angular rotation of the rotor axle of rotation from the folded position to the working position and back.

EFFECT: high reliability of the process of folding and releasing the main rotor in flight in a single-rotor convertiplane, eliminated possibility of cross-links in the attitude and heading control channels.

1 cl, 2 dwg

Description

The invention relates to aeronautical engineering, namely to vertical/short takeoff and landing aircraft. Designed for convertiplanes equipped with a jet-compressor drive of the main rotor, folded and deployed in flight.

Known aircraft vertical takeoff and landing with folding rotors in flight.

In the project of the Bell company (USA) (F.P. Kurochkin. "Design and construction of aircraft with vertical takeoff and landing", ed. Mashinostroenie, 1977, pp. 20, 22), when the transition speed was reached, a screw having a variable swing compensator was proposed , slow down and, using booster devices, set the blades downstream, and then, after turning, remove them into the nacelle of the fuselage fairing with subsequent closing of its flaps.

The disadvantage of the design is the exclusion of the converting energy of aerodynamic forces from the process of release and retraction of the main rotor, as well as the impossibility of automatic release and spin-up of the main rotor blades in the autorotation mode in case of engine failure.

In the project of the company Messerschmidt MeR.2020-4 (F.P. Kurochkin. "Design and construction of aircraft with vertical takeoff and landing", ed. Mechanical engineering, 1977, pp. 123, 124), after takeoff, the rotors on the wing consoles gradually stop and their blades fold downstream. The propeller sleeve moves forward in flight, and the blades, folded together, are partially closed by a fairing in the form of flaps.

The disadvantage of this solution is that in cruising flight, the open part of the stack of folded blades is always in a turbulent air flow, which induces their multi-frequency oscillations with mutual impacts, which leads to their accelerated wear.

The closest analogue of the present invention is the project of the Bell company (F.P. Kurochkin. “Fundamentals of designing aircraft with vertical takeoff and landing”, ed. , the power supply to the two cantilever rotors with a diameter of 11.6 m is turned off. The axes of rotation of the screws begin to deviate back with the transition to autorotation mode. Further, the angle of inclination of the axis of the propellers and the angle of installation of the blades increases until the blades move into the vane position. At the final section, with the help of booster devices, the blades are brought together by the trailing edges of the profiles to the flight position. The opening of the rotors before landing is carried out in the reverse order.

The project has a number of disadvantages:

- The retraction and release of the main rotor in flight can practically be reliably implemented only in convertiplanes with one main rotor. In twin-rotor convertiplanes, even in the presence of a synchronizing shaft between the screws, due to the difference in air flow around, especially with a crosswind, a dangerous imbalance of aerodynamic forces between the left and right screws will inevitably occur, leading to a hard-to-remove buildup of the entire device with a high probability of its collision with earth. A similar effect periodically occurs on the Osprei V-22 tiltrotor and has already caused several accidents near the ground.

- Two rotors operating in autorotation mode are sources of cross-links in the roll and course control channels, significantly complicating the piloting process. Thus, an increase in the angle of attack of the main rotor on one side in order to create a roll simultaneously increases its aerodynamic drag with the formation of a turning heading moment in the direction of this propeller, which, moreover, is difficult to parry at low forward flight speeds.

- In flight, the folded blades are not retracted into the gondola, but remain in a turbulent flow with the possibility of mutual oscillations of their consoles, because the number of blades is only three, and the automatic mutual fixation of the consoles by the trailing edges of the profiles occurs when the number of blades is five or more.

- The rotors of the project require a complex and heavy mechanical drive with a double set of gearboxes and transmission, and in addition to the synchronizing shaft between the screws, synchronization of the rotation angles of the axes of the opposite rotors is also required.

- Folding and opening of the rotor blades does not provide synchronization of their mutual angular motion. This leads to the fact that at the final section of the retraction of the propeller, the convergence of the blades into the package occurs in discordance with impacts on the trailing edges of the profiles.

The objective of the invention is to create a design of a main rotor that develops and opens in flight, with a jet-compressor drive, for a single-rotor tiltrotor with increased reliability and safety of use.

The objective of the invention is solved by the fact that the screw hub is fixed on the slider, which has freedom of movement along the axis of rotation of the screw, the swashplate is placed on the surface of the slider and has freedom of movement along it when the total pitch of the blades changes with the help of drive rods, and each blade is connected by a synchronizing mechanical connection with the end of the axis of rotation of the screw by means of equal hinged rods, in turn, the base of the slider has a power connection with the mechanism of angular rotation of the axis of rotation of the screw from the retracted position to the working position and vice versa, while the gear ratios of the links of the general kinematic connection of the angle of rotation of the axis of rotation of the screw with the angle of the cone of the blades and with the pitch angle of the blades, the possibility of coordinated aerodynamic interaction of the main rotor with the oncoming air flow during the folding or opening of the main rotor in flight is provided.

The obtained technical result is characterized by the following essential features:

- the screw hub is fixed on the slider, which has freedom of movement along the axis of rotation of the screw,

- the swashplate is located on the surface of the slider and has the freedom to move along it when the total pitch of the blades changes with the help of driving rods,

- each blade is connected by a synchronizing mechanical connection with the end of the axis of rotation of the propeller by means of equal articulated rods,

- the base of the slider has a power connection with the mechanism of angular rotation of the axis of rotation of the screw from the retracted position to the working position and vice versa,

- the gear ratios of the links of the general kinematic connection of the angle of rotation of the axis of rotation of the propeller with the angle of the cone of the blades and with the angle of the pitch of the blades provide the possibility of coordinated aerodynamic interaction of the main rotor with the oncoming air flow in the process of folding or opening the main rotor in flight.

On FIG. 1 shows the main rotor module in the folded form when it is positioned in a closed gondola.

On FIG. 2 shows the main rotor module at the beginning of the exhaust process when it exits the gondola.

In-flight folding and deploying rotor device according to FIG. 1 and FIG. 2 includes: blades (1), air distributor (2), composite articulated air ducts (3), blade sleeves (4) with drivers (5) and driver rods (6). The drive links (6) are hinged to the swashplate (7) which is mounted on the slider (8).

The base (9) of the slider (8) has a power connection with the retraction/extension mechanism of the main rotor (10) and the cam (11) for retracting the blades (1) in the retracted position. The base (9) also serves as the installation site for the actuating units (12) for controlling the swashplate (7). The main rotor bushing (13) is installed on the slider (8) in bearings. The slider (8) has freedom of movement along the axis of rotation (14) of the main rotor, which simultaneously serves as a channel for compressed air (gas) supplied to the main screw through the internal flow sections of the rotary assembly (15). The axis of rotation (14) of the main rotor has an interval of rotation by an angle from 0 to 90 degrees. The rotor blades (1) have the same rotation interval associated with the rotation axis (14).

The main rotor device, folding and deploying in flight, works as follows (Fig. 1, 2):

In the initial position, before the release, the blades (1) are brought together along the trailing edges of the profiles, the retraction/release mechanism (10) stands on the cam stop (11), which fixes the HB slider (8) in the leftmost position with the calculated axial force. The calculated force is necessary so that the blades (1), brought together along the trailing edges, form a rigid multi-ribbed beam, which is safely removed and brought into the gondola and fits compactly into it on soft concentric lodgements. The initial position of the folded blades is vane, i.e. the formed multi-rib beam, being placed in an oblique air flow, does not generate a torque.

In the direct cycle, after the “Release” signal is given, the gondola doors open and the mechanism rod (10) begins to extend, raising the axis of rotation of the screw (14) through the base of the slider (9) in the direction of increasing angle β (Fig. 2) and, at the same time, by shifting the sleeve (13) with the slider (8) along the axis to the right. The thrust-air ducts (3), transferring force to the sleeves (4) of the blades (1), and resting through the drive rods (6) against the docking nodes of the swashplate (7), deflect the blades (1) in the direction of increasing angle α, forming an expanding cone of the carrier screw. Driving rods (6) have an oblique stop in the drivers (5) of the blades (1). Due to this, the opening of the main rotor cone is accompanied by a synchronous rotation of the blade profiles (1) and their corresponding interaction with the oncoming flow, first in the windmill mode and then with the transition to the autorotating flow mode. As a result, a torque appears on the blades and rapidly increases, which, in the opening cycle of the main rotor cone, accelerates the propeller to flight speed. At the same time, the vector of the total aerodynamic force of the main rotor increases, which, acting along the axis of rotation (14), is added to the vector of the total aerodynamic force of the tiltrotor wing.

In transient conditions, the tiltrotor stabilizer creates a positive lifting force, because. until the vertical position of the axis of rotation (14) is reached, the line of action of the full aerodynamic force of the main rotor passes above the center of gravity of the tiltrotor. An important consequence of this is that at the beginning of the release or at the end of the retraction of the main rotor, the tail section of the tiltrotor fuselage and the narrow cone of the elastic blades (1), on which there is practically no centrifugal force in this sector, tend to symmetrically move away from each other in the oncoming air flow, reducing the risk of the oscillating ends of the blades approaching the surface of the fuselage and gondola doors.

In the reverse cycle, after the “Retract” signal is given to the mechanism (10), its rod begins to retract, lowering the axis of rotation (14) of the main rotor in the direction of decreasing the angle (3 (Fig. 2), simultaneously shifting the slider (8) and the bushing (13) along the (14) axis to the left. The entire process of interaction of the blades with the oncoming flow takes place in the reverse order. The main rotor cone narrows, the torque decreases, the propeller speed decreases. The difference in the aerodynamics of the cleaning process is only in the algorithm for changing the angles of attack of the profiles set by the control system blades (1), which should create braking components of the angular motion in such a way that by the moment the main rotor axis rotates by 80-85 degrees, the main rotor revolutions are close to 0. At the moment the blades (1) converge along the trailing edges (9) into the cam (11) with a calculated force, their package acquires the rigidity of a longitudinal multi-ribbed beam, which at the end of the harvesting cycle is softly and accurately inserted into the gondola. irritated by the closing of the valves.

The proposed device for the main rotor, folding and deploying in flight, made it possible:

- To ensure a high level of reliability of the process of cleaning and releasing the main rotor in flight for a single-rotor tiltrotor.

- Eliminate the possibility of cross-links in the roll and course control channels, significantly simplifying the process of piloting the device.

- Place the folded main rotor in the closed nacelle of the fuselage fairing and ensure long-term preservation of parts of its structure due to the fact that the internal volume of the nacelle is heated, protected from wind, rain and snow, the blades are not exposed to direct sunlight and turbulent flow in cruising flight.

- Use at least five blades to ensure their automatic mutual fixation along the trailing edges in the retracted position.

- Eliminate the complex and heavy mechanical drive of the main rotor with a double set of gearboxes and transmissions by optimizing the design of the folding system for a jet-compressor drive.

- Ensure the process of folding and opening the main rotor with rigid synchronization of the mutual angular motion of the blades.

Claims (1)

Main rotor, folding and deploying in flight, including variable-pitch blades, a propeller hub with horizontal hinges, an axis of rotation of the main rotor, a swashplate and cyclic pitch controls, characterized in that the propeller hub is mounted on a slider that has freedom of movement along the axis of rotation propeller, the swashplate is placed on the surface of the slider and has freedom of movement along it when the total pitch of the blades changes with the help of drive rods, and each blade is connected by a synchronizing mechanical connection with the end of the screw rotation axis by means of equal articulated rods, in turn, the base of the slider has a power connection with the mechanism of angular rotation of the axis of rotation of the screw from the retracted position to the working position and vice versa, while the gear ratios of the links of the general kinematic connection of the angle of rotation of the axis of rotation of the screw with the angle of the cone of the blades and with the angle of the pitch of the blades ensured the possibility of coordinated aerodynamic interaction of the main rotor with the incoming m airflow during the folding or opening of the main rotor in flight.

Images