aircraft

Abstract

An aircraft having a fuselage (12), two wings (14, 16) arranged on two opposite sides of the fuselage (12), a plurality of propeller devices (22, 24, 26, 28, 30, 32, 34, 36) arranged on the fuselage (12) and / or on the wings (14, 16), and a flight control system (40), wherein the aircraft neutral point (N) is arranged in the horizontal forward flight direction (HV) in front of the aircraft center of gravity (S), wherein the flight control system (40) comprises a plurality of elevons (42, 44, 46, 48) and at least one pitch trim control element (50) pivotable about a rotation axis (O) aligned in the transverse direction of the aircraft, wherein the flight control system (40) is designed such that the aircraft in a Horizontal flight phase is trimmed by the pitch trim control element (50) and the flight control is carried out by the elevons (42, 44, 46, 48).

Description

[0001] The invention relates to a VTOL aircraft having a fuselage, two wings arranged on two opposite sides of the fuselage, a plurality of propeller devices arranged on the fuselage and / or on the wings, and a flight control system.

[0002] Such VTOL aircraft are well known in the art and typically comprise a fuselage, two wings, propeller devices mounted on the wings or fuselage, and a flight control system for controlling the flight of the VTOL aircraft. It is important that the VTOL aircraft is balanced during various flight phases, i.e., the vertical flight phase and the horizontal flight phase. Balancing is typically performed by a nose lift unit (NLU). The nose lift unit is located at the front of the VTOL aircraft and includes a propeller.

[0003] Such a VTOL aircraft is disclosed, for example, in DE 10 2020 109 331 A1. The VTOL aircraft has several ducted propellers on each wing and a nose lift unit arranged on a boom in the forward area. For propulsion during a horizontal flight phase, the VTOL aircraft has a horizontally oriented ducted propeller.

[0004] A disadvantage of such a VTOL aircraft with a nose lift unit is that the VTOL aircraft is relatively large and, due to the nose lift unit, heavy. Furthermore, the nose lift unit limits the view for a passenger seated in a passenger cabin provided at the front and makes boarding and disembarking from the passenger cabin more difficult.

[0005] The object of the invention is therefore to provide a VTOL aircraft that is lightweight and compact. Furthermore, boarding and disembarking from the passenger cabin should be facilitated and visibility for the passenger seated in the passenger cabin, especially for a pilot during flight operations, should be improved.

[0006] The problem is solved by the features of claim 1. The VTOL aircraft has a fuselage and two wings, wherein the wings are arranged on two opposite sides of the fuselage. The VTOL aircraft has a plurality of propeller devices arranged on the fuselage, preferably in the rear region of the fuselage, and / or on the wings. Preferably, three propeller devices are arranged on the wings. These propeller devices are designed as ducted propellers and are positioned such that, taking into account all propeller devices involved in the vertical flight phase, a so-called center of thrust is adjacent to the center of gravity of the aircraft. The VTOL aircraft also has a flight control system.

[0007] According to the invention, the aircraft neutral point is arranged in front of the aircraft center of gravity in the horizontal forward flight direction, wherein the flight control system comprises a plurality of elevons and at least one pitch trim control element pivotable about a rotation axis oriented in a transverse direction of the aircraft, wherein the flight control system is configured such that the aircraft is trimmed by the pitch trim control element in a horizontal flight phase and the flight control is performed by the elevons.

[0008] Since the aircraft neutral point lies in front of the aircraft's center of gravity in the horizontal forward flight direction, the VTOL aircraft is designed with an unstable neutral point position, i.e., in level flight mode, the VTOL aircraft would be essentially in an unstable state. To still provide level flight operation and simple control of the VTOL aircraft in level flight operation, the flight control system includes a pitch trim control element to create artificial stability. Flight control in level flight mode, in particular the control of roll and pitch movement, is performed exclusively by the elevons. Preferably, two elevons are arranged on each wing, i.e., at the trailing edges of the wings, and are arranged side by side in the transverse direction.An elevon is a combination of an elevator and an aileron and can control both the pitch and roll of the VTOL aircraft.

[0009] By providing two elevons on each wing, improved flight control can be achieved.

[0010] The pitch trim control element is pivotable about a rotation axis aligned in the transverse direction of the VTOL aircraft, in particular pivotally mounted on the fuselage. For this purpose, an actuator is provided which is operatively connected to the pitch trim control element and adjusts the pitch trim control element between different positions. The actuator is controlled by a control unit such that artificial stability is created and the VTOL aircraft is trimmed by a corresponding position of the pitch trim control element. An aircraft is considered trimmed when no control forces from a pilot are required to maintain its flight attitude in a given aerodynamic situation, i.e., all other control elements, in this case the elevons, are in a neutral position.In other words, flight control, particularly roll and pitch, is performed exclusively by the elevons when the aircraft is trimmed by the pitch trim control during a level flight phase. Adjusting the elevons to trim the VTOL aircraft is not required.

[0011] This allows the size and weight of the VTOL aircraft to be reduced and the entry and exit from a passenger cabin to be improved, as well as the visibility from the passenger cabin, while flight control can be carried out in a simple manner, since flight control can be easily carried out by the elevons, despite the lack of a nose lift unit and the arrangement of the aircraft's neutral point in front of the aircraft's center of gravity.

[0012] Preferably, two propeller devices designed as ducted propellers are arranged in the rear region of the fuselage, with the pitch trim control element arranged transversely between the propeller devices. The pitch trim control element is arranged on the symmetry axis aligned in the longitudinal direction of the VTOL aircraft, and the ducted propellers are arranged mirrored with respect to the symmetry axis. This allows the pitch trim control element to be easily pivoted on the fuselage. The ducted propellers are preferably pivotable about a transverse axis of the VTOL aircraft between a horizontal orientation and a vertical orientation, so that the ducted propellers are used for propulsion in both the vertical and horizontal directions.The aircraft's center of gravity may vary depending on movement in a horizontal forward flight direction and a horizontal backward flight direction, with the aircraft's center of gravity in both cases being located behind the aircraft's neutral point in the horizontal forward flight direction.

[0013] Preferably, a passenger cabin is arranged in a forward region of the fuselage, wherein the pitch trim control element is adjustable depending on a load of the passenger cabin. In this way, the VTOL aircraft can be trimmed depending on the load, i.e. depending on the number of passengers traveling and / or depending on the baggage carried, so that the flight control of the VTOL aircraft can be carried out by the elevons independently of the load of the passenger cabin. A nose lift unit, which causes problems when entering the passenger cabin and significantly increases the weight of the VTOL aircraft, is not required for this purpose. Since the pitch trim control element is arranged in the rear region, passengers entering the passenger cabin are not negatively affected by the pitch trim control element when boarding and disembarking.

[0014] An embodiment of the invention is explained in more detail with reference to the drawing.

[0015] The figure shows a schematic plan view of an aircraft.

[0016] The figure depicts a VTOL aircraft 10. In addition to horizontal flight, such a VTOL aircraft 10 can take off and land vertically and without a runway. This requires that the aircraft 10 incorporate appropriate components.

[0017] The aircraft 10 comprises a fuselage 12 that extends the entire length of the aircraft 10 and forms the supporting element of the aircraft 10. The fuselage 12 includes a passenger cabin 18 in the front area, in which passengers and a pilot can fly to control the aircraft 10. A wing 14, 16 is arranged on each of two opposite sides of the fuselage 12, which are required for a horizontal flight phase.

[0018] The aircraft 10 also comprises a plurality of propeller devices 22, 24, 26, 28, 30, 32, 34, 36, which are designed as ducted propellers. Three propeller devices 22, 24, 26, 28, 30, 32 are arranged on the wings 14, 16 in each case. The propeller devices 22, 24, 26, 28, 30, 32 arranged on the wings 14, 16 are rigidly arranged on the wings 14, 16 and oriented in the vertical direction. The propeller devices 22, 24, 26, 28, 30, 32 are thus used in particular for a vertical flight phase, i.e., for vertical landing and takeoff. Two further propeller devices 34, 36 are arranged in the rear area of ​​the aircraft 10 and attached to the fuselage 12.The propeller devices 34, 36 are each pivotably mounted on the fuselage 12 about a rotational axis not shown in the figures and can be actively adjusted between a vertical and a horizontal position by an adjustment device not shown in the figures. By adjusting the propeller devices 34, 36, they are used in the vertical position for propulsion during the vertical flight phase and in the horizontal position for propulsion during the horizontal flight phase.

[0019] The aircraft 10 further comprises a flight control system 40 for controlling the aircraft 10 in the horizontal flight phase. The flight control system 40 comprises four elevons 42, 44, 46, 48 and a pitch trim control element 50. The VTOL aircraft 10 is configured such that the aircraft neutral point N lies in front of the aircraft center of gravity S in the horizontal forward flight direction, the VTOL aircraft being configured with an unstable neutral point position.

[0020] The elevons 42, 44, 46, 48 are flap-like and adjustable, with two elevons 42, 44, 46, 48 each arranged at a trailing edge of the wings 14, 16 and pivotably mounted on the corresponding wing 14, 16 about a rotation axis aligned in the transverse direction of the aircraft 10. The elevons 42, 44, 46, 48 serve, on the one hand, for roll control and, on the other hand, for pitch control. The elevons 42, 44, 46, 48 are moved simultaneously and in opposite directions to each other for roll control. The elevator 42, 44, 46, 48, which is moved downward, increases the lift on the corresponding side, thereby raising the corresponding wing 14, 16. The other element 42, 44, 46, 48, which is moved upward, causes a reduction in lift, and the corresponding wing 14, 16 descends. This results in a rolling motion around the longitudinal axis, which is necessary for turning.For the pitch movement, the elevons 42, 44, 46, 48 are pivoted together upward or downward, causing the VTOL aircraft to rotate about a transverse axis. By providing multiple elevons 42, 44, 46, 48 on both wings 14, 16, for example, the elevons 42, 44 can be adjusted in opposite directions to provide a roll movement of the VTOL aircraft, and the elevons 46, 48 can be adjusted in a common direction to provide a pitch movement at the same time.

[0021] The pitch trim control element 50 is arranged between the two propeller devices 34, 36 arranged in the rear region and is pivotally mounted on the fuselage 12 about a rotation axis O aligned in the transverse direction of the VTOL aircraft 10. To adjust the pitch trim control element 50, an actuator (not shown in the figure) is provided, which is operatively connected to the pitch trim control element 50. The actuator is controlled by a control unit such that artificial stability is created and the VTOL aircraft is trimmed by a corresponding position of the pitch trim control element 50. By adjusting the pitch trim control element 50, the VTOL aircraft 10 can be trimmed depending on the load of the passenger cabin 18.

[0022] Since the VTOL aircraft 10 is trimmed by the pitch trim control element 50, flight control during the horizontal flight phase is performed exclusively by the elevons 42, 44, 46, 48.

[0023] This allows the size and weight of the VTOL aircraft 10 to be reduced and the boarding and disembarkation from the passenger cabin 18 to be improved, with flight control being easily achieved by the elevons 42, 44, 46, 48. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 109 331 A1

[0003]

Claims

[1] Aircraft with a hull (12), two wings (14, 16) arranged on two opposite sides of the fuselage (12), a plurality of propeller devices (22, 24, 26, 28, 30, 32, 34, 36) arranged on the fuselage (12) and / or on the wings (14, 16), and a flight control system (40), characterized by , that the aircraft neutral point (N) is arranged in front of the aircraft center of gravity (S) in the horizontal forward flight direction (HV), wherein the flight control system (40) comprises a plurality of elevons (42, 44, 46, 48) and at least one pitch trim control element (50) which is pivotable about an axis of rotation (O) which is aligned in the transverse direction of the aircraft, wherein the flight control system (40) is designed such that the aircraft is trimmed in a horizontal flight phase by the pitch trim control element (50) and the flight control is carried out by the elevons (42, 44, 46, 48). [2] Aircraft according to claim 1, characterized by in that two propeller devices (34, 36) designed as ducted propellers are arranged in the rear region of the fuselage (12), wherein the pitch trim control element (50) is arranged in the transverse direction between the propeller devices (34, 36). [3] Aircraft according to claim 2, characterized bythat the propeller devices (34, 36) are pivotable between a horizontal orientation and a vertical orientation about a transverse axis. [4] Aircraft according to one of the preceding claims, characterized by that two elevons (42, 44, 46, 48) are arranged on each wing (14, 16). [5] Aircraft according to one of the preceding claims, characterized by that three propeller devices (22, 24, 26, 28, 30, 32) designed as ducted propellers are arranged on each wing (14, 16). [6] Aircraft according to one of the preceding claims, characterized by that a passenger cabin (18) is arranged in a front region of the fuselage (12), wherein the inclination trim control element (50) is adjustable depending on a load of the passenger cabin (18).

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