CN115946852A

CN115946852A - Supersonic tailless aircraft pneumatic layout

Info

Publication number: CN115946852A
Application number: CN202211457673.0A
Authority: CN
Inventors: 詹光; 石钧之; 刘晓冬; 李惠璟; 衣然
Original assignee: Shenyang Aircraft Design and Research Institute Aviation Industry of China AVIC
Current assignee: Shenyang Aircraft Design and Research Institute Aviation Industry of China AVIC
Priority date: 2022-11-18
Filing date: 2022-11-18
Publication date: 2023-04-11

Abstract

The application belongs to the field of aircraft design, and relates to a supersonic tailless aircraft pneumatic layout, which aims at the supersonic tailless layout aircraft to increase course stability, reduce supersonic resistance, reduce subsonic low-head moment and improve cruising performance, and is used for carrying out optimization design on components such as a front body, a rear body and a tail tip of the aircraft respectively. The optimization design method is suitable for all supersonic tailless layout airplanes, the airplane body comprises a front body and a rear body, the front body generally refers to the nose position of the airplane, the rear body generally refers to the structure from the gravity center to the tail of the airplane, and a middle airplane body is arranged between the front body and the rear body.

Description

Supersonic tailless aircraft pneumatic layout

Technical Field

The application belongs to the field of aircraft design, and particularly relates to a supersonic tailless aircraft aerodynamic layout.

Background

Modern military combat aircraft often have high stealth, supersonic speed, and weapons built-in requirements. In order to meet the requirement of high stealth performance, the aircraft is generally designed in a tailless or similar tailless layout, and the course stability of the aircraft body is greatly reduced due to the loss of vertical tails of the layout meter, so that pressure is brought to control surface operation. Particularly for supersonic aircraft, the layout of the supersonic aircraft has the characteristics of large slenderness ratio, small aspect ratio, large sweep angle and the like, and the further increased course instability and insufficient manipulation capability caused by small aspect ratio and large sweep angle bring great difficulty for pneumatic layout design.

The requirement for larger buried mission loads necessitates an increase in the buried weapons bay, which in turn necessarily increases the maximum cross-sectional area of the aircraft, which results in aerodynamic losses such as increased drag, reduced cruise performance, etc., which also makes supersonic flight difficult to achieve, increased engine performance requirements, etc.

For the unmanned aerial vehicle, the upper surface is smoother than a human-machine due to the fact that the cockpit is cancelled, so that the suction peak moves backwards, the head raising moment of the whole aircraft is reduced, therefore, the horizontal tail needs to deflect a certain angle all the time in the cruising flight process to be used for balancing the longitudinal moment of the whole aircraft, partial horizontal tail manipulation capacity is occupied, and the aircraft cannot exert higher performance level.

Therefore, in order to improve the comprehensive operational efficiency and viability of the airplane, a set of pneumatic layout design which considers the requirements of various capacities such as speed, stealth, viability and the like and simultaneously meets the requirement of stability performance in various stages such as take-off and landing, cruising, maneuvering operation and the like needs to be established.

Disclosure of Invention

The invention aims to provide a pneumatic layout of a supersonic tailless aircraft, which aims to solve the problems of large course static instability, large supersonic resistance and subsonic low head moment, and insufficient course control capability caused by large sweepback angle and small aspect ratio of the supersonic tailless aircraft in the prior art.

The technical scheme of the application is as follows: a supersonic tailless aircraft aerodynamic configuration comprises a fuselage, wings and a horizontal tail; the fuselage comprises a front body, a middle body and a rear body, wherein the lower surface of the front body is in a tangent ellipse shape, and the upper surface of the front body is in a spindle-shaped structure; the middle body is continuous with the curvature of the upper surface of the wing, and the upper surfaces of the front body, the middle body and the rear body smoothly transit along the flow direction.

Preferably, the ratio of the laterally projected area of the front side of the center of gravity of the fuselage to the rear side of the center of gravity of the fuselage is 1.4.

Preferably, the fuselage has a full fuselage slenderness ratio of 6.5.

Preferably, the width of the tail tip of the horizontal tail is 800mm, and the wing tip torsion angle of the wing and the horizontal tail is 2 degrees.

The aerodynamic layout of the supersonic tailless aircraft aims at the supersonic tailless aircraft to increase course stability, reduce supersonic resistance, reduce subsonic low-head moment and improve cruising performance, and optimized design is respectively carried out on components such as a front body, a rear body and a tail tip of the aircraft. The optimization design method is suitable for all supersonic tailless layout airplanes, the airplane body comprises a front body and a rear body, the front body generally refers to the nose position of the airplane, the rear body generally refers to the structure from the gravity center to the tail of the airplane, and a middle airplane body is arranged between the front body and the rear body.

Drawings

In order to more clearly illustrate the technical solutions provided by the present application, the following briefly introduces the accompanying drawings. It is to be expressly understood that the drawings described below are only illustrative of some embodiments of the invention.

FIG. 1 is a schematic side view of a prior art aircraft;

FIG. 2 is a schematic side view of an aircraft with the cockpit and tail removed according to the present application;

FIG. 3 is a schematic diagram of an optimized baseline layout according to the present application;

FIG. 4 is a schematic diagram illustrating the front-back comparison of the optimized front-back lateral projection area of the center of gravity of the present application;

FIG. 5 is a schematic diagram showing the cross-sectional shape of an aircraft forebody according to the present application in comparison before and after optimization;

FIG. 6 is a schematic diagram illustrating a front-to-back comparison of a fusion design of an aircraft wing body according to the present application;

FIG. 7 is a schematic diagram showing the comparison between the full-machine slenderness ratio optimization and the post-optimization of the full-machine slenderness ratio;

FIG. 8-1 is a schematic view of a prior art symmetrical plane curvature distribution;

FIG. 8-2 is a schematic diagram showing the comparison of the optimized front and back curvatures of the upper surface longitudinal splines of the fuselage according to the present application;

FIG. 9 is a schematic diagram showing a comparison between the front and rear of the variation of the aircraft nose height according to the present application;

FIG. 10 is a schematic diagram showing a comparison between the front and rear of the variation of the nose width of the airplane according to the present application.

1. A body; 2. an airfoil; 3. flattening the tail; 4. a precursor; 5. a middle body; 6. a rear body; 7. and (5) tail tip.

Detailed Description

In order to make the implementation objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application.

A supersonic tailless aircraft aerodynamic layout is shown in FIG. 1, which is a supersonic conventional layout aircraft, wherein the lateral projection area of the center of gravity is about 16.42m in normal state ² The rear lateral projection area of the gravity center is about 13.85m ² The ratio of the projected areas of the front and rear sides of the center of gravity is about 1.2, and the width-to-height ratio of the cross section at a distance of 3m from the nose tip (airplane zero point) is 1.22.

The cockpit and the vertical tail of the airplane are removed to form a supersonic tailless layout, and at the moment, the front lateral projection area of the center of gravity is reduced to 14.63m ² The rear lateral projection area of the gravity center is reduced to 8.53m ² The ratio of the front and rear lateral projection areas of the center of gravity is increased to 1.7, the width-height ratio of the section at the position 3m away from the nose tip (airplane zero point) is still 1.22, and layout optimization design is carried out by taking the ratio as a baseline scheme.

After the cockpit and the vertical tail are removed, the air resistance during flight can be effectively reduced, and the flight efficiency is improved.

The vertical tail of the airplane can keep the course balance, stability and operation of the airplane and keep turning to be carried out in a sideslip-free state; meanwhile, when the side wind lands, the machine head is kept aligned with the runway; while balancing the asymmetric yaw moment.

The removal of the cockpit of the aircraft may cause a certain amount of nose-down moment to the aircraft.

This application is getting rid of the function of vertical tail and cockpit, can compensate vertical tail and cockpit simultaneously, and the specific design is as follows:

the optimized baseline layout is shown in fig. 3 and mainly comprises a fuselage 1, wings 2 and a tail 3. The fuselage 1 comprises a front body 4, a fuselage 5 and a rear body 6, wherein the front body 4 is the nose position of the airplane, the rear body 6 is the structure from the center of gravity to the tail of the airplane, and the tail tip 7 is arranged at the central tail end of the rear body 6.

Firstly, course stability optimization design is carried out:

the first step is as follows: the ratio of the front and back lateral projection areas of the center of gravity is optimized.

As shown in figure 4, the length of the front body 4 is shortened by 200mm (the nose tip moves backwards, the zero point position of the airplane is unchanged), the height is reduced by 20mm (the position is 3m away from the zero point of the airplane), and the lateral projection area in front of the gravity center of the airplane is formed by 14.63m ² Reduced to 13.69m ² . The upper surfaces of the engine positions at the two sides of the rear body 6 are raised by about 250mm, the lower surfaces are unchanged, and the lateral projection area behind the center of gravity of the airplane is 8.53m ² Increased to 9.63m ² . The ratio of the front and rear lateral projection areas of the center of gravity is reduced from 1.7 to 1.4 by adjusting the lateral projection areas; the center of the airplane moves backwards by reducing the lateral projection area of the front part of the center of gravity of the airplane and increasing the lateral projection area of the back part of the center of gravity of the airplane, so that the course stability is improved.

The second step is that: the cross-sectional shape of the precursor 4 is optimally designed.

As shown in fig. 5, the precursor cross-section is of spindle design on the top surface and of tangent oval design on the bottom surface to form a diamond-type cross-section. Meanwhile, the width-height ratio of the cross section of the front body 4 is increased, the cross section 3m away from the zero point of the airplane is taken as an example, the height is reduced by 40mm, the width is increased by 100mm, the width-height ratio of the cross section is increased from 1.22 to 1.43, and the flattening design of the front body 3 is realized, so that the air flow resistance of the surface of the front body of the airplane is smaller, the flow area is larger, the buoyancy force borne by the airplane is larger, and the stability is further improved.

The third step: wing-body fusion design

As shown in fig. 6, the body 5 and the wing 2 adopt a wing body fusion design with continuous upper surface curvature. The upper surface profile of the cross section is subjected to integrated curvature optimization design, so that the upper surface of the airplane forms a smooth structure, and the retardation of the sideslip airflow when the sideslip airflow is subjected to the airframe 4 is reduced as much as possible.

Secondly, performing a span/supersonic velocity resistance optimization design:

the first step is as follows: full-machine slenderness ratio optimization design

As shown in fig. 7, under the condition that the maximum thickness position and height of the rear body 6 are not changed, the connection part of the rear body 6 and the horizontal tail 3 and the tail end of the tail tip 7 are extended backwards, and the length-to-thin ratio of the whole machine is increased to 6.5 by comprehensively considering the stealth constraint. The method can increase the ratio of the front and rear lateral projection areas of the center of gravity of the airplane and simultaneously ensure the length of the airplane body 1, thereby ensuring the slenderness ratio of the whole airplane when the equivalent diameter of the whole airplane is restricted by the arrangement of a gas inlet and exhaust system, an embedded equipment cabin and other large components.

The second step is that: machine body upper surface longitudinal spline curvature optimization design

As shown in FIGS. 8-1 and 8-2, the curvature high-order continuous design is carried out on the longitudinal splines of the upper surface of the airplane body, particularly the positions of the symmetrical surfaces, and the surface profile of the upper surface of the airplane body 1 is smoothly transited along the flow direction, so that the flow resistance of the airplane is further reduced.

And finally, performing subsonic cruise performance optimization design:

first, the optimum design of the curvature of the rear body

As shown in figure 9, the height of the tail end of the tail tip 7 is raised by 200mm, the negative camber of the rear body 6 of the airplane body is increased, and therefore the head-up moment is generated to counteract the head-down moment caused by the elimination of the cab.

Second, optimizing the design of the width of the tail tip

As shown in FIG. 10, the distance between the two hair strands is increased, the width of the tail tip 7 is increased from 350mm to 800mm, the head raising moment caused by raising the tail tip 7 is further increased, the full-aircraft head lowering moment can be reduced from about-0.05 to about-0.02 in the first two steps, and the head raising moment increment of about 0.03 is generated in total.

Thirdly, wing surface torsion optimization design

The wing tip of the wing 2 or the horizontal tail 3 is provided with a-2-degree torsion angle to bring about a head-up moment, and about 0.025 of head-up moment can be further brought about, so that the longitudinal moment characteristic of the whole airplane at a zero attack angle is a smaller positive value, and the whole airplane can be trimmed through a smaller angle below the horizontal tail, thereby reducing trimming resistance and improving the trimming lift-drag ratio of the whole airplane.

The method has the advantages that the comprehensive optimization design is carried out on the front body, the rear body, the tail tip, the wing surface and the like of the baseline layout by reducing the ratio of front and rear lateral projection areas of the gravity center of the airplane, increasing the width-to-height ratio of the front body section, optimizing the shape of the front body section, designing the wing body in a fused manner, increasing the length-to-fineness ratio of the whole airplane, optimizing the spline curvature of the airplane body, increasing the negative curvature and the tail tip width of the rear body, increasing the negative torsion of the wing and the horizontal tail and the like, so that the static instability of the course of the whole airplane is reduced from-0.0012 to-0.0009, and the improvement is about 25%; the cross/supersonic resistance surface is reduced from 6.3 to 5.67, an improvement of about 10%; the cruise lift-drag ratio is increased from 12.0 to 12.6, which is an improvement of about 5%. And the comprehensive optimization design of the flight performance of the whole aircraft is realized.

The requirements of the tailless aircraft on course stability, the requirements of cruising on stealth characteristics and lift-drag ratio and the requirements of supersonic flight on a full-aircraft resistance surface are considered, the requirement contradiction of each stage is solved, the use boundary of the aircraft is effectively expanded, and the comprehensive combat efficiency is improved.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. The utility model provides a supersonic speed tailless aircraft aerodynamic configuration which characterized in that: comprises a fuselage (1), wings (2) and a horizontal tail (3); the fuselage (1) comprises a front body (4), a middle body (5) and a rear body (6), wherein the lower surface of the front body (4) is in a tangent ellipse shape, and the upper surface of the front body is in a spindle-shaped structure; the middle body (5) is continuous with the curvature of the upper surface of the wing (2), and the upper surfaces of the front body (4), the middle body (5) and the rear body (6) are smoothly transited along the flow direction.

2. The supersonic tailless aircraft aerodynamic layout of claim 1, wherein: the lateral projection area ratio of the front side of the center of gravity of the fuselage (1) to the rear side of the center of gravity is 1.4.

3. The supersonic tailless aircraft aerodynamic layout of claim 1, wherein: the full-machine slenderness ratio of the machine body (1) is 6.5.

4. The supersonic tailless aircraft aerodynamic layout of claim 1, wherein: the width of a tail tip (7) of the horizontal tail (3) is 800mm, and the wing tip torsion angle between the wing (2) and the horizontal tail (3) is 2 degrees.