Cross-medium aircraft adopting box type wing tilt rotor design

Abstract

The invention discloses a cross-medium aircraft adopting a box type wing tilt rotor design. The cross-medium aircraft comprises an aircraft body, and rotor mechanisms and box type wings are arranged on the aircraft body; fixed wings are arranged on two sides of the fuselage; a vertically-through rotor wing mounting space is formed between the fixed wing and the fuselage; a left rotating rod / right rotating rod rotationally connected with the fuselage is arranged in the rotor wing mounting space, and the left rotating rod and the right rotating rod are coaxially arranged; a top power rotor wing is arranged above the left rotating rod / the right rotating rod, and a bottom power rotor wing is arranged below the left rotating rod / the right rotating rod; the machine body is connected with the left rotating rod through a left tilting motor, and the machine body is connected with the right rotating rod through a right tilting motor; according to the invention, the rotor mechanisms are arranged on the fuselage, so that vertical lifting can be carried out during medium crossing, the box-type wings are used during flight in the air to improve the flight efficiency, meanwhile, a fixed wing flight mode and a floating-down type water entry mode of the large-load medium-crossing aircraft are met, and the problem of water-air critical plane conversion of the large-load medium-crossing aircraft is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of unmanned aerial vehicles, and in particular relates to a trans-medium aircraft adopting a box-wing tilt-rotor design. Background Art

[0002] A cross-medium aircraft is an aircraft that can fly or operate between multiple media, typically including different environments such as air, water, and vacuum. The design of this type of aircraft usually needs to address the different physical conditions and technical challenges faced when transitioning between these media. The main application areas of cross-medium aircraft include ocean, air, and even space exploration. Currently, there are three types of cross-medium methods for aircraft: gliding, splashing, and floating. The gliding method uses the take-off and landing method of a seaplane, slowing down on the water surface before slowly diving underwater. The splashing method uses bionic principles, directly "plunging" into the water from the air. The floating method uses the take-off and landing method of a multi-rotor drone, falling into the water at a lower speed, and then switching to diving mode.

[0003] All three of the aforementioned water entry methods have been used to some extent. NASA has conducted research on splashdown trans-medium UAVs, but failed to address the strength issues of the fuselage materials. Shanghai Jiao Tong University has developed the "Nezha" trans-medium aircraft, which utilizes a quadrotor structure and is a typical floating trans-medium method. Harbin Engineering University has developed the "Longbow 1" and "Longbow 2" trans-medium aircraft, which utilize a gliding entry and splashdown exit method to address cross-domain control issues. This shows that vertical takeoff and landing and long range for large-payload trans-medium aircraft are contradictory issues and difficult to achieve simultaneously. Summary of the Invention

[0004] The purpose of the present invention is to provide a trans-medium aircraft with a box-wing tilt-rotor design to solve the water-air critical surface conversion problem of a large-load trans-medium aircraft.

[0005] The present invention adopts the following technical solution: a trans-medium aircraft adopting a box-wing tilt-rotor design comprises a fuselage on which a rotor mechanism and a box-wing are provided;

[0006] There are fixed wings on both sides of the fuselage;

[0007] There is a rotor installation space that runs vertically between the fixed wing and the fuselage;

[0008] A left rotation rod / right rotation rod connected to the fuselage rotation is provided in the rotor installation space, and the left rotation rod and the right rotation rod are coaxially arranged;

[0009] A top power rotor is provided above the left turning lever / right turning lever, and a bottom power rotor is provided below the left turning lever;

[0010] The fuselage is connected to the left rotating rod through a left tilt motor, and the fuselage is connected to the right rotating rod through a right tilt motor.

[0011] Furthermore, a trim rotor is provided at the tail of the fuselage.

[0012] Furthermore, the top power rotor and the bottom power rotor are coaxially arranged and rotate in opposite directions.

[0013] Furthermore, ailerons are provided on the outer sides of the fixed wings;

[0014] A box wing is provided on the outer side of the aileron, and the other end of the box wing is connected to the tail of the fuselage.

[0015] Furthermore, vertical tails are provided on both sides above the tail of the fuselage, and rudders are provided on the vertical tails.

[0016] Furthermore, a horizontal tail is provided between the tops of the two vertical tails, and an elevator is installed on the horizontal tail.

[0017] Furthermore, the tail end of the box wing is connected to the top of the vertical tail on the corresponding side.

[0018] Furthermore, the fuselage is provided with a main support rod running forward and backward;

[0019] The center of gravity of the trans-medium aircraft is located on the main support and behind the left rotation stick / right rotation stick.

[0020] Furthermore, the trim rotor is mounted on the main strut.

[0021] Furthermore, the rotor mechanisms and fixed wings on both sides of the fuselage are symmetrically arranged relative to the fuselage.

[0022] The beneficial effects of the present invention are as follows: the present invention can perform vertical ascent and descent when crossing a medium by arranging a rotor mechanism on the fuselage, and use box-type wings to improve flight efficiency when flying in the air, while meeting the fixed-wing flight mode and floating-down water entry mode of large-load cross-medium aircraft, and solving the water-air critical surface conversion problem of large-load cross-medium aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a trans-medium aircraft using a box-wing tilt-rotor design according to an embodiment of the present invention;

[0024] Figure 2 Schematic diagram of the structure of the rotor mechanism in an embodiment of the present invention;

[0025] Figure 3 Schematic diagram of force analysis of the rotor mechanism during ascent of a trans-medium aircraft according to an embodiment of the present invention;

[0026] Figure 4Schematic diagram of force analysis of the rotor mechanism during rolling of a cross-medium aircraft according to an embodiment of the present invention;

[0027] Figure 5 Schematic diagram of force analysis of the rotor mechanism when the cross-medium aircraft turns in an embodiment of the present invention;

[0028] Figure 6 Schematic diagram of the state of the cross-medium aircraft from submergence to vertical takeoff in an embodiment of the present invention;

[0029] Figure 7 A schematic diagram of a state of a cross-medium aircraft from a hovering state to a flying state in an embodiment of the present invention;

[0030] Figure 8 Schematic diagram of the state of a cross-medium aircraft from a flying state to a water entry state in an embodiment of the present invention.

[0031] Including: 100. fuselage;

[0032] 200. Box wing; 210. Fixed wing; 220. Aileron; 230. Box wing; 240. Elevator; 250. Rudder;

[0033] 300. Rotor mechanism; 310. Top powered rotor; 320. Bottom powered rotor; 330. Trimming rotor; 340.

[0034] Left tilt motor; 350. Right tilt motor; 360. Left rotation rod; 370. Right rotation rod; 380. Main support rod. DETAILED DESCRIPTION

[0035] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] The cross-medium aircraft described in the present invention is an aircraft that crosses both water and air. In the prior art, the sliding-down water entry method is generally used for fixed-wing cross-medium aircraft. Due to the fixed-wing design, the aircraft has higher flight efficiency (faster flight speed or longer range at the same energy consumption) and a larger payload. However, this design has the following problems:

[0037] First, the cross-medium landing process is complex. The landing process is similar to that of a fixed-wing seaplane, requiring a descent, a glide, and a dive. The entire process requires precise control over a long period of time. Second, it is sensitive to sea conditions. When wave heights exceed the limit, the aircraft cannot land, and thus cross-medium landing is impossible. Third, there are requirements for the size of the sea area. The glide-into-water process requires a long glide distance, making normal takeoff and landing in narrow inland waterways difficult.

[0038] Splashdown is generally used for trans-medium aircraft with variable-sweep wings. Since they also use fixed-wing designs, the aircraft has good flight efficiency. However, this design has the following problems:

[0039] First, the variable-sweep wing structure is complex. To achieve the retraction and extension of the swept wing, a complex and precise mechanical structure is required. Due to the impact during the cross-medium process, the retraction and extension mechanism is prone to failure. Second, the load is low. Due to the requirements of this method for the power system when exiting the water, the aircraft has a small cross-section and adopts a long water drop structure, resulting in a limited load capacity. Third, it is difficult to mannify. The impact during the air-water cross-medium stage is strong, and the instantaneous acceleration can reach over 9G. Fourth, the structural strength requirements are high. Also due to the impact during the air-water cross-medium stage, extremely high requirements are placed on the structural strength and skin materials.

[0040] Floating-type water-entry aircraft typically utilize a multi-rotor layout. This arrangement results in a compact structure and relatively simple attitude control. However, these aircraft present the following challenges: First, low flight efficiency. Due to the lack of fixed wings, the aircraft consumes high energy, has a short range, and carries a low payload. Second, the powertrain is poorly matched. The engine must provide power both in the air and underwater. Especially underwater, due to the high viscosity of water, conventional motors are prone to overpowering and failure. To maintain adequate underwater controllability, the propellers must sacrifice aerodynamic performance in the air.

[0041] To improve the aerial capabilities of a floating, cross-medium aircraft, Shanghai Jiao Tong University's "Nezha 3" fuses fixed-wing and multi-rotor aircraft, employing a tilt-rotor design. However, due to the lack of fixed-wing design requirements during the design phase (fixed-wing aircraft developed based on multi-rotor aircraft, rather than multi-rotor aircraft developed based on fixed-wing aircraft), the fixed-wing aircraft exhibits poor aerodynamic performance during level flight, requiring complex attitude control.

[0042] For cross-medium aircraft that use fixed wings + gliding water entry, since they completely adopt a fixed-wing layout, the process of crossing the air-water interface is complicated and has high requirements for sea conditions and sea areas, resulting in deployment restrictions.

[0043] For cross-medium aircraft that use variable swept wings + splashdown, due to its high water entry speed, the aircraft load is limited in order to meet the requirements for fuselage strength in the event of impact.

[0044] For a multi-rotor + floating cross-medium aircraft, since it completely uses rotors to provide lift, its flight efficiency is low, the range is short, and the payload is small.

[0045] To solve the above problems, a tiltrotor + floating-down design was adopted. This solution takes into account the low entry speed requirement of the floating-down design and the high flight efficiency and large payload advantages brought by the fixed-wing design.

[0046] Shanghai Jiao Tong University's "Nezha 3" cross-medium aircraft incorporates fixed wings on top of a multi-rotor system. However, its aerodynamic layout is still primarily multi-rotor, so the aircraft cannot fully achieve level flight like a fixed-wing aircraft, resulting in a shorter range.

[0047] The design concept of this invention is to add a multi-rotor design to a fixed-wing aircraft. The rotors are incorporated into the fixed-wing body using a coaxial engine arrangement, resulting in a more compact and stronger overall structure. Furthermore, the invention utilizes high-torque servos to tilt the rotors, enabling flexible switching between rotor and fixed-wing flight attitudes. This resolves the conflict between vertical takeoff and landing (VTOL) and long range, achieving the design criteria of a cross-medium, vertical takeoff and landing (VTOL) aircraft with a high payload, high maneuverability, and a long range.

[0048] Furthermore, the present invention utilizes a box-shaped wing to shift the center of lift behind the center of gravity (nose forward, tail aft), ensuring static stability during level flight. During vertical takeoff and landing, the center of gravity lies within the closed plane formed by the lift points of each engine, ensuring that each engine generates positive lift. This design balances stability and power requirements in both flight attitudes.

[0049] The present invention discloses a trans-medium aircraft adopting a box-wing tilt-rotor design, such as Figure 1 and Figure 2 As shown, it includes a fuselage 100, on which a rotor mechanism 300 and a box-type wing 200 are provided; fixed wings 210 are provided on both sides of the fuselage 100; a rotor installation space that passes through the fixed wings 210 and the fuselage 100 is provided; a left rotating rod 360 / right rotating rod 370 connected to the fuselage rotation is provided in the rotor installation space, and the left rotating rod 360 and the right rotating rod 370 are coaxially arranged; a top powered rotor 310 is provided above the left rotating rod 360 / right rotating rod 370, and a bottom powered rotor 320 is provided below; the fuselage 100 and the left rotating rod 360 are connected via a left tilt motor 340, and the fuselage 100 and the right rotating rod 370 are connected via a right tilt motor 350.

[0050] The present invention can perform vertical ascent and descent when crossing a medium by arranging a rotor mechanism 300 on the fuselage, and use box-type wings 200 to improve flight efficiency when flying in the air. At the same time, it meets the fixed-wing flight mode and floating-down water entry mode of large-load cross-medium aircraft, and solves the water-air critical surface conversion problem of large-load cross-medium aircraft.

[0051] Specifically, in the present invention, the left and right rotation levers 360 and 370 can rotate along their respective axes, and during this rotation, they simultaneously drive the top powered rotor 310 and the bottom powered rotor 320 to turn. When the left and right rotation levers 360 and 370 are in their initial state, the rotation axes of the top and bottom powered rotors 310 and 320 are both vertically arranged, which can drive the trans-medium aircraft to rise or fall in the vertical direction. When the left and right rotation levers 360 and 370 are rotated, the rotation axes of the top and bottom powered rotors 310 and 320 are arranged in the front-to-back direction of the trans-medium aircraft, which can provide the trans-medium aircraft with forward or backward power, thereby achieving the switching between rotary-wing flight and fixed-wing flight.

[0052] In an embodiment of the present invention, the rotor mechanisms 300 and fixed wings 200 on both sides of the fuselage 100 are symmetrically arranged relative to the fuselage, a balancing rotor is provided at the tail of the fuselage 100, and the top power rotor 310 and the bottom power rotor 320 are coaxially arranged and rotate in opposite directions.

[0053] Specifically, the entire aircraft adopts a box-type wing layout, and the main wing portion of the wing adopts a medium aspect ratio layout with a small sweep angle. The purpose is to move the aerodynamic center toward the tail while ensuring a high lift coefficient. Under the coupling effect of the box wing and the main wing, the aerodynamic center of the aircraft of the present invention is located behind the center of gravity, making the aircraft's level flight state a statically stable state, thereby improving flight stability.

[0054] Compared to conventional high-aspect-ratio aircraft (such as passenger and transport aircraft), the aircraft of the present invention lacks leading-edge slats and trailing-edge flaps. This is because slats and flaps are primarily used to increase wing camber during takeoff and landing, thereby achieving a higher lift coefficient. However, the aircraft of the present invention utilizes vertical takeoff and landing, eliminating the need for wing camber adjustment and, therefore, eliminating the need for slats and flaps.

[0055] In one embodiment, ailerons 220 are disposed on the outside of fixed wings 210; box wings 230 are disposed on the outside of ailerons 220, with the other end of box wings 230 connected to the tail of fuselage 100. Vertical stabilizers are disposed on both sides above the tail of fuselage 100, each equipped with a rudder 250. A horizontal stabilizer is disposed between the tops of the two vertical stabilizers, with an elevator 240 mounted on each horizontal stabilizer. The tail end of box wings 230 is connected to the top of the corresponding vertical stabilizer.

[0056] The aircraft of the present invention utilizes a V-shaped vertical tail with a trim rotor 330 positioned in the center. A horizontal stabilizer (i.e., horizontal tail) spans the vertical stabilizer (i.e., vertical tail), further enhancing the structural strength of the tail section. Furthermore, both the vertical and horizontal stabilizers are swept back to prevent the aircraft structure from affecting the aerodynamic efficiency of the trim rotor.

[0057] The present invention includes four lift rotors (two top powered rotors 310 and two bottom powered rotors 320), a trim rotor 330, and two tilting motors. The rotor system is connected to the fuselage via a carbon fiber tube. The power and tilting motors are arranged on a cross-shaped structure made of carbon fiber and aviation aluminum alloy, which has a high rigidity (compared to the fuselage). This prevents vibration from the motors from causing resonance in the fuselage, which could lead to strength issues.

[0058] The power rotor adopts a coaxial layout scheme, with the upper and lower sets of motors rotating in opposite directions, and the motors on the left and right wings rotating in opposite directions. Figure 3 、 Figure 4 and Figure 5 For force analysis of this arrangement, the torques generated by the upper and lower coaxial motors cancel each other out, with the trim rotor counteracting the tilt torque generated by the powered rotor. Adjusting the output power of the trim rotor 330 enables pitch control of the aircraft during hover. The trim rotor also generates a tilt torque, which is largely offset by the tilted trim tail 300. Fine-tuning the remaining torque is achieved by adjusting the rotational speed of the coaxial upper and lower powered rotors.

[0059] exist Figure 4 and Figure 5 Increasing the power output of one power motor on either side simultaneously can cause the aircraft to fly sideways in the opposite direction. Simultaneously adjusting the power output of the powered rotors on both sides can steer the aircraft to one side while maintaining the total lift. In summary, by adjusting the rotor power output, the aircraft of the present invention can achieve flight maneuvers similar to those of traditional rotorcraft (multi-rotor drones, helicopters).

[0060] To facilitate transport and quick installation of the aircraft, this invention incorporates quick-install mechanisms at the wing-to-fuselage and wing-to-tail connections. The main wings (i.e., fixed wings) are bolted to the fuselage, positioned by overlapping them. The box wings are also bolted to the tail, also using overlapping connections.

[0061] Due to the structural strength requirements of the bolted connection's preload, the wing is constructed of nylon carbon fiber. To increase wing rigidity, transverse and longitudinal ribs are installed within the wing. Carbon fiber tubes run through the wing to further enhance rigidity. At the quick-release connection, bolts are preloaded to secure the carbon fiber tubes and connect the two adjacent components.

[0062] The fuselage 100 is provided with a main strut 380 (i.e., the aforementioned carbon fiber tube; if the main strut 380 is hollow, it forms a tube). The center of gravity of the trans-medium aircraft is located on the main strut 380, behind the left rotation rod 360 and the right rotation rod 370. The trim rotor 330 is mounted on the main strut 380.

[0063] A trans-medium aircraft consists of an airframe, rotor propulsion system, underwater navigation system, and flight control system. The airframe provides the fundamental structural strength of the aircraft, while the rotor propulsion system enables vertical takeoff and landing (VTOL) and aerial flight. The underwater navigation system provides underwater propulsion and attitude control for the aircraft. The flight control system controls the aircraft's flight, navigation, and trans-medium attitude.

[0064] In one embodiment, the aircraft has a wingspan of 2990 mm and a fuselage length of 2560 mm. It adopts a straight-swept box-wing layout with an aspect ratio of 3.7. The power system consists of four coaxially arranged 6.8 kg propellers, resulting in a thrust-to-weight ratio of 2.25. The aircraft has a designed takeoff weight of 12 kg, with the engines operating at 50% power output. The redundant power is used for attitude control and short-term acceleration during the rotor-to-fixed wing attitude transition.

[0065] The cross-media method of the present invention is as follows Figure 6 、 Figure 7 and Figure 8 As shown. Figure 6 As shown, in the submerged state, the airbags installed inside the floats are inflated, increasing the buoyancy of the aircraft and allowing it to float from the submerged state to the surface. When floating on the surface, the motors are above the water level, at which point the power rotors and trim rotors are activated, allowing the aircraft to take off vertically from the water. To prevent accidental activation of the power rotors and trim rotors 330 during underwater navigation, which could damage the motors, these motors are locked while underwater. They automatically unlock when they clear the water.

[0066] like Figure 7 As shown, when the aircraft is in hover, the tilt motors tilt the powered rotors, accelerating the aircraft forward and transitioning from hover to fixed-wing flight. The aircraft's attitude is controlled by the control surfaces, and the flight control laws are the same as those of traditional fixed-wing aircraft. In level flight, the trim rotors are disabled, and pitch control relies entirely on the elevators.

[0067] like Figure 8 As shown, the aircraft decelerates at a high pitch angle to return to a hovering state from a level flight state, and inflates the airbags. It then floats down to the water surface, relocking the motors of the power and trim rotors 330. The airbags are then deflated, allowing the aircraft to re-enter the water.

[0068] In summary, the overall design of the cross-medium aircraft has been completed, especially the design of a box-wing layout, coaxial rotors, and tilt-rotors, which resolves the contradiction between cross-medium and long range and heavy load. Flexible floats are used to control diving and underwater posture; a floating-down method is used to cross the water-air medium; and a tilt-rotor is used to switch flight posture (rotor-fixed wing). The rotor system of the present invention is not a traditional four-rotor or six-rotor layout. It adopts a coaxial arrangement of power rotors and a rotor system with a balancing rotor to adjust the posture.

[0069] Furthermore, the traditional splashdown method requires high structural strength and a smooth fuselage, which limits the aircraft's external payload capacity. The present invention utilizes a tiltrotor method, resulting in a gentler crossover process while maintaining significantly higher efficiency than the "slip-down" method. However, the tiltrotor method requires the aircraft to switch between fixed-wing and rotor-wing configurations, especially at low altitudes during these transitions, which shortens the time required for emergency response. This necessitates that the flight control system be able to sense the aircraft's configuration in real time and rapidly control power output.

[0070] To maintain rapid control of the propulsion system, the primary power source utilizes a brushless motor, which is highly susceptible to power overload and even short circuit upon contact with water. Therefore, the motor must be shut down before the aircraft fully touches the water. Determining the shutdown altitude requires extensive simulation calculations to ensure that the propellers stop upon contact with the water while also ensuring that the impact with the water does not exceed the structural strength limits of the aircraft.

[0071] Compared with traditional cross-medium aircraft with multi-rotor layout, the cross-medium process has less impact on the fuselage structure due to the lack of large aspect ratio wings. However, under the layout adopted by the present invention, during the cross-medium stage of the water-air critical surface, the wing root position will be impacted by bending and torsional loads. Therefore, the present invention adopts a fusion design of winglets and wing-body (that is, the wing in the present invention integrates the winglets, and the winglets extend continuously from the front end of the fuselage to the rear end of the fuselage), the connection area between the wing and the fuselage is larger, and the structural strength is higher; at the same time, the presence of the winglets makes the connection between the wing and the fuselage have no sharp angles, reduces stress concentration, and improves the strength of the structure. In addition, the present invention adopts a box-type wing layout, which makes the fuselage stronger. However, the complex wing surface design makes the aerodynamic structure of the aircraft different from the traditional aircraft configuration, the aerodynamic characteristics are complex, and the control difficulty is also greater.

Claims

1. A trans-medium aircraft adopting a box-wing tilt-rotor design, characterized in that: It comprises a fuselage (100), wherein the fuselage (100) is provided with a rotor mechanism (300) and a box-type wing (200); Fixed wings (210) are provided on both sides of the fuselage (100); A rotor installation space is provided between the fixed wing (210) and the fuselage (100), which is connected vertically. A left rotation rod (360) and a right rotation rod (370) rotatably connected to the fuselage are provided in the rotor installation space, and the left rotation rod (360) and the right rotation rod (370) are coaxially arranged; A top power rotor (310) is provided above the left rotation rod (360) / right rotation rod (370), and a bottom power rotor (320) is provided below the left rotation rod (360) / right rotation rod (370); The fuselage (100) and the left rotating rod (360) are connected via a left tilt motor (340), and the fuselage (100) and the right rotating rod (370) are connected via a right tilt motor (350).

2. The trans-medium aircraft using a box-wing tilt-rotor design according to claim 1, characterized in that: The tail of the fuselage (100) is provided with a trim rotor.

3. The trans-medium aircraft using a box-wing tilt-rotor design according to claim 2, characterized in that: The top power rotor (310) and the bottom power rotor (320) are coaxially arranged and rotate in opposite directions.

4. A trans-medium aircraft using a box-wing tilt-rotor design according to claim 2 or 3, characterized in that: An aileron (220) is provided on the outer side of the fixed wing (210); A box wing (230) is provided on the outer side of the aileron (220), and the other end of the box wing (230) is connected to the tail of the fuselage (100).

5. The trans-medium aircraft using a box-wing tilt-rotor design according to claim 4, characterized in that: Vertical tails are provided on both sides above the tail of the fuselage (100), and rudders (250) are provided on the vertical tails.

6. The trans-medium aircraft using a box-wing tilt-rotor design according to claim 5, characterized in that: A horizontal tail is provided between the tops of the two vertical tails, and an elevator (240) is installed on the horizontal tail.

7. The trans-medium aircraft using a box-wing tilt-rotor design according to claim 7, characterized in that: The tail end of the box wing (230) is connected to the top of the vertical tail on the corresponding side.

8. A trans-medium aircraft using a box-wing tilt-rotor design as claimed in claim 2 or 3, characterized in that: The fuselage (100) is provided with a main support rod (380) extending forward and backward; The center of gravity of the trans-medium aircraft is located on the main support rod (380) and behind the left rotation rod (360) / right rotation rod (370).

9. The trans-medium aircraft using a box-wing tilt-rotor design according to claim 8, characterized in that: The trim rotor (330) is mounted on the main support rod (380).

10. The trans-medium aircraft using a box-wing tilt-rotor design according to claim 7, characterized in that: The rotor mechanisms (300) and the fixed wings (200) on both sides of the fuselage (100) are symmetrically arranged relative to the fuselage.

Images