US 20200010209A1 (19) United States (12) Patent Application Publication (10) Pub. N0.: US 2020/0010209 A1 Bender (43) Pub. Date: Jan. 9, 2020 (54) AIRCRAFT B64C 29/00 (2006.01) B64C 39/02 (2006.01) (71) Applicant: Dr. Ing. h.c. F. Porsche B641) 27/24 (2006.01) Stuttgart (DE) F28F 21/02 (2006.01) .. (52) US. Cl. (72) mentor: Stefan Bendeh Lochgau (DE) CPC B64D 33/08 (2013.01); B64C 3/56 (73) Assignee: Dr. Ing. h.c. F. Porsche Stuttgart (DE) (21) Appl. N0.: 16/502,331 (22) Filed: Jul. 3, 2019 (30) Foreign Application Priority Data Jul. 4, 2018 (DE) 1020181161468 Publication Classi?cation (51) Int. Cl. B64D 33/08 B64C 3/56 (2006.01) (2006.01) (2013.01); B64C 29/0033 (2013.01); B64C 29/0025 (2013.01); B64C 39/024 (2013.01); B64C 2201/108 (2013.01); F28F 21/02 (2013.01); B64C 2201/141 (2013.01); B64C 2201/06 (2013.01); B64C 2201/088 (2013.01); B64D 27/24 (2013.01) (57) ABSTRACT An aircraft includes a battery; an airfoil and heat conducting elements, and the heat conducting elements connect the battery thermally t0 the airfoil in such a way that heat which is produced in the battery is distributed to the airfoil. Patent Application Publication Jan. 9, 2020 Sheet 1 of 5 US 2020/0010209 A1 FIG. 1 Patent Application Publication Jan. 9, 2020 Sheet 2 of 5 US 2020/0010209 A1 Patent Application Publication Jan. 9, 2020 Sheet 3 of 5 US 2020/0010209 A1 Patent Application Publication Jan. 9, 2020 Sheet 4 of 5 US 2020/0010209 A1 Patent Application Publication Jan. 9, 2020 Sheet 5 of 5 US 2020/0010209 A1 US 2020/0010209 A1 AIRCRAFT CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority to German Patent Application No. 10 2018 116 146.8, ?led Jul. 4, 2018, the content of such application being incorporated by reference herein in its entirety. FIELD OF THE INVENTION [0002] The present invention relates to an aircraft, in particular a fully electric aircraft which is capable of taking off and landing vertically (vertical take-off and landing, VTOL). BACKGROUND OF THE INVENTION [0003] In aerospace technology, VTOL denotes, across all languages, any type of aircraft, drone or rocket which has the capability to take off and land again substantially vertically and without a runway. In the following text, this collective term is used in a broad sense which includes not only ?xed airfoil aircraft with airfoils, but also rotary airfoil aircraft such as helicopters, gyrocopters, gyrodynes and hybrids such as compound helicopters or compound gyroplanes and convertiplanes. Furthermore, aircraft are to be included with the capability of taking off and landing in particularly short distances (short take-off and landing, STOL), taking off in short distances but landing vertically (short take-off and vertical landing, STOVL) or taking off vertically but landing horizontally (vertical take-off and horizontal landing, VTHL). [0004] In order to cool an aircraft, US. Pat. No. 4,635, 709A, which is incorporated by reference herein, proposes a cooling plate below the airfoil for dissipating heat from the electronic components and cooling ?ns for dissipating the heat which is output by the cooling plate into the cooling air stream. In addition, a liquid coolant is provided in cavities which are con?gured in the cooling plate directly next to the electronic components. [0005] Said liquid coolant evaporates at elevated tempera- tures when the cooling air stream is not available, in order to cool the cold plate. The steam which is released by way of the evaporation of the liquid coolant is ejected from the heat exchanging apparatus through a hydrophobic ?lter membrane which covers a part of the cavities. The hydro- phobic membrane is impermeable for liquids, but is penne- able to gas. [0006] EP1764302A2, which is incorporated by reference herein, also discloses a passive cooling system for a wing. The passive cooling system comprises a ?uid transmission chamber which is adjacent with respect to the wing. A ?uid transmission element and coolant are arranged in the ?uid transmission chamber. The ?uid transmission element con- ducts a part of the coolant to the wing which dissipates the thermal energy. [0007] Finally, US20150000523A1, which is incorporated by reference herein, describes an aircraft fuel tank ?amma- bility reduction method by way of the feeding of compressed air into an air separation module which contains an oxygen separating membrane. The method comprises bringing the separating membrane into contact with the air feed, the penetrating of oxygen from the air feed through the sepa- rating membrane, and the generating of nitrogen-enriched Jan. 9, 2020 air from the air separating module as a consequence of the removal of oxygen from the air feed. The enriched air from the air separating module is cooled in a ?ow heat exchanger in the wing and is fed to the fuel tank. SUMMARY OF THE INVENTION [0008] Described herein is an aircraft, in particular a fully electric aircraft which is capable of taking off and landing vertically. The aircraft has a battery, an airfoil and heat conducting elements, and the heat conducting elements connect the battery thermally to the airfoil in such a way that heat which is produced in the battery is distributed to the airfoil. [0009] Bene?ts of this aircraft lie in its reduced complex- ity in comparison with active cooling systems and the correspondingly reduced weight of the resulting aircraft. [0010] The aircraft can be equipped with folded or even selectively foldable airfoils. One corresponding variant enlarges the wing area which is active during horizontal ?ying, without increasing the footprint of the aircraft, how- ever. [0011] Furthermore, the aircraft may have a rapidly chargeable battery system which provides the drive energy for vertical take OH and landing and horizontal ?ying, and makes brief charging of the aircraft at a standstill possible. [0012] Here, in order to drive the aircraft, instead of exposed rotors, a plurality of ducted fans, even of different size, can be used, as are known away from aeronautical engineering, for instance from hovercrafts or airboats. In an embodiment of this type, the cylindrical housing which surrounds the propeller is capable of considerably reducing the thrust losses as a consequence of vortices at the blade tips. Suitable ducted fans may be oriented horizontally or vertically, may be con?gured such that they can be pivoted between the two positions or, for aerodynamic reasons, may be covered by way of louvers during horizontal ?ying. In addition, a pure horizontal thrust generation by means of stationary ducted fans is conceivable. [0013] Finally, in addition to preferably fully autonomous operation of the aircraft, the granting of manual control to human pilots with su?icient quali?cations also comes into consideration, which imparts the greatest possible ?exibility in terms of handling to the apparatus according to aspects of the invention. BRIEF DESCRIPTION OF THE DRAWING [0014] One exemplary embodiment of the invention is shown in the drawing and will be described in greater detail in the following text. [0015] [0016] FIG. 2 depicts an isometric View of an aircraft, wherein the wings are shown in an extended con?guration and the rear propellers are shown in an angled orientation. [0017] FIG. 3 depicts a front elevation view of the aircraft of FIG. 2, wherein the wings are shown extended con?gu- ration and the rear propellers are shown in a cruising orientation. [0018] FIG. 4 depicts another front elevation View of the aircraft, wherein the wings are shown in a folded con?gu- ration and the rear propellers are shown in a take-off/landing orientation. FIG. 1 shows the perspective View of an aircraft. US 2020/0010209 A1 [0019] FIG. 5 depicts a top plan view of a portion of an aircraft, showing an internal duct extending between a nose of the aircraft and a horizontal fan mounted to the wing. [0020] FIG. 6 depicts moveable louvers applied on top of the horizontal fan of FIG. 5, wherein the louvers are shown in a closed position. [0021] FIG. 7 depicts the movable louvers of FIG. 6, wherein the louvers are shown in an open position. DETAILED DESCRIPTION OF THE INVENTION [0022] The terms ?fan,? ?rotor? and ?propeller? may be used interchangeably herein. [0023] FIG. 1 illustrates the structural features of one preferred re?nement of the battery-electric aircraft 10 according to aspects of the invention, the heat management of which can be regulated via the airfoil 12 which is distributed substantially to its wings on both sides. [0024] To this end, in addition to a high voltage battery 11 which is used for the drive, the aircraft 10 has heat con- ducting elements 13 which connect the battery 11 thermally to the airfoil 12 in such a way that the heat which is unavoidably produced in the battery 11 during ?ying opera- tion is distributed as homogeneously as possible to the airfoil 12. The airfoil 12 which is ?owed around to a pronounced extent during ?ying acts as a heat exchanger in this way. [0025] Guide plates 14, silicone, mica, aluminum oxide or other ceramic, polyimide (Kapton?), metal foil or graphite foil may be used, for example, as heat conducting elements 13. [0026] FIGS. 2-4 depict an aircraft 100. The aircraft 100 shown in those ?gures may appear different from the pre- viously described aircraft, however, many (if not all) of the details of the previously described aircraft also apply to aircraft 100. [0027] The aircraft 100 includes foldable wings 102. The wings 102 are shown in a folded con?guration in FIG. 4 and an extended con?guration in FIG. 3. A motor or solenoid is con?gured to move the wings between those con?gurations. [0028] Rear propellers 104 are mounted on the trailing edge of the airfoils or wings 102 the edge furthest from the nose 105). Propellers 104 may be referred to as cruising propellers because they are used during the cruising opera- tion of the aircraft (at least in one position of the propellers 104). The propellers 104 are con?gured to pivot between two di?erent positions, as shown in FIGS. 2-4. In the vertical position of the propellers 104 shown in FIG. 3, the propellers 104 generate maximum horizontal thrust for cruising operation of the aircraft while the aircraft is ?ying through the air). In the horizontal position of the propellers 104 shown in FIG. 4, the propellers 104 generate maximum vertical thrust for take-off and landing operations of the aircraft. A motor or solenoid is con?gured to move the propellers 104 between those two positions. Alternatively, the propellers 104 may be immovable and ?xed in a vertical position, as shown in FIG. 2. [0029] Horizontally mounted propellers 106 are ?xedly mounted and integrated into the wings 102. Unlike the propellers 104, the position of the propellers 106 is ?xed, however, those skilled in the art will recognize that the propellers 106 could be modi?ed so that they are pivotable between vertical and horizontal positions. The propellers 106 generate maximum vertical thrust for take-o? and Jan. 9, 2020 landing operations of the aircraft. The propellers 106 may also be referred to herein as lifting propellers. [0030] The propellers 104 and 106, which may also be referred to herein as fans, may be operated by a fully-electric drive. To that end, a battery charging system 108 including a charger, an inverter and a fast-charging battery are posi- tioned within the fuselage of the aircraft for powering the propellers 104 and 106. The fuselage may also be con?gured to carry one or more passengers. [0031] FIGS. 5-7 depict views of an aircraft 200. The aircraft 200 shown in those ?gures may appear different from the previously described aircraft 100, however, most (if not all) of the details of the previously described aircraft 100 also apply to aircraft 200. Only a segment of the aircraft 200 is shown in FIG. 5. An air duct 210 extends between an opening 212 formed on the nose 214 of the aircraft 200 and the horizontally mounted propeller 206 that is ?xedly mounted to the wing 202. In operation, air is delivered to the propeller 206 via the duct 210, as depicts by the arrows. Although not shown, air ducts that are similar to duct 210, may extend to the propeller 206 on the opposite wing 202, as well as any rear propellers 104 (not shown in these views). Accordingly, the propellers may be referred to as either ?ducted propellers? or ?ducted fans.? [0032] FIGS. 6 and 7 depict louvers 216 that are con?g- ured to selectively cover the horizontally mounted propellers 206. It is noted that the louvers 216 are omitted from FIG. 5 for clarity purposes. Each louver 216 is rotatable about a shaft (or otherwise moveable) between a closed position (FIG. 6) and an open position (FIG. 7). The louvers 216, which are ?ush with the top face of the wing 202, may be moved to the closed position during the cruising operation of the aircraft 200 for aerodynamic purposes. The louvers 216 may be moved to an open position at any time during operation of the propellers 206 to permit the exit or entrance of air therethrough. A motor or solenoid is con?gured to move the louvers 216 between those positions. It is to noted that the louvers are shown in a closed position in FIG. 2. [0033] A sealing ring 218 surrounds the louvers 216 and is moveable between a retracted position (FIG. 6) and a deployed position (FIG. 7). The louvers 216 are mounted to the sealing ring 218 and move therewith between the retracted and deployed positions. The lower surface of the sealing ring 218 is con?gured to be in sealing relationship with an opening 220 formed in the wing 202. It should be understood that the opening 220 accommodates the body of the propeller 206. The sealing ring 218 may be moved to the retracted position, which is ?ush with the top face of the wing 202, during cruising operation of the aircraft 200 for aerodynamic purposes. Alternatively, the sealing ring 218 may be moved to the deployed extended) position at any time during operation of the propellers 206 to permit the exit or entrance of air, as depicted by the arrows in FIG. 7. A motor or solenoid is con?gured to move the sealing ring 218 between those positions. What is claimed is: 1. An aircraft comprising a battery, an airfoil and heat conducting elements, wherein the heat conducting elements thennally connect the battery to the airfoil in such a way that heat, which is produced in the battery, is distributed to the airfoil. 2. The aircraft as claimed in claim 1, wherein the heat conducting elements comprise guide plates. US 2020/0010209 A1 3. The aircraft as claimed in claim 1, wherein the heat conducting elements comprise graphite foil. 4. The aircraft as claimed in claim 1, wherein the aircraft has a fully electric drive. 5. The aircraft as claimed in claim 1, wherein the aircraft comprises folded or foldahle airfoils. 6. The aircraft as claimed in claim 1, wherein the aircraft comprises a chargeable battery system. 7. The aircraft as claimed in claim 1, wherein the aircraft comprises horizontally ?xed ducted fans for take off and landing. 8. The aircraft as claimed in claim 7, wherein the aircraft has louvers, and the louvers are con?gured to selectively cover the horizontal ducted fans. 9. The aircraft as claimed in claim 1, wherein the aircraft comprises vertically ?xed ducted fans for generating pro- pulsion. 10. The aircraft as claimed in claim 1, wherein the aircraft is con?gured to be selectively controlled in a fully autono- mous manner. Jan. 9, 2020 US 20200009974A1 (19) United States (12) Patent Application Publication (10) Pub. N0.: US 2020/0009974 A1 Bender et al. (43) Pub. Date: Jan. 9, 2020 (54) POWER SUPPLY FOR AN AIRCRAFT AND B64C 29/00 (2006.01) CORRESPONDING AIRCRAFT B64C 3/54 (2006.01) B64D 27/24 (2006.01) (71) Applicant: Dr. Ing. h.c. F. Porsche B60L 53/16 (2006.01) Stuttgart (DE) (52) US. Cl. CPC B6015 53/18 (2019.02); B64C 39/024 (72) Inventors: Stefan Bender, Lochgau Mikel Fauri, Ludwigsburg (DE) (73) Assignee: Dr. Ing. h.c. F. Porsche Stuttgart (DE) (21) Appl. N0.: 16/460,442 (22) Filed: Jul. 2, 2019 (30) Foreign Application Priority Data Jul. 4, 2018 (DE) 1020181161646 Publication Classi?cation (51) Int. Cl. B601. 53/18 B64C 39/02 (2006.01) (2006.01) (2013.01); B64C 29/0025 (201301); 11601. 2210/10 (2013.01); B64D 27/24 (2013.01); B60L 53/16 (2019.02); 3601: 2200/10 (2013.01); B64C 3/546 (2013.01) (57) ABSTRACT A power supply for an aircraft includes a drone capable of ?ight and including rotors, a converter, a battery for driving the rotors and a locking device for securing a plug connection between the drone and the aircraft. The drone is set up to secure the plug connection by the locking device until the aircraft reaches a prescribed altitude, and the power supply is con?gured in such a way that the battery supplies power to the aircraft by the converter as long as the plug connection exists. Patent Application Publication Jan. 9, 2020 Sheet 1 of 6 US 2020/0009974 10\/ AL 18\ Patent Application Publication 15. Jan. 9, 2020 Sheet 2 of 6 US 2020/0009974 Patent Application Publication Jan. 9, 2020 Sheet 3 of 6 US 2020/0009974 A1 \w-Dbmw. mm $233! Patent Application Publication Jan. 9, 2020 Sheet 4 of 6 US 2020/0009974 A1 Patent Application Publication Jan. 9, 2020 Sheet 5 of 6 US 2020/0009974 A1 Patent Application Publication Jan. 9, 2020 Sheet 2020/0009974 A1 US 2020/0009974 A1 POWER SUPPLY FOR AN AIRCRAFT AND CORRESPONDING AIRCRAFT CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority to German Patent Application No. 10 2018 116 164.6, ?led Jul. 4, 2018, the content of such application being incorporated by reference herein in its entirety. FIELD OF THE INVENTION [0002] The present invention relates to an aircraft, in particular a fully electric vertical take-01f and landing (VTOL) aircraft. The invention also relates to a correspond- ing power supply. BACKGROUND OF THE INVENTION [0003] VTOL is the cross-language name given in the aerospace industry to any type of aircraft, drone or rocket that has the capability of lifting OE and landing again substantially vertically and without a runway. This collective term is used below in a further sense that includes not just ?xed-wing aircraft with wings, but rather also rotary-wing aircraft such as helicopters, gyrocopters, gyrodynes and hybrids such as composite or combination helicopters and convertiplanes. Short take-off and landing (STOL) aircraft, short take-01f and vertical landing (STOVL) aircraft and vertical take-off and horizontal landing (V THL) aircraft are also included. [0004] The power requirement during the take-off and landing phase of a VTOL is high. The battery of an electri- cally driven VTOL according to the prior art therefore has to meet extremely high requirements not only in terms of its capacity but also in terms of its power density. [0005] WO 2010/031384 A2, which is incorporated by reference herein, discloses a method for launching a drone by means of a launching catapult, which applies the launch- ing energy, in such a way that the launching catapult is ?rst aligned before the launch. Here, the launching catapult is covered by means of a screen, which is removed only after the alignment and immediately before the launch. DE10 2016 219 473 A1, which is incorporated by reference herein, relates to a drone for docking onto a vehicle. In this case, the drone comprises an energy storage element and a docking device for docking the drone onto the vehicle. Furthermore, the drone comprises at least one communication unit for communication with the vehicle and/or with an external device of a user of the vehicle as well as at least one position identi?cation unit for detecting a position of the user of the vehicle. In this case, the drone is designed, after a prede- terminable trigger able to be detected by the communication unit, to identify the position of the user by way of the position identi?cation unit, to undock from the vehicle, to return to the user of the vehicle according to the detected position and to follow said user automatically. [0006] DE10 2007 003 458 A1, which is incorporated by reference herein, describes a device for automatically sup- plying energy to a small battery-operated aerial vehicle in order to ensure a virtually uninterrupted use of the aerial vehicle and to avoid constantly providing an operator. For this purpose, a landing and loading platform is provided, which is assigned a battery magazine or underneath which a charging device is provided. Jan. 9, 2020 SUMMARY OF THE INVENTION [0007] To solve the problem outlined above, an alternative energy source that does not contribute to the overall weight of the aircraft is proposed. This proposal is based on the following knowledge: the aircraft equipped with an on- board battery has a mass Me and a rotor surface For the power Per/Tommi, required for lift-o?, the following holds true (Mel/T01. MsanJ3 - A evrw. [0008] When the battery is removed from the aircraft, for the power required for the lift-off thereof, the fol- lowing holds true 3 Mel/T01. - A [0009] A battery with its own rotors would have a mass and a rotor surface ABM. In this case, for the power required for lift-o?, the following holds true I P3011 A (M3011 Movzrhead)3 - Barr [0010] When the following equation is satis?ed, the power required overall for hovering is therefore reduced, with the result that an electrically driven VTOL having a coupled, autonomous ?ight battery would be advantageous: 3 (MEVTOL M3011 Moverhzad) (Mel/T01. AEVTOL Aam [0011] In view of the foregoing, described herein is an aircraft, in particular a fully electric vertical take-off and landing aircraft in the above sense, and a power supply for such an aircraft according to the independent claims. [0012] Further advantageous con?gurations of the inven- tion are speci?ed in the dependent patent claims. The aircraft may thus be equipped for instance with bent or even selectively bendable wings. A corresponding variant increases the effective wing surface in horizontal ?ight, without however increasing the footprint of the aircraft. [0013] The aircraft may furthermore have a fast-charging battery system that provides the drive energy for vertical take-off and landing and horizontal ?ight and allows quick charging of the aircraft when stationary. [0014] In this case, instead of free-moving rotors, a plu- rality of ducted fans, including of different sizes, may be used to drive the aircraft, as are known outside of the aerospace industry, for instance for hovercraft or fanboats. The cylindrical housing surrounding the fan may consider- ably reduce thrust losses caused by vortexes at the blade tips in such an embodiment. Suitable ducted fans may be aligned horizontally or vertically, designed so as to pivot between both positions or be covered by louvers during horizontal US 2020/0009974 A1 ?ight for aerodynamic reasons. Pure horizontal thrust gen- eration using ?xed ducted fans is additionally conceivable. [0015] Finally, in addition to preferably fully autonomous operation of the aircraft, it is also possible to consider granting manual control to human pilots if they are su?i- ciently quali?ed, which gives the device according to aspects of the invention the greatest possible ?exibility in terms of handling. BRIEF DESCRIPTION OF THE DRAWING [0016] One exemplary embodiment of the invention is illustrated in the drawings and will be described in more detail below. [0017] FIG. 1A shows the lift-off of an aircraft according to aspects of the invention. [0018] FIG. 1B shows the aircraft before its transition to cruising ?ight. [0019] FIG. 2 depicts an isometric view of an aircraft, wherein the wings are shown in an extended con?guration and the rear propellers are shown in an angled orientation. [0020] FIG. 3 depicts a front elevation view of the aircraft of FIG. 2, wherein the wings are shown extended con?gu- ration and the rear propellers are shown in a cruising orientation. [0021] FIG. 4 depicts another front elevation view of the aircraft, wherein the wings are shown in a folded con?gu- ration and the rear propellers are shown in a take-off/ landing orientation. [0022] FIG. 5 depicts a top plan view of a portion of an aircraft, showing an internal duct extending between a nose of the aircraft and a horizontal fan mounted to the wing. [0023] FIG. 6 depicts moveable louvers applied on top of the horizontal fan of FIG. 5, wherein the louvers are shown in a closed position. [0024] FIG. 7 depicts the movable louvers of FIG. 6, wherein the louvers are shown in an open position. DETAILED DESCRIPTION OF THE INVENTION [0025] The terms ?fan,? ?rotor? and ?propeller? may be used interchangeably herein. [0026] FIGS. 1A and 1B, when considered together, illus- trate the design features and functional features of a pre- ferred embodiment of the aircraft 10 according to aspects of the invention. [0027] During the launch illustrated in FIG. 1A, the rotor systems 11, 13 that are coordinated with one another by means of a communication connection 18 between the aircraft 10 and the drone 12 lift off together. A locking device 17 secures a plug connection 16 between the drone 12 and the aircraft 10. [0028] In this case, the aircraft 10 is the master and the drone 12 equipped with its own battery 15 is the slave. Both batteries 15 are connected to one another and supply power to both the aircraft 10 and the rotors 13 of the drone 12. A converter 14 on board the drone 12 ensures that the voltages match and controls the ?ow of energy. [0029] When the transition altitude is reached, the autono- mous battery drone 12 is released and ?ies back to the ground. The aircraft 10 then continues the ?ight exclusively using its own on-board battery 15. [0030] FIGS. 2-4 depict an aircraft 100. The aircraft 100 shown in those ?gures may appear dilferent from the pre- Jan. 9, 2020 viously described aircraft 10, however, most (if not all) of the details of the previously described aircraft 10 also apply to aircraft 100. [0031] The aircraft 100 includes foldable wings 102. The wings 102 are shown in a folded con?guration in FIG. 4 and an extended con?guration in FIG. 3. A motor or solenoid is con?gured to move the wings between those con?gurations. [0032] Rear propellers 104 are mounted on the trailing edge of the airfoils or wings 102 the edge furthest from the nose 105). Propellers 104 may be referred to as cruising propellers because they are used during the cruising opera- tion of the aircraft (at least in one position of the propellers 104). The propellers 104 are con?gured to pivot between two different positions, as shown in FIGS. 2-4. In the vertical position of the propellers 104 shown in FIG. 3, the propellers 104 generate maximum horizontal thrust for cruising operation of the aircraft while the aircraft is ?ying through the air). In the horizontal position of the propellers 104 shown in FIG. 4, the propellers 104 generate maximum vertical thrust for take-o? and landing operations of the aircraft. Amotor or solenoid is con?gured to move the propellers 104 between those two positions. Alternatively, the propellers 104 may be immovable and ?xed in a vertical position, as shown in FIG. 2. [0033] Horizontally mounted propellers 106 are ?xedly mounted and integrated into the wings 102. Unlike the propellers 104, the position of the propellers 106 is ?xed, however, those skilled in the art will recognize that the propellers 106 could be modi?ed so that they are pivotable between vertical and horizontal positions. The propellers 106 generate maximum vertical thrust for take-off and landing operations of the aircraft. The propellers 106 may also be referred to herein as lifting propellers. [0034] The propellers 104 and 106, which may also be referred to herein as fans, may be operated by a fully-electric drive. To that end, a battery charging system 108 including a charger, an inverter and a fast-charging battery are posi- tioned within the fuselage of the aircraft for powering the propellers 104 and 106. The fuselage may also be con?gured to carry one or more passengers. [0035] FIGS. 5-7 depict views of an aircraft 200. The aircraft 200 shown in those ?gures may appear di?erent from the previously described aircraft 100, however, most (if not all) of the details of the previously described aircraft 100 also apply to aircraft 200. Only a segment of the aircraft 200 is shown in FIG. 5. An air duct 210 extends between an opening 212 formed on the nose 214 of the aircraft 200 and the horizontally mounted propeller 206 that is ?xedly mounted to the wing 202. In operation, air is delivered to the propeller 206 via the duct 210, as depicts by the arrows. Although not shown, air ducts that are similar to duct 210, may extend to the propeller 206 on the opposite wing 202, as well as any rear propellers 104 (not shown in these views). Accordingly, the propellers may be referred to as either ?ducted propellers? or ?ducted fans.? [0036] FIGS. 6 and 7 depict louvers 216 that are con?g- ured to selectively cover the horizontally mounted propellers 206. It is noted that the louvers 216 are omitted from FIG. 5 for clarity purposes. Each louver 216 is rotatable about a shaft (or otherwise moveable) between a closed position (FIG. 6) and an open position (FIG. 7). The louvers 216, which are ?ush with the top face of the wing 202, may be moved to the closed position during the cruising operation of the aircraft 200 for aerodynamic purposes. The louvers 216 US 2020/0009974 A1 may be moved to an open position at any time during operation of the propellers 206 to permit the exit or entrance of air therethrough. A motor or solenoid is con?gured to move the louvers 216 between those positions. It is noted that the louvers are shown in a closed position in FIG. 2. [0037] A sealing ring 218 surrounds the louvers 216 and is moveable between a retracted position (FIG. 6) and a deployed position (FIG. 7). The louvers 216 are mounted to the sealing ring 218 and move therewith between the retracted and deployed positions. The lower surface of the sealing ring 218 is con?gured to be in sealing relationship with an opening 220 formed in the wing 202. It should be understood that the opening 220 accommodates the body of the propeller 206. The sealing ring 218 may be moved to the retracted position, which is ?ush with the top face of the wing 202, during cruising operation of the aircraft 200 for aerodynamic purposes. Altematively, the sealing ring 218 may be moved to the deployed extended) position at any time during operation of the propellers 206 to permit the exit or entrance of air, as depicted by the arrows in FIG. 7. A motor or solenoid is con?gured to move the sealing ring 218 between those positions. What is claimed is: 1. A power supply for an aircraft, comprising: a drone con?gured for ?ight, said drone comprising rotors, a converter, a battery for driving the rotors and a locking device for securing a plug con- nection between the drone and the aircraft, wherein the drone is con?gured to secure the plug connection by means of the locking device until the aircraft reaches a prescribed altitude; and Jan. 9, 2020 wherein the power supply is con?gured in such a way that the battery supplies power to the aircraft by means of the converter as long as the plug connection exists. 2. The power supply as claimed in claim 1, wherein the drone is further con?gured to automatically return to ground level after the prescribed altitude has been reached. 3. The power supply as claimed in claim 1, wherein the drone is further con?gured to enter into a communication connection with the aircraft in order to adjust a common ?ight behavior. 4. The power supply of claim 1 further comprising the aircraft, wherein the aircraft comprises the power supply and a ?illy electric drive. 5. The aircraft as claimed in claim 4, wherein the aircraft comprises bent or bendable wings. 6. The aircraft as claimed in claim 4, wherein the aircraft comprises a fast-charging battery system. 7. The aircraft as claimed in claim 4, wherein the aircraft comprises horizontally ?xed ducted fans for take-off and landing. 8. The aircraft as claimed in claim 7, wherein the aircraft has louvers, and the horizontal ducted fans are con?gured to be selectively covered by the louvers. 9. The aircraft as claimed in claim 4, wherein the aircraft comprises vertically ?xed ducted fans for generating a propulsion. 10. The aircraft as claimed in claim 4, wherein the aircraft is con?gured to be selectively controlled in a fully autono- mous manner.