Different Stages Of Flight Research Articles

Principles and examples of drag reduction in civil airliners

Civil aviation has grown rapidly over the past hundred years as demand from air travellers has increased. Since the mid to late 20th century, there have been recurring global energy crises due to political and economic upheavals. In this international context, airlines have tended to operate less draggy, more fuel efficient aircraft in order to maximise profits through fuel cost savings . To this end, aircraft manufacturers have historically tried a variety of methods to address the issue of drag reduction.This paper highlights the importance of three drag reduction methods utilized on modern subsonic airliners by introducing their basic principle and evaluating their effectiveness based on previous research and typical experiments. This paper summarizes and analyzes different approaches to reduce drag in civil aviation. It first investigates the principle behind frictional, induced, and profile drag in theoretical aspects. It then discusses in detail the biomimicry microstructure based on shark skin and its uniqueness on aircraft fuselages surface to reduce frictional drag, the split scimitar winglet and its ideal performance to reduce induced drag when compared with other wingtip devices with different cant angles. The newly introduced adaptive lifting surface changes the wings geometric configuration momentarily, and its ability to reduce profile drag at different stages of flight. This paper also comprehensively compares both the benefits and potential compromises of these drag reduction methods.

The Emissions of Water Vapour and NOx from Modelled Hydrogen-Fuelled Aircraft and the Impact of NOx Reduction on Climate Compared with Kerosene-Fuelled Aircraft

A kerosene fuelled aircraft was modelled within a performance tool and fuel burn and the emissions of nitrogen oxides (NOx) and water vapour at different stages of flight throughout the mission were estimated. Adaptions were made to engine and aircraft parameters within the performance tool to accommodate a liquid hydrogen fuel over the same given mission. Once an iterative design process had been completed to ensure the aircraft could perform the given mission, the performance tool was again used to calculate total fuel burn. Fuel burn results alongside predicted emission indices were used to estimate the emissions of NOx, water vapour from hydrogen-fuelled aircraft. The use of hydrogen fuel over kerosene fuel in the modelled aircraft resulted in the removal of carbon-based emission species alongside 86% reduction in NOx and 4.3 times increase in water vapour emission. The climate impact of this switch with the reduction in NOx emission was assessed by a 3D global atmospheric chemistry and transport model, STOCHEM-CRI, which found a significant reduction in the concentration of a potent greenhouse gas, ozone, and an oxidizing agent, OH, by up to 6% and 25%, respectively. The reduction of OH levels could induce a positive radiative forcing effect as the lifetime of another important greenhouse gas, methane, is increased. However, the magnitude of this increase is very small (~0.3%), thus the overall impact of the reduction in NOx emissions is likely to have a net negative radiative forcing effect, improving aviation’s impact on the environment. However, further work is warranted on effects of other emission species, specifically water vapour, particulate matter and unburned hydrogen.

Herbicide Ballistic Technology for Unmanned Aircraft Systems

Miconia is a highly invasive plant species with incipient plants occupying remote areas of Hawaiian watersheds. Management of these incipient plants is integral to current containment strategies. Herbicide Ballistic Technology (HBT) has been used for 8 years from helicopters as a precision approach to target individual plants. We have developed a prototype HBT applicator integrated onto an unmanned aircraft system, HBT-UAS, which offers the same precision approach with a semi-automated flight plan. Inclusion of the HBT payload resulted in statistically significant deviations from programmed flight plans compared to the unencumbered UAS, but the effect size was lower than that observed for different stages of flight. The additional payload of the HBT-UAS resulted in a large reduction in available flight time resulting a limited range of 22 m. The projectile spread of the HBT-UAS, within a 2–10 m range, had a maximum CEP of 1.87–5.58 cm. The most substantial limitation of the current prototype HBT-UAS is the available flight time. The use of larger capacity UAS and potential for beyond visual line of sight operations would result in a substantial improvement in the serviceable area and utility of the HBT-UAS for containment of invasive plants.

Erratum to: Methodology for Assessing the Risks of the Human Factordue to Pilot Errors in the Process of Piloting an Aircraft

This paper analyzes the types of flight accident events, their causes and statistics on accidents at different stages of flight. By studying the subjective pilot rating, the law of its probability distribution was established as well as the possibility of using this law to assess the risk of accidents. The methodology for assessing the risk of an accident during manual control in nonstationary conditions associated with a sharp change in the controlled element dynamics is considered.

Study of the correlation of sensory loads and the cardiovascular system condition of pilots of civil aviation

The study of the link between the work intensity and indicators of the cardiovascular system is presented. The assessment of sensory loads and daily monitoring of the arterial pressure of civil aviation pilots during a training flight at the training complex were carried out. The increase in the number of sensory signals at different stages of flight leads to an increase in arterial pressure.

MATHEMATICAL MODEL OF THE ESTIMATION OF THE EFFICIENCY OF THE CONTROL OF RADIO ELECTRONIC COUNTERACTION OF THE AIRPORT STATION OF ACTIVE CONTEMPORARY INTERFERENCES IN THE CONDITIONS OF CREATING A POLARIZATION INTERFACE ON A FIXED PLANE OF IT

In the article, based on the analysis of the use of modern individual on-board electronics and electronic search and guidance systems, it is concluded that one of the promising directions for their further development is the search for methods of not only protection from the means of radio-electronic suppression, but also an active counteraction to these means, the so-called counter-radio electronic counteraction One of the most effective obstacles that can be created by radar detection systems by stations is the active barrier of individual enemy protection - this is a polarizing obstacle, so the issue of reducing the effectiveness of the polarizing effect on the system of automatic support for the direction of the on-board radar weapon control system is quite relevant today. In order to counteract the station's active interference in the conditions of its creation of a polarization obstacle, it is proposed to change the plane of polarization on the receiving side. As a result, a useful signal will be taken in polarization, which does not coincide with the polarization plane of the radiation signal. Failure to match polarization when receiving a reflected signal will not significantly affect the power of a useful signal. In order to implement the proposed method in the article, a mathematical model for evaluating the effectiveness of the counter-radio-electronic counteraction of the on-board station was proposed to obstruct the enemy's individual protection in the conditions of its creation of a polarization obstacle on a fixed plane of polarization, as well as features of the practical realization of such counteraction during air combat and restrictions on its creation. The mathematical model of the evaluation of the effectiveness of the counter-electronic counteraction to the aircraft station's active barriers in the conditions of its creation of a polarization obstacle on a fixed plane of polarization is developed, it will allow to formulate practical recommendations regarding the application of the developed method at different stages of air combat. KELP management in different ways, on the one hand, slightly reduces the effectiveness of the on-board management of weapons at different stages of flight, but on the other hand, the effectiveness of the airborne equipment of the airborne ejection of the enemy significantly decreases, which will increase the effectiveness of the use of weapons and the likelihood of damage to the enemy aircraft using the means of destruction, which today have a significant cost.

Shape morphing and adjustment of pantographic morphing aerofoil section structure

This study concerns with morphing structures, e.g. as applied in the aerospace industry. A morphing aerofoil structure capable of variable geometry was developed, which was shown to be able to cater for the different aerodynamic requirements at different stages of flight. In this work, the useful and relatively simple method has been applied, which provides a direct method for calculating required morphing shape displacements via finding the most effective bar through calculating bar sensitivity to displacement and calculating set of length actuations for bar assembly to control/adjust shape imperfection of prestressable structural assemblies including complex elements (macro-elements, e.g., the pantographic element), involving Matrix Condensation. The technique has been verified by experiments on the physical model of an aerofoil shaped morphing pantographic structure. Overall, experimental results agree well with theoretical prediction. Furthermore, the technique of multi-iteration adjustment was presented that effective in eliminating errors that occur in the practical adjustment process itself. It has been demonstrated by the experiments on the physical model of pantographic morphing structure. Finally, the study discusses identification of the most effective bars with the objective of minimal number of actuators or minimum actuation.

Comparison of finite and boundary element methods in problems of oscillations of a composite shell of revolution with a liquid

The phenomenon of sloshing can be described as the movement of the free surface of a liquid contained in a reservoir under the action of a suddenly applied load. H. Olsen cited the classification of free-surface fluctuations in liquids by identifying three main forms of sloshing: a) longitudinal sloshing, b) vertical sloshing c) rotating sloshing. Sloshing is a phenomenon that is found in a wide range of industrial applications: in containers for storing liquefied gas, fuel tanks of missiles and airplanes, in tanks of cargo tankers. The vibrations of the real tanks are caused by sloshing of the fluid and vibration of the elastic walls. In completely (or almost completely) filled tanks, the free surface cannot experience strong oscillations. This corresponds to the launch of the launch vehicle. However, in further stages of flight, when the level of liquid aggregate falls, the sloshing effect becomes dominant. It was repeatedly noted that powerful sloshing can lead to a violation of the flight trajectory, as happened, for example, during the launch of the Falcon 1 launch vehicle in 2006, 2007 and 2008. The next important problem in the study of the oscillations of the fuel tanks is the study of the associated hydro-elastic oscillations of the fluid interacting with the elastic walls of the tank. New analytical method and computer technology have been developed for analyzing free and forced vibrations of composite fuel tanks of missiles at different stages of flight: during overloads and in microgravity conditions, including sloshing fuel. The proposed method allows us for more accurate analysis of fuel tank oscillations, taking into account the mutual influence of elastic deformations of tank walls and tank filling levels changing during missions and the shape of the free surface of the liquid, the presence of elastic and rigid damping internal partitions, and the change in acceleration of gravity. A mathematical model has been developed for the analysis of fuel sloshing at large amplitudes. The free oscillations of the launch vehicle tanks are considered.

STRUCTURAL SYNTHESIS OF NAVIGATION SUPPORT OF TRIAD INTEGRATED NAVIGATION SYSTEM ON THE BASIS OF INERTIAL AND SATELLITE TECHNOLOGIES

In connection with the increasing complexity of aircraft navigation support, with growing demands placed on them, it is increasingly necessary to develop integrated navigation data processing system by solving synthesis problems based on optimal filtering methods. One of the promising ways to improve aircraft navigation support is to create an integrated navigation system (INS). In this work the triadic structure of a promising integrated navigation system based on inertial and satellite technologies is proposed. Combining nautical meters as part of the triad concept allows the flexible use of various navigation data processing algorithms and trajectory optimization ones at different stages of flight. Based on optimal filtering theory methods the integrated navigation data processing algorithm, which is an extended Kalman filter, is synthesized. A distinctive feature of the algorithm is that the variables of the state vector which are to be measured, are the errors in the determination of appropriate navigation and timing parameters. Priori information about the dynamics of errors is more reliably known than the one about aircraft motion variables. It is shown that the use of the proposed navigation system as a navigation aid for problem solving of highly accurate aircraft position indication satisfies the requirements for navigation and timing data accuracy. The imitating statistical modeling of optimal filtering algorithm of the triad integrated system is carried out. The accuracy characteristics of subsystems for different operating configurations of the constellation are given. Analysis of the results of the accuracy characteristics study of INS in various operating conditions has showed that the positioning accuracy in the navigation computer is up to date satellite navigation receivers.

Adaptation of the water-electrolyte metabolism to space flight and at its imitation

50-years study of water-electrolytes exchange, the condition of water environments of the organism and the hormonal regulation in space flights, and also in postflight period or in its on ground modeling (hypokinesia, bed rest, immersion etc.) has shown the important role of the water-salt homeostasis in adaptation of the human and animal organisms to weightlessness. It has been revealed, that in weightlessness conditions for development of negative balance of a liquid (hypohydration) and the basic electrolytes are created. After the termination of long space flights attributes of development adaptive reactions compensating for extracellular liquid's volume come to light. In order to assess the state of the kidneys and water-electrolyte metabolism in cosmonauts and investigators, functional load tests and especial methods of diagnostic were developed. This is the basis for researches directed on improvement of the scheme of correction hydrogenous the status of an organism of the cosmonauts at the different stages of flight.

Quantitative aspects of proline utilization during flight in tsetse flies

ABSTRACT. The proline concentration of the haemolymph in resting tsetse flies provides a reasonable indication of their total proline content. Estimates of pre‐flight proline content obtained on this basis were compared with the proline content of flies that had been flown for different durations to provide an estimate of the rate of proline consumption at different stages of flight. The results indicate that the apparent ability of tsetse flies to continue flight after their proline reserves have been exhausted is an artefact of experimental procedure. It is concluded that the flight capacity of tsetse flies is effectively limited by the magnitude of their proline reserve, although this reserve is capable of being supplemented to some extent by the limited synthetic capacity of the fat body.