Aircraft

Abstract

An aircraft according to one embodiment comprises a propeller and a fuselage on which the propeller is provided, wherein the propeller may include a rotatable hub, a plurality of blades pivotably connected to the hub, and a rotor that transmits driving force to the hub, and the plurality of blades may be configured to include a first blade, a second blade adjacent to the first blade, and a third blade adjacent to the second blade, wherein the third blade is adjacent to the second blade and is located opposite to the rotational direction of the hub from the second blade, and the angle between the first blade and the second blade may be greater than the angle between the second blade and the third blade.

Description

Technology Field

[0001] The present invention relates to an aircraft. Background Technology

[0002] The aircraft propeller system is one of the critical technical components used in aircraft such as airplanes and helicopters. Propellers play the role of moving the aircraft by efficiently pushing air. Propellers can consist of multiple wings or blades. These wings can have specific angles and curvatures, which move the air to generate thrust. As such, propeller designs can take into account the aerodynamic problems that occur during high-speed rotation.

[0003] Aircraft can be operated under various flight conditions, and propeller systems can be finely controlled to suit these conditions. Efficiency can be enhanced during flight by adjusting the propeller angle using mechanisms such as electronic pitch control. Propellers rotate by effectively receiving power transmitted from the engine. To achieve this, gear systems or drive shafts between the engine and the propeller may be used. The propeller system can have a significant impact on the aircraft's efficiency and fuel economy.

[0004] An adjustable propeller device and a method for distributing fluid to / from such adjustable propeller device are disclosed in Korean Registered Patent Publication No. 10-1525647.

[0005] The aforementioned background technology is one that the inventor possessed or acquired in the process of deriving the content of the disclosure of the present application, and it cannot be considered as prior art disclosed to the general public prior to the filing of this application. The problem to be solved

[0006] The objective according to one embodiment is to provide an aircraft that ensures baggage loading convenience for an aircraft such as a delivery eVTOL unmanned aircraft.

[0007] An objective according to one embodiment is to provide an aircraft having propellers arranged at unequal intervals.

[0008] An objective according to one embodiment is to provide an aircraft that improves factors affecting propeller performance, such as wake flow generated from a forward propeller. means of solving the problem

[0009] An aircraft according to one embodiment comprises a propeller and a fuselage on which the propeller is provided, wherein the propeller may include a rotatable hub, a plurality of blades pivotably connected to the hub, and a rotor that transmits driving force to the hub, and the plurality of blades may be configured to include a first blade, a second blade adjacent to the first blade, and a third blade adjacent to the second blade, wherein the third blade is adjacent to the second blade and is located opposite to the rotational direction of the hub from the second blade, and the angle between the first blade and the second blade may be greater than the angle between the second blade and the third blade.

[0010] According to one aspect, the tip of the first blade and the tip of the second blade may be located beyond the effective area of ​​the lower surface of the body.

[0011] According to one side, the pivot centers of the blades may be located at unequal intervals on a circle concentric with the center of the hub.

[0012] According to one aspect, the plurality of blades may be configured to further include a fourth blade between the third blade and the first blade, the first blade and the third blade may be arranged symmetrically at 180 degrees around the hub, the second blade and the third blade may be arranged symmetrically at 180 degrees around the hub, and the angle of attachment of the first blade or the angle of attachment of the third blade may be greater than the angle of attachment of the second blade or the angle of attachment of the fourth blade.

[0013] According to one aspect, the aircraft may further include a pitch adjustment unit that supports the plurality of blades on the hub and adjusts the pitch of the blades.

[0014] According to one side, the aircraft may have a pitch adjustment unit that can increase or decrease the pitch of at least one of the plurality of blades.

[0015] According to one side, the pitch adjustment unit can determine an additional angle of attachment of the third blade to compensate for the reduced effective angle of attack of the third blade due to the induced airflow generated by the second blade. Effects of the invention

[0016] An aircraft according to one embodiment can ensure the convenience of loading cargo on an aircraft such as a delivery eVTOL unmanned aircraft.

[0017] An aircraft according to one embodiment may have propellers arranged at equal intervals.

[0018] An aircraft according to one embodiment can improve factors affecting propeller performance, such as wake flow generated from a forward propeller. Brief explanation of the drawing

[0019] FIG. 1 shows a top view of a propeller system of an aircraft according to one embodiment. FIG. 2 shows a perspective view of a propeller system of an aircraft according to one embodiment. FIG. 3 shows the difference in attachment angle between the propeller blades of an aircraft according to one embodiment. FIG. 4 shows a change in propeller performance according to a change in the angle of attachment between the propeller blades of an aircraft according to one embodiment. FIG. 5 shows an example of applying a propeller system for cargo loading in an aircraft according to one embodiment. Specific details for implementing the invention

[0020] Hereinafter, embodiments are described in detail with reference to the attached drawings. However, various modifications may be made to the embodiments, and thus the scope of the patent application is not limited or restricted by these embodiments. It should be understood that all modifications, equivalents, and substitutions to the embodiments are included within the scope of the rights.

[0021] The terms used in the embodiments are for illustrative purposes only and should not be interpreted as intended to be limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0022] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the embodiments pertain. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0023] In addition, when describing with reference to the attached drawings, identical components are assigned the same reference numeral regardless of drawing symbols, and redundant descriptions thereof are omitted. In describing the embodiments, if it is determined that a detailed description of related prior art could unnecessarily obscure the essence of the embodiments, such detailed description is omitted.

[0024] In addition, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the embodiments. These terms are intended merely to distinguish the components from other components, and the nature, order, or sequence of the components is not limited by these terms. Where it is stated that a component is "connected," "combined," or "connected" to another component, it should be understood that while the component may be directly connected or connected to the other component, another component may also be "connected," "combined," or "connected" between each component.

[0025] Components included in any one embodiment and components having common functions shall be described using the same names in other embodiments. Unless otherwise stated, the description in any one embodiment may also apply to other embodiments, and specific descriptions shall be omitted to the extent of overlap.

[0026] Embodiments of the present invention are described in detail below with reference to the attached drawings so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, parts unrelated to the explanation have been omitted from the drawings to clearly explain the present invention.

[0027] FIG. 1 shows a top view of a propeller system of an aircraft according to one embodiment. FIG. 2 shows a perspective view of a propeller system of an aircraft according to one embodiment.

[0028] An aircraft (10) according to one embodiment may be, for example, a vertical take-off and landing (VTOL) aircraft combining fixed wings and rotary wings. An aircraft according to one embodiment may be proposed with a four-blade propeller system arranged at unequal intervals to secure cargo space for a delivery drone.

[0029] Referring to FIGS. 1 and 2, an aircraft (10) according to one embodiment may include a propeller (200) and a body (100) having the propeller (200). The propeller (200) may include a rotatable hub (300), a plurality of blades (210, 220, 230, 240) pivotally connected to the hub (300), and a rotor (not shown) that transmits driving force to the hub (300).

[0030] A plurality of blades (210, 220, 230, 240) may be configured to include a first blade (210), a second blade (220) adjacent to the first blade (210), a third blade (230) adjacent to the second blade (220), and a fourth blade (240) between the third blade (230) and the first blade (210).

[0031] As shown in FIG. 1, the aircraft according to one embodiment may have the angular spacing between the blades of the propeller (200) arranged asymmetrically so as to secure a spacing between the blades of the propeller (200).

[0032] Referring to FIGS. 1 and 2, the third blade (230) is adjacent to the second blade (220) and is located opposite to the rotational direction of the hub (300) from the second blade (220). The first blade (210) and the third blade (230) can be arranged symmetrically at 180 degrees around the hub (300). The second blade (220) and the third blade (230) can be arranged symmetrically at 180 degrees around the hub (300).

[0033] The angle between the first blade (210) and the second blade (220) may be greater than the angle between the second blade (220) and the third blade (230). In this way, the pivot centers of the blades (210, 220, 230, 240) may be positioned at unequal intervals on a circle concentric with the center of the hub (300). Through the propellers (200) arranged at unequal intervals, the aircraft (10) can secure a space for cargo to be accommodated.

[0034] Referring to FIG. 2, the aircraft (10) may further include a blade pitch adjustment adapter (400) that supports a plurality of blades (210, 220, 230, 240) on a hub (300) and adjusts the pitch of the blades (210, 220, 230, 240).

[0035] The pitch in the aircraft (10) according to one embodiment is a concept that reflects the twist angle, and the pitch refers to the distance the propeller moves forward through the air or pushes the air backward when it rotates one full turn along the blade angle.

[0036] Generally, because a propeller rotates through the air, it cannot advance or push forward exactly according to the angle of the blade, resulting in slip. Propeller pitch is divided into 'geometric pitch,' which is the theoretical distance the propeller advances in one rotation along the blade angle, and 'effective pitch,' which is the actual distance the propeller advances in one rotation; the difference between geometric pitch and effective pitch is called 'slip.' The efficiency of the propeller varies depending on the amount of this slip.

[0037] Since the relative wind itself is the wind received when actually moving forward, if geometric pitch is based on the blade angle, then the effective pitch can be based on the angle of the relative wind. Slip is the difference between the angle of the relative wind and the blade angle, and it can also be viewed as the 'angle of attack'. In other words, slip is the difference equal to the angle of attack received by the propeller blade, which represents the distance that can be advanced when rotating one full revolution.

[0038] The 'angle of attack' (angle of attack, angle of attack) of the aircraft (10) according to one embodiment refers to the angle between the chord line of the airfoil and the resultant relative wind, where the resultant relative wind is the addition of an induced flow to the rotational relative wind.

[0039] In an aircraft (10) according to one embodiment, as lift is generated, an induced airflow is generated as a byproduct of the lift, and the induced airflow can be a force that attempts to lower the aircraft (10). The angle of attack may change due to the rotational relative wind generated as the main rotor rotates and the induced airflow generated as the airflow is introduced.

[0040] In an aircraft (10) according to one embodiment, the angle of attack may change according to the change in the angle of attack that the pilot changes, and the angle of attack may also change due to the increase or decrease in the guiding airflow.

[0041] The 'angle of attack' (mounting angle, projection angle) of the aircraft (10) according to one embodiment is the angle formed by the chord line of the airfoil and the path of travel (relative wind rotation) of the airfoil, and represents a constant value that does not change in the span direction by tilting the angle of attack of the wing by a constant angle.

[0042] In an aircraft (10) according to one embodiment, the pilot can adjust the angle of attack through the collective and the cyclic, that is, change the pitch of the airfoil. That is, the angle of attack can be adjusted in the aircraft (10) according to one embodiment, and it can be expressed that the pilots give more pitch when controlling.

[0043] The 'twist angle' of the aircraft (10) according to one embodiment refers to the angle of attack of the airfoil (wind plate) in the span direction of the wing (or blade). In the case of the propeller (200) of the aircraft (10) according to one embodiment, when the angle of attack becomes larger towards the center and smaller towards the end, the wing may be described as being 'twisted'.

[0044] A pitch adjustment unit (400) of an aircraft (10) according to one embodiment can increase or decrease the pitch of at least one of a plurality of blades (210, 220, 230, 240).

[0045] Referring to FIGS. 1 and 2, the pitch adjustment unit (400) may include a protrusion extending from the hub (300) and having an interior that is open toward the radial direction of the hub (300).

[0046] At the end of the protrusion, a propeller blade root grip (500) connected to each of the plurality of propellers (210, 220, 230, 240), as shown in FIG. 2, may be provided.

[0047] The root grip (500) on the pitch adjustment unit (400) is connected to the blade, and the attachment angle of the blade can be adjusted through the operation of the root grip (500). For example, the root grip (500) can be formed in the shape of a pin that penetrates the end of the blade and the end of the protrusion.

[0048] A pitch adjustment unit (400) of an aircraft (10) according to one embodiment may be composed of a fixed angle adapter. Alternatively, it may be composed of a variable pitch adapter including a servo motor, a pitch link, and a bearing.

[0049] Root grip (500) is, for example

[0050] FIG. 3 shows the difference in attachment angle between the propeller blades of an aircraft according to one embodiment.

[0051] Referring to FIG. 3, the angle of attachment of the third blade (230) may be greater than the angle of attachment of the second blade (220). Also, the angle of attachment of the first blade (210) may be greater than the angle of attachment of the fourth blade (240).

[0052] When propellers (200) are arranged to have the same angle of attack, in the case of the third blade (230), the influence of the wake generated by the second blade (220) is large, so the effective angle of attack of the third blade (230) becomes smaller compared to the effective angle of attack of the second blade (220), and thus the efficiency of the propellers may decrease relative to equal spacing.

[0053] Accordingly, as shown in FIG. 3, an aircraft (10) according to one embodiment can reduce the influence of the wake generated from the second blade (220) by using a pitch adjustment unit (400) to make the angle of attachment of the third blade (230) larger than the angle of attachment of the second blade (220).

[0054] The pitch adjustment unit (400) can determine an additional angle of attack of the third blade (230) to compensate for the lowered effective angle of attack of the third blade (230) due to the induced airflow generated by the second blade (220).

[0055] In an aircraft (10) according to one embodiment, when the attachment angle of each propeller is adjusted, the efficiency of the third blade (230) can be improved, and the operating range of the propeller (200) can also be adjusted. The twist angles of the second blade (220) and the third blade (230) can be made different.

[0056] FIG. 4 shows a change in propeller performance according to a change in the angle of attachment between the propeller blades of an aircraft according to one embodiment.

[0057] Referring to Fig. 4, the propeller efficiency can vary with respect to the advance ratio for equally spaced propellers and unequally spaced propellers, respectively.

[0058] Here, the progress ratio is a dimensionless indicator representing wind speed and propeller rotational speed, and can be calculated as J = V / nD (V: wind speed, n: rotations per second, D: diameter). Accordingly, propeller efficiency can be determined by flight speed and propeller rotational speed. Generally, if the pitch ratio is constant for the same diameter, similar propellers will have similar maximum efficiency points (the J value at which maximum efficiency occurs).

[0059] According to one embodiment, the maximum efficiency point of the non-uniform propeller performance curve according to the aircraft (10) may be changed compared to the equal-uniform propeller performance curve by changing the angle of attachment. For example, as shown in FIG. 4, the maximum efficiency point of the equal-uniform propeller performance curve exists between a progression ratio of 0.6 and 0.7, whereas the maximum efficiency point of the non-uniform propeller performance curve according to one embodiment may be close to a progression ratio of 0.8.

[0060] FIG. 5 shows an example of applying a propeller system for cargo loading in an aircraft according to one embodiment.

[0061] As shown in FIG. 5, the tip of the first blade (210) and the tip of the second blade (220) may be located beyond the effective area of ​​the lower surface of the fuselage (100). Through this arrangement of the propeller (200), the aircraft (10) according to one embodiment can easily carry cargo inside the aircraft and can fly long distances.

[0062] In one embodiment, when a cargo is mounted on the lower outer part of the fuselage of a delivery drone, the aircraft (10) may be capable of being used for short-distance delivery or longer due to changes in the center of gravity according to the weight of the cargo and increased drag due to the shape of the cargo.

[0063] An aircraft (10) according to one embodiment can provide the advantage that the size of the cargo is not limited by the spacing of the rear-mounted propeller when approaching the rear of the fuselage for cargo loading inside the aircraft.

[0064] In one embodiment, the problem of the wake flow generated from the forward propeller affecting propeller performance can be solved through the propellers (200) arranged at equal intervals of the aircraft (10).

[0065] The angle of attack of the airfoil responsible for both lift and thrust can be changed by the pilot's operation and can also be changed frequently by external factors, and even if the direction of the air acting on the blades in the forward and backward directions does not act evenly and the direction of the air acting on the blades in the forward and backward directions constantly changes, the aircraft (10) according to one embodiment can be maneuvered stably.

[0066] An aircraft (10) according to one embodiment is equipped with a vertical take-off and landing (VTOL) propeller and a cruising propeller, respectively, and can be used in an aircraft of the type of engine dedicated to vertical take-off and landing and a engine dedicated to horizontal flight (Cruise Engine).

[0067] Although the embodiments have been described above with reference to the limited drawings, those skilled in the art can apply various technical modifications and variations based on the above. For example, suitable results may be achieved even if the described techniques are performed in a different order than described, and / or if the components of the described system, structure, device, circuit, etc. are combined or assembled in a form different from described, or replaced or substituted by other components or equivalents.

[0068] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims set forth below. Explanation of the symbols

[0070] Aircraft: 10 Fuselage: 100 Propeller: 200 1st Blade: 210 Second Blade: 220 Third Blade: 230 4th Blade: 240 Hub: 300 Pitch adjustment unit: 400 Blade Root Grip: 500 Cargo: C

Claims

Claim 1 An aircraft comprising a propeller and a fuselage on which the propeller is provided, wherein the propeller comprises: a rotatable hub; and a plurality of blades pivotably connected to the hub; and a rotor that transmits driving force to the hub; wherein the plurality of blades are configured to include a first blade, a second blade adjacent to the first blade, and a third blade adjacent to the second blade, wherein the third blade is adjacent to the second blade and is located opposite to the rotational direction of the hub from the second blade, and the angle between the first blade and the second blade is greater than the angle between the second blade and the third blade, and the plurality of blades are further configured to include a fourth blade between the third blade and the first blade, wherein the first blade and the third blade are arranged symmetrically at 180 degrees around the hub, and the second blade and the third blade are arranged symmetrically at 180 degrees around the hub, and the attachment angle of the third blade is greater than the attachment angle of the second blade, or the attachment angle of the first blade is greater than the attachment angle of the fourth blade, and further include a pitch adjustment unit that supports the plurality of blades on the hub and adjusts the pitch of the blades, and An aircraft, wherein the pitch adjustment unit individually adjusts the angle of attachment of the blades to reduce the effect of the wake flow generated in the forward blade on the rear blade by the asymmetric angle arrangement between the blades. Claim 2 In claim 1, the tip of the first blade and the tip of the second blade are located beyond the effective area of ​​the lower surface of the fuselage, in a flying body. Claim 3 An aircraft according to claim 1, wherein the pivot centers of the blades are located at unequal intervals on a circle concentric with the center of the hub. Claim 4 delete Claim 5 delete Claim 6 In claim 1, the pitch adjustment unit increases or decreases the pitch of at least one of the plurality of blades, the aircraft. Claim 7 In claim 6, the pitch adjustment unit determines an additional angle of attack of the third blade to compensate for the reduced effective angle of attack of the third blade due to the induced airflow generated by the second blade.

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