Combat Aircraft Research Articles

Airborne Multi Target Track to Track Fusion of Radar and IRST for Advanced Multi Role Combat Aircrafts

This paper presents multi sensor fusion architecture to fuse multi target tracks from the Radar and an Infrared Search & Track (IRST) system. The proposed architecture uses global nearest neighborhood (GNN) algorithm for data association between target tracks of Radar and IRST. Further a GNN based central track manager is proposed to maintain the fused tracks from Radar and IRST. The Radar track outputs are modelled in Cartesian coordinates, providing the target position and velocity states with their corresponding covariance, while the radar detections are in polar coordinates. The IRST track output provides angle only information of the targets with their corresponding covariance. Simulations are carried out in single aircraft - multi target scenario and it is observed that the fused track output has improved angle accuracy with lesser variance.

IR Susceptibility of Supersonic Aircraft according to Omni-directional Detection Angle

Infrared guided weapons act as threats that greatly degrade the survivability of combat aircraft. Infrared weapons detect and track the target aircraft by sensing the infrared signature radiated from the aircraft fuselage. Therefore, in this study, we analyzed the infrared signature and susceptibility of supersonic aircraft according to omni-directional detection angle. Through the numerical analysis, we derived the surface temperature distribution of fuselage and omni-directional infrared signature. Then, we calculated the detection range according to detection angle in consideration of IR sensor’s parameters. Using in-house code, the lethal range was calculated by considering the relative velocity between aircraft and IR missile. As a result, the elevational susceptibility is larger than the azimuthal susceptibility, and it means that the aircraft can be attacked in wider area at the elevational situation.

MODEL OF OPERATION OF COMBAT AIRCRAFT GROUND TRANSPORTATION SERVICE SYSTEMS

The article analyzes the current state and prospects of development of systems of ground transport maintenance of aircraft, which allowed to form the purpose of the study in this development. The chosen topic is quite relevant, because effective organization of combat aircraft maintenance allows raising combat effectiveness of Ukrainian air forces. One of the directions of maintenance cost reduction is effective use of resources. The study establishes that in order to improve the quality of transport maintenance and increase the combat effectiveness of the Armed Forces and National Guard of Ukraine, it is necessary to pay attention to the use of new transport vehicles, especially modular designs and development of technology to determine the optimal distribution of transport resources for aircraft maintenance, for different conditions of the transport complex and different types of aircraft maintenance. The authors propose to consider two aircraft maintenance schemes – existing using existing technology and proposed using a modular design. In a modular design, a wheeled tractor acts as a tug, which drives mobile modules, which are special means for servicing aircraft. Such an energy-efficient vehicle may consist of 4 modules at a time. The process of delivering the cargo required for servicing the aircraft at the airport is estimated at costs, which form a set of cost values for each technological process of servicing the aircraft. The set criterion is influenced by the parameters: the cost of performing a unit of the corresponding operation, the cost of one hour of work of one worker, the time of performing the corresponding operation, the number of modules involved to perform the corresponding service, the number of aircraft. The developed models of functioning of combat aircraft maintenance systems for maintenance will allow to take into account the influence of random factors, to assess the possibility of using modular designs, as well as to determine the efficiency of existing resources on airfields in Ukraine.

Forward Design Method of Avionics System Based on Communication

With the rapid development of computer technology, electronic technology, and control technology, communication-based avionics systems can provide greater potential for the improvement of aircraft combat capabilities. Moreover, during the flight, passengers have an increasing demand for space communications. How to provide passengers with a communication-based aerospace electronic system that is indistinguishable from the ground during the flight is a problem that needs to be solved urgently. The research on the forward design method of this system has been highly valued by experts at home and abroad. This article is a communication-based forward design method for avionics systems. Based on the development of aerospace data communication technology, this article discusses the advantages of the application of the CCSDS (Consultative Committee for Space Data Systems) protocol in the design of aerospace electronic communication systems. This research designs the technical scheme of the entire aerospace communication electronic system and refers to the relevant CCSDS protocol to complete the design of the distributor’s fast transmission telemetry package and the distributor’s slow transmission telemetry package. This article introduces the two existing architectures of the integrated avionics system, compares and analyzes them, and then elaborates the integrated avionics system architecture based on trusted computing and the trust chain transfer mechanism. The experimental results show that the method designed in this paper uses the NBSP basic protocol in an aeronautical communication environment with a nesting depth of 2 s. When the data transmission delay is 2 s, the NBSP scheme is 0.9 and the NERON scheme is 0.4. This shows that the design method of this study is able to meet the requirements of the system and technical indicators.

The Evolution Towards the Partial Strategic Autonomy of Sweden’s Essential Security Interests

ABSTRACT This article describes how Sweden developed a hybrid defence-industrial infrastructure with three prioritized ‘essential strategic interests’ pointing to parts of the domestic defence industry: ‘a partial strategic autonomy’. The article focuses on Sweden’s declared three essential security interests – combat aircraft capability; underwater capabilities; and integrity-critical parts of the command, control, communication and intelligence domain (C3I). The article finds that the possibilities and ways forward for the essential security interests vary, with a general trend towards more shared and increasingly partial autonomy. Six change factors are formulated as drivers towards Sweden’s partial strategic autonomy of today: Autonomy as a result of failed internationalization; Techno-nationalist perception of Sweden leading to industrial protectionism; Strategic choice; Corporate lobbying; Export incentives leading to political support of technologies; and Europeanization of the EU defence industry. Techno-nationalism and strategic choice are the factors with the most evident impact. The overall governance of the defence industry is clear on the priority of ensuring security of supply and a high degree of autonomy regarding the three essential security interests. Other parts of the defence industry operate under globalized and more competitive conditions. In order to apply increased economic rationality and strive for shared autonomy, Sweden must increase its engagement in multilateral arms collaboration.

Vulnerability assessment to projectiles: Approach definition and application to helicopter platforms

Survivability is defined as the capability of a platform to avoid or withstand a man-made hostile environment. Military aircraft in particular, but also other kinds of platforms subjected to external, impacting threats, are commonly designed according to increasing survivability requirements. The concept of survivability was first formalized by R. Ball in 1985 in its seminal work on combat aircraft survivability. On the basis of the theory presented in his work, many computer programs have been developed which implement the modelling techniques and computations required by vulnerability assessments. However, a clear and general view of the operative computational procedures is still lacking. Moreover, to date only a limited number of applications to helicopter platforms have been investigated in the survivability field, even though these platforms experience numerous flight conditions exposing the system to different types of threats. In this context, this work aims at establishing a multi-purpose general framework for the vulnerability assessment of different types of platforms subjected to external threats, with a focus on helicopters. The in-house software specifically developed for this application is here described in detail and employed to present a case study on a representative military helicopter.

Separable and semiparametric network-based counting processes applied to the international combat aircraft trades

AbstractWe propose a novel tie-oriented model for longitudinal event network data. The generating mechanism is assumed to be a multivariate Poisson process that governs theonsetandrepetitionof yearly observed events with two separate intensity functions. We apply the model to a network obtained from the yearly dyadic number of international deliveries of combat aircraft trades between 1950 and 2017. Based on the trade gravity approach, we identify economic and political factors impeding or promoting the number of transfers. Extensive dynamics as well as country heterogeneities require the specification of semiparametric time-varying effects as well as random effects. Our findings reveal strong heterogeneous as well as time-varying effects of endogenous and exogenous covariates on theonsetandrepetitionof aircraft trade events.

Peregrine Falcon’s Dive: Pullout Maneuver and Flight Control Through Wing Morphing

During the pullout maneuver, peregrine falcons were observed to adopt a succession of specific flight configurations that are thought to offer an aerodynamic advantage over aerial prey. Analysis of the flight trajectory of a falcon in a controlled environment shows it experiencing load factors up to , and further predictions suggest this could be increased up to almost during high-speed pullout. This can be attributed to the high maneuverability promoted by lift-generating vortical structures over the wing. Wind-tunnel experiments on life-sized models in the different configurations together with high-fidelity computational fluid dynamics simulations (large-eddy simulations) show that deploying the hand wing in a pullout creates extra vortex lift, which is similar to that of combat aircraft with delta wings. The aerodynamic forces and the position of the aerodynamic center were calculated from the simulations of the flow around the different configurations. This allowed for an analysis of the longitudinal static stability in the early pullout phase, confirming that the falcon is flying unstably in pitch with a positive slope in the pitching moment and a trim angle of attack of about 5 deg, which is possibly to maximize responsiveness. The hand wings/primaries were seen to contribute to the augmented stability, acting as “elevons” would on a tailless blended-wing/body aircraft.

Feasibility study of FSW, LBW and TIG joining process to fabricate light combat aircraft structure

In this research, friction stir welding (FSW), laser beam welding (LBW) and tungsten inert gas (TIG) welding are used to join precipitation hardening aluminum alloy 2014-T6. This alloy is a potential candidate in heavy structural fabrication industries due to strength ratio. However, the joining of this alloy is a major problem in assembly line. Hence, to find an ideal method for welding this alloy, three processes were compared in terms of mechanical and metallurgical properties of welded joints. Results showed that the FSW joints disclosed better strength than other LBW and TIG joints. In comparison to LBW and TIG joints, FSW conceived narrow heat-affected zone and recorded maximum hardness of 135 VHN. Similarly, the maximum hardness in the LBW and TIG welded joints were 110 VHN and 92 VHN respectively. The reason for maximum strength in FSW joints is the finer size and uniform distribution of strengthening precipitate. (Particle size diameter of 39 nm, thickness of 29 nm).

Evaluation of unmanned aerial vehicle tactics through the metrics of survivability

Aircraft survivability is a classical consideration of combat aircraft design and tactical development, but the fundamental model of aircraft survivability must be updated to be able to consider modern tactical scenarios that are applicable to unmanned aircraft. This paper seeks therefore to define the set of design tradeoffs and an evaluation of the tactical effectiveness for unmanned aircraft survivability. Traditional and modern survivability evaluation methods are presented and integrated into a computational simulation to create a probabilistic evaluation of unmanned aircraft survivability. The results demonstrate the development of design tradeoffs for a hypothetical unmanned C-130J Hercules against a single man-portable air defense system. The discussion focuses on the demonstration of the utility of this survivability evaluation framework for consideration of survivability in unmanned aerial vehicle (UAV) design, the utility of considering survivability in the design of multi-UAV configurations (including the loyal wingman and swarms), and the value of the probabilistic survivability model for multi-aircraft simulations.

Normalized Partial Scattering Cross Section for Performance Evaluation of Low-Observability Scattering Structures

The development of diffusion metasurfaces created new opportunities to elevate the stealthiness of combat aircraft. Despite the potential significance of metasurfaces, their rigorous design methodologies are still lacking, especially in the context of meticulous control over the scattering of electromagnetic (EM) waves through geometry parameter tuning. Another practical issue is insufficiency of the existing performance metrics, specifically, monostatic and bistatic evaluation of the reflectivity, especially at the design stage of metasurfaces. Both provide limited insight into the RCS reduction properties, with the latter being dependent on the selection of the planes over which the evaluation takes place. This paper introduces a novel performance metric for evaluating scattering characteristics of a metasurface, referred to as Normalized Partial Scattering Cross Section (NPSCS). The metric involves integration of the scattered energy over a specific solid angle, which allows for a comprehensive assessment of the structure performance in a format largely independent of the particular arrangement of the scattering lobes. We demonstrate the utility of the introduced metric using two specific metasurface architectures. In particular, we show that the integral-based metric can be used to discriminate between the various surface configurations (e.g., checkerboard versus random), which cannot be conclusively compared using traditional methods. Consequently, the proposed approach can be a useful tool in benchmarking radar cross section reduction performance of metamaterial-based, and other types of scattering structures.

Air combat training – high energy at lowest cost

PurposeThe purpose of this paper is to reduce the exploitation cost below the standard supersonic training aircraft. The idea will benefit from the latest aerodynamic software and modern avionics, allowing to use much lighter trainer (due to using composite materials and minimizing on board avionic systems), and hence, decreasing the fuel consumption and cost of operation. The need to reform advanced jet training also covers the “red air” missions (manned targets for exercise and training). Red air missions need dedicated more realistic and less costly platforms. However, this makes sense only if the performance of these platforms is comparable to a front-line combat aircraft, particularly in terms of high specific excess power (SEP) and high levels of agility. Failure to address this issue would lead to unrealistic training scenarios and a negative training experience.Design/methodology/approachThe paper focuses on required research and the feasibility studies of a low-cost operationally effective solution for air combat pilot training, combining a very agile air platform, fully dedicated to training, and a flexible, interoperable, integrated training system (ITS) using simulations to provide a complete Live Virtual Constructive (LVC) solution. This study will explore innovations applicable to the learning and maintaining of skills, develop a first pilot physiological survey and propose a follow-up program aimed at developing a fully European air combat training service by 2028 or beyond.FindingsThe volume inside the SEP envelope shows the available SEP potential depending on Mach number and Altitude: SEP is directly representative for climb rate and acceleration or a combination of both. The surface of the volume represents steady-state conditions, i.e. at 1 g (no turns), enabling us to conclude that supersonic trainer and fighter present high energy potentials (SEP) required in air combat manoeuvres and that a subsonic trainer cannot match those qualities and does not fulfil advanced trainer requirements.Practical implicationsA major difficulty for the air forces in their training syllabus lies in the fact that in peacetime supersonic flight is restricted to dedicated areas or over the sea. However, a real beyond visual range fight can often start in the supersonic and continue into the high subsonic regime after a few minutes. Therefore, this novel trainer superior performance in the transonic region will bring the following advantages, for example in the rare opportunities to train in the lower supersonic regime, it can provide similar performance like combat aircraft and in the usual advanced training in the high subsonic regime, this novel trainer offers excellent realistic performance in a region where the conventional advanced trainer performance collapses beyond Mach 0.8 and does not provide realistic training results. The feasibility study shall be executed in close cooperation between User (Requirements) and Study Team (Solutions). The early conceptual design with basic layout and data (T/W and W/L) is key for operational utility and must be addressed with the User right at the beginning. The users are therefore offered early participation in the requirements development.Originality/valueThe presented methodology is an original approach to the combat pilot training. The core of the methodology is a study of a solution that aims to reduce training costs through an affordable operational air vehicle and an agile ITS. This goal will be reached by a design methodology that will concentrate the innovation and the developments to the critical issues for the concept (aerodynamics, propulsion, simulated weapon system, ITS architecture, etc.): the remaining topics will be adapted from existing solution, optimizing the development.

Evaluation of Mechanical/Electromagnetic Preformation of Single-Sided Active Frequency Selective Surface for Stealth Radomes

In this study, a pattern for an active frequency selective surface (AFSS) applicable to stealth radomes was designed and manufactured. Subsequently, its effectiveness was verified via measurements of its electromagnetic performance, and its mechanical performance was numerically evaluated in an actual flight environment. An AFSS equipped with a PIN diode was designed to have a transmission frequency in the X-band using only one side of a surface. To evaluate the mechanical performance when the designed AFSS was applied to a stealth radome, flow analysis was performed on the basis of the shape of the F-35 combat aircraft. Moreover, structural analysis of the stealth radome was performed using the pressure distribution at the maximum velocity of the F-35, as determined via the flow analysis. On the basis of the structural analysis results, the mechanical performance of the designed stealth radome was evaluated via analysis of the stress distribution of the AFSS diode. Through this study, an AFSS pattern applicable to stealth radomes was proposed, and its mechanical/electromagnetic performance was evaluated to verify the feasibility of stealth radomes incorporated with AFSSs.

Analysis of the State of the Aerodrome Network of Air Forces of the Armed Forces of Ukraine and Ways of its Development

The article deals and analyzed how the most appropriate loss of hostile aviation is considered, a scientific approach to the definition of the essence of the aerodrome network of the Air Forces of the Armed Forces of Ukraine is considered. The scientific novelty is that the changes in the aerodrome network of the Air Force of the Armed Forces of Ukraine during the last 30 years are analyzed. The aerodrome network includes airfields, maneuver, spare, advanced, rear and false. The survivability of aviation is possible to provide “dispersed by operational airfields, civil aviation aerodromes, airfields of roads on drivers, etc. The purpose of the study is to analyze the state of the aerodrome network in Ukraine, its influence on the capacity of aircraft AF of Ukraine to complete the task of appointment. Considered how many aircraft has reached Ukraine from the Armed Forces of the USSR, and the branching of the airfield network for 1992. As of 01.01.92: the aerodrome network of military forces of the Armed Forces of Ukraine accounted for 119 aerodromes. Investigated as less, at the beginning of the ATO in 2014, in the States of the Armed Forces of Ukraine, military and military transport aircraft. This led to a decrease in the number of airfields used by the AF of Ukraine. At the time of the ATO, the number of AF of Ukraine, created on the basis of Air Force and PPA, was about 43 thousand people. As part of the Ukrainian AF of Ukraine at the beginning of 2014, there were about 160 combat aircraft and 20 military transport, which are based on 20 airfields. Considered whom when the excess aerodromes of the AF of Ukraine are transmitted with. Since the beginning of the ATO for April 2015, more than 200 units of PS equipment were restored and repaired, during 2017, another 9 airfields were repaired. The Russian military aggression AF of Ukraine used only a quarter of all military flyers in the country. At the beginning of 2018, this quantity has doubled. Conclusions. In our opinion, instead of dismantling of runways and selling aerodrome slabs, it would be more advisable to convey aerodromes that are not used by aircraft AF of Ukraine, aircrubs, commercial firms related to aviation, provided that they will be responsible for maintaining runways, strips and equipment provided. Key words: airfield, spare airfield, airfield network, air force, aviation, runway.

Безымянка – ядро авиационного комплекса Среднего Поволжья в годы Великой Отечественной войны

During the Great Patriotic War, the Middle Volga Region became one of the centers for military-industrial complex enterprises evacuation from the western regions of the country. The city of Kuybyshev (now Samara) accepted 40 largest enterprises. The factories of the People’s Commissariat of the Aviation Industry functioned as their basis. This decision was associated with the ongoing construction of three aircraft factories in the city. By the beginning of the war, the construction had not been completed and the completion degree of the plants buildings varied. The decision to evacuate aviation production to the city was also influenced by the presence of the metalworking industry, energy capacities and labor concentrated in one of the largest camps of the GULAG system – Bezymyanlag. The equipment of the evacuated enterprises was arriving at the Bezymyanka station of the Kuibyshev railway where aviation factories were being constructed. Unloading and placing the equipment caused considerable difficulties. The machines were installed in unfinished facilities or even simply on the ground. A large industrial center developed near the city where the enterprises of the aviation complex were located. A closed production cycle was created for the first time in the country here; it produced the Ilyushin IL-2 and the Ilyushin IL-10 Shturmoviks. The Ilyushin IL-2 attack aircraft was recognized as the best one in World War II. The production establishment faced great difficulties: placement on unsuitable production manufacturing sites, extremely tight timeline for manufacturing production, and the need for its constant modernization. The personnel issue was especially urgent. It was decided to mobilize women, youth and adolescents to work for manufacturing enterprises. However, their low qualifications caused production problems. It was self-sacrifice and labor heroism that helped to tackle these tasks. The work of the Bezymyanka aviation complex supplied the country’s armed forces with combat aircraft. The presence of a large aviation complex predetermined the development of the industrial cluster of the Samara Region.

Comparative Analysis of Aerodynamic Characteristics of F16 and F22 Combat Aircraft using Computational Fluid Dynamics

This paper presents the computational investigation of air flow over an aircraft at realistic speeds while demonstrating the importance of extending the existing analysis to the complete airplane and how pivotal it is in improving its in-flight performance. The study is done for F16 and F22 aircraft using ANSYS Fluent (19.2) to obtain pressure distribution, shear stress distribution and temperature variation on the complete surface of the aircraft. Since the front section of the aircraft is prone to direct initial impact of surrounding environment, this portion is also examined. Here, as the speed is doubled from Mach 1 to Mach 2, a rise in the value of all the three variables is noticed for the F16 aircraft, whereas the pressure distribution for F22 aircraft shows strange behaviour for the highest speed (Mach 2). On comparing the results over the whole surface, it is seen that F16 experiences smaller pressure (29% lower for Mach 1 and 30% for Mach 2), temperature (9.5% lower for Mach 1 and 30% for Mach 2) and shear stress relative to F22 and the stress shows a huge change (90% lower for Mach 1 and 83% for Mach 2). Results of the present study imply that the design of the aircraft highly influences its performance as the parameters discussed touch their limits.

Designer Solid Shims for Assembly of Advanced Carbon Composite Pre-preg based Aircraft Structures

A modern combat aircraft uses considerable amount of advanced composite material in structure build for better flight performance, stealth requirement and higher payload. Combat aircrafts made using composite structure require large numbers of custom shims of various thickness and shapes throughout interface surface, which are presently prepared by suit on assembly process to fill gaps measured between sub-structure parts and skin. The scope of study is four plus generation combat aircraft like Indian Light combat aircraft. These gaps arise due to composite raw material characteristics, mould tool and manufacturing process which results in geometry variation. This research has focussed the delta wing integral fuel tank composite structure. However, these research findings can be applied in other wing shapes made by composite part within the scope. The shims, whether liquid or solid, are necessary to eliminate gaps, maintain structural performance and minimize pull-down forces required to bring the aircraft into engineering nominal configuration for aerodynamic efficiency. Customized shims amount to significant delays in production with much of the time being spent in the critical path of the aircraft assembly. In this research work, we present an alternative strategy for the use of designer solid shim, based on redesign of lay-up moulding tool (female type) and shims manufacturing with change in existing manufacturing value stream. The experimented method has reduced the manufacturing cost of wing assembly, shorten the shimming process cycle and improve the assembly efficiency, product quality and performance.

'A Sixth Generation Fighter?' An Update

Abstract: This working paper endeavors, with an eye to the author's prior discussion of the sixth generation fighter aircraft (initially drafted in 2010), consider the development of the technology in the past decade as revealed through the publicly available literature on the subject, and that development's interaction with the technological, economic and political changes of the period. It concludes that while (as the author had suggested would be the case) technological change has been slower than predicted, and economic growth slow, making implausible the development and large-scale procurement of the radical aircraft in question (morphing, hypersonic, intercontinental-range, potentially unmanned fighter aircraft with integral directed-energy weaponry), the more aggressive relations among the major powers have seen them more determined to acquire the most advanced combat aircraft available. The result is the presently aggressive pursuit of new fighter designs of more advanced but less revolutionary character (which, if characterized as sixth generation fighters, may ultimately prove to be fifth generation or fifth generation+ planes).

Military autonomous drones (UAVs) - from fantasy to reality. Legal and Ethical implications.

Unmanned aerial vehicles, (UAVs), called drones, have recently greatly increased their role from simple surveillance and reconnaissance to increasingly controversial targeted killings. Autonomous drones raise important judicial and ethical issues about responsibility for unintentional harm which will be discussed in this paper. Autonomy refers to respect for human autonomy (in contrast with the autonomy of a drone) and includes the free choice of individuals and groups. In the context of drones used, the ethical principle of autonomy is translated into the human values, responsibility and trust. Some features of these unmanned combat aircraft (UAVs), such as flying at high altitudes, the ability to collect effective information and their impact on civilians, influence decisions on the legality of these weapons, and the distance between the operator of the aircraft and military targets also affects the principles of international law and humanitarian law. The paper will analyze the legal and ethical issues on using drones as a weapon.

Microwave photonic radar warning receiver: airborne antenna over fiber optic

Electronic warfare had great importance mainly in the Second World War. Radar was one of the greatest inventions in the area at that time, reinventing the way war was viewed until then. Nowadays, modern combat aircraft has sophisticated warfare systems. One of them is known as radar warning receiver (RWR), responsible for alerting pilots to possible radar detection and guiding the direction in which it is being radiated. Technological innovations allowed the interaction of the microwave and optoelectronics area, leading to an area known as microwave photonics (MWP). This article presents a photonic link to replace the copper cables used by RWR systems, applying photonic technology in order to improve performance and benefit from the intrinsic characteristics that optical fiber offers to the system, offering a totally passive remote system, in which only one phase modulator is connected to the RWR antenna. The results obtained for a totally photonic link by experiment were satisfactory. As expected, a gain above the unit was obtained. However, the observed noise figure was higher than expected, which ended up resulting in a lower signal noise ratio.