A modular multi-propeller aerodynamic interference model

Abstract

This invention provides a modular multi-rotor aerodynamic interference model, with a nacelle system connected to the wing system. The wing system consists of a front left wing, a front right wing, a rear left wing, and a rear right wing. The nacelle system includes a rotor hub fairing, a rotor system, a drive motor, a balance heat shield, and a rotor force balance. The rotor system includes an upper rotor hub, a lower rotor hub, a rotor clamp, and rotor blades. The rotor hub fairing is formed by integral milling and hollowing out an aluminum part, with multiple fan-shaped grooves on its lower circumference. The rotor hub fairing is connected to multiple arms of the lower rotor hub in the rotor system. The rotor system is connected to the drive motor through the lower rotor hub. The upper and lower rotor hubs are connected, and the rotor clamp is located on the upper and lower rotor hubs. The balance heat shield is located between the drive motor and the rotor force balance. This invention can quickly meet the aerodynamic interference research needs of rotors and wings with different configurations, such as different numbers of rotors, adjustable wing positions, nacelle tilting, rotor tilting, and wing tilting.

Description

Technical Field

[0001] This invention belongs to the field of wind tunnel testing technology for multi-propeller tilting aircraft, and particularly relates to a modular multi-propeller aerodynamic interference model aircraft. Background Technology

[0002] With the rapid development of electric rotorcraft, the direct-drive rotor method is simple and quick, resulting in electric rotorcraft exhibiting complex configurations such as multi-rotor, multi-tilt, and compound configurations. These configuration characteristics make the aerodynamic interference mechanism of the entire aircraft more complex. In order to carry out aerodynamic mechanism research on complex configurations of multi-rotor tilt rotors, different configuration test models will be developed. However, at present, the test models are mostly multi-point arrangements of rotors or separate arrangements of tilt mechanisms, which do not well integrate rotors, fuselage, and wings. There is no complete test aerodynamic interference model of the entire aircraft with multiple configurations that include wing tilt, nacelle tilt, rotor tilt, and adjustable relative positions of the front and rear wings. Summary of the Invention

[0003] To address the shortcomings of existing technologies in effectively integrating the rotor, fuselage, and wings, and the lack of a comprehensive multi-configuration aerodynamic interference model that includes adjustable wing tilt, nacelle tilt, rotor tilt, and relative positions of the fore and aft wings, this invention provides a modular multi-rotor aerodynamic interference model. The technical solution is as follows: Firstly, a modular multi-rotor aerodynamic interference model is provided, including: nose, tail, fuselage, wing system, and nacelle system; The head and tail are connected to the body. The head and tail are formed by whole-machine milling and internal hollowing, which can reduce the weight of the whole machine while ensuring the shape. The head and tail are divided into left and right halves, which are snapped together. The nacelle system is connected to the wing system; the wing system consists of a front left wing, a front right wing, a rear left wing, and a rear right wing, each composed of an upper wing and a lower wing, and connected to the fuselage via a tilt axis; the nacelle system includes: a rotor hub fairing, a rotor system, a drive motor, a balance heat shield, and a rotor force balance; the rotor system includes an upper rotor hub, a lower rotor hub, rotor clamps, and rotor blades; the rotor hub fairing is formed by integral milling and hollowing out of an aluminum component, which reduces incoming flow resistance while ensuring strength, and has multiple fan-shaped grooves on its lower circumference to ensure smooth rotor blade pitch control; the rotor hub fairing is connected to multiple arms of the lower rotor hub in the rotor system; the rotor system is connected to the drive motor via the lower rotor hub, enabling blade pitch control; the upper and lower rotor hubs are connected, the rotor clamps are located on the upper and lower rotor hubs, and the balance heat shield is located between the drive motor and the rotor force balance.

[0004] The upper and lower rotor hubs are connected by T-slots. The rotor clamp is a T-shaped structure installed in the T-slot between the upper and lower rotor hubs, using a clearance fit to ensure the freedom of the rotor tip in the circumferential direction. After the upper and lower rotor hubs are connected, the rotor clamp can rotate 360 ​​degrees within the rotor hub. Each end face of the upper and lower rotor hubs has two threaded holes, which are on the same circumference and 90° apart, and are symmetrical about the rotor hub. The tightening or loosening of the set bolts in these bolt holes allows the "-" end face of the T-shaped rotor clamp to be loosened or tightened within the rotor hub. The end faces of the upper and lower rotor hubs are engraved with angle lines ranging from ±60°, with adjacent angle lines spaced 5° apart. This allows for quick changes in rotor collective pitch without disassembling the rotor clamp.

[0005] Among them, the upper surface of the balance heat insulation component is connected to the lower surface of the drive motor, and the lower surface is connected to the rotor force balance; the bolts connecting the balance heat insulation component to the drive motor and the bolts connecting the balance heat insulation component to the force balance do not contact each other directly and need to be arranged in layers. The balance's heat insulation components are made of mica sheet material, which can effectively prevent the high temperature during the high-speed, long-term rotation of the drive motor from being transferred to the rotor force balance, causing force drift and resulting in inaccurate measurements.

[0006] The rotor force balance has a cylindrical configuration and adopts an integrated milling design, which can effectively prevent the force measuring rod of the force balance from breaking due to excessive vibration load during rotor rotation. The lower end face of the rotor force balance is connected to the wing system. The rotor force balance has eight force measuring rods, four of which are vertically set in the upper middle part of the rotor force balance, and the other four are horizontally set at the bottom of the rotor force balance and arranged around the center of the bottom of the rotor force balance. Each force measuring rod is equipped with a resistance strain gauge. By loading decoupling, the six force elements of the rotor can be measured.

[0007] The front left wing, front right wing, rear left wing, and rear right wing are all composed of an upper wing, a lower wing, a tilting nacelle, and flaps. The upper wing has four positioning holes at its four corners, and the lower wing has four positioning round bosses at its four corners. These four positioning round bosses are connected to the four positioning holes of the upper wing through a transition fit to ensure the installation and positioning of the upper and lower wings. The middle surfaces of the upper and lower wings are tightly connected. Each upper wing is equipped with a nacelle system connection interface, which can meet the layout research of different rotor numbers of different models of the whole aircraft. The tilt nacelle is installed on the wingtip of the upper wing and can tilt at multiple different angles relative to the upper wing; the flaps are connected to the upper wing.

[0008] in, The tilt nacelle has four rows of holes with different circumferential radii. The first row has one hole, which is the shaft hole, serving as the tilt axis of the tilt nacelle. The second row has two holes, which are the position holes for the tilt nacelle relative to the wing at 60° and 90°. The third row has two holes, which are the position holes for the tilt nacelle relative to the wing at 0°, 15°, 30°, 60°, and 90°. The fourth row has three holes, which are the position holes for the tilt nacelle relative to the wing at 0°, 15°, and 30°. Thus, there are two positioning holes for each angle on different circumferential radii. The upper wing tip surface is also provided with four rows of holes with the same circumference as the tilt nacelle. Each radius has only one threaded hole. When the tilt nacelle needs to achieve a certain angle relative to the wing, the positions of the positioning bolts in the second to fourth rows can be changed to quickly achieve precise positioning and tilting of the tilt nacelle in a small space.

[0009] Each of the flaps has a threaded hole on its left and right end faces, with the centers of the two threaded holes on the same horizontal axis. The flaps are connected to the upper wing via connecting bolts, and the flaps can rotate freely around these connecting bolts. The flaps are simulated relative to the wing at deflection angles of 0°, 30°, 60°, and 90° using a three-dimensional digital model. A portion of solid material is cut out from the lower surface of the flaps and the left and right sides of the lower wing to form angle blocks. By replacing these angle blocks, the position of the flaps relative to the wing can be changed rapidly.

[0010] The upper and lower wing halves are constructed using a single-piece milling process with an aluminum profile, maintaining a thickness of 3-4 mm. Reinforcing ribs are designed along the chord direction at the connection point between the upper wing and the nacelle system, as well as along the spanwise direction of both halves. There are four longitudinal reinforcing ribs and two transverse reinforcing ribs, which reduces wing weight while maintaining wing strength. Pressure measurement holes, each 1 mm in diameter, are located on both the upper and lower wing halves, with their central normal plane tangent to the wing surface. These holes are densely arranged at the leading edge and sparsely arranged at the trailing edge. The machining accuracy of the wing profile containing the pressure measurement holes is no greater than 0.08 mm to ensure accurate pressure measurement on the wing surface. A stainless steel pressure measurement tube with an outer diameter of 1 mm and an inner diameter of 0.6 mm is bonded to the pressure measurement holes. After connecting the stainless steel pressure measurement tube to the flexible hose and miniature pressure scanning valve, the airtightness and permeability of the entire pressure measurement link must be checked, thus completing the wing pressure measurement design.

[0011] in, For the head and tail, the left half of the structure is provided with a positioning boss, and the left half of the structure is provided with a groove at the position corresponding to the positioning boss. The left and right halves of the structure are connected together by the positioning boss and the groove and are connected together by bolts; the thickness of the head and tail is 4-6mm. The head and body, and the tail and body are connected by positioning bosses and bolts. The positioning bosses are located on the head and tail, and the corresponding positions on the body are provided with grooves that engage with the positioning bosses. The rotor hub fairing is 2-3mm thick and is directly connected to the threaded holes on the four arms of the lower rotor hub in the rotor system. The angle of each sector slot is 26°.

[0012] The fuselage includes the left fuselage, right fuselage, wing tilt mechanism, central load-bearing frame, and tilt axis; The middle load-bearing frame is connected to the external whole-machine force-measuring balance; The left and right fuselages are connected to the central load-bearing frame, which bears the weight of the wing itself and the aerodynamic forces generated during the test. It is formed by integral milling of aluminum material, and is locally thickened to enhance the strength of the contact point between the tilt axis and the fuselage. The left and right fuselage front surfaces have nine cross-shaped position adjustment holes for mounting the tilt axis. By installing the tilt axis in different positions of the adjustment holes, the forward and backward and vertical positions of the front left and front right wings can be adjusted. The left and right fuselage rear surfaces have five position adjustment holes in the vertical direction for mounting the tilt axis. By installing the tilt axis in different positions of the adjustment holes, the vertical positions of the rear left and rear right wings can be adjusted. The wing tilt mechanism is fixedly installed inside the central load-bearing frame. The wing tilt mechanism includes a tilt servo and a transmission mechanism. The tilt servo is connected to the transmission mechanism, and the tilt shaft is interference-fitted with the gear pair of the transmission mechanism. It can rotate around the needle roller bearings installed on the position adjustment holes of the left and right fuselage. The left and right ends of the tilt shaft are connected to the upper wing through annular clamping parts and bolts. The tilt servo drives the tilt shaft to rotate, thereby causing the wing to rotate to achieve a tilt of 0-90°.

[0013] The transmission mechanism consists of a primary reduction gear pair and a secondary reduction gear pair. The use of secondary gear transmission can ensure that the size of the wing tilt mechanism is small enough in the confined space of the fuselage, and that the tilt speed is stable. It also amplifies the torque output of the tilt servo. If the tilt servo operates within an angle range of 0-270° and the maximum long-term operating torque is 40Nm, it needs to drive the wing to tilt from 0-90°. Assuming the number of teeth on the driving gear of the first-stage reduction gear pair is n1 and the number of teeth on the driven gear is n2, and the number of teeth on the driving gear of the second-stage reduction gear pair is n3 and the number of teeth on the driven gear is n4, with n2 and n3 being gears mounted on the same transmission shaft, and the number of each gear satisfying n1=n2=n3, then the actual wing tilt angle θ=270°*n1 / n2*n3 / n4. From n1=n2=n3, we can obtain n4 / n1≤3; the wingtip output torque T=40Nm*n2 / n1*n4 / n3=40*n4 / n1; the wingtip tilt angle range and output torque are opposite. Based on the installation space of the transmission mechanism, under the condition of meeting the tilt range and torque requirements, larger values ​​for n4 and n1 should be selected to ensure the stability of the wing tilt mechanism.

[0014] This invention is based on a modular design and can quickly meet the research needs of rotor and wing aerodynamic interference with different configurations such as different numbers of rotors, adjustable wing positions, nacelle tilting, rotor tilting, and wing tilting. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the entire model of the present invention; Figure 2 This is a schematic diagram of the machine head of the present invention; Figure 3 This is a schematic diagram of the tail section of the present invention; Figure 4 This is a schematic diagram of the nacelle system of the present invention; Figure 5 This is another schematic diagram of the nacelle system of the present invention; Figure 6 This is a schematic diagram of the propeller hub fairing of the present invention; Figure 7 This is a schematic diagram of the angle line of the rotor hub end face of the present invention; Figure 8 This is a cross-sectional view of the thermal insulation component of the balance of the present invention; Figure 9 This is a schematic diagram of the arrangement of the force measuring rods in this invention; Figure 10 This is a schematic diagram of the wing system of the present invention; Figure 11 This is a schematic diagram of the connection interface arrangement of the nacelle system of the present invention; Figure 12 This is a schematic diagram of four rows of holes on the wingtip surface of the present invention; Figure 13 This is a schematic diagram of the angle block of the present invention; Figure 14 This is a schematic diagram of the pressure measuring hole of the present invention; Figure 15 This is a schematic diagram of the fuselage design of the present invention; Figure 16 This is a schematic diagram of the position adjustment holes on the rear surface of the left and right fuselage of the present invention; Figure 17 This is a schematic diagram of the wing tilting mechanism of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0018] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited from each other.

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] One embodiment of the present invention provides a modular multi-propeller aerodynamic interference model, see below. Figure 1 It includes: nose 1, tail 2, fuselage 3, wing system 4, nacelle system 5; The machine head and tail are machined as a single piece with internal hollowing, with a thickness of 4-6mm. Both the machine head and tail are divided into left and right halves: left machine head, right machine head, left machine tail, and right machine tail. (See attached image.) Figure 2 and Figure 3 The left and right halves are snapped together, maintaining the shape while reducing the overall weight of the machine. The nacelle system design includes: a rotor hub fairing 501, a rotor system 502, a drive motor 503, a balance heat shield 504, and a rotor force balance 505. (See attached image) Figure 4 and Figure 5 The rotor system includes an upper rotor hub 506, a lower rotor hub 507, a rotor clip 508, and a rotor blade 509. The rotor hub fairing is made of a single piece of aluminum, milled and hollowed out, with a thickness of 2-3mm. This ensures strength while reducing incoming flow resistance. Four fan-shaped slots are designed on the lower circumference, each with an angle of 26°, to ensure smooth rotor blade pitch control. The rotor hub fairing is directly bolted to multiple arms of the lower rotor hub in the rotor system. (See...) Figure 6 .

[0021] The rotor system is connected to the drive motor via the lower rotor hub, and the rotor system can achieve variable blade pitch.

[0022] During the test, the rotor collective pitch needs to be changed according to the test conditions. The rotor pitch control structure includes an upper hub 506, a lower hub 507, and a rotor clip 508. The upper and lower hubs are connected by four bolts. T-slots are cut on the connection surfaces of both the upper and lower hubs. See Figure 6 The propeller clamp is T-shaped and installed in the T-slot between the upper and lower propeller hubs. It uses a clearance fit to ensure freedom of movement in the circumferential direction of the propeller tip. Once the upper and lower propeller hubs are connected, the propeller clamp can rotate 360 ​​degrees freely within the hubs. Each end face of the upper and lower propeller hubs has two M3 threaded holes machined on the same circumference, spaced 90° apart, symmetrical about the propeller hub. The tightening or loosening of the "-" end face of the T-shaped propeller clamp within the hub is achieved by adjusting the set screws in these bolt holes. Additionally, angle lines are engraved on the end faces of the upper and lower propeller hubs, ranging from ±60°, with each pair of graduations spaced 5° apart. See [link / details]. Figure 7 This allows for rapid rotor collective pitch conversion without disassembling the propeller clips.

[0023] The 504 balance insulation component is installed between the drive motor and the rotor force balance. The upper surface of the insulation component is bolted to the lower surface of the drive motor, and the lower surface is bolted to the rotor force balance. The bolts connecting the insulation component to the drive motor and to the force balance must not be in direct contact; they must be arranged in layers. (See...) Figure 8 The diagram shows a cross-sectional view of the balance's heat insulation component. The heat insulation component is made of mica sheet material, which can effectively prevent the high temperature during the high-speed, long-term rotation of the drive motor from being transferred to the rotor force balance, causing force drift and resulting in inaccurate measurements.

[0024] The rotor force balance has a cylindrical configuration and adopts an integrated milling design, which effectively avoids breakage of the force balance rods due to excessive vibration load during rotor rotation. The lower end of the rotor force balance is connected to the wing system. The rotor force balance has eight force-measuring rods, four of which are vertically positioned in the upper middle part of the rotor force balance, and the other four are horizontally positioned at the bottom of the rotor force balance, arranged around the center of the bottom of the rotor force balance. A resistance strain gauge is installed on each force-measuring rod. By loading decoupling, the six force elements of the rotor can be measured. See Figure 9 .

[0025] The wing system includes the upper wing 401, the lower wing 402, the tilt nacelle 403, and the flaps 404, see Figure 10The upper wing has four positioning holes at its four corners, and the lower wing has four positioning bosses at its four corners. These four positioning bosses are connected to the four positioning holes on the upper wing using a transition fit to ensure proper installation and positioning of the upper and lower wings. Additionally, several bolts are designed for fastening the upper and lower wings together on their mid-surface surfaces. Each upper wing has three nacelle system connection interfaces, which can accommodate layout studies of different rotor numbers for different models of the aircraft. (See...) Figure 11 .

[0026] The tilt nacelle is bolted to the wingtip surface of the wing and can tilt at five different angles relative to the wing: 0°, 15°, 30°, 60°, and 90°. The different tilt angles are achieved using a variable radius perforation method: four rows of holes with different circumferential radii are designed on the tilt nacelle. The first row has one hole, serving as the nacelle's tilt axis; the second row has two holes for the nacelle's 60° and 90° positions relative to the wing; and the third row has two holes for the nacelle's 0°, 15°, and 30° positions relative to the wing. Positioning holes are drilled at 60°, 90°, and three holes are drilled on the fourth row of the circumference for the tilt nacelle's relative angles of 0°, 15°, and 30° to the wing. This results in two positioning holes at each angle on different circumferential radii. Similarly, four rows of holes with the same circumferential radius as the tilt nacelle are designed on the wingtip surface connecting to the upper wing. However, only one threaded hole is needed for each radius. When the tilt nacelle needs to achieve a certain angle relative to the wing, only the positions of the positioning bolts in the second to fourth rows need to be changed to quickly and accurately position and tilt the tilt nacelle in a small space. See [link to documentation]. Figure 12 .

[0027] Each of the left and right end faces of the flap has a threaded hole, with the centers of the two threaded holes on the same horizontal axis. They are connected to the upper wing via bolts, allowing the flap to rotate freely around these bolts. A 3D digital model simulates the flap's deflection angles relative to the wing at 0°, 30°, 60°, and 90°. Solid sections are cut out from the lower surface of the flap and from each side of the lower wing to form angle blocks. By replacing these angle blocks, the flap's position relative to the wing can be rapidly changed. (See...) Figure 13 .

[0028] The upper and lower wing halves are machined from a single piece of aluminum, retaining a thickness of approximately 3-4 mm. Reinforcing ribs are designed along the chord direction at the connection point between the upper wing and the nacelle system, as well as along the spanwise direction of both halves. A total of four longitudinal reinforcing ribs and two transverse reinforcing ribs are designed, which reduces wing weight while maintaining wing strength. Several pressure measurement holes are designed on both the upper and lower wing halves, each with a diameter of 1 mm. The normal plane of the hole's center must be tangent to the wing surface. The pressure measurement holes should be densely arranged at the leading edge and sparsely arranged at the trailing edge. The machining accuracy error of the wing section containing the pressure measurement holes should not exceed 0.08 mm to ensure the pressure measurement accuracy of the wing surface. A stainless steel pressure measurement tube with an outer diameter of 1 mm and an inner diameter of 0.6 mm is bonded to the pressure measurement holes. After connecting the stainless steel tube to the flexible hose and miniature pressure scanning valve, the airtightness and permeability of the entire pressure measurement link must be checked to complete the wing pressure measurement design. See [link to design]. Figure 11 and 14 .

[0029] The fuselage mainly includes the left fuselage 301, the right fuselage 302, the wing tilting mechanism 303, the central load-bearing frame 304, and the tilting shaft 305, see Figure 15 The intermediate load-bearing frame is connected to the external overall force-measuring balance and is welded from 30CrMnSiA high-strength steel. The left and right fuselages are connected to the central load-bearing frame by bolts, primarily bearing the weight of the wings and the aerodynamic forces generated during testing. They are constructed using a single-piece milling process from aluminum, with localized thickening and reinforcement at the location where the tilt axis passes through. Nine cross-shaped adjustment holes are designed on the forward surface of both the left and right fuselages to allow for adjustment of the forward and backward, and vertical positions of the left and right forward wings. Five forward and backward adjustment holes are designed on the rear surface of both the left and right fuselages to allow for adjustment of the relative forward and backward position of the rear wing. This facilitates the study of the interference mechanisms of different relative positions of the forward and rear wings. (See...) Figure 16 .

[0030] The wing tilt mechanism is bolted to the interior of the intermediate load-bearing frame. The wing tilt mechanism includes a tilt servo 306 and a transmission mechanism 307. (See attached image) Figure 17 The tilt servo is connected to the transmission mechanism, and the tilt shaft is connected to the gear pair of the transmission mechanism through an interference fit. It can rotate around the needle roller bearings installed on the position adjustment holes of the left and right fuselage. The left and right ends of the tilt shaft are connected to the upper wing through annular clamping parts and bolts. The tilt servo drives the tilt shaft to rotate, thereby driving the wing to rotate to achieve a tilt of 0-90°.

[0031] The transmission mechanism consists of a primary reduction gear pair and a secondary reduction gear pair. The use of secondary gear transmission can ensure that the size of the wing tilt mechanism is small enough in the narrow space of the fuselage, and that the tilt speed is stable. It also amplifies the torque output of the tilt servo motor. If the tilt servo's operating angle range is known to be 0-270°, and its maximum long-term operating torque is 40 Nm, and it needs to drive the wing to tilt from 0-90°, assuming the first-stage reduction gear pair has n1 teeth on the driving gear and n2 teeth on the driven gear, and the second-stage reduction gear pair has n3 teeth on the driving gear and n4 teeth on the driven gear, with n2 and n3 mounted on the same drive shaft, and the number of gears satisfying n1=n2=n3, then the actual wing tilt angle θ=270°*n1 / n2*n3 / n4. From n1=n2=n3, we can obtain θ=2 70°*n1 / n2*n3 / n4, if θ=90° then n4 / n1≤3; the output torque at the wingtip T=40Nm*n2 / n1*n4 / n3=40*n4 / n1, it can be seen that the tilt angle range and output torque at the wingtip both depend on the value of n4 / n1. However, the larger n4 / n1 is, the larger the output torque at the wingtip and the smaller the tilt angle range. It is necessary to select larger n4 and n1 values ​​as much as possible based on the installation space of the transmission mechanism, under the condition of meeting the tilt range and torque requirements, in order to ensure the stability of the wing tilt mechanism.

[0032] The modular multi-rotor aerodynamic interference model and design method of the present invention, based on modular design, can quickly meet the aerodynamic interference research of rotors and wings with different configurations such as different numbers of rotors, adjustable wing positions, nacelle tilting, rotor tilting, and wing tilting.

[0033] The modular multi-rotor aerodynamic interference model and design method of the present invention, based on modular design, can quickly meet the research needs of rotor and wing aerodynamic interference with different configurations such as different numbers of rotors, adjustable wing positions, nacelle tilting, rotor tilting, and wing tilting.

[0034] The above description merely illustrates embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Furthermore, any parts of the present invention not described in detail are conventional techniques.

Claims

1. A modular multi-propeller aerodynamic interference model, characterized in that, include: Nose, tail, fuselage, wing system, nacelle system; The head and tail are connected to the body. The head and tail are formed by whole-machine milling and internal hollowing. The head and tail are divided into left and right halves, which are snapped together. The nacelle system is connected to the wing system; the wing system is divided into a front left wing, a front right wing, a rear left wing, and a rear right wing. Each of the four wings consists of an upper wing and a lower wing, and is connected to the fuselage via a tilt axis; the nacelle system includes: a rotor hub fairing, a rotor system, a drive motor, a balance heat shield, and a rotor force balance; the rotor system includes an upper rotor hub, a lower rotor hub, rotor clips, and rotor blades; the rotor hub fairing is formed by integral milling and hollowing out of an aluminum part, with multiple fan-shaped slots on the lower circumference, and the rotor hub fairing is connected to multiple arms of the lower rotor hub in the rotor system; the rotor system is connected to the drive motor through the lower rotor hub; the upper rotor hub and the lower rotor hub are connected, the rotor clips are located on the upper rotor hub and the lower rotor hub, and the balance heat shield is located between the drive motor and the rotor force balance; The fuselage includes the left fuselage, right fuselage, wing tilt mechanism, central load-bearing frame, and tilt axis; The middle load-bearing frame is connected to the external whole-machine force-measuring balance; The left and right fuselages are connected to the central load-bearing frame, which bears the weight of the wing itself and the aerodynamic forces generated during the test. It is formed by integral milling of aluminum material, and is locally thickened to enhance the strength of the contact point between the tilt axis and the fuselage. The front surfaces of the left and right fuselages have nine cross-shaped position adjustment holes, and the rear surfaces of the left and right fuselages have five position adjustment holes in the vertical direction for installing the tilt shaft. The wing tilt mechanism is fixedly installed inside the central load-bearing frame. The wing tilt mechanism includes a tilt servo and a transmission mechanism. The tilt servo is connected to the transmission mechanism, and the tilt shaft is interference-fitted with the gear pair of the transmission mechanism. It can rotate around the needle roller bearings installed on the position adjustment holes of the left and right fuselage. The left and right ends of the tilt shaft are connected to the upper wing through annular clamping parts and bolts. The tilt servo drives the tilt shaft to rotate, thereby causing the wing to rotate to achieve a tilt of 0-90°.

2. The modular multi-propeller aerodynamic interference model according to claim 1, characterized in that, Both the upper and lower propeller hubs have T-slots on their connecting surfaces. The propeller clamp is a T-shaped structure and is installed in the T-slot between the upper and lower propeller hubs, using a clearance fit. After the upper and lower propeller hubs are connected, the propeller clamp can rotate 360 ​​degrees within the propeller hub. Each end face of the upper and lower propeller hubs has two threaded holes, which are on the same circumference and spaced 90° apart, and are symmetrical about the propeller hub. Angle lines are engraved on the end faces of the upper and lower propeller hubs, with a range of ±60° and an interval of 5° between adjacent angle lines.

3. The modular multi-propeller aerodynamic interference model according to claim 1, characterized in that, The upper surface of the balance insulation component is connected to the lower surface of the drive motor, and the lower surface is connected to the rotor force balance. The bolts connecting the balance insulation component to the drive motor and the bolts connecting the balance insulation component to the force balance do not contact each other directly and need to be arranged in layers. The balance insulation component is made of mica board material.

4. The modular multi-propeller aerodynamic interference model according to claim 1, characterized in that, The rotor force balance has a cylindrical shape and adopts an integrated milling design. The lower end face of the rotor force balance is connected to the wing system. The rotor force balance has eight force measuring rods, four of which are vertically set in the upper part of the rotor force balance, and the other four are horizontally set at the bottom of the rotor force balance and arranged around the center of the bottom of the rotor force balance. Each force measuring rod is equipped with a resistance strain gauge.

5. The modular multi-propeller aerodynamic interference model according to claim 1, characterized in that, The front left wing, front right wing, rear left wing, and rear right wing are all composed of an upper wing, a lower wing, a tilting nacelle, and flaps. The upper wing has four positioning holes at its four corners, and the lower wing has four positioning round bosses at its four corners. These four positioning round bosses are connected to the four positioning holes of the upper wing in a transition fit, and the upper and lower wings are fastened together at their mid-surface. Each upper wing has a nacelle system connection interface. The tilt nacelle is installed on the wingtip of the upper wing and can tilt at multiple different angles relative to the upper wing; the flaps are connected to the upper wing.

6. The modular multi-propeller aerodynamic interference model according to claim 5, characterized in that, The tilt nacelle has four rows of holes with different circumferential radii. The first row has one hole, which is the shaft hole, serving as the tilt axis of the tilt nacelle. The second row has two holes, which are the position holes for the tilt nacelle at 60° and 90° relative to the wing. The third row has two holes, which are the position holes for the tilt nacelle at 0°, 15°, 30°, 60°, and 90° relative to the wing. The fourth row has three holes, which are the position holes for the tilt nacelle at 0°, 15°, and 30° relative to the wing. The upper wing tip surface is also provided with four rows of holes with the same circumference as the tilting nacelle, with only one threaded hole in each radius.

7. The modular multi-propeller aerodynamic interference model according to claim 5, characterized in that, Each of the left and right end faces of the flap has a threaded hole, and the centers of the two threaded holes are on the same horizontal axis. The flap is connected to the upper half of the wing by a connecting bolt, and the flap can rotate freely around the connecting bolt. The deflection angles of the flap relative to the wing at 0°, 30°, 60° and 90° are simulated by a three-dimensional digital model. A portion of solid material is cut out from the lower surface of the flap and the left and right sides of the lower half of the wing to form angle blocks.

8. The modular multi-propeller aerodynamic interference model according to claim 5, characterized in that, The upper and lower wing halves are machined from a single piece of aluminum. Reinforcing ribs are designed along the chord direction at the connection point between the upper wing and the nacelle system, as well as along the spanwise direction of the upper and lower wing halves. There are four longitudinal reinforcing ribs and two transverse reinforcing ribs. Pressure measurement holes are provided on the upper and lower wing halves, with their central normal plane tangent to the wing surface. The pressure measurement holes are densely arranged on the leading edge of the upper and lower wing halves and sparsely arranged on the trailing edge. Stainless steel pressure measurement tubes are bonded to the pressure measurement holes. After the stainless steel pressure measurement tubes are connected to the flexible hoses and miniature pressure scanning valves, the airtightness and ventilation of the entire pressure measurement link need to be checked, thus completing the design of the wing pressure measurement.

9. The modular multi-propeller aerodynamic interference model according to claim 1, characterized in that... For the head and tail, the left half of the structure is provided with a positioning boss, and the left half of the structure is provided with a groove at the position corresponding to the positioning boss. The left and right halves of the structure are connected together by the positioning boss and the groove. The head and body, and the tail and body are connected by positioning bosses and bolts. The positioning bosses are located on the head and tail, and the corresponding positions on the body are provided with grooves that engage with the positioning bosses. The rotor hub fairing is directly connected to the threaded holes on the four arms of the lower rotor hub in the rotor system, with each sector having an angle of 26°.

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