TECHNICAL FIELD

The present disclosure relates to aviation technology. More specifically, the present disclosure relates to an airplane propulsion system, a drivetrain for use in an airplane propulsion system, an apparatus for use in an airplane propulsion system, a set of components configured to fit an airplane with an airplane propulsion system, an airplane, anda method to install an airplane propulsion system in an airplane.

BACKGROUND OF THE INVENTION

Conventional airplane propulsion systems comprise one or more engines that each drive a propulsion rotary device such as an airscrew, hereinafter referred to as propeller. In an airplane with a tractor configuration, an engine is mounted with a propeller in front of the engine so that the airplane is "pulled" through the air. In an airplane with a pusher configuration a propeller is mounted behind the engine. Some airplane are equipped with coaxial contra-rotating propellers. Two propellers are arranged one behind the other, and power is transferred from one engine via a gear transmission. An airplane constructed with a push-pull configuration has a combination of forward-mounted tractor (pull) propeller, and backward-mounted (pusher) propeller.

A common problem is lack of safety in the event of an engine failure. Some airplane are equipped with a parachute to keep the airplane from hitting the ground too hard in the event of an engine failure.

WO 2012/023066 Al discloses a propulsion and motion-transmission assembly for a rotary-wing aircraft. The assembly comprises a first motor-reducer assembly and a second motor-reducer assembly. The first and second motorreducer assemblies are arranged for driving in rotation at least one rotor of a rotary-wing aircraft. Each of the first and the second motor-reducer assemblies comprises a mechanical differential that includes a first input shaft, a second input shaft and an output shaft, a first electric motor and a second electric motor.

GB 2 491 129 A discloses a rocket or ballistic launch rotary wing air vehicle. The air vehicle has an elongate body with a detachable propulsion system at a lower end. Towards an upper end, the air vehicle comprises a first rotor system and a second rotor system.

US 2014/0248168 Al discloses a rotary-wing aircraft. The aircraft comprises a plurality of rotors and/or a plurality of airscrews caused to rotate by means of at least one shaft. The aircraft comprises a distributed electric motor unit configured to ensure the propulsion and/or the lifting of the aircraft by rotating the shaft. The motor unit is a distributed electric motor unit connected directly to the rotating shaft.

US 2021/0039796 Al discloses a redundant propulsion device. The device includes a propeller and electric motors. The electric motors are configured to drive the propeller. The electric motors are disposed with respect to a propeller shaft of the propeller so that, around the propeller shaft, at least one of the electric motors is disposed at each of the locations in the longitudinal direction of the propeller shaft.

US 2017/0174337 Al discloses a redundant propeller drive system. The drive system comprises a frame, a propeller, a drive shaft coupled to the propeller, a first motor axially aligned with the drive shaft and coupled to the frame, a first one-way clutch bearing, a second motor axially aligned with the drive shaft and coupled to the frame, and a second one-way clutch bearing.

US 2017/0217600 Al discloses a propulsion system assembly that comprises a driveshaft rotatably mounted to a casing about a drive axis. The propulsion system assembly further comprises a plurality of electric motor modules in axially stacked relationship with one another with respect to the drive axis to define an electric motor module stack. The propulsion system assembly further comprises an electric motor module. US 2020/0407052 Al discloses a thrust producing unit that comprises a rotor and a fail-safe electrical drive unit. The electrical drive unit comprises first and second input shafts, first and second fixedly attached belt pulleys, an output shaft that is coupled to the rotor, first and second freewheeling belt pulleys, first and second belts, first and second electric motors, and first and second tensioners.

DE 10 2015 226 836 Al relates to an electrical redundant drive system for a propulsion means of an aircraft and to a method for driving the propulsion means. The drive system has two or more separate electric motors. The electric motors are coupled by means of freewheels.

US 5370341 A discloses a helicopter that comprises a frame, an engine mounted on the frame, a rotor assembly mounted on the frame and coupled to the engine for rotation, and a rotor pitch control mechanism to adjust the pitch of the plurality of rotors. The helicopter further comprises a throttle control mechanism to adjust the rotational speed of the rotor assembly and a pilot containing carrier assemblage connected to the frame.

US 2010/0161155 Al relates to an autonomous helicopter. The helicopter comprises at least two optical receivers, at least one optical emitter, at least two channels for processing signals of the receivers, and at least two motors controlling at least two propellers.

DE 33 47 679 Al discloses a double propeller arrangement that comprises two coaxial propellers axially offset, a central shaft carrying one propeller, and a hollow shaft concentric with the central shaft and surrounding the central shaft. Each of the shafts includes drive means for driving the respective propeller

DE 36 29 867 Al discloses a gear drive arrangement for driving one aircraft propeller or helicopter rotor. The gear drive arrangement comprises two transmissions with two laterally displaced drive shafts and at least one driven shaft connected to a propeller shaft or rotor shaft. The two transmissions comprise two spatially separated individual drive mechanisms, a separate housing for each of the drive mechanisms and housing sections of the driven shaft. US 2019/0193848 Al discloses an aircraft that comprises a main body having an outer periphery, and blades that rotate about the outer periphery of the main body to generate a thrust having a thrust direction. The aircraft further comprises flaps pivotally coupled at the outer periphery of the main body to rotate between a first position and a second position.

DE 10 2018 116 161 Al discloses an aircraft that comprises a passenger cabin and a battery. The passenger cabin and the battery are configured to be displaceable and mountable along a pitch axis of the aircraft. The aircraft comprises a full electric drive.

DE 10 2011 105 880 Al relates to a drive device for an aircraft. The device draft comprises at least one battery for storing electrical energy, an electric motor for driving a propeller, a conduit for transferring the electrical energy from the battery to the electric motor, and a first control means for controlling the electric motor.

OVERVIEW

Thus, there is a need to overcome drawbacks of prior art. In particular, it is an object of the subject matter according to the independent claims to overcome the disadvantages associated with the conventional airplane propulsion systems.

The various aspects of the present invention overcome drawbacks of the prior art. The following presents a simplified overview in order to provide a basic understanding of one or more aspects of the present disclosure. This overview is not an extensive overview of the invention, and is neither intended to identify key or critical elements of the invention, nor to delineate the scope thereof. Rather, the primary purpose of the overview is to present some embodiments of the invention.

In a first aspect, a drivetrain is provided for use in an airplane propulsion system that comprises a plurality of engines and a propulsion rotary device. The drivetrain comprises a driveshaft that is configured to transmissively couple the propulsion rotary device to a respective engine shaft of the plurality of engines. At least one effect can be that, in operation of the plurality of engines, the respective engine shaft contributes to torque applied on the driveshaft and, thus, each of the plurality of engines can contribute to torque that causes the propulsion rotary device to rotate. Thus, an airplane using the drivetrain can be safer in the event of engine failure. Some embodiments of the drivetrain comprise an engineside gearing that engages the driveshaft. The engine-side gearing is configured to engage a plurality of respective engine gears on the respective engine shaft of the plurality of engines. In some embodiments, the drivetrain is configured to engage a belt of a belt drive provided on the respective engine shaft of the plurality of engines.

Some embodiments comprise a gearing on a propulsion rotary device-side of the drivetrain. The gearing is configured to transmissively couple the drivetrain to the propulsion rotary device. At least one effect can be to avoid duplication of gearing provided on the engine-side of the drivetrain.

In a second aspect, a drivetrain apparatus for use in an airplane propulsion system comprises a first drivetrain configured to transmissively couple a first engine to a first propulsion rotary device, wherein the first drivetrain comprises a first driveshaft. Further, the apparatus comprises a second drivetrain configured to transmissively couple a second engine to a second propulsion rotary device, wherein the second drivetrain comprises a second driveshaft. The first driveshaft and the second driveshaft are aligned coaxially.

In some embodiments, the first drivetrain is configured to transmissively couple a first plurality of engines to the first propulsion rotary device. In some embodiments, the second drivetrain is configured to transmissively couple a second plurality of engines to the second propulsion rotary device.

In some embodiments, the first driveshaft and the second driveshaft are permanently decoupled from one another. Thus, the drivetrain apparatus is configured to enable the first driveshaft and the second driveshaft to be driven at least mechanically independently from one another. At least one effect can be that the first engine and the second engine can be controlled and operated independently from one another. For example, that a rotational speed of the first driveshaft can be changed while a rotational speed of the second driveshaft is kept constant, and vice versa. Thus, an airplane using the apparatus can be safer in the event of engine failure.

In some embodiments, the first driveshaft is hollow and has an inner diameter that is larger than an outer diameter of the second driveshaft. The second driveshaft coaxially penetrates the first driveshaft.

In some embodiments, the first drivetrain is a provided as a drivetrain according to the disclosure in the first aspect. Further, the second drivetrain is provided as a drivetrain according to the disclosure in the first aspect.

Some embodiments of the drivetrain apparatus further comprise a first engine-side gearing that engages the first driveshaft. The first engine-side gearing is configured to engage a respective engine gear on the respective engine shaft of the first plurality of engines.

Some embodiments of the drivetrain apparatus further comprise a second engine-side gearing that engages the second driveshaft. The second engine-side gearing is configured to engage a respective engine gear on the respective engine shaft of the second plurality of engines.

Some embodiments of the drivetrain apparatus further comprise a first propulsion rotary device-side gearing configured to transmissively couple the first driveshaft to the first propulsion rotary device.

Some embodiments of the drivetrain apparatus further comprise a second propulsion rotary device-side gearing configured to transmissively couple the second driveshaft to the second propulsion rotary device.

Some embodiments of the drivetrain apparatus further comprise a first propulsion rotary device which is transmissively coupled to the first driveshaft. At least one effect can be that a rotary motion of first driveshaft causes a rotary motion of the first propulsion rotary device.

Some embodiments of the drivetrain apparatus further comprise a second propulsion rotary device which is transmissively coupled to the second driveshaft. At least one effect can be that a rotary motion of second driveshaft causes a rotary motion of the second propulsion rotary device.

In some embodiments, the drivetrain apparatus is configured to rotate the first propulsion rotary device and the second propulsion rotary device in opposite rotational directions to one another. In some embodiments, the drivetrain apparatus further comprises a firewall arranged between at least a first engine of the first plurality of engines and a second engine of the second plurality of engines so as to separate a first compartment that comprises the first engine from a second compartment that comprises the second engine. At least one effect can be that spread of a fire in one of the first compartment and the second compartment to the other of the first compartment and the second compartment can be slowed down or even inhibited.

In some embodiments, the drivetrain apparatus further comprises a reservoir configured to store an extinguisher substance. In some embodiments the reservoir is communicatively coupled to at least one of the first compartment and of the second compartment. In some embodiments, the drivetrain apparatus further comprises a release device configured to selectively control release of the extinguisher substance from the reservoir into one or more of the at least one of the first compartment and of the second compartment.

In particular, in some embodiments, the control is based on a signal indicative of a fire to occur in the at least one of the first compartment and of the second compartment. At least one effect can be that the release device can control release of extinguisher substance to a compartment where the signal indicates the fire to occur. In some embodiments, the extinguishing substance comprises nitrogen. In some embodiments, the extinguishing substance comprises a noble gas.

In a third aspect, an airplane propulsion system comprises a propulsion rotary device and a drivetrain according to the disclosure in the first aspect. In some embodiments, the propulsion rotary device is provided as a propeller. In some embodiments, the propulsion rotary device is provided as a tractor propeller. In some embodiments, the propulsion rotary device is provided as a push propeller. In some embodiments, the propulsion rotary device is provided as a turbine. Further, the airplane propulsion system comprises a plurality of engines transmissively coupled to the gearing of the drivetrain. In a fourth aspect, an airplane propulsion system comprises at least one pair of propulsion rotary devices. For each of the at least one pair of propulsion rotary devices, the airplane propulsion system further comprises an associated drivetrain apparatus according to the disclosure in the second aspect. Still further, the airplane propulsion system comprises a plurality of engines transmissively coupled to the gearing of respective drivetrain of the associated apparatus.

In some embodiments according to the disclosure in the third aspect and/or according to the disclosure according to the fourth aspect, the pair of propulsion rotary devices are configured as tractor propellers. The tractor propellers are adapted to provide traction by spinning in opposite rotational directions. In some embodiments, the plurality of engines comprises electrical engines. In some embodiments, the plurality of engines comprises a combustion engine. In some embodiments, each of the plurality of engines is provided as an electrical engine.

In some embodiments, the airplane propulsion system further comprises a rechargeable electrical energy storage device such as a rechargeable battery.

In some embodiments, the airplane propulsion system further comprises a fuel cell. The fuel cell is configured to generate power using fuel. In some embodiments, the fuel cell is provided as an arrangement of a plurality of elementary cells that are, for example, stacked or otherwise arranged together. In some embodiments, the airplane propulsion system comprises a plurality of fuel cells that are controllable to functionally replace one another, whereby the plurality of fuel cells are redundant. At least one effect can be that safety of the airplane propulsion system is increased. In particular, in the event of a failure of a first fuel cell of the plurality of fuel cells, a second fuel cell of the plurality of fuel cells can compensate some or all of the functionality of the first fuel cell. In some embodiments the airplane propulsion system is configured for the fuel cell to supply power to the plurality of engines. In one embodiment, the airplane propulsion system is configured to use a fuel that comprises at least one of a group of fuels consisting of methanol, ethanol, ammonia. In one embodiment, the airplane propulsion system is configured to use a fuel that comprises liquid hydrogen. In one embodiment, the airplane propulsion system is configured to use a fuel that comprises gaseous hydrogen.

In some embodiments, the airplane propulsion system comprises a power distribution unit which is coupled to the fuel cell. The fuel cell is configured to supply electrical power to the power distribution unit. The power distribution unit is configured to supply electrical power to the plurality of electrical engines. In some embodiments, the airplane propulsion system comprises a rechargeable electrical energy storage cell which is coupled to the fuel cell. The fuel cell is configured to charge the rechargeable electrical energy storage cell. In some embodiments the airplane propulsion system is configured for the fuel cell to charge a rechargeable battery. In some embodiments, the rechargeable electrical energy storage cell is coupled to the power distribution unit. The rechargeable electrical energy storage cell is configured to supply electrical power to the power distribution unit.

In some embodiments, the power distribution unit comprises a memory unit configured to store instructions and a processing unit coupled to the memory unit and configured, when executing instructions stored in the memory unit, to control supply of power from the power distribution unit to the plurality of electrical engines. In some embodiments, the processing unit is configured to control supply of power from the rechargeable electrical energy storage cell and/or the fuel cell to the power distribution unit.

In some embodiments, the airplane propulsion system further comprises a tank configured to store fuel. The fuel can be liquid fuel. In some embodiments, the fuel is gaseous. The tank can be provided in fluid communication to the fuel cell. In some embodiments, the tank is directly connected to the fuel cell. At least one effect can be that the fuel can be supplied from the tank to the fuel cell.

In some embodiments, the airplane propulsion system further comprises a combustion engine configured to drive a generator. In some embodiments, the generator is coupled to the electrical energy storage device and configured to charge the electrical energy storage device.

In some embodiments at least one of the plurality of electrical power supply cells is configured to be movable so as to move a center of mass of the airplane propulsion system. In some embodiments, the plurality of electrical supply cells are provided on a sledge. In some embodiments, the plurality of electrical supply cells are configured to be moved by actuating a worm gear. For example, the worm gear can be coupled to the sledge so as to move the sledge. In some embodiments, a belt drive is provided and configured to move the plurality of electrical supply cells. In some embodiments, the afore-described components are provided in a plurality and configured so as to selectively move the plurality of the electrical supply cells. In some embodiments the plurality of electrical supply cells is configured such that one or more cells can be moved in a direction parallel to an axis of rotation of at least one of the propulsion rotary devices.

In a fifth aspect, a set of components is provided that are configured to fit, i.e., to equip an airplane with the apparatus according to the second aspect of the disclosure. The set of components comprises a first driveshaft for use in a first drivetrain configured to couple a first engine to the first propulsion rotary device. Further, set of components comprises a second driveshaft for use in a second drivetrain configured to couple a second engine to the second propulsion rotary device. The first driveshaft is hollow and has an inner diameter that is larger than an outer diameter of the second driveshaft.

Some embodiments comprise a control unit which is configured to control driving of the first driveshaft and/or driving of the second driveshaft. At least one effect can be that an individual variation of rotational speed of the first driveshaft and of the second driveshaft, respectively, is possible under control of the control unit.

In some embodiments, the set of components of further comprises a first engine-side gearing configured to engage the first driveshaft. Further, the set of components of comprises a second engine-side gearing configured to engage the second driveshaft.

In some embodiments, the first engine-side gearing is configured to engage a first plurality of respective engine gears on the respective engine shaft of a first associated plurality of engines. The second engine-side gearing is configured to engage a second plurality of respective engine gears on the respective engine shaft of a second associated plurality of engines.

In some embodiments, the set of components further comprises a control device configured to control a supply of power from a source of electrical energy to a plurality of engines, when the set of components is fitted into an airplane. In some embodiments, the set of components further comprises a plurality of electrical engines, wherein a number N_ee of electrical engines in the set of components is determined by:

N_ee = 2 * N_ds * N_es; (equation 1) wherein N_ds is the number of pairs of driveshafts, and wherein N_es is the number of engines provided for coupling to one driveshaft.

In some embodiments, the set of components further comprises a plurality of electrical power supply cells configured to supply power to the plurality of electrical engines. The plurality of electrical power supply cells comprises at least one of a group of electrical power supply cells consisting of a rechargeable electrical energy storage cell and a fuel cell. In some embodiments, the rechargeable electrical energy storage cell is provided as an arrangement of a plurality of elementary battery cells that are, for example, stacked or otherwise arranged together. In some embodiments, the set of components comprises a plurality of rechargeable batteries that are controllable to functionally replace one another, whereby the plurality of rechargeable batteries are redundant. At least one effect can be that safety of the airplane propulsion system is increased. In particular, in the event of a failure of a first rechargeable battery of the plurality of rechargeable batteries, a second rechargeable battery of the plurality of rechargeable batteries can compensate some or all of the functionality of the first rechargeable battery.

In some embodiments, the set of components further comprises a generator configured to be coupled to the rechargeable electrical energy storage cell so as to charge the rechargeable electrical energy storage cell.

In some embodiments, the set of components according to the fifth aspect is adapted to retrofit the airplane. In some embodiments, the set of components is provided as a retrofit kit that can be used to transform a conventional airplane into an airplane as disclosed herein.

In a sixth aspect, an airplane comprises at least one drivetrain according to the first aspect. In a seventh aspect, an airplane comprises at least one drivetrain apparatus according to the second aspect. In an eighth aspect, an airplane comprises an airplane propulsion system according to the third aspect. In some embodiments, the airplane is fitted with the set of components according to the disclosure in the fourth aspect.

In a ninth aspect, a method of providing an airplane according to the sixth aspect comprises retrofitting a combustion engine propelled airplane with a set of components according to the invention. In some embodiments, the method further comprises stripping the airplane of combustion engines. In some embodiments, the method comprises fitting an airplane propulsion system according to the fourth aspect into the airplane.

This overview is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. This overview is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. Those skilled in the art will recognise additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. It is to be noted that elements of these embodiments may be combined with each other unless specifically noted to the contrary.

The independent claims define the invention in various aspects. The dependent claims state embodiments according to the invention in the various aspects. Underlying all embodiments is the motivation to increase system safety and an insight into the benefit of being selective in providing redundancy of components in an airplane that, on one hand, are needed to securely land the airplane, while, on the other, hand such components frequently fail.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing that shows a schematic view of an airplane propulsion system according to some embodiments.

FIG.2 is a drawing that shows a transparent three dimensional view of an airplane according to some embodiments. FIG. 3 is a drawing that shows a schematic view of an airplane propulsion system according to some embodiments.

FIG. 4 is a drawing that shows a schematic view of an airplane propulsion system according to some embodiments.

FIG. 5 is a drawing that shows a schematic view of an airplane propulsion system according to some embodiments.

It should be understood that drawings are not drawn to scale.

DETAILED DESCRIPTION OF THE INVENTION

Below, embodiments, implementations and associated effects are disclosed with reference to the drawings that illustrate views of some embodiments. It should be noted that views of exemplary embodiments are merely to illustrate selected features of the some embodiments. In particular, cross-sectional views are not drawn to scale and dimensional relationships of the illustrated structures can differ from those of the illustrations. As used herein, like terms refer to like elements throughout the description.

It is to be understood that the features of various embodiments described herein may be combined with each other, unless specifically noted otherwise. In some instances, well-known features are omitted or simplified to clarify the description of the exemplary implementations. The order in which the embodiments/implementations and methods/ processes are described is not intended to be construed as a limitation, and any number of the described implementations and processes may be combined.

An exemplary airplane propulsion system according to some embodiments will now be described with reference to FIG. 1 and FIG. 2.

The exemplary airplane propulsion system comprises a first set of three electrical engines 123, 126, 129, and a first set of three batteries 143, 146, 149. Further, the exemplary airplane propulsion system comprises a first set of three power supply lines 133, 136, 139. The power supply lines 133, 136, 139 connect each of the first batteries 143, 146, 149 to an associated one of the electrical engines 123, 126, 129, respectively. Thus, the first set of batteries 143, 146, 149, via the first set of power supply lines 133, 136, 139, can supply power to the three electrical engines 123, 126, 129 of the first set of electrical engines.

The exemplary airplane propulsion system further comprises a second set of three electrical engines 173, 176, 179, and a second set of three batteries 193, 196, 199. Further, the exemplary airplane propulsion system comprises a second set of power supply lines 183, 186, 189. The power supply lines 183, 186, 189 connect each of the second set of three batteries 183, 186, 189 to an associated one of the first set of three electrical engines 183, 186, 189, respectively. Thus, the second set batteries 193, 196, 199, via the second set of three power supply lines 183, 186, 189, can supply power to the three electrical engines 173, 176, 179 of the second set of electrical engines.

The exemplary airplane propulsion system comprises a first drivetrain 115, and a first propeller 110 that is transmissively coupled to the first drivetrain 115. The first drivetrain 115 comprises a first driveshaft 120 and a first set of engineside gears. The first set of engine-side gears is configured such that each electrical engine of the first set of three electrical engines 123, 126, 129 can apply torque to the first driveshaft 120. In one exemplary embodiment, each of the three electrical engines 123, 126, 129 of the first set of electrical engines has a drive gear mounted on an engine shaft. The first set of engine-side gears comprises a first driven gear that engages the drive gears on the respective engine shafts.

The first propeller 110 is mounted on the first driveshaft 120. Thus, the first propeller 110 is configured to turn with the first driveshaft 120. In some embodiments (not shown), the first drivetrain comprises a propeller-side gearing that is configured to transmissively couple the first drivetrain to the first propeller.

The exemplary airplane propulsion system further comprises a second drivetrain 165, and a second propeller 160 that is transmissively coupled to the second drivetrain 165. The second drivetrain 165 comprises a second driveshaft 170 and a second set of engine-side gears. The second set of engine-side gears is configured such that each electrical engine of the second set of electrical engines 173, 176, 179 can apply torque to the second driveshaft 170. In one exemplary embodiment, each of the three electrical engines 173, 176, 179 of the second set of electrical engines has a drive gear mounted on an engine shaft. The second set of engine-side gears comprises a second driven gear that engages the drive gears on the respective engine shafts.

The second propeller 160 is mounted on the second driveshaft 170. Thus, the second propeller 160 is configured to turn with the second driveshaft 170. In some embodiments (not shown), the second drivetrain comprises a propulsion rotary device-side gearing that is configured to transmissively couple the second drivetrain to the second propeller.

The first driveshaft 120 is hollow. An inner diameter of the first driveshaft is larger than an outer diameter of the second driveshaft 170. The second driveshaft 170 is provided rotatable inside the first driveshaft 120. At least one effect can be that the first driveshaft 120 and the second driveshaft 170 are coaxially rotatable.

Now, with reference in particular to FIG. 2, the exemplary airplane propulsion system is retrofitted into an airplane 200 such as an Antonov AN-2 which was previously propelled by a single combustion engine. For example, the first set of three batteries 143, 146, 149 and the second set of three batteries (not shown) can be accommodated in a wing 150 of the airplane 200. At least one effect can be an improved safety of the airplane due to an increased number of engines. Thus, the airplane can be admitted to travel where previously the airplane was not admitted to travel. In particular, the airplane can be admitted to travel across water.

An exemplary airplane propulsion system according to some embodiments will now be described with reference to FIG. 3 and FIG. 2.

The exemplary airplane propulsion system comprises a first set of three electrical engines 323, 326, 329, and a first set of three batteries 343, 346, 349. In some embodiments, the first set of three electrical engines 323, 326, 329 are provided in a first engine compartment 301. Further, the exemplary airplane propulsion system comprises a first set of three power supply lines 333, 336, 339. The power supply lines 333, 336, 339 connect each of the first batteries 343, 346, 349 to an associated one of the electrical engines 323, 326, 329, respectively. Thus, the first set of batteries 343, 346, 349, via the first set of power supply lines 333, 336, 339, can supply power to the three electrical engines 323, 326, 329 of the first set of electrical engines.

The exemplary airplane propulsion system further comprises a second set of three electrical engines 373, 376, 379, and a second set of three batteries 393, 396, 399. The electrical engines of the second set of three electrical engines are coaxially aligned. In some embodiments, the second set of three electrical engines are provided in a second engine compartment 302.

In some embodiments, as in the example illustrated in FIG. 3, the first engine compartment 301 and the second engine compartment 302 are separated from one another by a firewall 305.

Further, the exemplary airplane propulsion system comprises a second set of power supply lines 383, 386, 389. The power supply lines 383, 386, 389 connect each of the second set of three batteries 383, 386, 389 to an associated one of the first set of three electrical engines 383, 386, 389, respectively. Thus, the second set batteries 393, 396, 399, via the second set of three power supply lines 383, 386, 389, can supply power to the three electrical engines 373, 376, 379 of the second set of electrical engines.

The exemplary airplane propulsion system comprises a first drivetrain 315, and a first propeller 310 that is transmissively coupled to the first drivetrain 315. The first set of engine-side gears is configured such that each electrical engine of the first set of three electrical engines 323, 326, 329 can apply torque to the first driveshaft 320. In some embodiments, the electrical engines of the first set of three electrical engines 323, 326, 329 are coaxially aligned on the driveshaft 320.

The first propeller 310 is mounted on the first driveshaft 320. Thus, the first propeller 310 is configured to turn with the first driveshaft 320. In some embodiments (not shown), the first drivetrain comprises a propeller-side gearing that is configured to transmissively couple the first drivetrain to the first propeller. The exemplary airplane propulsion system further comprises a second drivetrain 365, and a second propeller 360 that is transmissively coupled to the second drivetrain 365. The second drivetrain 365 comprises a second driveshaft 370. The second set of engine-side gears is configured such that each electrical engine of the second set of electrical engines 373, 376, 379 can apply torque to the second driveshaft 370. In some embodiments, the electrical engines of the second set of three electrical engines 373, 376, 379 are coaxially aligned on the driveshaft 370.

The second propeller 360 is mounted on the second driveshaft 370. Thus, the second propeller 360 is configured to turn with the second driveshaft 370. In some embodiments (not shown), the second drivetrain comprises a propulsion rotary device-side gearing that is configured to transmissively couple the second drivetrain to the second propeller.

The first driveshaft 320 is hollow. An inner diameter of the first driveshaft is larger than an outer diameter of the second driveshaft 370. The second driveshaft 370 is provided rotatable inside the first driveshaft 320. At least one effect can be that the first driveshaft 320 and the second driveshaft 370 are coaxially rotatable.

Now, with reference in particular to FIG. 2, the exemplary airplane propulsion system is retrofitted into an airplane 200 such as an Antonov AN-2 which was previously propelled by a single combustion engine. For example, the first set of three batteries 343, 346, 349 and the second set of three batteries (not shown) can be accommodated in a wing 350 of the airplane 200. At least one effect can be an improved safety of the airplane due to an increased number of engines. Thus, the airplane can be admitted to travel where previously the airplane was not admitted to travel. In particular, the airplane can be admitted to travel across water. While in the examples shown in FIG. 1 and in FIG. 2 as well as in FIG. 3 and in FIG. 2 discussed above, the airplane propulsion system comprises two times three electrical engines, it should be understood that the number is for the purpose of illustration only and could differ. In one example (not shown), the airplane propulsion system comprises merely two single electrical engines, one to drive the first drivetrain and another one to drive the second drivetrain. In another example (not shown), the airplane propulsion system comprises two times five electrical engines electrical engines, but any other even number of electrical engines can also be contemplated.

In some embodiments (not shown), the number of electrical engines in the first set of electrical engines that is supplied with power from one battery in the set of batteries is larger than one. Thus, one battery can supply power to more than one electrical engine, whereby the efficiency of the airplane propulsion system is increased.

In some embodiments (not shown), the number of batteries of the first set of batteries is larger than the number of electrical engines of the first set of electrical engines. Thus, one electrical engine can be supplied with power from more than a one battery, whereby the safety of the airplane propulsion system against failure of one battery is increased.

In some embodiments, the airplane propulsion system comprises a control system configured to control components of the airplane propulsion system. The control system is configured to control a supply of power from the batteries to the electrical engines. In one embodiment, the airplane propulsion system is configured to detect a temperature at the batteries. The control system can be configured to process detected temperature values. Further, the control system can be configured, based on the detected temperature values, to selectively disconnect batteries. Thus, a risk of the disconnected battery to overheat is reduced. Accordingly, a risk of the disconnected battery to catch fire is reduced.

In some embodiments, a plurality of receptacles is provided for a corresponding plurality of batteries. In some embodiments the receptacle is configured as a battery compartment that is sized to accommodate the battery. In some embodiments, the plurality of receptacles are provided with release means. For example, the receptacles can be provided with a trap door that is configured to open and to release the battery from the receptacle. For example, the receptacle is provided with an explosion device that can be activated to release the battery received in the receptacle in the event of an emergency such as a fire of the battery. In some embodiments, the receptacle comprises a parachute. The parachute is configured to be connected to the battery received in the receptacle. The receptacle is configured to release the parachute, whereby the battery is released from the receptacle.

A sensor can be arranged in the receptacle, for example a temperature sensor and or a pressure sensor, that provides a signal indicative of conditions in the receptacle. Provided processing of the signal by an adequately configured processing unit, a malfunction state or other dangerous condition related to the battery in the receptacle can be determined. The processing unit can be configured to initiate opening of the trap door and/or release of the battery from the receptacle upon determination of the malfunction state.

An exemplary airplane propulsion system according to some embodiments will now be described with reference to FIG. 4.

The exemplary airplane propulsion system comprises a first set of electrical engines 423, 426, 429. Though the first set of electrical engines is shown to comprise three engines, the number is only selected for illustrative purposes and the number of engines could be two or more than three. In some embodiments, the first set of three electrical engines 423, 426, 429 are provided in a first engine compartment 401. In some embodiments, the electrical engines of the first set of three electrical engines 423, 426, 429 are coaxially aligned.

The exemplary airplane propulsion system further comprises a second set of electrical engines 473, 476, 479. Though the second set of electrical engines is shown to comprise three engines, the number is only selected for illustrative purposes and the number of engines could be two or more than three. In some embodiments, the second set of electrical engines 473, 476, 479 are provided in a second engine compartment 402. In some embodiments, the electrical engines of the second set of three electrical engines 473, 476, 479 are coaxially aligned.

In some embodiments, as in the example illustrated in FIG. 4, the first compartment 401 and the second compartment 402 are separated from one another by a firewall 405. The exemplary airplane propulsion system comprises a first drivetrain, for example as described above with reference to FIG. 1, wherein the first drivetrain comprises a first drive shaft 420. Further, the exemplary airplane propulsion system comprises a first propeller 410 that is transmissively coupled to the first drivetrain. A first set of engine-side gears is configured such that each electrical engine of the first set of three electrical engines 423, 426, 429 can apply torque to the first driveshaft 420. In some embodiments, the electrical engines of the first set of three electrical engines 423, 426, 429 are coaxially aligned on the driveshaft 420.

In some embodiments, the first propeller 410 is mounted on the first drive shaft 420. Thus, the first propeller 410 is configured to turn with the first driveshaft 420. In some embodiments (not shown), the first drivetrain comprises a propeller-side gearing that is configured to transmissively couple the first drivetrain to the first propeller.

The exemplary airplane propulsion system further comprises a second drivetrain, for example as described above with reference to FIG. 1, wherein the second drivetrain comprises a second drive shaft 470. Further, the exemplary airplane propulsion system comprises a second propeller 460 that is transmissively coupled to the second drivetrain. The second drivetrain comprises a second driveshaft 470. The second set of engine-side gears is configured such that each electrical engine of the second set of electrical engines 473, 476, 479 can apply torque to the second driveshaft 470. In some embodiments, the electrical engines of the second set of three electrical engines 473, 476, 479 are coaxially aligned on the driveshaft 470.

In some embodiments, the second propeller 460 is mounted on the second driveshaft 470. Thus, the second propeller 460 is configured to turn with the second driveshaft 470. In some embodiments (not shown), the second drivetrain comprises a propulsion rotary device-side gearing that is configured to transmissively couple the second drivetrain to the second propeller.

The first driveshaft 420 is hollow. An inner diameter of the first driveshaft is larger than an outer diameter of the second driveshaft 470. The second driveshaft 470 is provided rotatable inside the first driveshaft 420. At least one effect can be that the first driveshaft 420 and the second driveshaft 470 are coaxially rotatable. In some embodiments, the exemplary airplane propulsion system is configured to drive the second propeller 460 in a rotational direction that is opposite to a rotational direction of a rotation of the first propeller 410.

The exemplary airplane propulsion system further comprises a first fuel cell 443 and a first power distribution circuit 446. The first power distribution circuit 446 is configured to distribute power generated by the first fuel cell 443 to each of the first set of electrical engines 423, 426, 429. Further, the exemplary airplane propulsion system comprises a first set of three power supply lines 433, 436, 439. The power supply lines 433, 436, 439 couple the first power distribution circuit 446 to the electrical engines 423, 426, 429, respectively. The fuel cell 443, via the first power distribution circuit 446 and the first set of power supply lines 433, 436, 439, is configured to supply power to the three electrical engines 423, 426, 429 of the first set of electrical engines 423, 426, 429.

The exemplary airplane propulsion system further comprises a second fuel cell 493 and a second power distribution circuit 496. The second power distribution circuit 496 is configured to distribute power generated by the second fuel cell 493 to each of the second set of electrical engines 473, 476, 479. Further, the exemplary airplane propulsion system comprises a second set of three power supply lines 483, 486, 489. The power supply lines 483, 486, 489 couple the second power distribution circuit 496 to the electrical engines 473, 476, 479, respectively. The fuel cell 493, via the second power distribution circuit 496 and the second set of power supply lines 483, 486, 489, is configured to supply power to the electrical engines 473, 476, 479 of the second set of electrical engines 473, 476, 479.

The exemplary airplane propulsion system is configured to couple to at least one fuel tank 499 so as to provide a fluid connection from the fuel tank 499 to the first fuel cell 443 and/or to the second fuel cell 493. For example, the fuel tank 499 comprises a plurality of chambers communicatively coupled to the fuel cell. In some embodiments, the chambers are provided in wings of an airplane. In some embodiments, the exemplary airplane propulsion system is configured to be retrofitted in a traditional airplane. Operation of the airplane according to some embodiments will now be described with reference to FIG. 4. The tank 499 can be loaded with fuel such as methanol. The fuel is supplied from the tank 499 to the first fuel cell 443 and to the second fuel cell 446. The first fuel cell 443 and the second fuel cell 446 generate electrical power and supply the electrical power to the first power distribution unit 446 and to the second power distribution unit 496, respectively. The first power distribution unit 446 controls supply of the electrical power via the first set of power supply lines 433, 436, 439 to the electrical engines 473, 476, 479 of the first set of electrical engines, respectively. The second power distribution unit 496 controls supply of the electrical power via the second set of power supply lines 483, 486, 489 to the electrical engines 473, 476, 479 of the second set of electrical engines, respectively. In some embodiments, each power distribution unit is configured to control supply of electrical power to each electrical engine irrespective of whether it belongs to the first set of electrical engines that drive the first driveshaft or whether it belongs to the second set of electrical engines that drive the second driveshaft. At least one effect can be a functional redundancy whereby safety is increased.

The electrical engines 423, 426, 429 of the first set of electrical engines drive the first driveshaft 420, whereby the first propeller 410 is rotated. The electrical engines 473, 476, 479 of the second set of electrical engines drive the second driveshaft 470, whereby the second propeller 420 is rotated. The control of the engines 423, 426, 429, 473, 476, 479 is performed individually for each engine, for example, by the first power distribution unit 446 and/or by second the power distribution unit 496. Thus, an independent rotational speed and/or torque can be applied to the respective driveshaft 420, 470. At least one effect can be to enable control so as to optimize overall performance, for example of the engines, in accordance with predetermined performance criteria such as fuel efficiency.

An exemplary airplane propulsion system according to some embodiments will now be described with reference to FIG. 5.

The exemplary airplane propulsion system comprises a first set of electrical engines 523, 526, 529. Though the first set of electrical engines is shown to comprise three engines, the number is only selected for illustrative purposes and the number of engines could be two or more than three. In some embodiments, the first set of three electrical engines 523, 526, 529 are provided in a first engine compartment 501. In some embodiments, the electrical engines of the first set of three electrical engines 523, 526, 529 are coaxially aligned.

The exemplary airplane propulsion system further comprises a second set of electrical engines 573, 576, 579. Though the second set of electrical engines is shown to comprise three engines, the number is only selected for illustrative purposes and the number of engines could be two or more than three. In some embodiments, the second set of electrical engines 573, 576, 579 are provided in a second engine compartment 502. In some embodiments, the electrical engines of the second set of three electrical engines 573, 576, 579 are coaxially aligned.

In some embodiments, as in the example illustrated in FIG. 5, the first compartment 501 and the second compartment 502 are separated from one another by a firewall 505.

The exemplary airplane propulsion system comprises a first drivetrain, for example as described above with reference to FIG. 1, wherein the first drivetrain comprises a first drive shaft 520. Further, the exemplary airplane propulsion system comprises a first propeller 510 that is transmissively coupled to the first drivetrain. A first set of engine-side gears is configured such that each electrical engine of the first set of three electrical engines 523, 526, 529 can apply torque to the first driveshaft 520. In some embodiments, the electrical engines of the first set of three electrical engines 523, 526, 529 are coaxially aligned on the driveshaft 520.

In some embodiments, the first propeller 510 is mounted on the first drive shaft 520. Thus, the first propeller 510 is configured to turn with the first driveshaft 520. In some embodiments (not shown), the first drivetrain comprises a propeller-side gearing that is configured to transmissively couple the first drivetrain to the first propeller.

The exemplary airplane propulsion system further comprises a second drivetrain, for example as described above with reference to FIG. 1, wherein the second drivetrain comprises a second drive shaft 570. Further, the exemplary airplane propulsion system comprises a second propeller 560 that is transmissively coupled to the second drivetrain. The second drivetrain comprises a second driveshaft 570. The second set of engine-side gears is configured such that each electrical engine of the second set of electrical engines 573, 576, 579 can apply torque to the second driveshaft 570. In some embodiments, the electrical engines of the second set of three electrical engines 573, 576, 579 are coaxially aligned on the driveshaft 570.

In some embodiments, the second propeller 560 is mounted on the second driveshaft 570. Thus, the second propeller 560 is configured to turn with the second driveshaft 570. In some embodiments (not shown), the second drivetrain comprises a propulsion rotary device-side gearing that is configured to transmissively couple the second drivetrain to the second propeller.

The first driveshaft 520 is hollow. An inner diameter of the first driveshaft is larger than an outer diameter of the second driveshaft 570. The second driveshaft 570 is provided rotatable inside the first driveshaft 520. At least one effect can be that the first driveshaft 520 and the second driveshaft 570 are coaxially rotatable. In some embodiments, the exemplary airplane propulsion system is configured to drive the second propeller 560 in a rotational direction that is opposite to a rotational direction of a rotation of the first propeller 510.

The exemplary airplane propulsion system further comprises a first fuel cell 543 and a first power distribution circuit 546. The first power distribution circuit 546 is configured to distribute power generated by the first fuel cell 543 to each of the first set of electrical engines 523, 526, 529. Further, the exemplary airplane propulsion system comprises a first set of three power supply lines 533, 536, 539. The power supply lines 533, 536, 539 couple the first power distribution circuit 546 to the electrical engines 523, 526, 529, respectively. The fuel cell 543, via the first power distribution circuit 546 and the first set of power supply lines 533, 536, 539, is configured to supply power to the three electrical engines 523, 526, 529 of the first set of electrical engines 523, 526, 529.

The exemplary airplane propulsion system further comprises a second fuel cell 593 and a second power distribution circuit 596. The second power distribution circuit 596 is configured to distribute power generated by the second fuel cell 593 to each of the second set of electrical engines 573, 576, 579. Further, the exemplary airplane propulsion system comprises a second set of three power supply lines 583, 586, 589. The power supply lines 583, 586, 589 couple the second power distribution circuit 596 to the electrical engines 573, 576, 579, respectively. The fuel cell 593, via the second power distribution circuit 596 and the second set of power supply lines 583, 586, 589, is configured to supply power to the electrical engines 573, 576, 579 of the second set of electrical engines 573, 576, 579.

The exemplary airplane propulsion system further comprises a rechargeable booster battery 549. It should be understood that, although the example is described with one rechargeable booster battery 549, the airplane propulsion system can comprise more than one rechargeable booster battery. The rechargeable booster battery can be comprised of a plurality of rechargeable battery cells that are, for example, stacked or otherwise arranged together. The rechargeable battery cells of the rechargeable booster battery 549 can be provided in various locations of the airplane. The rechargeable booster battery 549 is configured to couple with the first fuel cell 543 and/or with the second fuel cell 593. The rechargeable booster battery 549 is further configured to couple with the first power distribution circuit 546 and/or with the second power distribution circuit 596. In some embodiments, the rechargeable booster battery 549 is configured to store power generated by the first fuel cell 543 and/or the second fuel cell 593.

In some embodiments, the rechargeable booster battery 549 is configured to be charged by power generated by the first fuel cell 543 and/or the second fuel cell 593. In some embodiments, the rechargeable booster battery 549 is configured to distribute the stored power from the rechargeable booster battery 549 to the first power distribution circuit 546 and/or to the second power distribution circuit 596. In some embodiments, the rechargeable booster battery 549, via the first power distribution circuit 556 and the first set of power supply lines 533, 536, 539, is configured to supply power to the electrical engines 523, 526, 529 of the first set of electrical engines 523, 526, 529. In some embodiments, the rechargeable booster battery 549, via the second power distribution circuit 596 and the second set of power supply lines 583, 586, 589, is configured to supply power to the electrical engines 573, 576, 579 of the second set of electrical engines 573, 576, 579.

The exemplary airplane propulsion system is configured to couple to at least one fuel tank 599 so as to provide a fluid connection from the fuel tank 599 to the first fuel cell 543 and/or to the second fuel cell 593. For example, the fuel tank 599 comprises a plurality of chambers communicatively coupled to the fuel cell. In some embodiments, the chambers are provided in wings of an airplane.

Operation of the airplane according to some embodiments will now be described with reference to FIG. 5. The tank 599 can be loaded with fuel such as methanol. The fuel is supplied from the tank 599 to the first fuel cell 543 and to the second fuel cell 546. The first fuel cell 543 and the second fuel cell 546 generate electrical power and supply the electrical power to the first power distribution unit 546 and to the second power distribution unit 596, respectively. Further, the first fuel cell 543 and the second fuel cell 546 supply the electrical power to the rechargeable booster battery 549 thereby charging the rechargeable booster battery 549. Still further, the rechargeable booster battery 549 can supply power to the first power distribution unit 546 and/or to the second power distribution unit 596.

The first power distribution unit 546 controls supply of the electrical power via the first set of power supply lines 533, 536, 539 to the electrical engines 523, 526, 529 of the first set of electrical engines, respectively. The second power distribution unit 596 controls supply of the electrical power via the second set of power supply lines 583, 586, 589 to the electrical engines 573, 576, 579 of the second set of electrical engines, respectively. In some embodiments, each power distribution unit is configured to control supply of electrical power to each electrical engine 523, 526, 529, 573, 576, 579 irrespective of whether it belongs to the first set of electrical engines that drive the first driveshaft 520 or whether it belongs to the second set of electrical engines that drive the second driveshaft 570. At least one effect can be a functional redundancy whereby safety is increased.

The electrical engines 523, 526, 529 of the first set of electrical engines drive the first driveshaft 520, whereby the first propeller 510 is rotated. The electrical engines 573, 576, 579 of the second set of electrical engines drive the second driveshaft 570, whereby the second propeller 520 is rotated. The control of the engines 523, 526, 529, 573, 576, 579 is performed individually for each engine, for example, by the first power distribution unit 546 and/or by second the power distribution unit 596. Thus, an independent rotational speed and/or torque can be applied to the respective driveshaft 520, 570. At least one effect can be to enable control so as to optimize overall performance, for example of the engines, in accordance with predetermined performance criteria such as fuel efficiency. In a situation, where a high level of power is needed, for example, to accelerate the airplane during takeoff and/or initial climb, the first distribution unit 546 and/or the first distribution unit 596 draw power from the rechargeable booster battery 549. In contrast, in a situation, where a low level of power is needed, for example, while taxiing or, in some embodiments, during steady flight at cruising altitude and/or at cruising speed, the first fuel cell 543 and/or the second fuel cell 593 can be controlled so as to charge the rechargeable booster battery 549. At least one effect can be that the airplane can be optimized in accordance with predetermined criteria such as fuel efficiency, speed, range, payload. Optimizing the airplane comprises sizing and/or configuring the fuel cells and the rechargeable booster battery 549 with a view to achieving the .

In some embodiments, the exemplary airplane propulsion system is configured to be retrofitted in a conventional airplane, for example, an Antonov AN-2 as illustrated in FIG. 2. A method of providing an airplane according to the disclosure comprises providing a conventional airplane, in particular an airplane having a combustion engine, removing the combustion engine from the airplane, and fitting a set of components according to the disclosure described above in the airplane. In some embodiments tanks of the conventional airplane are left in place and are configured to hold fuel such as methanol for supply to a fuel cell installed in the body of the airplane. In some embodiments, the method comprises providing rechargeable energy storage cells such as rechargeable batteries in the body of the airplane. Some embodiments comprise creating room to receive a rechargeable battery in the wing of the airplane. To this end, some embodiments comprise removing a portion of the tank from the wing of the conventional airplane. Some embodiments comprise replacing the tank of the conventional airplane by a smaller tank. An effect of installing the airplane propulsion system in the airplane can be that the airplane can be more efficient by realizing fuel savings whereby an overall carbon emission footprint can be reduced. As the first driveshaft and the second driveshaft are decoupled from one another, a single engine machine can be transformed in effect to an airplane provided with multiple independent engines. At least one effect can be an increased safety of the retrofitted airplane vis-a-vis the conventional airplane. As a result, the airplane can be used in a larger variety of operational scenarios.

As used herein "transmissively couple A to B" means to couple A and B to one another so as to enable a transmission of torque, as the case may be, from A to B or from B to A.

As used herein "the first driveshaft and the second driveshaft are permanently decoupled from one another" means that the first driveshaft and the second driveshaft cannot be brought into any mechanical connection, whereby the second driveshaft is mechanically forced to rotate in a direction and to rotate at a speed which are predetermined by the direction of rotation and rotational speed of the first driveshaft, when the first driveshaft rotates; in contrast, for example, to a coupling provided by a first gear on the first driveshaft and a second gear on the second driveshaft with the second gear intermeshing with the first gear.

Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein.

The implementations herein are described in terms of exemplary embodiments. However, it should be appreciated that individual aspects of the implementations may be separately claimed and one or more of the features of the various embodiments may be combined.