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    Інформаційна система попередження наближення землі сучасного літака

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    Робота публікується згідно наказу ректора від 27.05.2021 р. №311/од "Про розміщення кваліфікаційних робіт вищої освіти в репозиторії НАУ". Керівник дипломної роботи: доцент кафедри авіоніки, Чужа Олексій ОлександровичIn the late 1960s, a series of Controlled Flight Into Terrain (CFIT) accidents, in which the pilots did not lose control of the aircraft, killed hundreds of passengers. Controlled flight into terrain (CFIT) is an accident in which an aircraft strikes the ground, water, or an obstacle without the pilot flying losing control. Although a mechanical problem can be the cause of a CFIT, pilot error is the most common factor. It may be due to navigational error, weather misjudgement, lack of awareness of terrain height, or spatial disorientation. Accidents resulting from a voluntary action by the person flying, such as an act of terrorism or pilot suicide, are not considered CFIT, nor are situations where the aircraft is out of control at the time of impact.The term was invented by Boeing engineers in the late 1970s. According to Boeing, for the period 2003 to 2012, CFIT type of accident was the second most deadly after LOC (Lost Of Control), causing almost a thousand deaths in aircraft and among outsiders during this period. So, during the 1970s, numerous studies were conducted to discover the causes of these accidents. These accidents could have been avoided if the aircraft had been equipped with ground proximity warning systems (GPWS). In 1974, the Federal Aviation Administration declared GPWS mandatory on large aircraft to prevent accidents. In 2000, the FAA amended its operating rules to require that all US-registered turboprop aircraft with six or more passenger seats (excluding pilot and co-pilot seats) be equipped with an FAA-approved ground proximity warning system. The distance between the aircraft and the ground is measured by the radiosonde (or radio altimeter). Depending on the height and the flight configuration, the computer can inform the pilot of a danger by audio or visual messages. Nowadays, manufacturers and airlines are still constantly working to reduce accidents connected with CFIT. The most common solutions are improved pilot training, mainly by asking pilots to pay attention to their on-board instrumentation, but also the develop and improve of efficient safety systems, such as the ground proximity warning system (GPWS) that today became mandatory for all commercial aircrafts and not only. The main input data of modern GPWS systems are values from the radar altimeter and barometric altimeter sensors. When entering the GPWS system, these data are analyzed according to certain algorithms (which also take into account the current position of the mechanization of the wheels, the position of the chassis, etc.) by the on-board computer of the system, which then issues the appropriate visual and sound signals to the pilot.Наприкінці 1960-х років серія аварій з контрольованим польотом на землю (CFIT), в яких пілоти не втратили керування літаком, загинули сотні пасажирів. Контрольований політ на землю (CFIT) — це нещасний випадок, під час якого повітряне судно стикається з землею, вода або перешкода без втрати керування пілотом. Хоч і механічний проблема може бути причиною CFIT, помилка пілота є найпоширенішим фактором. Це може бути через до навігаційної помилки, неправильної оцінки погоди, відсутності інформації про висоту місцевості або просторову дезорієнтація. Аварії, що сталися внаслідок добровільних дій особи, яка здійснює політ, наприклад дії тероризм чи самогубство пілота не вважаються CFIT, а також ситуації, коли літак знаходиться поза контролем у момент зіткнення. Термін був винайдений інженерами Boeing наприкінці 1970-ті роки. За даними компанії Boeing, за період з 2003 по 2012 роки тип аварії CFIT був другий за смертоносністю після LOC (втрата контролю), спричинивши майже тисячу смертей у літаків і серед сторонніх осіб у цей період. Тому протягом 1970-х років було проведено численні дослідження, щоб виявити причини цього аварії. Цих аварій можна було б уникнути, якби літак був оснащений системи попередження про наближення до землі (GPWS). У 1974 році Федеральна авіаційна адміністрація оголосила GPWS обов'язковою для великих літаків щоб запобігти нещасним випадкам. У 2000 році FAA внесло зміни до своїх правил експлуатації, вимагаючи, щоб усі зареєстровані в США турбогвинтові двигуни повітряне судно з шістьма або більше пасажирськими місцями (за винятком місць пілота та другого пілота). із схваленою FAA системою попередження про наближення до землі. Відстань між літаком і землею вимірюється радіозондом (або радіо висотомір). Залежно від висоти та конфігурації польоту комп’ютер може інформувати пілот про небезпеку за допомогою звукових або візуальних повідомлень. Сьогодні виробники та авіакомпанії все ще постійно працюють над зменшенням кількості аварій пов'язаний з CFIT. Найпоширенішими рішеннями є вдосконалення підготовки пілотів, головним чином просять пілотів звернути увагу на свої бортові прилади, а також на розробку та вдосконалення ефективних систем безпеки, таких як система попередження про наближення до землі (GPWS), яка сьогодні стала обов'язковою для всіх комерційних літаків і не тільки. Основними вхідними даними сучасних систем GPWS є значення радіолокаційного висотоміра та датчики барометричного висотоміра. При вході в систему GPWS ці дані аналізуються за певними алгоритмами (які також враховують поточну позицію механізація коліс, положення шасі тощо) за допомогою бортового комп'ютера система, яка потім подає відповідні візуальні та звукові сигнали пілоту

    Piezoelectric energy harvester for harnessing rotational kinetic energy through linear energy conversion

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    This article belongs to the Special Issue Energy Harvesting State of the Art and Challenges IIReal-time condition monitoring of various types of machinery using sensor technology has gained significant importance in recent years. However, relying on batteries to power these sensors proves to be sub-optimal, as it necessitates regular charging or replacement. To address this, harvesting waste energy from ambient sources emerges as a more efficient alternative. Everyday applications like vehicle wheels, fans, and turbines present ambient sources of waste rotational energy. In this study, we propose a novel rotational energy harvester design that converts rotational energy into linear energy. This linear energy impacts a piezoelectric disk, generating an electric potential. Through simulations, the expected electric potential at varying frequencies was evaluated. Subsequently, experimental tests were conducted by connecting the harvester to a rectifier for AC-to-DC signal conversion and an oscilloscope for voltage measurement. A DC motor replicated the rotational motion at the frequencies from the simulation, and the power output was measured. Using the power transfer theorem, simulation and experimental power outputs were calculated, resulting in values of 188, 513, and 1293 μW and 88.89, 336, and 923 μW, respectively. These results reveal that the designed harvester is competitive with those of existing rotational energy harvester designs, demonstrating the promising potential of this novel harvester

    Runway Safety Improvements Through a Data Driven Approach for Risk Flight Prediction and Simulation

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    Runway overrun is one of the most frequently occurring flight accident types threatening the safety of aviation. Sensors have been improved with recent technological advancements and allow data collection during flights. The recorded data helps to better identify the characteristics of runway overruns. The improved technological capabilities and the growing air traffic led to increased momentum for reducing flight risk using artificial intelligence. Discussions on incorporating artificial intelligence to enhance flight safety are timely and critical. Using artificial intelligence, we may be able to develop the tools we need to better identify runway overrun risk and increase awareness of runway overruns. This work seeks to increase attitude, skill, and knowledge (ASK) of runway overrun risks by predicting the flight states near touchdown and simulating the flight exposed to runway overrun precursors. To achieve this, the methodology develops a prediction model and a simulation model. During the flight training process, the prediction model is used in flight to identify potential risks and the simulation model is used post-flight to review the flight behavior. The prediction model identifies potential risks by predicting flight parameters that best characterize the landing performance during the final approach phase. The predicted flight parameters are used to alert the pilots for any runway overrun precursors that may pose a threat. The predictions and alerts are made when thresholds of various flight parameters are exceeded. The flight simulation model simulates the final approach trajectory with an emphasis on capturing the effect wind has on the aircraft. The focus is on the wind since the wind is a relatively significant factor during the final approach; typically, the aircraft is stabilized during the final approach. The flight simulation is used to quickly assess the differences between fight patterns that have triggered overrun precursors and normal flights with no abnormalities. The differences are crucial in learning how to mitigate adverse flight conditions. Both of the models are created with neural network models. The main challenges of developing a neural network model are the unique assignment of each model design space and the size of a model design space. A model design space is unique to each problem and cannot accommodate multiple problems. A model design space can also be significantly large depending on the depth of the model. Therefore, a hyperparameter optimization algorithm is investigated and used to design the data and model structures to best characterize the aircraft behavior during the final approach. A series of experiments are performed to observe how the model accuracy change with different data pre-processing methods for the prediction model and different neural network models for the simulation model. The data pre-processing methods include indexing the data by different frequencies, by different window sizes, and data clustering. The neural network models include simple Recurrent Neural Networks, Gated Recurrent Units, Long Short Term Memory, and Neural Network Autoregressive with Exogenous Input. Another series of experiments are performed to evaluate the robustness of these models to adverse wind and flare. This is because different wind conditions and flares represent controls that the models need to map to the predicted flight states. The most robust models are then used to identify significant features for the prediction model and the feasible control space for the simulation model. The outcomes of the most robust models are also mapped to the required landing distance metric so that the results of the prediction and simulation are easily read. Then, the methodology is demonstrated with a sample flight exposed to an overrun precursor, and high approach speed, to show how the models can potentially increase attitude, skill, and knowledge of runway overrun risk. The main contribution of this work is on evaluating the accuracy and robustness of prediction and simulation models trained using Flight Operational Quality Assurance (FOQA) data. Unlike many studies that focused on optimizing the model structures to create the two models, this work optimized both data and model structures to ensure that the data well capture the dynamics of the aircraft it represents. To achieve this, this work introduced a hybrid genetic algorithm that combines the benefits of conventional and quantum-inspired genetic algorithms to quickly converge to an optimal configuration while exploring the design space. With the optimized model, this work identified the data features, from the final approach, with a higher contribution to predicting airspeed, vertical speed, and pitch angle near touchdown. The top contributing features are altitude, angle of attack, core rpm, and air speeds. For both the prediction and the simulation models, this study goes through the impact of various data preprocessing methods on the accuracy of the two models. The results may help future studies identify the right data preprocessing methods for their work. Another contribution from this work is on evaluating how flight control and wind affect both the prediction and the simulation models. This is achieved by mapping the model accuracy at various levels of control surface deflection, wind speeds, and wind direction change. The results saw fairly consistent prediction and simulation accuracy at different levels of control surface deflection and wind conditions. This showed that the neural network-based models are effective in creating robust prediction and simulation models of aircraft during the final approach. The results also showed that data frequency has a significant impact on the prediction and simulation accuracy so it is important to have sufficient data to train the models in the condition that the models will be used. The final contribution of this work is on demonstrating how the prediction and the simulation models can be used to increase awareness of runway overrun.Ph.D

    Decarbonization of aviation via hydrogen propulsion: technology performance targets and energy system impacts

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    The aviation sector is challenging to decarbonize since aircraft require high power and energy per unit of weight. Liquid hydrogen is an interesting solution due to its high gravimetric energy density, minimal warming impact, and low-carbon production potential. We quantify the performance targets for fuel cell systems and on-board storage to enable hydrogen-powered regional aviation. We then explore the energy infrastructure impacts of meeting this additional H2 demand in the European context under deep decarbonization scenarios. We find that minimal payload reduction would be needed for powering regional aviation up to 1000 nmi if fuel cell system specific power of 2 kW/kg and tank gravimetric index of 50% can be achieved. The energy systems analysis highlights the importance of utilizing multiple technology options: such as nuclear expansion and natural gas reforming with CCS for hydrogen production. Levelized cost of liquid hydrogen as low as 3.5 Euros/kg demonstrates pathways for Europe to achieve cost-competitive production.Comment: 25 pages, 6 figures. (38 pages with SI, 7 SI figures

    Integration and evaluation of a 180-kw turboprop engine with a turboelectric ground test rig

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    This paper presents the integration of a PBS Aerospace 180-kW turboprop engine with a Cessna 172, four seat, 1,090-kg (2,400-lbf) max takeoff weight aircraft for use as a turboelectric ground test rig. The quickly growing segment of hybrid propulsion aircraft, commonly used in the urban air mobility sector, are pressing regulatory bodies to develop new certification requirements for these unique aircraft. Small-scale turboelectric systems used in unmanned aerial systems are well documented, but large-scale manned systems are comparatively rare. Therefore, it is critical to develop a large-scale turboelectric ground test rig to study turboelectric system integration phenomena to inform new certification standards from regulatory bodies. To conduct large-scale turboelectric research designing an engine mount, generator mount, a power transfer system, and a propeller spacer are required. The goal of this study was to design, fabricate, install, and test an engine mount, generator mount, propeller spacer and power transfer system for a turboelectric aircraft ground test rig. The methodology included computer aided design, finite element analysis, static component tests and fully integrated tests to acquire data to validate analysis. Electric power demand of the electric propulsors were set as 20 to 30-kW using a 50-kW generator, this power rating drove the design of the belting system. Turboelectric architecture is a parallel partial hybrid system with power being delivered to a 1.8-m three blade propeller while a portion of the engine power is siphoned to the generator. The generator drives two electric motors with 1.3-m two blade propellers mounted to the wing leading edges while also maintaining battery charge. A static torque test of over 1,300-N∙m, peak engine torque is 800-N∙m, was conducted on the engine mount before engine integration to verify its integrity. Observations from testing the full turboelectric system installation, without generator load, indicate the engine successfully operated at all power levels with the engine mount delivering expected structural strength. Another observation from testing shows that the propeller spacer performed well within expected parameters without erratic propeller dynamics. Results from testing the full turboelectric system installation, without generator load, indicate the engine mount withstood all engine loads within expected torsional deflections from the static torque test of around 2 degrees of twisting

    Structural Design, Modeling, And Analysis Of The Wing For A World Speed Record-Breaking Turbo-Prop Racing Airplane

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    The Cal Poly SLO Turbo-Prop Racer (TP Racer) is a vehicle in development with the goal to break the world record for fastest turbo-prop aircraft measured over a 3-kilometer strip. This thesis presents the structural design, modeling, and analysis of the wing of Cal Poly SLO TP Racer. Methodology behind analyzing the wing is presented through finite element modeling elements and a mesh study. This is followed by development of structure through geometry and laminate estimations. The wing structure estimates and loading conditions are then modeled in FEMAP. Initial estimates are analyzed and reviewed – overbuilt, underbuilt, and incorrectly modeled regions of the structure are corrected. Finally, a refined finite element model is analyzed to present a satisfactory aircraft wing

    System Level Trade Study of Hybrid Parallel Propulsion Architectures on Future Regional and Thin Haul Turboprop Aircraft

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    Presented at the AIAA SCITECH 2023 ForumThis paper evaluates the potential benefits of applying hybrid parallel propulsion architectures to future turboprop aircraft that are expected to enter into service in 2030. Two baseline aircraft models are established by infusing viable 2030 airframe and engine technologies on state-of-the-art 19-passenger and 50-passenger aircraft models. Two parametric parallel hybrid architectures are proposed and applied on both size classes: Architecture 1 has two propellers, each driven by an engine and an electric motor in parallel, and allows in-flight recharging; Architecture 2 has four propellers, each driven by either an engine or an electric motor, and allows parallel operation during the cruise. A design space exploration is conducted on the powertrain design variables and the electric component key performance parameters. A constrained optimization implies that Architecture 1 and 2 can achieve fuel savings of about 2.6% and 6.6%, respectively, given 2030 electric component technology assumptions. Electric taxi consistently results in fuel saving when battery technology is beyond the projected 2030 level. Preliminary sensitivity studies show that the performance of Architecture 2 is more sensitive to the battery technology compared to Architecture 1 due to its extensive use of battery energy during the cruise.NATIONAL INSTITUTE OF AEROSPACE, GR0001018

    Ducted fan propulsion system study for ONAerospace eVTOL

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    In recent years, the relentless advance of climate change forces society to adapt to more sustainable modes of transportation. In a not so distant future, urban transport is envisioned to expand to the skies with new innovative electric Vertical Take-Off and Landing (eVTOL) aircraft. Although this idea seems very futuristic, the concept of an electric aircraft might not be as far away as previously thought. ONAerospace aims to take part in this future by designing its own eVTOL aircraft. This project focuses on the ongoing propulsion system design. On its first iteration the project introduced ducted fan propulsion, electric motors and bateries. This second iteration delves into ducted fan performance in order to give a more accurate design of the aircraft¿s propulsive units, and better predict its performance capabilities. Two propulsion configurations have been studied separately: a takeoff and hovering configuration, which uses two ducted fans before the wings and one coaxial ducted fan embedded inside the aircraft¿s tail; and a cruise configuration which uses just the two front engines. The propulsive units are designed to be adaptive ducted fan. This means that, each ducted fan can morph and adapt to optimize its performance to any given condition. Ducted fan performance has been predicted using two theoretical analyses: momentum theory, and blade element theory. These methods have been used to size the propulsive units in order to ensure that the thrust requirements are met. Also, the power required in each configuration and flight phase has been computed. Finally, experimental data on the effects of varying different design parameters was reviewed with the objective to give a more detailed design of each ducted fan

    Feasibility tool and business plan for the adaptation of airports to hydrogen-powered aircraft

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    The study aims to analyse the viability of implementing a network of Zero-carbon Emission Flight (ZEF) in Spain’s aviation market based on liquid hydrogen-powered aircraft and focusing on the specific case of Barcelona Airport. In order to achieve this objective, the project is divided into two parts. The first part involves a study of the different types of hydrogen-propelled aircraft which are planned to be available in the market in the near future. Furthermore, the main Spanish airports are organised into different categories according to their volume of operations, this classification is made in order to forecast the amount of hydrogen needed at each type of airport. Moreover, as is difficult to forecast the welcome of this new technology, three scenarios are going to be considered, an optimistic one, where the complete fleet is hydrogen-propelled aircraft, a balanced one, where half of the fleet is considered to be the one suggested and finally a pessimistic one where the hydrogen-propelled aircraft doesn’t play a significant role in the aeronautic industry. In the second phase, a remodelling model is designed in order to adapt the Josep Tarradellas Barcelona-El Prat airport’s infrastructure to embrace the future aircraft minimising the time and the cost. In addition, to illustrate the recondition a 3D model is provided: Finally, a detailed budget for the Prat Airport adaptations cost is developed as well as a feasibility and environmental impact study. The results of the project are interesting not only for research but also for utility airports, plane manufacturers, airlines and fuel suppliers that should invest in new and more sustainable technologies to provide a solution to global climate change

    A Simulation of the Impacts of Climate Change on Civil Aircraft Takeoff Performance

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    Climate change affects the near-surface environmental conditions that prevail at airports worldwide. Among these, air density and headwind speed are major determinants of takeoff performance, and their sensitivity to global warming carries potential operational and economic implications for the commercial air transport industry. Previous archival and prospective research observed a weakening in headwind strength and predicted an increase in near-surface temperatures, respectively, resulting in an increase in takeoff distances and weight restrictions. The main purpose of the present study was to update and generalize the extant prospective research using a more representative sample of worldwide airports, a wider range of climate scenarios, and next-generation climate models. The research questions included how much additional thrust and payload removal will be required to offset the centurial changes in takeoff conditions. This study relied on a quantitative method using the simulation instrument. Forecast climate data corresponding to four shared socioeconomic pathways (SSP1‒2.6, SSP2‒4.5, SSP3‒7.0, and SSP5‒8.5) over the available 2015‒2100 period were sourced from a high-resolution CMIP6 global circulation model. These data were used to characterize the six-hourly near-surface environmental conditions prevailing at all 881 airports worldwide having at least one million passengers in pre-COVID‒19 traffic. The missing air density was iii numerically derived from the air temperature, pressure, and humidity variables, while the headwind speed for each airport’s active runway configuration was triangulated from the wind vector components. Separately, a direct takeoff-dynamics simulation model was developed from first principles and calibrated against published performance data under international standard atmospheric conditions for two narrowbody and two widebody aircraft. The model was used to simulate 1.8 billion unique takeoffs, each initiated at 75% of maximum takeoff thrust and 100% of maximum takeoff mass. When the resulting takeoff distance required exceeded that available, the takeoff thrust was gradually increased to 100%, after which the takeoff mass was gradually decreased to an estimated breakeven load factor. In total, 65 billion takeoff iterations were simulated. Longitudinal changes to takeoff thrust, distance, and payload were recorded and examined by aircraft type, climate scenario, and climate zone. The results show that despite a marked centurial increase in the global mean air temperature of 9.4%‒18.0% relative to the year 2015 under SSP2‒4.5 and SSP3‒7.0, air density will only decrease by 0.6%‒1.1% due to its weak sensitivity to temperature. Likewise, mean headwinds were observed to remain almost unchanged relative to the 2015 baseline. As a result, the global mean takeoff thrust was found to increase by no more than 0.3 percentage point while payload removals did not exceed 1.1 passenger. Significant deviations from the mean were observed at climatic outlier airports, including those located around the Siberian plateau, where takeoff operations may become more difficult. This study contributes to the air transport climate adaption body of knowledge by providing contrasting results relative to earlier research that reported strong impacts of global warming on takeoff performance
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