RU2842754C1 - Aircraft aerodynamic configuration - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: invention relates to aircraft engineering and can be used in designing subsonic transport aircraft. Aerodynamic configuration of the aircraft is characterized by the fact that the aircraft is made as a low-wing of a normal aerodynamic configuration with a fuselage, a swept wing, a horizontal and vertical tail unit, incorporates two turbojet engines arranged in engine nacelles arranged on opposite sides of fuselage and attached to swept wing by means of underwing pylons. Takeoff-and-landing lift devices are arranged on wing while deflecting nose and slat sections are arranged on wing leading edge. At rear edge are sections of rotary flap. Besides, wing accommodates control elements, i.e. aileron, spoiler sections and brake flap sections. In the joint area of swept wing and fuselage ventral fairing is made. Wherein swept wing consists of centre section, outer wings and tip and features definite profile. Engine nacelles are made without mixing of flows of external and internal contours, are pushed forward so that their outer contour along axis of symmetry does not go under the wing. Angles of their installation in vertical and horizontal planes are 1.5° down with toe and 1.5° tip to fuselage, respectively. Engine-to-wing attachment pylons feature curvature of their shaping in tail section to decrease local velocity on pylon surface. Stabilizer has elongation 4.93 and sweep 34° by ¼ chord. In this case, the stabilizer profiling has a negative curvature of ~1% and a relative thickness of 10%; at the location of the stabilizer on the fuselage, the side surfaces are flattened in a “pike tail” type. vertical empennage – keel – has elongation 1.61, sweep 40.8° by ¼ of chords and relative thickness of 10%.

EFFECT: improving aerodynamic qualities in cruising mode, id est low drag with the required lift, by selecting optimal geometric shapes of aircraft components that affect aerodynamic characteristics.

1 cl, 7 dwg

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[0001] The invention relates to aviation technology and can be used in the design of subsonic transport category aircraft.

[0002] The preferred field of application of the invention is wide-body long-range aircraft with cruising flight at transonic speed.

LEVEL OF TECHNOLOGY

[0003] Various aerodynamic designs of modern passenger aircraft are known, for example, the design of the Boeing B-777-200 aircraft is known (see Passenger Aircraft of the World, compiled by Belyaev V.V., pp. 226-227, Moscow, ASPOL, Argus 1997), in which the aircraft wing is designed with an aspect ratio of λ = 12.04, a narrowing of η = 4.5, and a sweep of χ1/4 = 35°.

[0004] The closest analogue to the claimed technical solution is the aerodynamic design of the Boeing-787 and Airbus-350 aircraft.

[0005] The creation of an aircraft capable of effectively performing transport tasks at transonic speeds is a complex technical problem. One of the main problems is ensuring high aerodynamic quality in cruising mode, i.e. low drag with the required lifting force. This is ensured by optimal geometric shapes of the aircraft.

DISCLOSURE OF THE ESSENCE OF THE INVENTION

[0006] The technical problem that the claimed invention is aimed at solving consists of creating a wide-body long-range aircraft with high aerodynamic quality and fuel efficiency at subsonic cruising flight speeds in the range of Mach numbers Mcreis = 0.84-0.86 and improved takeoff and landing characteristics and characteristics in icing conditions.

[0007] The technical result achieved by implementing the claimed invention consists in creating an aerodynamic design for a wide-body long-range aircraft that ensures high aerodynamic qualities in cruising mode, i.e. low drag with the required lift force due to the selection of optimal geometric shapes of aircraft components that affect the aerodynamic characteristics.

[0008] The claimed technical result is achieved due to the fact that the aerodynamic configuration of the aircraft is characterized by the fact that the aircraft is made as a low-wing aircraft of normal aerodynamic design, includes a fuselage, a swept wing, horizontal and vertical tail units, two turbojet engines located in nacelles spaced on opposite sides of the fuselage and attached to the wing using underwing pylons, takeoff and landing mechanization is located on the wing, a deflectable nose and slat sections are on the leading edge, and rotary flap sections are on the trailing edge, and control bodies are also located on the wing - an aileron, interceptor sections and brake flaps sections, a ventral fairing is made in the area of the junction of the wing and fuselage, while the swept wing of the aircraft consists of a center section, consoles and a tip, and is made with with an aspect ratio along the basic trapezoid of λ = 12.04 taking into account the tip, a taper of η = 4.5 and a sweep along the leading edge of X = 35°, formed from supercritical profiles, the leading edge of the wing is straight when viewed from above, the trailing edge is made with an overlap and a break in the form of rounding, the value of the radii of the wing section leads, related to the local chord of the section, is r _n = 0.8-1.4%, and the average line of the wing profiles up to 30% of the span in shape has a negative curvature of up to 1.7% of the chord, the average line of profiles from 30 to 50% of the span has zero curvature up to 45% of the chord and positive curvature in the tail part of the profile, the average line of profiles from 50 to 100% of the span has a positive curvature increasing along the chord up to 2%, the wing tip has a span 7% of the wing span, variable sweep X _pc = 35…58°, formed from supercritical profiles with a relative thickness of 9-11%, while the middle lines of the profiles at the tip have a maximum curvature of up to 3% closer to the middle of the profile;

the engine nacelles are made without mixing the flows of the outer and inner contours, the engine nacelles are extended forward in such a way that their outer contour along the axis of symmetry does not go under the wing, while the angles of their installation in the vertical and horizontal planes are 1.5° downwards with the nose and 1.5° with the nose towards the fuselage, respectively;

the pylons for attaching the engines to the wing are designed with a curvature of their profile in the tail section, leading to a decrease in local speeds on the surface of the pylon;

the stabilizer has an aspect ratio of 4.93 and a sweep of 34° at ¼ chord, while the stabilizer profile has a negative curvature of ~ 1% and a relative thickness of 10%, at the location of the stabilizer on the fuselage, the side surfaces are flattened in the “pike tail” type;

The vertical tail (keel) has an aspect ratio of 1.61, a sweep angle of 40.8° at ¼ chord and a relative thickness of 10%.

BRIEF DESCRIPTION OF DRAWINGS

[0009] The implementation of the invention is explained by drawings, which depict:

Fig. 1 - general view of the aircraft;

Fig. 2 - general view of the aircraft (front view);

Fig. 3 - plane view;

Fig. 4 - general view of the swept wing of the aircraft and basic sections of the wing;

Fig. 5 - distribution of the relative maximum thickness of the profiles along the wing span;

Fig.6 - typical profile of the wing console;

Fig. 7 - distribution of wing twist along the span.

[0010] In the drawings, the positions have the following designations:

1 - fuselage; 2 - swept wing; 3 - horizontal tail; 4 - vertical tail; 5 - engine nacelle; 6 - pylon; 7 - fairing; 8 - main landing gear; 9 - nose landing gear; 10 - wingtip; 11 - leading edge; 12 - slat sections; 13 - rotary flap; 14 - aileron; 15 - spoilers; 16 - airbrake; 17 - elevator; 18 - rudder; 19 - center section; 20 - wing console; 21 - leading edge; 22 - trailing edge; 23 - break; 24 - overlap; 25 - supercritical profile; 26 - nose; 27 - upper surface; 28 - lower surface; 29 - section of strong curvature; 30 - flattening "pike tail".

IMPLEMENTATION OF THE INVENTION

[0011] The wide-body long-range aircraft is designed as a low-wing monoplane of normal aerodynamic configuration with a fuselage 1 (Fig. 1) of cylindrical shape, swept wing 2, all-moving horizontal 3 and fixed vertical 4 tail unit. The aircraft has two turbojet engines under the wing. The engines are located in nacelles 5, spaced on opposite sides of the fuselage and attached to the wing by means of underwing pylons 6. In the area where the wing and fuselage join, a fairing 7 (Fig. 1, 2) is made, into which the main landing gear 8 is retracted. The front landing gear 9 is retracted into the nose section of the fuselage 1.

[0012] The swept wing 2 of the wide-body long-range aircraft (Fig. 4) consists of a center section 19, a console 20 and a tip 10, and is made with an aspect ratio of λ = 12.04 taking into account the tip, a taper of η = 4.5 and a sweep along the leading edge of X = 35°, without an overlap or break along the leading edge 21 and with a break 23 and an overlap 24 on the trailing edge 22 of the wing. The break 23 along the trailing edge 22 is made in the form of a rounding, due to which the wing has a more uniform distribution of the thickness of the sections (C) along the wing span (Z/L) (Fig. 5).

[0013] Due to the absence of a break along the leading edge 21, the wing has a more uniform distribution of the thickness of the sections along the wing span (Fig. 5) and lower loads on the wing structure compared to wings that have an extension on the leading edge of the wing. This, in turn, makes it possible to reduce the weight of the wing structure.

[0014] The swept wing 2 is formed by thirteen basic sections (I – XIII in Fig. 4), obtained using a multi-stage aerodynamic design procedure. The swept wing 2 is formed from supercritical profiles (Fig. 4), the leading edge 21 of the wing is rectilinear when viewed from above, the trailing edge 22 is made with an extension 24. The value of the radii of the leading edges 26 of the wing sections, related to the local chord, is r _n = 0.8-1.4%. The center line between the upper 27 and lower 28 surfaces of the wing profiles up to 30% of the span has a negative curvature of up to 1.7% of the chord (or 0.017 of the chord), the center line of the profiles from 30 to 50% of the span has zero curvature up to 45% of the chord and positive curvature in the tail section of the profile 29, the center line of the profiles from 50 to 100% of the span has a positive curvature increasing along the chord up to 2%, the center line of the profiles at the tip 10 has a maximum curvature of up to 3% closer to the middle of the profile. The increased radii of the noses 26 of the profiles r _n = 0.8-1.4% lead to a lower intensity of ice deposits build-up during flights in icing conditions, and also increase the lifting properties of the wing at high angles of attack.

[0013] Wing tip 10 is designed using a special technology that provides for increased aerodynamic performance in cruising and takeoff modes and a reduction in the wing bending moment in extreme modes. Wing tip 10 is formed from supercritical profiles with a relative thickness of 9-11% and has a special geometric twist (Fig. 7). The span of wing tip 10 is 7% of the wing span. The sweep angle of wing tip 10 is variable Хпк = 35…58° and is selected for the required wing unloading at high velocity pressures.

[0014] The swept wing 2 contains takeoff and landing mechanization to ensure the required characteristics at low speeds: on the leading edge, a deflectable nose 11 (in Fig. 3) and slat sections 12, on the trailing edge, sections of a rotating flap 13. Also located on the wing are controls: an aileron 14, sections of spoilers 15 and sections of brake flaps 16. In takeoff and landing modes, the spoilers and brake flaps can be deflected downward, optimizing the size of the gap between their trailing edge and the flap. In takeoff and landing modes, the ailerons can be symmetrically deflected downward to increase the lift force.

[0015] The engine nacelles 5 are made without mixing the flows of the outer and inner contours, and are placed under the swept wing 2 in such a way as to minimize their harmful interference with the wing. For this purpose, the engine nacelles 5 are extended forward in such a way that their outer contour along the axis of symmetry does not go under the wing, the angles of their installation in the vertical and horizontal planes are optimal - 1.5° downwards with the nose and 1.5° with the nose toward the fuselage 1, respectively.

[0016] The pylons 6 for attaching the engines to the wing have a geometric shape that ensures minimum drag in all flight modes due to the curvature of their profile in the tail section, leading to a decrease in local speeds on the pylon surface. The pylons 6 are made in the form of a body with smooth contours, formed by the side walls, their parallel placement relative to each other in the front part of the pylon and their connection to each other in the nose and tail sections. The pylon is also made with a rounded conjugation of the side walls in the nose section, and in the tail section by connecting them at an acute angle to each other, by making the joint of the side walls in the tail section in the form of a segment oriented at an obtuse angle to the lower end of the pylon, by working the ends of the pylon shell with cuts in the form of elongated template curves and orienting their convexities towards each other. Pylon 6 also has a fairing for the engine control equipment, made in the form of an elongated tetrahedral body with rounded edges, partially recessed into the body of the pylon, and placed at the top of the tail section of the pylon with a deviation in the direction of the fuselage.

[0017] The fuselage of the 1 aircraft is made cylindrical in shape, the cross-section is close to a circle of large diameter.

[0018] The tail section of the fuselage 1 houses the horizontal tailplane (stabilizer) 3 (Fig. 1). The stabilizer 3 has an aspect ratio of 4.93 and a sweep of 34° at ¼ chord, which ensures its efficient operation and, at the same time, low induced drag. The stabilizer profile has a negative curvature of ~ 1% and a relative thickness of 10%. The area of the horizontal tailplane 1 is 86.0 ^m2 (25.39% Sкр) (where Sкр is the wing area along the base trapezoid, which is 339 ^m2 ) and the static moment (over the area of the wing base trapezoid) is 1.098.

[0019] The stabilizer 3 is made adjustable - to balance the aircraft, it can rotate around an axis perpendicular to the plane of symmetry of the aircraft, with the nose up and down. In order to minimize the gaps between the stabilizer 3 and the fuselage 1 during rotation, at the location of the stabilizer on the fuselage, a flattening of the side surfaces of the "pike tail" type 30 is made.

[0020] The stabilizer consoles 3 accommodate elevators 17 - controls that, like the stabilizer itself, balance the aircraft. The elevators can be deflected up and down with their tails.

[0021] The vertical tail (keel) 4 installed in the tail section of the fuselage 1 has an area of 46 ^m2 (13.58% Sкр) and a static moment of 0.061, ensuring safe flight of the aircraft in all modes. Its aspect ratio is 1.61, sweep 40.8° by ¼ chord, relative thickness - 10%, allowing flight at high speeds without additional drag. The rudder 18 is installed on the keel, providing control in the lateral channel.

[0022] In this way, it is possible to create an aerodynamic configuration of the aircraft that has the following advantages:

- high aerodynamic quality and fuel efficiency at subsonic cruising flight speeds in the range of Mach numbers Mcreis = 0.84-0.86;

- improved takeoff and landing characteristics and performance in icing conditions.

Claims (5)

The aerodynamic configuration of the aircraft is characterized by the fact that the aircraft is designed as a low-wing monoplane of normal aerodynamic configuration with a fuselage (1), swept wing (2), horizontal (3) and vertical (4) tail unit, has two turbojet engines located in nacelles (5), spaced on opposite sides of the fuselage (1) and attached to the swept wing (2) by means of underwing pylons (6), on the swept wing (2) is located the takeoff and landing mechanization, on the leading edge - a deflectable nose (11) and slat sections (12), on the trailing edge - rotary flap sections (13), also on the wing are located the controls - an aileron (14), spoiler sections (15) and brake flaps sections (16), in the area of the junction of the swept wing (2) and the fuselage (1) is equipped with a ventral fairing (7), while the swept wing of the aircraft (2) consists of a center section (19), consoles (20) and a tip (10) and is made with an extension along the base trapezoid λ = 12.04 taking into account the tip, a narrowing of η = 4.5 and a sweep along the leading edge of X = 35°, formed from supercritical profiles, the leading edge (21) of the wing is straight when viewed from above, the trailing edge (22) is made with an extension (24) and a break (23) in the form of rounding, the value of the radii of the noses (26) of the wing sections, referred to the local chord of the section, is r _n = 0.8-1.4%, and the mean line of the wing profiles up to 30% of the span in shape has a negative curvature of up to 1.7% of the chord, the mean line profiles from 30 to 50% of the span have zero curvature up to 45% of the chord and positive curvature in the tail section of the profile, the middle line of profiles from 50 to 100% of the span has positive curvature increasing along the chord up to 2%, the wingtip (10) has a span of 7% of the wing span, variable sweepback X _pc = 35…58°, formed from supercritical profiles with a relative thickness of 9-11%, while the middle lines of the profiles at the wingtip (10) have a maximum curvature of up to 3% closer to the middle of the profile; the engine nacelles (5) are made without mixing the flows of the outer and inner contours, they are extended forward in such a way that their outer contour along the axis of symmetry does not go under the wing (2), while the angles of their installation in the vertical and horizontal planes are 1.5° downwards with the nose and 1.5° with the nose towards the fuselage (1), respectively; the pylons (6) for attaching the engines to the wing (2) are made with a curvature of their profile in the tail section, leading to a decrease in local speeds on the surface of the pylon; The stabilizer (3) has an elongation of 4.93 and a sweep of 34° chord, while the stabilizer profile has a negative curvature of ~ 1% and a relative thickness of 10%; at the location of the stabilizer on the fuselage, the side surfaces are flattened in the “pike tail” type (30); The vertical tail (4) has an aspect ratio of 1.61, sweep angle of 40.8° chords and a relative thickness of 10%.