Description:Technical field of the invention
[0002] The present invention relates to an alula-integrated propeller. The invention particularly relates to a propeller that integrates the alula wing shape, resulting in increased thrust at varying Revolution Per Minutes (RPMs).

Background of the invention
[0003] The technology of propellers has indeed been in existence for centuries and is extensively utilized in various applications, such as aviation, marine transportation, and wind turbines. Propellers play a fundamental role in generating thrust by utilizing the rotation of blades to push air or water in the opposite direction, thereby propelling vehicles such as aircraft, boats, and submarines or devices forward. The propellers consist of multiple blades that rotate around a central hub and interact with the surrounding fluid (air or water) to create propulsion. As the blades rotate, they create a pressure difference between the front and back surfaces, generating lift and producing a propulsive force. The angle, shape, and twist of the blades of the propellers are carefully designed to maximize efficiency and performance. The propellers can be found in different configurations and designs, depending on the application and requirements.
[0004] While propellers have proven to be effective in many scenarios, they do have limitations, particularly in certain conditions. For instance, at low speeds, steep angles of attack, and in turbulent flow conditions, conventional propellers may encounter inefficiencies and performance challenges. These limitations can lead to reduced thrust, decreased efficiency, and potential loss of control.
[0005] While propeller technology has a long-standing history and widespread usage, to circumvent these constraints, different propeller designs and technologies have been investigated. These technologies include sophisticated blade profiles, variable pitch propellers, ducted propellers, and even wholly novel concepts like veiled or rim-driven propellers. In the realm of Unmanned Air Vehicles (UAVs), several techniques have been developed to enhance the performance of propellers and address the aforementioned challenges. These techniques aim to improve efficiency, maneuverability, reduce issues like drag, separation, noise, and vibration and further alleviate the consequences of difficult operating circumstances.
[0006] One such approach involves the use of winglets or wingtip devices, which are small structures attached to the tips of the propeller blades. Winglets help reduce drag by minimizing the formation of vortices at the blade tips, thereby improving overall aerodynamic efficiency. Additionally, the winglets can increase lift and reduce induced drag, contributing to improved performance and fuel efficiency. Another such technique involves the incorporation of vortex generators, which are small devices strategically placed on the surface of the propeller blades. The vortex generators create vortices that energize the boundary layer, enhancing airflow attachment and reducing the likelihood of flow separation. By minimizing separation, propellers can maintain higher levels of efficiency and thrust production, particularly in challenging conditions such as low speeds and high angles of attack.
[0007] The demand for increased propulsion in propellers is driven by the need for improved efficiency, maneuverability, and reduced noise and vibration levels. This is especially relevant in applications such as Unmanned Air Vehicles (UAVs) and small aircraft, where the thrust-to-weight ratio plays a crucial role in determining flight performance and payload capacity. By optimizing the design and performance of propellers, including the implementation of techniques such as winglets and vortex generators, higher levels of efficiency, control, and overall flight performance can be achieved. Such techniques have been effective to some extent, but they frequently result in propellers with limiting features such as restricted possible rakes and pitch.
[0008] The Patent number US20130287585A1 titled “Propeller blade with lightweight insert” relates to a propeller blade including a foam core and a structural layer that surrounds at least a portion of the foam core and includes a face side and a camber side is disclosed. The propeller blade also includes a bulkhead disposed in the foam core in operable contact with the face side and the camber side of the structural layer and extending in a chord wise direction of the propeller blade.
[0009] The Patent number CN101255873B titled “Blade tip alula of gas-pressing automotive leaf” relates to a tip vane of guided vane of compressor related to field of impeller machine, which comprises a front edge wing, a pressure surface wing, a pressure surface wing, a suction surface wing and a tail edge wing, the pressure surface wing and the suction surface wing are little vanes expended between front edge point A and tail edge point B of leaf along circumference, front edge point D and C of pressure surface wing and suction surface wing are lied on front edge point A or between front edge point A and most thickness part of guided vane; tail edge point F and E of pressure surface wing and suction surface wing are lied on tail edge point B or between tail edge point B and the most thickness part of guided vane; the front edge wing and tail edge wing are connected smoothly with the pressure surface wing and suction surface wing, and the front edge wing and tail edge wing are extended parts of pressure surface wing and suction surface wing at front edge and tail edge. The present invention reduces the effect of flow field in channel by tip leakage, tip leakage vortex and scraping gyres, improves cascade flow field, and enhances mechanical efficiency of impeller at the same time.
[0010] The Patent number CN107742011B titled “Design method of drag-reducing micro-texture for impeller blades” relates to a design method of a blade surface drag reduction micro-texture and belongs to the field of blade drag reduction. Establishing a flow field area according to an impeller blade model; carrying out numerical simulation on the flow field area to obtain a flow chart of the middle section of the blade in the height direction, and accordingly determining a backflow area of an airfoil pressure surface, a boundary layer separation area and an airfoil suction surface as a microtextured placing area; arranging a micro-texture section in a micro-texture placing area in close contact with the airfoil shape of the blade, and enabling the micro-texture section to be swept into ribs or grooves on the surface of the blade along the height direction of the blade; and (3) optimizing the placing position and the cross section shape of the micro texture by adopting finite element simulation on the blade model with the rib or groove micro texture to obtain the placing position and the cross section shape of the micro texture with the best resistance reduction, so as to construct the resistance reduction micro texture on the surface of the blade. The resistance of the optimized blade surface resistance-reducing micro-texture reaches 5 to 10 percent, the energy consumption is reduced, the fuel oil resource is saved, and the design method of the resistance-reducing micro-texture can be popularized and applied to other fields.
[0011] The patent number WO2020049270A1 titled “A Wing Tip Device” relates to a wing tip device for a fixed wing aircraft. The wing or wing tip device has an alular-like projection. In particular the wing or wing tip device has a first leading edge region having a first sweep angle, a second leading edge region outboard of the first leading edge region in a spanwise direction and having a second sweep angle greater than the first sweep angle, a third leading edge region outboard of the second leading edge region in the spanwise direction and adjacent a tip end of the wing tip device and having a third sweep angle greater than the first sweep angle. The second leading edge region is adapted to generate a first vortex, and the third leading edge region is adapted to generate a second vortex which builds towards the tip end of the wing tip device.
[0012] Hence, there exists a need for propellers that exhibit improved efficiency, performance and are suitable for noise-sensitive environments or applications as compared to conventional propellers.
Summary of the invention:
[0013] The present invention overcomes the drawbacks of the prior art by disclosing an alula-integrated propeller for thrust enhancement, wherein the propeller comprises an alula wing positioned at a distance one eighth of the distance from the hub of the propeller to the tip of a blade towards the leading edge of the propeller for maximizing thrust production, wherein the length of the alula wing being one sixth the length of the propeller. In one embodiment of the present invention, the alula wing is configured for maximizing thrust production at varying Revolutions Per Minute (RPM).
[0014] The present invention aims to address the demand for propellers that exhibit reduced drag, increased lift at low speed, stable airflow, and minimized turbulence. By incorporating these features, the invention offers enhanced efficiency, performance, and safety across a wide range of applications, spanning from aviation to marine and renewable energy. In addition to the aforementioned advantages, the present invention also caters to the specific requirements of applications such as Unmanned Aerial Vehicles (UAVs), drones, and electric aircraft by providing propellers capable of maintaining stable flight and extended flight times.
[0015] Moreover, the present invention recognizes the significance of extended flight times in UAVs, drones, and electric aircraft applications. To address this need, the propellers developed by the invention focus on maximizing aerodynamic efficiency, reducing drag, and minimizing energy losses. The extended flight time capability enables prolonged missions, longer flight ranges, and improved productivity in various operational scenarios.
Brief description of the drawings:
[0016] The foregoing and other features of embodiments will become more apparent from the following detailed description of embodiments when read in conjunction with the accompanying drawings. In the drawings, like reference numerals refer to like elements.
[0017] FIG 1 illustrates a perspective view of an alula integrated propeller, in accordance with an embodiment of the present invention.
[0018] FIG 2 illustrates an isometric view of the alula integrated propeller, in accordance with an embodiment of the present invention.
[0019] FIG 3 illustrates a front view of the alula integrated propeller, in accordance with an embodiment of the present invention.
[0020] FIG 4 illustrates a side view of the alula integrated propeller, in accordance with an embodiment of the present invention.
[0021] FIG 5 illustrates a top view of the alula integrated propeller, in accordance with an embodiment of the present invention.
[0022] FIG 6 illustrates a comparison of thrust measurement using a commercial propeller and thrust measurement using the alula integrated propeller, in accordance with an embodiment of the present invention.
Detailed description of the invention:
[0023] Reference will now be made in detail to the description of the present subject matter, one or more examples of which are shown in the figures. Each example is provided to explain the subject matter and not a limitation. Various changes and modifications obvious to one skilled in the art to which the invention pertains are deemed to be within the spirit, scope, and contemplation of the invention.
[0024] Referring to FIG. 1, a perspective view of an alula-integrated propeller, in accordance with an embodiment of the present invention is illustrated. The propeller (100) comprises an alula wing (101) positioned at a distance one eighth of the distance from the hub (102) of the propeller (100) to the tip of a blade (103) towards the leading edge of the propeller (100) for maximizing thrust production, wherein the length of the alula wing (101) being one sixth the length of the propeller (100).
[0025] The alula integrated propeller (100) introduces a novel form of propeller design that combines the unique characteristics of the alula wing (101) shape with a standard sized propeller. This innovative design incorporates an alula wing (101) at the leading edge of the propeller (100), positioned at specific dimensions and orientations for optimal performance.
[0026] In an embodiment, the alula integrated propellers (100) are inspired by the alula wing (101) found in birds. The alula design incorporates a unique structure that helps to reduce drag and increase lift, especially at low speeds. This characteristic is particularly beneficial for propellers as it allows them to maintain stable flight and achieve extended flight times. By minimizing drag and optimizing lift generation, the alula wing (101) design enhances the overall efficiency and performance of the propellers. One of the key features of the alula wing (101) design is its ability to create a highly efficient and stable airflow pattern. The alula design minimizes the negative effects of turbulent flow, which can disrupt the propeller's performance and stability. By promoting a more laminar and controlled airflow, the alula wing (101) design helps to maintain consistent thrust generation, improve flight stability, and reduce power consumption.
[0027] Referring to FIG 2, an isometric view of the alula integrated propeller, in accordance with an embodiment of the present invention is illustrated. In an embodiment of the present invention, the alula wing (101) is located 1/6th of the size of the propeller (100), measured from the leading edge, and positioned 1/8th of the span from the hub (102). This placement ensures that the alula wing (101) effectively interacts with the airflow, contributing to improved aerodynamic performance and thrust generation. The alula wing (101) itself follows a single-blade design, similar to a propeller, allowing for seamless integration into the overall propeller structure. The use of a single-blade design maintains consistency in the airflow patterns and interactions between the alula wing (101) and the rest of the propeller (100).
[0028] Referring to FIG 3, a front view of the alula integrated propeller, in accordance with an embodiment of the present invention is illustrated. In an embodiment of the present invention, to optimize the performance of the alula integrated propeller (100), the hub-to-tip axis of the propeller blade (103) and the longitudinal axis of the alula wing (101) are positioned at an angle of 30 degrees with regard to one another. The 30-degree specific angle enables efficient circulation and lift generation, promoting enhanced thrust and overall propeller performance.
[0029] Referring to FIG 4, a side view of the alula integrated propeller, in accordance with an embodiment of the present invention is illustrated. In an embodiment, the bird wings utilize the alula to regulate airflow and prevent stalling during slow speeds or maneuvering. Similarly, incorporating this characteristic into the propeller design enables the alula integrated propeller (100) to generate increased thrust specifically at lower speeds. This advantage significantly enhances the overall performance of the propeller, allowing for improved maneuverability, stability, and efficiency. By mimicking nature's solution, the alula integrated propeller (100) leverages the alula wing shape to optimize airflow patterns and mitigate the risk of stalling.
[0030] Referring to FIG 5, a top view of the alula integrated propeller, in accordance with an embodiment of the present invention is illustrated. The alula wing (101) serves as an aerodynamic aid, promoting smoother airflow and maintaining lift even at reduced speeds. This increased thrust production at lower speeds translates to enhanced control and maneuverability, particularly during takeoff, landing, or operating in confined spaces.
[0031] Referring to FIG 6, a comparison of thrust measurement using a commercial propeller and thrust measurement using the alula integrated propeller, in accordance with an embodiment of the present invention is illustrated. By the way of an example, an experimental testing of the alula integrated propeller (100) is conducted using a thrust stand, while on the contrary computational testing is performed utilizing a Computational Fluid Dynamics (CFD) solver. A comparative analysis is carried out between the aula integrated propeller (100) (with alula wing of size approximately 0.8- 0.85 inches integrated to the standard propeller of 10x 4.5-inch size) and the standard propeller (for example: 10x4.5-inch sized propeller, wherein the diameter of propeller is of 10 inches, pitch of 4.5 inches, length 5 inches). The results of the thrust stand testing revealed that the alula integrated propeller (100) consistently generates greater thrust across all measured RPMs. Furthermore, it was observed that the difference in thrust between the alula integrated propeller (100) and the standard propeller increases exponentially as the RPMs increases. More particularly, the exponential growth in the difference of thrust at higher RPMs indicates the increasing efficiency and effectiveness of the alula integrated propeller (100) as rotational speed increases.
[0032] In an embodiment, the thrust stand tests unequivocally demonstrated that the alula integrated propeller (100) outperforms conventional propeller designs. Notably, the alula integrated propeller (100) seamlessly integrates with conventional propellers, enhancing its versatility.
[0033] In an embodiment, the thrust stand test is a method used to measure the thrust generated by a propeller. It involves mounting the propeller on a stand and subjecting it to controlled conditions while measuring the force it produces. Further, the thrust stand tests provide valuable insights into the thrust characteristics of a propeller, allowing for performance evaluation, optimization, and comparison with other designs.
[0034] In an embodiment, based on the results of comprehensive tests and evaluations, it has been observed that the propeller design incorporating the alula wing (101) shape demonstrates superior performance in generating thrust across a range of rotational speeds compared to existing designs. This enhanced thrust production can be attributed to the unique characteristics of the alula wing (101) shape, which facilitates more efficient circulation and lift generation. The improved thrust generation achieved through the alula wing shape offers notable benefits, particularly in terms of enhanced efficiency. By increasing thrust and reducing drag, alula integrated propeller design can operate more efficiently, resulting in extended flight times and reduced battery consumption. This advancement holds significant value for drone applications that require prolonged flight durations, as it enables longer missions, increased productivity, and reduced downtime for recharging or battery replacement.
[0035] Moreover, the alula wing (101) shape provides a high degree of flexibility and adaptability to cater to different applications and environmental conditions. By exploring various configurations and adaptations of the alula wing shape, propeller performance can be optimized to meet specific requirements. This customization capability empowers users to tailor the propeller design to their particular needs, ensuring optimal performance, stability, and efficiency across diverse operating environments. The ability to customize propellers with the alula wing shape is a significant advantage, as it allows for the fine-tuning of the propeller's characteristics to match specific application demands. For instance, propellers can be tailored for specific payloads, flight conditions, or operational requirements, resulting in improved performance and more effective drone operations.
[0036] In an embodiment, by incorporating biomimetic alula designs, propellers have the potential to generate increased thrust, thereby enhancing the overall performance of drones. The improved thrust capabilities allow for carrying heavier payloads or extending flight durations, expanding the range of applications for drones and enabling more robust and versatile operations. The utilization of bio-inspired alula wing (101) designs in propellers effectively reduce drag and increase lift. This enhancement in aerodynamic efficiency translates into more efficient propeller performance, requiring less power to maintain flight. As a result, drones equipped with these propellers achieve extended flight times while consuming less battery power. This improved efficiency contributes to optimized flight operations, increased productivity, and reduced operational costs.
[0037] The implementation of bio-inspired alula designs in propellers leads to decreased energy consumption, making the technology more environmentally friendly. By reducing the reliance on non-renewable energy sources and minimizing overall power requirements.

Reference numbers:
Components Reference Numbers
Alula integrated propeller 100
Alula wing 101
Hub 102
Blade 103
, C , Claims:We claim:
1. An alula-integrated propeller for thrust enhancement, the propeller (100) comprising:
a. an alula wing (101) positioned at a distance one eighth of the distance from the hub (102) of the propeller (100) to the tip of a blade (103) towards the leading edge of the propeller (100) for maximizing thrust production, wherein the length of the alula wing (101) being one sixth the length of the propeller (100).

2. The propeller (100) as claimed in claim 1, wherein the alula wing (101) is configured for maximizing thrust production at varying Revolutions Per Minute (RPM).

3. The propeller (100) as claimed in claim 1, wherein the alula wing (101) has a similar airfoil shape and structural characteristics as that of the propeller blade.

4. The propeller (100) as claimed in claim 1, wherein the alula wing (101) is tilted or twisted relative to the propeller blade (103), with a 30-degree angle between the hub-to-tip axis of the blade and the longitudinal axis of the alula wing (101).

5. The propeller (100) as claimed in claim 1, wherein the alula wing (101) is positioned at the leading edge of the propeller (100) for managing the air flow, thereby allowing the propeller (100) to retain lift and maneuverability at lower speed.

6. The propeller (100) as claimed in claim 1, wherein the curvature of the alula wing (101) is optimized to match the single propeller blade (103), ensuring a seamless merger with the propeller (100) design thereby producing no drag or turbulence.