Aircraft and its manufacture

Abstract

Aircraft with the following characteristics: - the aircraft has wings (10) with integrated ducted fans (11-20) and - the ducted propellers (11-20) each have a duct (11, 14) with recesses (20) and a guide vane (12) inserted into the recesses (20), characterized by the following feature: - the ducted propellers (11-20) have an electric motor (13) supported by the guide grid (12).

Description

[0001] The present invention relates to an aircraft, in particular a fully electric, vertical take-off and landing (VTOL) aircraft, and to an advantageous method for producing such an aircraft. State of the art

[0002] In aerospace engineering, VTOL refers to any type of aircraft, drone, or rocket capable of taking off and landing essentially vertically without a runway. This collective term is used in a broad sense below, encompassing not only fixed-wing aircraft with wings, but also rotary-wing aircraft such as helicopters, gyroplanes, and helicopters, as well as hybrids such as compound helicopters or combination helicopters, as well as convertible aircraft. It also includes aircraft capable of particularly short takeoff and landing (STOL), short takeoff and vertical landing (STOVL), or vertical takeoff and horizontal landing (VTHL).

[0003] CN 104 691 751 A discloses a safe, triangular-supported, lightweight multi-rotor aircraft with a pin-and-slot structure, consisting of a fuselage, rotors, a flight control module located in the center of the fuselage, and an integrated wiring harness. The fuselage includes a horizontal structural plate and a plurality of lightweight vertical structural plates connected by pins and slots to form a triangular support structure, the outer surface of which forms a frame and the inner surface of which is supported at an opposite angle. The rotors are arranged vertically at the outermost intersection points of the vertical plates, while the horizontal plate is connected to the vertical surface of the frame and used for attachment.A plurality of circular rotor holes, which protect the rotors and whose diameters are slightly larger than those of the rotors, are formed in the horizontal plate, using the rotor drive shaft as the center of the circle. Finally, a plurality of pins are arranged at the contact point of each vertical and horizontal plate, each of which is provided with corresponding slots that connect to the pins.

[0004] DE 12 00 140 A discloses the subject matter of the preamble of claim 1.

[0005] DE 20 2015 003 815 U1, DE 12 09 001 A and DE 12 05 392 A show aircraft having wings with integrated ducted propellers, each having a duct.

[0006] DE 10 2014 012 801 A1 and DE 39 21 171 A1 show ducted propellers with grids.

[0007] US 8 020 804 B2 teaches the installation of a prefabricated ducted propeller unit, into which a guide vane has previously been mounted, into an aircraft. Disclosure of the invention

[0008] The invention provides an aircraft, in particular a fully electric aircraft capable of vertical takeoff and landing in the above sense, and a method for producing such a vehicle according to the independent claims.

[0009] The inventive approach is based on the insight that a VTOL aircraft that can be used in urban environments requires propulsion units in different positions and orientations that are capable of handling each flight phase (takeoff, transition, cruise and landing) while not exceeding a manageable number of individual parts.

[0010] Instead of a free-running rotor, ducted fans integrated into the wing are used to provide the aircraft's lift, similar to those found in hovercraft and airboats outside of aeronautical technology. The cylindrical housing of the air duct—hereafter referred to as the duct—reduces the thrust losses caused by turbulence at the blade tips of such a ducted propeller.

[0011] According to the invention, this shroud is provided with recesses that allow it to be modularly equipped—i.e., according to a modular or building block principle—with a guide vane (stator) optimized for the installation variant and rotation direction of the respective propeller drive. The same concept can be applied to other installation variants, allowing shrouds and specific guide vanes to be combined as desired to achieve cost savings.

[0012] Further advantageous embodiments of the invention are specified in the dependent patent claims. For example, the vanes can be integrally joined into the recesses and, in particular, glued into them. By using such a universal "adhesive garage" on the housings, specific stator variants can be manufactured cost-effectively in various designs and used universally. Short description of the drawings

[0013] An embodiment of the invention is illustrated in the drawings and is described in more detail below. Fig. 1 shows the isometric view of a wing with partially transparent planking and outer skin. Fig. Figure 2 shows the isometric view of the ducted propellers of the wing without engine. Fig. 3 shows one of the Fig. 2 corresponding view from an elevated perspective. Fig. 4 shows the isometric view of a propeller with partially transparent inlet and outlet. Fig. 5 shows the front view of two shell parts in two different installation variants. Fig. Figure 6 shows the isometric view of a shell and guide vane in one of the variants according to Fig. 5. Fig. Figure 7 shows the inventive joining connection of the shell and guide vane in detail. Fig. Figure 8 shows the isometric view of a shell and guide vane in the other variant according to Fig. 5. Embodiments of the invention

[0014] Fig. Figure 1 illustrates the structure of a wing (10) for an optionally fully autonomously or manually controlled aircraft, which is approximately divided into quadrants by spars and ribs. A ducted propeller is integrated into each of these quadrants, the propeller's guide vanes (12) arranged within the wing (11) supporting a central electric motor (13). For this purpose, the three cylindrical electric motors (13) are bolted radially to the respective guide vanes (12) in such a way that their struts, made of carbon or carbon fiber reinforced plastic (CFRP), can support the electric motor (13) from opposite sides in an axially and rotationally symmetrical arrangement.

[0015] In the illustrated configuration, two of the struts of each guide vane (12) run parallel to each other in the direction of flow of the blade (10) and flank the associated electric motor (13) tangentially. Two beams joined to these cheeks complement the beams of the other cheek, diametrically opposite the motor (13), to form a St. Andrew's or diagonal cross, stiffening the electric motor (13) such that the guide vane (12) absorbs all horizontal forces in the motor plane. As the illustration suggests, the struts of the guide vane (12) have a width that roughly corresponds to the height of the electric motor (13).

[0016] The Fig. 2 and Fig. 3 illustrate the different installation variants (X, Y) of the shell (11). This variation is achieved by the Fig. 4 based on the construction variant Y and in Fig. 5 by comparing the variants X and Y: The shell (here: 11, 14) consists of inlet areas (11) and outlet areas (14), which are separated by a circumferential ring (17, 18, 19 - Fig. 4) be stiffened.

[0017] Fig. Figure 6 draws the viewer's attention to the joining connection of the guide grid (12) essential to the invention using an exemplary casing (here: 11, 14, 19) of installation variant Y. For this purpose, the outlet regions (14) of the casing (11, 14, 19) of the present embodiment have two pairs of diametrically opposed recesses (20), into which the associated guide grid (12) can be inserted from below, as shown in the illustration.

[0018] Fig. Figure 7 illustrates this manufacturing step in a detailed view. The recess (20) shown has—clearly visible in this view—approximately the shape of an isosceles trapezoid, the longer base of which ends in the lower edge of the outlet area (14) shown in the illustration. The strut of the guide grille (12) to be inserted into this recess has a complementary shape, allowing the grille (12) positioned below the outlet area (14) to be joined to the casing upwards along the central axis of the casing and glued into its recesses (20).

[0019] The advantage of this approach becomes apparent when viewed in conjunction with the Fig. 8: Thanks to the trapezoidal shape of the recesses (20) which is consistent between all installation variants (X, Y), an identical guide grid (12) can be inserted into the outlet area (14) of a shell (11, 14, 19) of variant Y.

[0020] The individual propeller shells (11, 14) can, for example, be composed of honeycomb cores with inserts and then preferably coated with multiple layers of CFRP. In this context, this refers to any composite material in which carbon fibers are embedded in a plastic matrix, which serves to bond the fibers and fill the interstices. In addition to conventional epoxy resin, other thermosets or thermoplastics can also be used as the matrix, without departing from the scope of the invention.

[0021] In the present embodiment, the electric motor (13 - Fig.1) as an air-cooled internal rotor with integrated control. It is understood that in an alternative embodiment, for example, an external rotor or liquid cooling may be used without departing from the scope of the invention. Further exemplary options are disclosed, for example, by DUFFY, Michael, et al. "Propulsion scaling methods in the era of electric flight." In: 2018 AIAA / IEEE Electric Aircraft Technologies Symposium (EATS). IEEE, 2018. pp. 1-23.

Claims

[1] Aircraft having the following characteristics: - the aircraft has wings (10) with integrated ducted propellers (11-20) and - the ducted propellers (11-20) each have a duct (11, 14) with recesses (20) and a guide vane (12) fitted into the recesses (20), characterized by following feature: - the ducted propellers (11-20) have an electric motor (13) carried by the guide vane (12). [2] Aircraft according to claim 1, characterized by following feature: - the guide vanes (12) are integrally fitted into the recesses (20). [3] Aircraft according to claim 2, characterized by following feature: - the guide grids (12) are glued into the recesses (20). [4] Aircraft according to one of claims 1 to 3, characterized by following features: - the ducted propellers (11-20) have different installation variants (X, Y) of the duct (11, 14) and - the recesses (20) have a shape that is consistent between all installation variants (X, Y). [5] Aircraft according to claim 4, characterized by following features: - the shape is an isosceles trapezoid and - the recesses (20) are arranged in pairs at diametrically opposite positions of the casing (11, 14). [6] Aircraft according to one of claims 1 to 5, characterized by following feature: - the casing regions (11, 14) each have a circumferential stiffness ring (17, 18, 19). [7] Aircraft according to claim 6, characterized by following feature: - the shells (11, 14) are each composed of inlet areas (11) and outlet areas (14) and - the outlet areas (14) carry the stiffness rings (17, 18, 19) and have the recesses (20). [8] Aircraft according to one of claims 1 to 7, characterized by following features: - the shells (11, 14) have honeycomb cores with inserts and - the jackets (11, 14) are coated with multiple layers of carbon fibre reinforced plastic. [9] Method for manufacturing an aircraft according to one of claims 1 to 8, characterized by following features: - the guide vanes (12) are fitted into the recesses (20) of the casings (11, 14) and - the ducted propellers (11-20) are inserted into the blades (10) in different installation positions.

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