DE20303024U1 - Combination aircraft has rotor lift for telescoping of rotor power unit and makes it possible for rotor drive to be withdrawn completely from aerodynamic influence in plane flying by recessing into fuselage or to extend it from fuselage - Google Patents

Abstract

The combination aircraft has a rotor lift (1) for telescoping of the rotor power unit and makes it possible for the rotor drive to be withdrawn completely from the aerodynamic influence in plane flying by recessing into the fuselage (6), or to extend it from the fuselage. A leading edge slat (2) is installed below the canard wings (7) under the fuselage and enables stabilizing of the flying craft even during the telescoping of the rotor drive during the transition of plane flying to rotary wing operation, and vice versa.

Description

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Description

The invention is a combination aircraft capable of vertical and horizontal take-off, flight and landing with long-distance flight characteristics and special aerodynamic properties.

It is known that the use of helicopters - so-called rotary-wing aircraft - is advantageous wherever there is little space available for take-off and landing and where it is necessary to be able to operate in hover flight, i.e. at low speeds or even in reverse flight. The disadvantage is the inability to operate at higher cruising speeds and to cover greater distances economically and quickly.

It is known that fixed-wing aircraft are advantageous wherever longer distances have to be covered economically. The disadvantage is the need for more extensive infrastructure on the ground in the form of runways and the inability to reduce the cruising speed to zero over a target area in the air in order to carry out operational tasks.

According to the state of the art, it is also known that there have been and are many approaches to combining the advantages of both propulsion systems (rotor, surface) (so-called combination aircraft). However, these have not been able to prevail to date due to known design problems with these approaches, as their concepts are always very closely based on those of existing aircraft types. For example, a jet aircraft is known from the military sector in England that can swivel its jet engines on the main wings by around 90° and thus generate a vertical thrust with which it can take off. The transition to fixed-wing flight is problematic, however, because during the swiveling process of the engines, either thrust in the vertical or horizontal direction is lost to a considerable extent if it is not possible to build up a thrust that is uneconomically high for operation. The same concept was also tested with propeller aircraft, although landing as a fixed-wing aircraft was/is difficult or impossible for many of these prototypes due to the considerable propeller diameter required. Such approaches can be found in the patents US 3797783 A, US 4789115 A, US 05085315 A, US 05381985 A, etc.

The disadvantages of the current state of the art are in particular:

A realization according to patent no. US 4789115 A shows the disadvantage that the two-bladed propellers are aligned in the longitudinal direction of the aircraft during fixed-wing flight and thus, in addition to their air resistance, dramatically limit the pitch agility of the vehicle.

A realization according to patent US 3797783 A shows the disadvantage that a technical implementation is very complex and the rotor blades are significantly damaged by the

Surface wings are covered, resulting in only a low level of efficiency. ....... ........ ....·.·: .··..··.: _m : : .:

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A realization according to patent US 05085315 A also works according to the well-known principle of the tilt rotor, but the rotor blades are folded back in fixed-wing flight, which reduces their aerodynamic influence but does not eliminate it. The disadvantage remains a complex synchronization of the rotors and unstable behavior in the transition phase.

A realization according to patent US 05381985 A also works according to the known principle of the tilt rotor, but a double rotor with counter-rotating propellers is used on each wing. Here the entire wing is tilted, but this does not overcome the problems that are solved by the invention presented.

Prototypes of so-called tilt-rotor aircraft include Bell: XV-3, Bell-Boeing: V22, Bell-Agusta: BA609, AgustaWestland/Eurocopter: TRISYD.

Other concepts favor the so-called compound design, in which a helicopter is equipped with an additional turbine that generates additional horizontal thrust (e.g. GB 2238995, DE 4039027 A1, IT 1242176 B, etc.). The disadvantage is that the rotor blades are always exposed to the air flow and thus significantly limit the maximum possible forward speed, while at the same time the material load may be significantly increased.

Boeing designed a so-called HOVTOL (horizontal or vertical takeoff arid landing aircraft) with the designation X-50A CRW (canard rotor/wing, see US 05454530 A), which uses a two-bladed rotor that is so wide that it is positioned and locked in horizontal flight and is intended to act as a wing. A wide main rotor, however, has an adverse effect on the climb behavior. This concept is currently only being tested for small unmanned vehicles and it is doubtful whether it is technically feasible for fast-flying aircraft due to the aerodynamic load. This patent (US 05454530 A) comes closest to the invention documented in this illustration, but differs significantly in that the main rotor must always represent a technically unsatisfactory compromise due to its dual use as a fixed-wing wing and helicopter rotor and that the lack of a slat leads to a significant limitation in stability.

The patent US 3792827 A describes a VTOL aircraft with a cross-shaped main rotor, which, however, always remains under aerodynamic influence. The transition between rotor and fixed-wing flight is critical, since in this phase the rotor speed must be reduced to zero and the influence of the comparatively wide rotor blade on the aerodynamics is extremely variable.

Furthermore, a patent (US 5,890,441 A) from 1999 is known, in which a HOVTOL is described that uses two vertically arranged fans integrated into the fuselage with a longitudinal offset to generate a vertically directed thrust vector. Since these fans are integrated in the fuselage, the small diameter (compared to a helicopter rotor) resulting from the unfavorable flow conditions results in a disproportionately high power loss. Patent WO 8800556 A1 describes a similar aircraft, but the air flow in the vertical direction is controlled by slats.

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steers, which leads to a low efficiency compared to the classic helicopter drive with swashplate.

Patent US 3647315 A describes a helicopter that can fold its rotor blades backwards, thereby reducing their aerodynamic influence during fixed-wing flight. Since both the fixed wings and the fuselage are located under the rotor, the rotor efficiency is significantly reduced. A stable transition between rotor and fixed-wing flight appears to be very complex.

Patent US 4196877 A describes a torus in which a vertical rotor operates and to which two horizontal units are attached. The problem is that the rigidity of the vehicle is difficult to classify, so that it is hardly suitable for transporting loads.

The object of the invention is to overcome the problems presented in the prior art by achieving a stable transition between rotor and fixed-wing flight, ensuring high maneuverability as well as stability and a high efficiency of the aircraft through its design and enabling simple implementation while at the same time providing good emergency flight characteristics.

The above-mentioned problem is solved by the features listed in the patent claims.

These are characterized by the fact that the aircraft contains two independent propulsion systems consisting of a tail drive for fixed-wing flight and a rotary wing drive for vertical flight, whereby the complete rotary wing unit, consisting of the rotor head and rotor blades, can be completely and reversibly removed from all aerodynamic influences in fixed-wing flight and thus all the advantages of fixed-wing aircraft and rotary wing aircraft are optimally combined.

The aircraft is constructed in such a way that this rotary wing unit (3, 10) can be lowered on the ground, but in particular also during flight by folding the rotor blades (3) in the upper fuselage area of the vehicle (6) via a telescopic device (1), the so-called rotor lift, in the so-called rotor shaft (11) (Fig. 2). The fuselage can be opened and closed to maintain the aerodynamic properties. This process of lowering the rotary wing drive can be reversed at any time, both on the ground and in particular during flight, in order to enable the vehicle to land as a rotary wing aircraft after a fixed-wing flight, for example (Fig. 1). During fixed-wing flight, the rotor blades (3) of the rotary wing drive lowered in the fuselage are fixed in such a way that the vehicle does not lose its inverted flight properties.

To ensure that the vehicle does not become aerodynamically unstable or even roll over during the telescoping process of the rotary wing drive, the vehicle is equipped with a slat (2) which is mounted under the bow and under the Canar wings (7) of the vehicle. Only with the extended head control (Canar + slat) implemented here are the necessary parameters for a change in the state of the drive type

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(fixed flight, rotor flight) are achieved on a scale that is necessary for the use of such a vehicle. This means in particular that this is the only way to influence the pitch angle of the vehicle so strongly, even at low speeds in the transient phase, that the rotary wing drive can be telescoped in the slipstream of the vehicle's fuselage, so to speak, and thus only with the need for small forces. With a previously known design using conventional canar wings, these forces could not be made available in a stable manner, which means that a transition between rotary wing operation and fixed wing operation would only be possible with considerably more drive power or by accepting a considerable loss of altitude and unstable flight behavior in the transient phase.

Furthermore, both the canary wings (7) and the rear wings (8) of the aircraft can be completely swiveled around an internal wing rotation axis relative to the fuselage, i.e. can be adjusted, which allows the vehicle's lift to be adjusted over a much larger range than with the previously known use of wings with conventional flap control. This makes the vehicle extremely manoeuvrable. At the rear of the vehicle there are pusher propellers or jet engines to generate thrust in forward flight. The canary wings and the rear surface wings of the vehicle are designed in such a way that they do not significantly affect the air flow of the rotary wing drive. The torque compensation in rotary wing operation can be achieved by controlled lateral air outlet, e.g. in the form of a tail rotor covered by the fuselage.

What is new is the combination of rotor telescoping (1) together with a specially coordinated geometry of the vehicle in the form of a slat located below the Canar wings (2), so that in addition to simple technical and economic feasibility, the overall system also meets the safety requirements of a stable mode change from fixed-wing flight to rotor flight. This is achieved by

a) that the rotor blades (3) can, if necessary, i.e. before entering rapid forward flight, be completely removed from aerodynamic influence by being lowered into the fuselage (6) of the aircraft (Fig. 2) (deactivation),

b) that the rotor blades can be reactivated during operational operation depending on the flight condition, i.e. extended from the fuselage and unfolded (Fig. 1),

c) that the rotor lift (1) for telescoping the rotor head (10) with rotor blades and rotor blade contraction mechanism is designed either according to a large number of known mechanisms or by means of a previously unused longitudinally toothed shaft in such a way that it can safely absorb and transmit the required forces and moments even under the dynamic loads to which the aircraft is exposed,

d) that the geometric design of a forewing slat (2) arranged under the bow and fully or partially adjustable canary wings (7) and fully or partially adjustable main wings (8) as well as fuselage design and wing control (5) with the possibility of

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By changing the angle of attack of the entire wing, a transition between fast forward flight and rotary-wing mode and vice versa can be achieved without significant temporary loss of altitude and the aircraft at the same time achieves very high maneuverability,

(e) that the aircraft has dual emergency landing capabilities, such that it can be landed both as a fixed-wing aircraft (glider capability) and as a helicopter (autorotation) without or with reduced propulsion power,

(f) that the aircraft can be propelled by both pusher propellers and jet engines (4),

g) that the aircraft can optionally be equipped with a sensor carrier (9) which enables a particularly advantageous localisation of navigation sensors,

h) that a combination mode of operation is also possible in which, in slow fixed-wing flight, the use of the rotary wing propulsion system can also achieve altitude change rates that a fixed-wing aircraft alone cannot achieve at slow speeds.

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Claims (9)

1. A combination aircraft capable of vertical and horizontal take-off, flight and landing, which combines the advantageous properties of a rotary-wing aircraft and the advantageous properties of a fixed-wing aircraft, characterized in that - that a rotor lift ( 1 ) is used, which is used to telescopically extend the rotary wing drive ( 3 ) and makes it possible to completely remove the rotary wing drive from the aerodynamic influence in fixed-wing flight by sinking it in the fuselage ( 6 ) of the vehicle ( Fig. 2) or to extend it out of the fuselage of the aircraft again ( Fig. 1) and - that a slat ( 2 ) is arranged under the front canary wings ( 7 ) under the fuselage, which enables the aircraft to be stabilized even during telescoping of the rotary wing drive, i.e. during the transition from fixed-wing flight to rotary wing operation and vice versa. 2. Combination aircraft according to claim 1, characterized in that the rear wings ( 8 ) are fully adjustable in their angle relative to the fuselage ( 5 ), thereby resulting in enhanced aerodynamic properties of the aircraft with regard to agility and in particular also high rolling speed. 3. Combination aircraft according to one of the preceding claims, characterized in that the canary wings ( 7 ) are completely adjustable in their angle with respect to the fuselage, whereby enhanced aerodynamic properties of the aircraft with regard to agility and in particular also high rolling speed result and corresponding flaps at the wing tip can be dispensed with. 4. Combination aircraft according to one or more of the preceding claims, characterized in that the aircraft, due to its described construction (in particular slats and rotor lift), can be realized as a HOVTOL drone (horizontal or vertical take off and landing aircraft) for both long-distance and long-term missions. 5. Combination aircraft according to one or more of the preceding claims, characterized in that the rotor lift ( 1 ) for telescoping the rotary wing drive is designed such that a longitudinally toothed shaft leads into the rotor unit or, alternatively, this is designed as a cardan unit. 6. Combination aircraft according to one or more of the preceding claims, characterized in that the rotary wing propulsion and the fixed-wing propulsion are active in parallel in order to enable a faster gain in altitude at slow horizontal speeds than would be possible by fixed-wing operation alone. 7. Combination aircraft according to one or more of the preceding claims, characterized in that instead of the landing gear, airbags can be activated under the fuselage, so that the aircraft can also land on water, take off and move as a watercraft. 8. Combination aircraft according to one or more of the preceding claims, characterized in that the rotary wing drive is additionally supplemented by further retractable or non-retractable rotor systems. 9. Combination aircraft according to claim 8, characterized in that one or more of the additional rotor systems serve for control.