CN210027898U

CN210027898U - Power system and unmanned aerial vehicle

Info

Publication number: CN210027898U
Application number: CN201920566131.4U
Authority: CN
Inventors: 刘全; 巴航; 刘城斌
Original assignee: Beijing Jingdong Qianshi Technology Co Ltd
Current assignee: Beijing Jingdong Qianshi Technology Co Ltd
Priority date: 2019-04-24
Filing date: 2019-04-24
Publication date: 2020-02-07
Anticipated expiration: 2029-04-24

Abstract

The utility model belongs to the technical field of unmanned aerial vehicle, a driving system and unmanned aerial vehicle are specifically disclosed. The power system comprises a fuel engine, a rotor shaft, a generator and a storage battery, wherein the fuel engine is connected with the rotor shaft and drives the rotor shaft to rotate, the rotor shaft is connected with the generator and drives the generator to rotate, and the storage battery is electrically connected with the generator and used for storing electric energy. Unmanned aerial vehicle includes foretell driving system. The utility model provides a driving system and unmanned aerial vehicle can simplify driving system's structure, improves unmanned aerial vehicle's duration.

Description

Power system and unmanned aerial vehicle

Technical Field

The utility model relates to an unmanned air vehicle technique field especially relates to an unmanned aerial vehicle driving system and unmanned aerial vehicle.

Background

A drone is an unmanned aircraft that is operated by a radio remote control device and a self-contained program control device. Along with the development of unmanned aerial vehicle technology, unmanned aerial vehicle has been widely used in fields such as frontier patrol, aviation camera shooting, distribution and distribution delivery, building site survey and drawing.

The existing unmanned aerial vehicle is generally driven by a storage battery, a fuel engine or oil-electricity hybrid power, wherein the cruising ability of the oil-electricity hybrid power type unmanned aerial vehicle is relatively long, and the unmanned aerial vehicle can be applied to the unmanned aerial vehicle with long voyage time and long voyage distance. And the unmanned aerial vehicle engine that prior art provided produces the electric energy through setting up the generator, has improved unmanned aerial vehicle's duration. But unmanned aerial vehicle among the prior art is bulky, complete machine weight is heavier to connect and transmission structure complexity.

SUMMERY OF THE UTILITY MODEL

An object of the embodiment of the utility model is to provide a driving system to simplify unmanned aerial vehicle driving system's structure, improve unmanned aerial vehicle's duration.

The utility model discloses another aim at provides an unmanned aerial vehicle simplifies unmanned aerial vehicle's structure, improves unmanned aerial vehicle's duration.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the utility model provides a power system, includes fuel engine, rotor shaft, generator and battery, fuel engine with rotor shaft is connected and the drive rotor shaft rotates, rotor shaft with the generator is connected and is driven the generator rotates, the battery with the generator electricity is connected for the storage electric energy.

Preferably, the storage battery is electrically connected with the fuel engine for starting the fuel engine.

As a preferred scheme of a power system, the rotor shaft is vertically arranged, the output shaft of the fuel engine is horizontally arranged, and a reversing transmission assembly is connected between the rotor shaft and the output shaft.

Preferably, the rotor shaft is arranged coaxially with the input shaft of the generator.

Preferably, the generator is a three-phase ac generator, and a rectifier module and/or a voltage stabilizer module are disposed between the generator and the battery.

An unmanned aerial vehicle comprising a powered system as described above.

As an unmanned aerial vehicle's preferred scheme, unmanned aerial vehicle includes the rotor subassembly, the upper end of rotor shaft with the rotor subassembly is connected, the lower extreme of rotor shaft with the generator is connected.

As an unmanned aerial vehicle's preferred scheme, the rotor subassembly has the multiunit, every group the rotor subassembly is connected with one set respectively driving system.

As an unmanned aerial vehicle's preferred scheme, the rotor subassembly has the multiunit, every group the rotor subassembly corresponds and is provided with the rotor shaft, the rotor shaft all with fuel engine connects, and at least one be connected with on the rotor shaft the generator.

As an optimal scheme of the unmanned aerial vehicle, airborne electric control equipment is arranged in the unmanned aerial vehicle, and the storage battery is electrically connected with the airborne electric control equipment.

As a preferable scheme of the unmanned aerial vehicle, the unmanned aerial vehicle is a tandem helicopter or a lateral helicopter.

The embodiment of the utility model provides a beneficial effect lies in:

the power system provided by the embodiment of the utility model adopts the fuel engine to connect with the rotor shaft, the rotor shaft is connected with the generator, the generator is electrically connected with the storage battery, the mechanical energy generated by the rotation of the rotor can be converted into electric energy through the generator to be output and stored in the storage battery, the recycling of the mechanical energy generated by the rotation of the rotor is improved, and the energy utilization rate of the unmanned aerial vehicle is improved; the electric energy storage of the storage battery is increased by the power generation and utilization of the mechanical energy generated by the rotation of the rotor shaft, and the flight endurance of the unmanned aerial vehicle is improved; and because the fuel engine only drives the rotor shaft to rotate, the structural complexity of the existing unmanned aerial vehicle power generation system when the fuel engine is connected with the rotor shaft and the generator at the same time is simplified, the required size and volume of the fuel engine are reduced, and the structure of a power system is simplified.

The embodiment of the utility model provides an unmanned aerial vehicle through adopting foretell driving system, has simplified unmanned aerial vehicle's structure, has improved unmanned aerial vehicle's energy storage capacity.

Drawings

Fig. 1 is a schematic structural diagram of an unmanned aerial vehicle provided in an embodiment of the present invention;

fig. 2 is a schematic diagram of a power system according to an embodiment of the present invention.

The figures are labeled as follows:

1-a power system; 2-body; 3-flight control system; 4-a rotor assembly; 5-a landing gear; 6-onboard electronic control equipment; 7-control surface assembly;

11-a fuel engine; 12-a generator; 13-a storage battery; 14-a rectification module; 15-a voltage stabilization module; 16-a rotor shaft; 17-a reversing transmission assembly; 171-drive bevel gear; 172-driven bevel gear; 18-an intermediate transmission assembly; 19-a transmission shaft.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, detachably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact between the first and second features, or may comprise contact between the first and second features not directly. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present invention, the terms "upper", "lower", "right", etc. are used in the orientation or positional relationship shown in the drawings only for convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to have a special meaning.

Fig. 1 is the utility model provides an unmanned aerial vehicle's schematic structure diagram, fig. 2 is the utility model provides a driving system 1's schematic diagram, as shown in fig. 1 and 2, this embodiment provides an unmanned aerial vehicle, can be applied to frontier defense patrol, aviation camera, distribution delivery, building site survey and drawing, fields such as agricultural plant protection, and this embodiment does not restrict unmanned aerial vehicle's the concrete scene of using.

Specifically, unmanned aerial vehicle includes organism 2, rotor subassembly 4, driving system 1, flight control system 3, control surface subassembly 7 and undercarriage 5 etc.. The unmanned aerial vehicle is characterized in that the machine body 2 is made of metal materials and provides support and protection for the whole unmanned aerial vehicle, and the machine body 2 is symmetrically arranged along the longitudinal central line of the machine body so as to ensure the stability of the whole structure of the unmanned aerial vehicle; the rotor wing assembly 4 is used for providing lift force for the flight of the unmanned aerial vehicle; the power system 1 is used for driving the rotor wing assembly 4 to rotate and providing electric energy for an airborne electronic control device 6 in the unmanned aerial vehicle; the control surface component 7 adjusts the angle of the control surface through a steering engine, and changes the incident flow angle of the unmanned aerial vehicle relative to the airflow, so that the flying direction and attitude of the unmanned aerial vehicle are changed; the flight control system 3 is used for controlling the flight state of the unmanned aerial vehicle; undercarriage 5 is used for assisting the unmanned aerial vehicle steadily to rise and fall.

Preferably, in this embodiment, the unmanned aerial vehicle is a tandem unmanned helicopter or a lateral unmanned helicopter. In other embodiments, the drone may be of other types as well, and the invention is not limited thereto. And the setting of the specific structure of shape and structural design, rotor subassembly 4, flight control system 3, rudder face subassembly 7 and undercarriage 5 of unmanned aerial vehicle organism 2 is the conventional setting in unmanned aerial vehicle field, and this embodiment does not inject the specific structural style of above-mentioned structure, and current unmanned aerial vehicle's organism 2, rotor subassembly 4, flight control system 3, rudder face subassembly 7 and/or undercarriage 5 homoenergetic are used extremely the utility model discloses in, the utility model discloses no longer carry out concrete repeated description.

In the present embodiment, the power system 1 mainly includes a rotor shaft 16, a fuel engine 11, a generator 12, and a battery 13. An output shaft of the fuel engine 11 is connected with the rotor shaft 16 and drives the rotor shaft 16 to rotate, so as to provide rotating torque and rotating speed for the rotation of the rotor assembly 4; the rotor shaft 16 is connected with an input shaft of the generator 12 and drives the generator 12 to rotate to generate electricity so as to output electric energy; the generator 12 is electrically connected with the storage battery 13, so that the electric energy output by the generator 12 is input into the storage battery 13 for storage; the battery 13 is electrically connected to the fuel engine 11 for supplying electric power for ignition and the like of the fuel engine 11.

According to the power system 1 provided by the embodiment, the fuel engine 11 is connected with the rotor shaft 16, the rotor shaft 16 is connected with the generator 12, and the generator 12 is electrically connected with the storage battery 13, so that mechanical energy generated by rotation of the rotor shaft 16 can be converted into electric energy through the generator 12 and then is output and stored in the storage battery 13, recycling of mechanical energy generated by rotation of the rotor shaft 16 is improved, and the energy utilization rate of the unmanned aerial vehicle is improved; the electric energy storage of the storage battery 13 is increased by the power generation and utilization of the mechanical energy generated by the rotation of the rotor shaft 16, and the flight endurance of the unmanned aerial vehicle is improved; and because fuel engine 11 only drives rotor shaft 16 and rotates, simplified the current unmanned aerial vehicle power generation system, fuel engine 11 and rotor shaft 16 and generator 12 when being connected simultaneously the structural complexity, reduced fuel engine 11 required size and volume, simplified driving system 1's structure.

In this embodiment, the power system 1 further includes a fuel tank, and the fuel engine 11 is communicated with the fuel tank through a fuel pipeline, so that the fuel tank inputs power oil for the fuel engine 11. The connection of the fuel tank to the fuel engine 11 is conventional in the art, and will not be described in detail in this embodiment. Be provided with liquid level detection device in the oil tank, liquid level detection device is connected with flight control system 3 electricity to make flight control system 3 according to the oil tank liquid level control unmanned aerial vehicle's that liquid level detection device detected flight state.

In this embodiment, fuel engine 11 can adopt current fuel engine types such as gasoline engine, diesel engine, and the highest oil mass in model, power and the fuel tank of fuel engine 11 should carry out specific settings according to unmanned aerial vehicle's size, unmanned aerial vehicle's application scene etc. and this kind of setting is to the conventional technological means in this field, and this kind is no longer repeated in this embodiment.

In the present embodiment, a first transmission assembly is used to connect the output shaft of fuel engine 11 to rotor shaft 16. Since in an unmanned aerial vehicle the power take-off shaft of the fuel engine 11 is generally horizontally disposed and the rotor shaft 16 is vertically disposed, the first transmission assembly preferably comprises a reversing transmission assembly 17.

Further, in this embodiment, the reversing transmission assembly 17 is a bevel gear set, the bevel gear set includes a driving bevel gear 171 connected to the end of the output shaft of the fuel engine 11 and a driven bevel gear 172 sleeved on the rotor shaft 16, and the driving bevel gear 171 is engaged with the driven bevel gear 172 to realize the conversion between the horizontal rotation of the output shaft of the fuel engine 11 and the vertical rotation of the rotor shaft 16. In other embodiments, the reversing gear assembly 17 may also take other types of configurations, such as a worm and gear assembly.

In this embodiment, it is preferable that the first transmission assembly further includes a transmission shaft 19 and an intermediate transmission assembly 18, the transmission shaft 19 is horizontally disposed, one end of the transmission shaft is connected to the output shaft of the fuel engine 11 through the intermediate transmission assembly 18, and the other end is sleeved with a drive bevel gear 171. Through setting up middle transmission assembly 18, be favorable to reducing the injecture to fuel engine 11 arrangement position on the one hand, rational utilization unmanned aerial vehicle inner space, on the other hand can adopt middle transmission assembly 18 to carry out 11 rotational speed of fuel engine and slow down, improves the input torque of rotor shaft 16.

In this embodiment, the intermediate transmission assembly 18 may be a speed reducer, an input shaft of which is connected to an output shaft of the fuel engine 11, and an output shaft of which is connected to the transmission shaft 19, so as to reduce the input rotation speed of the rotor shaft 16 and increase the input torque of the rotor shaft 16. Furthermore, the input shaft of the speed reducer and the output shaft of the fuel engine 11 and the output shaft of the speed reducer and the transmission shaft 19 are connected through couplings, so that the coaxiality among the speed reducer, the fuel engine 11 and the transmission shaft 19 is ensured. In another embodiment, the intermediate transmission assembly 18 may adopt a belt transmission, that is, the transmission shaft 19 and the output shaft of the fuel engine 11 are respectively sleeved with a synchronous wheel, and the two synchronous wheels are connected by a synchronous belt, so that the rotation of the output shaft of the fuel engine 11 drives the transmission shaft 19 to rotate. The belt transmission is adopted, so that the transmission stability can be improved, and the transmission noise is reduced. In other embodiments, the intermediate transmission assembly 18 may also be in other transmission structures commonly used at the output end of the fuel engine 11, and the description of the embodiment is omitted.

In another embodiment, the first drive assembly may include only the reversing drive assembly 17, i.e. the effect of reducing the speed and increasing the input torque to the rotor shaft 16 may be achieved by setting the gear ratio of the bevel gear set. In other embodiments, the output shaft of the fuel engine 11 may be arranged vertically, with the first transmission assembly comprising only the intermediate transmission assembly 18, as the arrangement conditions permit.

In this embodiment, rotor subassembly 4 is provided with two sets ofly, and two sets of rotor subassemblies 4 set up along the longitudinal center line interval of organism 2, and the cross axle symmetry that two sets of rotor subassemblies 4 correspond relative organism 2 centrobaric sets up to ensure unmanned aerial vehicle's balance and stability. Further, the two sets of rotor assemblies 4 rotate at the same speed and in opposite directions, so that the two sets of rotor assemblies 4 provide the same amount of lift force while canceling out the spin torque on the airframe 2 with a single rotor assembly 4.

In the present embodiment, it is preferable that each rotor assembly 4 is provided with the power system 1, that is, the rotor shaft 16 of each rotor assembly 4 is connected with one fuel engine 11 and one generator 12, each generator 12 is connected with one storage battery 13, and each storage battery 13 is connected with the corresponding fuel engine 11; or the two generators 12 can be connected with the same storage battery 13, and the storage batteries 13 are respectively electrically connected with the two fuel engines 11. In other embodiments, two sets of rotor assemblies 4 may share one power system 1, that is, the rotor shafts 16 of two rotor assemblies 4 are driven by the same fuel engine 11, and each rotor shaft 16 is connected with a generator 12, each generator 12 is electrically connected with a battery 13, and the battery 13 is electrically connected with the fuel engine 11.

In other embodiments, three or more rotor assemblies 4 may be provided, and rotor assemblies 4 are generally provided in pairs, and each pair of rotor assemblies 4 may be provided symmetrically with respect to a cross section of body 2 at the center of gravity, or symmetrically with respect to a longitudinal section of body 2 at the center of gravity. The setting mode of rotor subassembly 4 on unmanned aerial vehicle is the conventional technological means in this field, and this embodiment is no longer described any more.

In the present embodiment, one end of the rotor shaft 16 extends out of the body 2 and is connected with the rotor assembly 4, and the other end of the rotor shaft 16 is coaxially connected with the generator 12. Under the condition that the rotating speed of the generator 12 is matched with the rotating speed of the rotor shaft 16, the input shaft of the generator 12 can be directly connected with the rotor shaft 16 through a coupler, and the torque can be transmitted. In the case that the rotation speed of the generator 12 itself is not matched with the rotation speed of the rotor shaft 16, the input shaft of the generator 12 and the rotor shaft 16 can be connected through the second transmission assembly to increase the input rotation speed of the generator 12 and reduce the input torque.

In this embodiment, the input shaft of the generator 12 is preferably arranged vertically, which simplifies the connection between the generator 12 and the rotor shaft 16. In other embodiments, the input shaft of the generator 12 may also be disposed horizontally, and in this case, the input shaft of the generator 12 may be connected to the rotor shaft 16 by a reversing component such as a worm and gear assembly, a bevel gear assembly, or a rack and pinion assembly.

In the present embodiment, the generator 12 is preferably an alternator, and the generator 12 can be reduced in size and weight, and the power generation capability at low rotation speed of the generator 12 can be improved. And more preferably, the generator 12 is a synchronous three-phase permanent magnet generator. In other embodiments, the generator 12 may also be a DC generator or other type of alternator.

Unmanned aerial vehicle is from taking off to falling to the ground and roughly divide into three process, take off the stage promptly, cruise stage and landing stage, wherein, in the stage of taking off, the rotational speed of rotor shaft 16 is increased to the required operating speed of unmanned aerial vehicle normal navigation by zero, in the landing stage, the rotational speed of rotor shaft 16 is reduced to zero by operating speed, in the phase of endurance, the rotational speed of rotor shaft 16 is stable relatively, and the time length that unmanned aerial vehicle is in the phase of endurance is usually far greater than the time length of unmanned aerial vehicle in the stage of taking off and landing stage. Therefore, in the present embodiment, the rated rotation speed corresponding to the rated power generation of the generator 12 should be set according to the operating rotation speed of the rotor shaft 16 during the cruising phase of the unmanned aerial vehicle, i.e. the rated rotation speed of the generator 12 is related to the operating rotation speed of the rotor shaft 16, the efficiency of the generator 12 and the transmission ratio of the second transmission assembly. The design and determination of the rated speed, the rated power, the input voltage and the current of the generator 12 are conventional technical means in the field, and the present embodiment will not be described in detail.

In the present embodiment, the generator 12 is electrically connected to the battery 13, and the battery 13 is electrically connected to the fuel engine 11, so that the electric energy in the battery 13 is used for ignition of the fuel engine 11. And still be provided with all kinds of machine in the unmanned aerial vehicle and carry automatically controlled equipment 6, like all kinds of sensors, electric power instrument and meter etc. consequently, in this embodiment, battery 13 still is connected with rudder face subassembly 7, flight control system 3 and other machine and carries automatically controlled equipment 6, charges for all kinds of consumer in the unmanned aerial vehicle, satisfies all kinds of consumer's user demand, improves all kinds of consumer's duration.

In this embodiment, the onboard electronic control device 6 mounted on the unmanned aerial vehicle is related to the flight mission performed by the unmanned aerial vehicle, and this embodiment does not limit the type and number of the onboard electronic control device 6 mounted on the unmanned aerial vehicle.

In the present embodiment, since various types of electric power equipment are usually driven by direct current, in order to enable the electric energy input into the storage battery 13 by the generator 12 to be used for charging various types of onboard electric control equipment 6, in the present embodiment, a rectifier module 14 is disposed between the generator 12 and the storage battery 13. The rectifier module 14 is a rectifier, the generator 12 is electrically connected to an input terminal of the rectifier, an output terminal of the rectifier is electrically connected to the battery 13, and a three-phase rectifier bridge inside the rectifier rectifies a three-phase ac power output from the generator 12 into a dc power necessary for describing an electric power facility.

Because unmanned aerial vehicle is in zero to the change process of operating speed at the rotational speed of taking off the stage with descending the stage, and unmanned aerial vehicle also can have the change of 16 rotational speeds of rotor shaft in the stage of cruising, consequently, for the stability that improves generator 12 output voltage, still be provided with voltage stabilizing module 15 between generator 12 and the battery 13. The voltage stabilizing module 15 may be a rectifying and voltage stabilizing circuit integrally formed with the rectifier, or may be a voltage stabilizing device such as a voltage stabilizing diode provided separately from the rectifier.

In the embodiment, the power utilization characteristics of the unmanned aerial vehicle onboard electronic control equipment 6 are combined, and the stabilized output voltage is 30-55V, the output current is 16.8-20A, and the withstand voltage is 100V. The rectifier, the zener diode, or the rectifying and voltage-stabilizing circuit are conventional technical means in the field, and the description of this embodiment is omitted.

In the present embodiment, the storage battery 13 is preferably a lithium ion rechargeable battery, which has the advantages of good safety performance, high voltage, high specific energy, and the like. In other embodiments, the battery 13 may be other batteries capable of being charged and discharged.

In this embodiment, the storage battery 13 is electrically connected to the motor and each onboard electronic control device 6 by wires, and the electrical connection manner between the storage battery 13 and the electrical devices is a conventional technical means in the art, and the details of this embodiment are not repeated.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims

1. The power system is characterized by comprising a fuel engine (11), a rotor shaft (16), a generator (12) and a storage battery (13), wherein the fuel engine (11) is connected with the rotor shaft (16) and drives the rotor shaft (16) to rotate, the rotor shaft (16) is connected with the generator (12) and drives the generator (12) to rotate, and the storage battery (13) is electrically connected with the generator (12) and used for storing electric energy.

2. A power system according to claim 1, characterized in that the battery (13) is electrically connected to the fuel engine (11) for starting the fuel engine (11).

3. The power system of claim 1, characterized in that the rotor shaft (16) is arranged vertically, the output shaft of the fuel engine (11) is arranged horizontally, and a reversing transmission assembly (17) is connected between the rotor shaft (16) and the output shaft.

4. A power system according to claim 1, characterized in that the rotor shaft (16) is arranged coaxially with the input shaft of the generator (12).

5. A power system according to claim 1, characterized in that the generator (12) is a three-phase alternator (12), and that a rectifier module (14) and/or a voltage stabilizer module (15) are arranged between the generator (12) and the battery (13).

6. An unmanned aerial vehicle, characterized in that it comprises a power system (1) according to any one of claims 1-5.

7. The drone of claim 6, comprising a rotor assembly (4), the upper end of the rotor shaft (16) being connected with the rotor assembly (4), the lower end of the rotor shaft (16) being connected with the generator (12).

8. Unmanned aerial vehicle according to claim 7, wherein there are a plurality of sets of rotor assemblies (4), each set of rotor assemblies (4) having a respective set of power system (1) connected thereto.

9. The unmanned aerial vehicle of claim 7, wherein there are multiple sets of rotor assemblies (4), each set of rotor assemblies (4) is provided with the corresponding rotor shaft (16), the rotor shafts (16) are connected with the fuel engine (11), and the generator (12) is connected to at least one of the rotor shafts (16).

10. Unmanned aerial vehicle according to claim 6, characterized in that, be provided with on-board electrical control equipment (6) in the unmanned aerial vehicle, battery (13) is with on-board electrical control equipment (6) electricity is connected.

11. A drone according to any of claims 6 to 10, characterised in that the drone is a tandem helicopter or a lateral helicopter.