KR20140131108A - Aerodynamic Characteristics and performance Prediction Device of Light Armed Helicopter with External Weapon Systems - Google Patents

Abstract

Provided is a device for predicting aerodynamic characteristics and performance of a light armed helicopter according to an external weapon system, comprising a helicopter sizing analysis module which performs repeated design and optimizes a shape so that the needs of a person who offers a weapon is satisfied and the parasite resistance of an adapted weapon system helicopter is minimized after determining a fuselage size through the analysis of a current helicopter in use; an aerodynamic characteristics predicting module which calculates a fuselage resistance feature by predicting the basic fuselage resistance of the adapted weapon system helicopter and comparing the resistance feature of weapon/non-weapon shapes according to the change of an attack angle; and a performance analysis module which analyzes the change of a main performance degree according to the increase of the weight and the resistance size of the adapted weapon system helicopter and calculates a result. The present invention is provided to analyze and predict an external weapon of a small weapon system helicopter and the change in the aerodynamic characteristics and the main performance degree according to the external weapon; to select an adaptation target helicopter which satisfies the requirement performance of a buyer by accurately confirming the performance degradation of an adaptation target helicopter; and to accurately predict an adapted range, thereby maximizing adapted efficiency of the weapon helicopter.

Description

TECHNICAL FIELD [0001] The present invention relates to an aerodynamic characteristic and a performance predicting device for a light armored helicopter,

The present invention relates to an aerodynamic characteristic and a performance predicting device for a light armored helicopter according to an external armed force, and particularly, by analyzing the aerodynamic characteristics and the change of a major performance index according to the external arming and major external installation shapes of the small armed helicopter The present invention relates to a device for predicting aerodynamic characteristics and performance of a light armored helicopter according to an external armed force, which maximizes the efficiency of reconstruction of an armed helicopter by reflecting it on a modified helicopter.

In general, a maneuvering helicopter is a helicopter that performs armed forces and major equipment operations on a main mission, while an armed helicopter is a helicopter that can carry out combat missions with an attacking helicopter. And the above-mentioned armed helicopter is a helicopter that is equipped with a weapon for carrying or reconnaissance helicopter, and is made by modifying civilian or military maneuver helicopter which is usually proven as a normal performance. In addition, the armed helicopter is advantageous in terms of development cost and duration although its attack ability and survivability are lower than that of an attack helicopter designed as an attack mission since its design. In Korea, there is a growing interest in armed helicopters such as the search and development project to replace the army's old-age helicopters, such as the 500MD and AH-1S, with development armored helicopters in Korea. At this time, since the armed helicopter operates various external arming systems such as a gun, an air-to-ground missile, and a rocket depending on the nature of the mission, the major performance index is expected to be changed when the helicopter is converted into an armed helicopter. In addition, the above-mentioned armed helicopter increases the weight of the gas according to the type of armed weapon mounted when the basic helicopter (civil or military transport helicopter) having limited performance is converted into the armed helicopter, When rockets, guns, etc. are mounted outside the fuselage, additional performance degradation may occur due to increased drag and, in some cases, steering problems due to aerodynamic interference with the wings of the external and armed support and the fuselage. Therefore, at the development of the armed helicopter through the modification as described above, it is possible to accurately select the performance degradation level and to select the modification target base helicopter that can meet the required performance of the military, and the range of the modification can be predicted.

The method for modifying the conventional armored helicopter as described above includes a first step (S1) of selecting a base helicopter to be modified based on the weight of the aircraft and the number of passengers according to the type of the mounted arm as shown in FIG. 1;

A second step S2 of designing an alteration procedure and a location based on the information of the arming type, the boarding seat, etc. required for the base chopper to be modified after the first step S2;

And a third step (S3) of modifying the object base helicopter based on the modified drawing designed after the second step (S2) and fabricating and testing the object helicopter with the armed helicopter.

The conventional method of modifying the conventional armored helicopter will be described in more detail with reference to various types of external weapons such as guns, air-to-ground missiles, rockets, and the like depending on the specifications required by the purchasers, Select the base chopper to be converted based on the weight and information on the passengers. When the base chopper to be modified is selected as described above, the modification procedure and position are designed for the base chopper to be modified based on the information of the required arming type and boarding seat. In addition, when the modification drawings for the modification procedure and the location are completed as described above, the basic helicopter to be modified is modified according to the designed modified drawings, and is made into an armed helicopter. Then, the performance of the modified helicopter is tested and the result is finally reflected.

However, in the conventional method of modifying the armed helicopter, there is no specific procedure to grasp the performance of the modified helicopter when developing the armed helicopter. Therefore, it is difficult to develop an armed helicopter capable of meeting the performance requirements of the purchaser of the helicopter, In addition, since the modified armed helicopter is remodeled without being secured, the handling stability of the modified armed helicopter is significantly reduced.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a remodeled helicopter capable of accurately grasping the degradation level of the helicopter to be remodeled, The object of the present invention is to provide a device for predicting the aerodynamic characteristics and performance of a light-duty helicopter according to an external weapon capable of selecting a helicopter and accurately estimating a range of modification.

It is a further object of the present invention to provide a method and apparatus for predicting a handling problem due to aerodynamic interference with a wake of an external arming and arming support and a fuselage through a base helicopter analysis, And to provide an apparatus for predicting aerodynamic characteristics and performance of a light-duty helicopter according to the present invention.

In order to achieve the above object, according to the present invention, the size of the fuselage is determined through the trend analysis of the current helicopter, and the repeated design is performed so as to minimize the harmful drag of the modified armed helicopter while satisfying the requirement of the requester, A helicopter sizing interpretation module;

An aerodynamic characteristic prediction module for predicting the basic body drag of the modified armed helicopter in a predetermined manner and comparing the drag characteristics of the armed / unarmed shape according to the change in angle of attack;

There is provided an aerodynamic characteristic and performance prediction device for a light armored helicopter according to an external weapon including a performance analysis module for analyzing a change in a major performance index according to a change in weight and a drag strength area of the retrofitted armed helicopter.

According to the present invention, by analyzing and analyzing the aerodynamic characteristics and the change of the major performance index according to the external weapon of the small arming helicopter and the shape of the major external installation, when the armed helicopter is developed through the modification, , It is possible to precisely predict the range of the modified base chopper, which can meet the performance requirements of the buyer, thereby maximizing the remodeling efficiency of the armed helicopter.

The present invention as described above predicts the handling problem due to the aerodynamic interference with the wake of the external arming and arming support and the vehicle body through the basic helicopter analysis and reflects it to the modified helicopter as much as possible so that the steering stability of the modified helicopter is also significantly improved There is also.

1 is an explanatory view for explaining an example of a conventional method of modifying an armed helicopter;
2 is an explanatory view for explaining an aerodynamic characteristic and performance prediction apparatus of a light armored helicopter according to an external armament according to the present invention.
3 is a graph showing drag force comparisons of a one-tenth magnitude model according to the inventive device.
4 is an explanatory view for explaining an electric field drag force predicting method according to the present invention apparatus.
FIG. 5A is an explanatory view for explaining a comparison of the drag characteristics of the armed / unarmed shape according to the angle of attack angle according to the apparatus of the present invention. FIG.
(b) is a graph showing the comparison of the drag force of the landing gear according to the inventive device,
(c) are explanatory diagrams showing the flow field characteristics of the arming support shape according to the present invention apparatus,
(d) is an explanatory diagram showing an arming combination according to the inventive device.
6 (a) is an explanatory view for explaining a change in a main figure of merit when the chair according to the present invention is installed,
(b) is an explanatory view for explaining a change in major performance index according to the shape of a missile according to the present invention apparatus,
(c) is an explanatory view for explaining a change in a major figure of merit of the shape of the armed support according to the inventive device.

Best Mode for Carrying Out the Invention Hereinafter, a preferred embodiment of an aerodynamic characteristic and performance predicting device for a light armored helicopter according to the present invention will be described with reference to the accompanying drawings.

However, the present invention may be embodied in other forms without being limited to the embodiments of the aerodynamic characteristics and performance prediction apparatus of the light-armed helicopter according to the present invention described herein. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals designate like elements throughout the specification. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The term " comprises " And / or "comprising" does not exclude the presence or addition of one or more other elements, steps, operations, and / or elements.

Example

FIG. 2 is an explanatory view schematically illustrating an aerodynamic characteristic and performance prediction apparatus of a light-duty helicopter according to the present invention. FIG. 3 is a graph showing a comparison of drag forces FIG. 4A is an explanatory view for explaining an electric field strength predicting method according to the present invention apparatus, FIG. 5A is a graph comparing the drag characteristics of armed / unarmed shapes according to the angle of attack angle according to the apparatus of the present invention (B) is a graph showing a comparison of a drag force characteristic according to the landing gear configuration according to the present invention device, and (c) is an explanatory diagram showing a flow field characteristic according to the shape of the arming rod according to the present invention device FIG. 6A is an explanatory diagram for explaining a change in the main figure of merit when the chair according to the present invention is installed, FIG. According to the present invention apparatus (C) is an explanatory view for explaining a change in the major performance index of the shape of the arm support according to the apparatus of the present invention.

Referring to FIG. 2, an aerodynamic characteristic and performance prediction apparatus for a light armored helicopter according to an exemplary embodiment of the present invention includes:

A helicopter sizing analysis module 2 for optimizing the shape by repeating the design so as to minimize the harmful drag of the modified armed helicopter 1 while determining the size of the body through the trend analysis of the helicopter currently in use, and;

An aerodynamic characteristic prediction module (3) for predicting a basic body drag force of the modified armed helicopter (1) in a predetermined manner and comparing the drag characteristics of armed / unarmed shapes according to a change in angle of attack to calculate a body drag characteristic;

And a performance analysis module 4 for analyzing the change of the major performance index according to the weight and the drag strength area of the modified armed helicopter 1 and calculating the result.

The helicopter sizing analysis module 2 divides the helicopter sizing into a rotor and a fuselage sizing. The initial helicopter weight for sizing is calculated in accordance with the requirements of the military, for example, About 11,000 lbs, and the radius, the number of spikes, the cord length, the number of revolutions, and the like of the blade are calculated by considering the sizing trend of the similar-sized helicopter and the main shape parameters. At this time, the helicopter sizing analysis module 2 initially determines the size of the fuselage through trend analysis of the helicopter currently in use, and then repeats the design so as to minimize the harmful drag while satisfying the requirement of the group, for example, .

In the modified helicopter designed by the helicopter sizing analysis module 2, for example, the moving body has a total length of 13500 mm, a total width of 2100 mm, and a total height of 4700 mm. The target acquiring device and the infrared ray detecting device are arranged at the upper part of the nose, It can be designed at the bottom of the nose. In the modified armored helicopter 1, a deflector and a wire cutter are disposed in front of the cowl and the lower portion of the cowl, and the landing gear is selected as a skid type in consideration of the weight. The frontal angle of the landing gear, Set to be avoided, and apply pairing to reduce drag. In addition, the modified armed helicopter 1 minimizes the increase of the drag by making the intake port half-pressurized, and exhausts the engine exhaust in the upward direction so that hot exhaust gas is discharged rapidly It is designed to be mixed. Furthermore, although the modified armored helicopter (1) considered the conventional type in the initial sizing of the tail rotor, it adopted the ducted fan type method excellent in noise reduction, safety, and maneuverability through the offset study. In addition, in the modified armed helicopter 1, the installation position of the horizontal stabilizer is limited due to the structural characteristics of the fan tail. Although the horizontal stabilizer is mounted on the side portion of the tee boom in the front portion of the fan tail through the offset study, In order to compensate for the short distance from the center of gravity of the helicopter aerodynamically, it is disadvantageous to compensate the performance of the control surface by designing the end of the horizontal stabilizer as a winglet.

On the other hand, the aerodynamic characteristic prediction module 3 utilizes CFD software using SC / Tetra, which is a commercial program based on an unstructured grid, as a method of predicting a body drag force, for basic body drag prediction. The performance of the CFD tool was verified using the results of the KWH (C4222A) wind tunnel test. As shown in FIG. 3, when the CFD analysis value and the wind tunnel test (WT) value were measured at -20 <AoA < It can be confirmed that they are almost exactly the same. Here, referring to the above-described drag force verification result, the grid of the armed helicopter analysis area is composed of, for example, about 6 million, and the grid is densified so that the y + value of the wall surface is 10 or less. Then, the aerodynamic characteristic prediction module 3 uses the wind tunnel model (1/10) to estimate the body drag of the actual body (1/1) In the present invention device 5, the electric field strength prediction method as shown in FIG. 4 is applied for such correction. Here, the aerodynamic characteristic prediction module 3 estimates and predicts a CFD analysis for a 1/10 size shape with a drag force of a smooth body excluding a main rotor and a tail rotor as a basic airframe drag, Apply the value of similar helicopter. Here, the wind tunnel test environment correction drag force is used for predicting the aerodynamic characteristics, and in this wind tunnel test, since the cost, the stiffness of the model, and the size of the test section are limited, it is difficult to match the Reynolds superposition condition. The difference in Reynolds number between the wind tunnel test and the actual flight test constitutes a part of the drag error, and the effect of the Reynolds number is large in the wind tunnel model Is known as the rotor hub. Therefore, the aerodynamic characteristic prediction module 3 sets the aerodynamic characteristic prediction module 3 with reference to the correction value calculated through the wind tunnel test and the flight test analysis performed at the time of development of the KUH (Korean type helicopter) in the drag prediction of the armed helicopter considering the above points . In addition, the aerodynamic characteristic prediction module 3 considers the surface roughness correction drag as a method of predicting the body drag. Generally, a wind tunnel model is produced by simulating a gas surface in the same manner as a real gas, without simulating the surface of the gas. That is, the rivet head on the surface of the gas, the joining portion of the plate, and the open gap are omitted. Therefore, the drag force of a wind tunnel model is inevitably lower than that of an actual gas. Therefore, the aerodynamic characteristic prediction module 3 applies about 15% of the basic body drag by subtracting the rotor hub drag from the drag correction by model simplification. Further, the aerodynamic characteristic prediction module 3 uses the engine correction drag force as a method of predicting the body drag force. At this time, the engine correction drag force causes a difference in momentum of air as the air enters through the engine intake port and is discharged through the exhaust port during the forward flight. The drag force generated at this time is a ram drag, We estimated the air inflow of the helicopter engine based on momentum theory. In addition, the aerodynamic characteristic prediction module 3 uses an external fixture drag force as a method for predicting a drag force. The external fixture drag force uses a KUH test value as a total drag force of an external device for performing a mission (Considering only relatively large equipment such as wire cutting equipment, various antenna types, FLIR, and deicing equipment).

Meanwhile, the aerodynamic characteristic prediction module 3 predicts by taking into account the characteristics of the body drag. The characteristics of the body drag include electric drag drag force, landing gear drag force characteristic, drag force characteristic according to the arm support shape, To predict the aerodynamic characteristics.

In this case, as shown in FIG. 5 (a), a configuration in which two air-to-ground missiles are mounted on the right and left sides of the fuselage in an armed type S-type armed support, It is predicted that the drag force increases with 0.4 m ² drag area increase and the increase of the angle of attack, and that the increase of the drag force at the high angle of attack is more influenced by the shape of the S type arm support than the arm itself have.

As shown in FIG. 5 (b), the drag force characteristics of the landing gear system are compared with the drag characteristics of a typical landing gear type SKID type and a wheel type. At this time, in the above comparison, the drag magnitudes of the fixed wheel and the SKID type are almost similar, and the two shapes exhibit a larger drag force than the other shapes, and the SKID decreases the drag area by 0.29 m ² when the pairing is mounted appear. This is about 50% reduction of SKID self-drag. In addition, the landing gear shows the lowest drag when the folding wheel is mounted, and it can be predicted that the additional drag reduction effect can be obtained by optimizing the design of the storage space of the wheel. The slope of the drag graph for each landing gear is similar and is in parallel with the type of landing gear, and the minimum drag appears at approximately 0 ㅀ <AOA <5 ㅀ.

On the other hand, various kinds of armed support members mounted on the helicopter are developed and used according to the structure characteristics of the fuselage and the mission of the aircraft. Therefore, in the aerodynamic characteristic prediction module 3 according to the present invention apparatus, the representative shapes Wing type, S type, Suspension type arming support are set as targets. In this case, since the purpose of the relative comparison of the arm support is to compare, the main flow is not considered in the analysis, and the armed support Wing type is disadvantageous in terms of structure but it is advantageous from the aerodynamic aspect, Because it acts as a small, incremental lift factor. It is predicted that the increase in lift by the Wing helps to improve the maximum speed of the helicopter by reducing the main power of the helicopter, and that the pressure difference (Cp) distribution of the Wing section shows a large pressure difference at the upper and lower parts of Wing . However, since the Wing-type arming support causes a large drag in the vertical rising state, the vertical rising performance of the helicopter can be reduced. On the other hand, the above-mentioned armed support S type is advantageous in terms of structure but disadvantageous in terms of aerodynamic force. Such an armed support S type has a large frontal cross-sectional area and a large increase in drag during forward flight. When the fuselage is in a positive angle of attack, It is predicted that flow will occur and cause aerodynamic interference with the fuselage. Further, the suspension support structure of the arm support suspension type has a substantially circular cross-section, and the circular cross-section generates a large drag when the forward-backward pressure difference of the circular cross section is large during forward flight. This suspension type is generally known to generate a drag force more than 20 times higher than the streamlined section of the same thickness. Therefore, it is expected that the circular section shape should be avoided in reducing the drag when designing the suspension type support.

In addition, the drag characteristics according to the armed combination analyze drag influence on various weapon options such as turret gun, missile, 70mm rocket, Pod gun. 6 (d), the base has an unarmed shape with only an arm support (S-type), and the A-type has a turret gun and four guided missiles And type B and type C are equipped with turret gun, 14mm and 70mm rocket, respectively, and 28mm, respectively. Type D is equipped with 14mm 70mm rocket and pod gun without turret gun, (3) analyzes the drag force for each armed combination as described above, and calculates the result. For example, the electric field drag force increases by 17% to 26% with respect to the base type according to the combination of armed forces, and the drag force having the shape of 28 strokes of 70 mm rocket is the largest.

Meanwhile, the performance analysis module 4 analyzes the change in the main performance index according to the increase or decrease in the aircraft weight and the drag strength area, and then calculates the result. For example, in the performance analysis module 4, it is predicted that the in-flight performance (HOGE) decreases by about 1,000 ft and the vertical rate of increase (VROC) decreases by 100 fpm as the aircraft weight increases by 100 lbs. Also, the performance analysis module 4 predicts that the vertical related performance is not different when the drag area is increased by 1 ft ² , but decreases by about 1.7 kt in the case of the maximum cruise speed (Vmax). And the performance analysis module 4 confirms that the weight increase sensitively affects the in-situ flight and vertical uplift performance. When the armed support, four air-to-surface missiles and a 20-mm turret gun were installed, the predicted drag area increase by CFD analysis was about 0.43 m ² . Therefore, the maximum cruising speed of the armed helicopter used by the present invention as described above is expected to be reduced by about 8 kts. In addition, as shown in FIG. 6 (a), when the turret gun is installed, the performance index of the main armament is predicted by the performance analysis module 4, It is confirmed that additional weight increase factor occurs due to structural reinforcement and it is mounted on the front face of the aircraft to increase the drag force. Therefore, it is confirmed that the turret gun has a considerable effect on the in-flight performance and vertical increase rate, do. 6 (b), when the performance analysis module 4 estimates the performance of four air-to-surface missiles or 14 rockets of 70 mm, (About 146 lbs), the HOGE and VROC performances can be predicted to increase but not to be large. As shown in FIG. 6 (c), the Wing type is slightly superior to the basic type (S type) as a whole, while the performance index analysis results of the armed support structures predicted by the performance analysis module (4) It can be predicted that the maximum cruising speed reduction is about 4kts because the drag is bigger than the basic type (S type), and the other figure of merit is similar or slightly better than the basic type. Therefore, through the analysis of the aerodynamic characteristics and performance prediction device 5 of the light-duty helicopter according to the present invention, the aerodynamic characteristics and the change of the main performance index according to the external arming and the shape of the major external installation of the small- As a result of analyzing using the model of some basic retrofit helicopters, for example, the increase in the drag area is about 0.43 m ² in the first armed installation, and the maximum cruise speed of the helicopter is expected to be reduced by about 8 kts. It was confirmed that the turret gun equipped with the LoNoZ part greatly increased the weight and the area of increase of the drag area, thereby significantly reducing the in-flight performance and the vertical rate of rise. Third, in the forward flight, the maximum support cruise speed The vertical performance was predicted to be excellent.

1: modified armed helicopter 2: helicopter sizing interpretation module
3: aerodynamic characteristic prediction module 4: performance analysis module
5: Aerodynamic characteristics and performance prediction device

Claims (8)

A helicopter sizing analysis module for determining a size of a fuselage through analysis of trends of current helicopters and then optimizing the shape by repeatedly designing the harmful drag forces of the modified armed helicopter to be minimized while satisfying the needs of the requester;
An aerodynamic characteristic prediction module for predicting the basic body drag of the modified armed helicopter in a predetermined manner and comparing the drag characteristics of the armed / unarmed shape according to the change in angle of attack;
And a performance analysis module for analyzing the change of the main figure of merit according to the increase and decrease of the drag area and the weight of the modified armed helicopter, and calculating the result of the analysis. The method according to claim 1,
The helicopter sizing analysis module divides the helicopter sizing into a rotor and a fuselage sizing, sets the initial helicopter weight for sizing to reflect the requirements of the requester and the form of work required for the small armed helicopter, and determines the radius, Wherein the shape of the modified armed helicopter is calculated by calculating the code length and the number of revolutions in consideration of the sizing trend of the similar type helicopter and the calculation of the main shape parameters. 3. The method of claim 2,
The modified armed helicopter designed by the helicopter sizing analysis module is designed to mount a horizontal stabilizer on a side portion of a tear boom of a front portion of the fan tail through an offset study and to design the end of the horizontal stabilizer as a winglet. Aerodynamic Characteristics and Performance Prediction Apparatus. 3. The method of claim 2,
Wherein the aerodynamic characteristics prediction module uses CFD software using SC / Tetra based on an unstructured grid as a driving force predicting method for predicting basic body drag, and a device for predicting aerodynamic characteristics and performance of a light armored helicopter . The method according to claim 1,
The aerodynamic characteristics predicting module predicts CFD analysis for a 1/10 size shape by drag force of the body excluding the main and tail rotors, while applying the value of the similar class helicopter to the main and tail rotor hub drag , And a wind tunnel model is used to correct the error caused by the size, accuracy, and test environment constraints of the model when predicting the body drag of the actual airframe, the aerodynamic characteristics and performance Prediction device. The method according to claim 1,
Wherein the aerodynamic characteristic prediction module uses a basic body drag force, a wind tunnel test environment correction drag force, a surface roughness correction drag force, an engine correction drag force and an external fixture drag force as electric force drag prediction elements, Aerodynamic Characteristics and Performance Prediction Apparatus. The method according to claim 1,
Wherein the aerodynamic characteristic prediction module utilizes an electric field drag characteristic, a landing device drag characteristic, a drag characteristic according to a shape of a support arm, and a drag characteristic according to an arming combination as an element of a body drag characteristic, Aerodynamic characteristics and performance prediction device. The method according to claim 1,
In the performance analysis module, since the weight of the turret gun needs to reinforce the structure of the airframe as well as its own weight in order to mount it, it is a factor that significantly affects on-flight and vertical lift performance. And then the resultant data is calculated. The aerodynamic characteristic and performance prediction apparatus of the light armament helicopter according to the external armament.

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