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Journal articles on the topic 'Turboprop transports'
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1
Henderson, W. P. "Airframe/Propulsion Integration at Transonic Speeds." Journal of Engineering for Gas Turbines and Power 113, no. 1 (January 1, 1991): 51–59. http://dx.doi.org/10.1115/1.2906530.
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A significant level of research is ongoing at NASA’s Langley Research center on integrating the propulsion system with the aircraft. This program has included nacelle/pylon/wing integration for turbofan transports, propeller/nacelle/wing integration for turboprop transports, and nozzle/afterbody/empennage integration for high-performance aircraft. The studies included in this paper focus more specifically on pylon shaping and nacelle bypass ratio studies for turbofan transports, nacelle and wing contouring, and propeller location effects for turboprop transports, empennage effects, and thrust vectoring for high-performance aircraft. The studies were primarily conducted in NASA Langley’s 16-Foot Transonic Tunnel at Mach numbers up to 1.20.
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Čokorilo, Olja, Slobodan Gvozdenović, Petar Mirosavljević, and Ljubiša Vasov. "MULTI ATTRIBUTE DECISION MAKING: ASSESSING THE TECHNOLOGICAL AND OPERATIONAL PARAMETERS OF AN AIRCRAFT." TRANSPORT 25, no. 4 (December 31, 2010): 352–56. http://dx.doi.org/10.3846/transport.2010.43.
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Regional aircraft are playing a significant role in airline operations. This paper considers the problem of selecting an appropriate aircraft from the airline fleet for optimal regional air travel realization. Complexity balance between air travel demand (passengers, goods) and the proposed aircraft capacity presents the priority in airline operations. A principal feature of the methodology considered in this paper is a multi attribute analysis of technological and operational aircraft characteristics (turboprop and turbojet). A comparison of the presented regional aircraft parameters is based on the following criteria: technological (aerodynamic efficiency, structural efficiency, fuel flow at the optional FL, cruise endurance and requested trip fuel for the fixed cruise range), operational (max range with max payload, ground efficiency (aircraft maintainability based on external dimensions) and climb capability. With the aim of defining aircraft rank, the TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) method was applied. Therefore, the Saaty scale was used for developing the weight of different criteria. The conducted research included a sample of four representative regional aircraft: Do328, CRJ100er, Saab2000 and ERJ145. The results obtained would help in determining the airline fleet or selecting the optional solution from the existing fleet.
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Lange, Roy H. "A review of advanced turboprop transport aircraft." Progress in Aerospace Sciences 23, no. 2 (January 1986): 151–66. http://dx.doi.org/10.1016/0376-0421(86)90003-5.
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Bakunowicz, Jerzy. "Single engine turboprop aeroplane class in small air transport." Aircraft Engineering and Aerospace Technology 90, no. 7 (October 1, 2018): 1033–41. http://dx.doi.org/10.1108/aeat-01-2017-0009.
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Purpose This paper aims to present the analysis of introduction of single engine turbo-prop aeroplane class in terms of certification specifications and flight crew licensing regulations. Design/methodology/approach Following the results of flight testing and additional performance and sizing calculations, the proposed class was placed among the existing aeroplane taxonomy in terms of performance, flight loads, mass penalty, fuel economy and several other factors. Concerning small air transport initiative, the new class was tried to be placed as a starting point in commercial pilot career. Findings The paper points the potential market for single engine turbopropeller aeroplanes and lists today obstacles in wider introduction. Therefore, remarks about required change of regulations and requirements for design process, as well as for crew licensing, are underlined. Practical implications The results of the study would be helpful in preliminary design of a new low-power turboprop aeroplane, as well as during tailoring the certification specifications. Originality/value The approach presented in this paper is a detailed extension of an original idea presented by author for the first time during Clean Sky/small air transport workshop.
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Жорник, Олег Володимирович, Ігор Федорович Кравченко, and Михайло Михайлович Мітрахович. "Удосконалення характеристик кільцевого вхідного пристрою авіаційної силової установки з гвинтовентилятором." Aerospace technic and technology, no. 4sup2 (August 27, 2021): 11–18. http://dx.doi.org/10.32620/aktt.2021.4sup2.02.
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The article considers the method of improving the characteristics of the ring inlet device, taking into account the influence of the propeller of an aircraft power plant with a turboprop engine. It is shown that increasing the total pressure loss in the inlet device by 5% increases, approximately, the specific fuel consumption by 3% and reduces engine thrust by 6%, and uneven flow at the inlet to the engine is the cause of unstable compressor of the turboprop engine. It is proposed to improve the characteristics of the input device by modifying the shape of its shell and channel. Evaluation of the influence of the shape of the shell and the channel of the annular axial VP on its main aerodynamic characteristics, taking into account the non-uniformity of the flow on the fan in the calculated mode of operation of the SU is carried out by calculating the full pressure recovery factor. The object of the study is an annular axial input device in front of which is a coaxial fan turboprop fan. The process of modeling the influence of the shape of the shell and the channel on the recovery factor of total pressure, circular and radial non-uniformity of the flow through the input device is implemented in the software system of finite element analysis ANSYS CFX. Geometric models of coaxial screw fan, fairing and inlet device are built in ANSYS SpaceClaim and transferred using the built-in import function in ANSYS Workbench. Block-structured grid models of air propellers of the first and second rows of the fan in the amount of 1.9 million, fairing and inlet device, in the amount of 3.9 million, are built in the ANSYS TurboGrid environment. The standard Stern (Shear Stress Transport) Gamma Theta Transition was used to close the Navier-Stokes equation system. Based on the results of mathematical modeling of flow in coaxial fans and subsonic ring inlet device on the maximum cruising mode of the turboprop engine, the full pressure recovery factor is calculated and it is established that the most influential factor that increases its full pressure recovery factor.
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MacLeod, J. D., and J. C. G. Laflamme. "Compressor Coating Effects on Gas Turbine Engine Performance." Journal of Engineering for Gas Turbines and Power 113, no. 4 (October 1, 1991): 530–34. http://dx.doi.org/10.1115/1.2906273.
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In an attempt to increase the time between maintenance actions and to improve performance retention of turboprop engines installed in transport and maritime patrol aircraft, the Canadian Department of National Defence is evaluating an erosion and corrosion-resistant blade coating, for use on compressors. As coatings could appreciably alter engine performance by virtue of their application thickness and surface quality, the National Research Council of Canada was asked to quantify any performance changes that could occur. A project was initiated, utilizing a new Allison T56 turboprop engine, to assess not only the performance changes resulting from the coating, but also those from dismantling and reassembling the compressor, since the compressor must be completely disassembled to apply the coating. This paper describes the project objectives, the experimental installation, and the measured effects of the coating application on compressor performance. Performance variations due to compressor rebuilds on both engine and compressor characteristics are discussed. As the performance changes were small, a rigorous measurement uncertainty analysis is included. The coating application process and the affected overhaul procedures are examined. The results of the pre- and postcoating compressor testing are presented, with a discussion of the impact on engine performance.
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PAČAIOVÁ, Hana, Marianna TOMAŠKOVÁ, Michaela BALÁŽIKOVÁ, and Jozef KRAJŇÁK. "Analysis of air-traffic threats." Scientific Journal of Silesian University of Technology. Series Transport 110 (March 1, 2021): 143–55. http://dx.doi.org/10.20858/sjsutst.2021.110.12.
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Globally, air transport has seen a greater increase in recent years. This manuscript is divided into three parts for analysing the negative effects of aviation. The first part is focused on the identification of sources of aircraft noise. While the second part of this article describes the basic principles of the construction and operation of an aircraft jet engine concerning the gaseous emissions produced by such an engine (Third part missing?). The main benefit of this article is the evaluation of the reliability of the human factor because the human factor is an integral part of technical systems and processes. Reliability assessment was performed using the TESEO method. The ergonomic parameter, that is, the cabin noise, was quantified in the given method. The measurement was performed on two types of aircraft, namely in the cabin of a transport jet aircraft and in the cabin of asmall transport aircraft equipped with turboprop engines.
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Nicolosi, Fabrizio, Danilo Ciliberti, Pierluigi Della Vecchia, Salvatore Corcione, and Vincenzo Cusati. "A comprehensive review of vertical tail design." Aircraft Engineering and Aerospace Technology 89, no. 4 (July 3, 2017): 547–57. http://dx.doi.org/10.1108/aeat-11-2016-0213.
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Purpose This work aims to deal with a comprehensive review of design methods for aircraft directional stability and vertical tail sizing. The focus on aircraft directional stability is due to the significant discrepancies that classical semi-empirical methods, as USAF DATCOM and ESDU, provide for some configurations because they are based on NACA wind tunnel (WT) tests about models not representative of an actual transport airplane. Design/methodology/approach The authors performed viscous numerical simulations to calculate the aerodynamic interference among aircraft parts on hundreds configurations of a generic regional turboprop aircraft, providing useful results that have been collected in a new vertical tail preliminary design method, named VeDSC. Findings The reviewed methods have been applied on a regional turboprop aircraft. The VeDSC method shows the closest agreement with numerical results. A WT test campaign involving more than 180 configurations has validated the numerical approach. Practical implications The investigation has covered both the linear and the non-linear range of the aerodynamic coefficients, including the mutual aerodynamic interference between the fuselage and the vertical stabilizer. Also, a preliminary investigation about rudder effectiveness, related to aircraft directional control, is presented. Originality/value In the final part of the paper, critical issues in vertical tail design are reviewed, highlighting the significance of a good estimation of aircraft directional stability and control derivatives.
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CHIESA, Sergio, Marco FIORITI, and Roberta FUSARO. "POSSIBLE HYBRID PROPULSION CONFIGURATION FOR TRANSPORT JET AIRCRAFT." Aviation 20, no. 3 (September 29, 2016): 145–54. http://dx.doi.org/10.3846/16487788.2016.1200849.
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This research is aimed at studying the possible advantages of installing, for a hybrid propulsion aircraft, electric motors and related propellers into the dedicated supplementary nacelles. This innovative solution is different from the configuration, already studied for a regional turboprop (Chiesa et al.2013), in which the electric motors are in the same nacelles of the internal combustion engines. As it has been expected, it offers the advantages of avoiding mechanical links between the two units and, more importantly, can also be applied to jet aircraft. In fact, the main contribution of electric motors is expected during ground operations, take-off and descent phases (i.e. at low speed), in which it can be useful to integrate the propellers or even substitute the jet engines with them. At high speed, the propellers, of course, are configured in order to reduce drag. When considering the design of a new airliner concept, a preliminary design study is necessary to optimize the location of the supplementary nacelles. The nacelles, which only hold the electrical motor, can also be considered retractable, as is usual for a RAT (Ram Air Turbine). Please note that in the hybrid propulsion context, the RAT function can be clearly allocated to the electric motor, with the advantages of optimizing drag at high speed, taking into account installation problems.
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Yoshikawa, Hiroyuki, Terukazu Ota, Kazuyuki Higashino, and Shunichiro Nakai. "Numerical Analysis on Dynamic Characteristics of Cryogenic Hydrostatic Journal Bearing." Journal of Tribology 121, no. 4 (October 1, 1999): 879–85. http://dx.doi.org/10.1115/1.2834150.
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Dynamic characteristics of a two row staggered recess cryogenic hydrostatic journal bearing used in the liquid hydrogen turbopump of rocket engines for space transport systems are numerically analyzed. Effects of the rotational speed and the shaft eccentricity are studied in the analysis. Their effects on the stiffness and damping coefficients and the whirl frequency ratio are clarified. Moreover, effects of the orifice parameter, the distance between two recess rows, and the number of recesses on these dynamic characteristics are investigated.
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Gesell, Hendrik, Florian Wolters, and Martin Plohr. "System analysis of turbo-electric and hybrid-electric propulsion systems on a regional aircraft." Aeronautical Journal 123, no. 1268 (August 1, 2019): 1602–17. http://dx.doi.org/10.1017/aer.2019.61.
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ABSTRACTThe increasing environmental requirements in the air transport sector pose great challenges to the aviation industry and are key drivers for innovation. Besides various approaches for increasing the efficiency of conventional gas turbine engines, electric propulsion systems have moved into the focus of aviation research. The first electric concepts are already in service in general aviation. This study analyses the potentials of electric and turbo hybrid propulsion systems for commercial aviation. Its purpose is to compare various architectures of electrical powertrains with a conventional turboprop on a regional aircraft, similar to the ATR 72, on engine and flight mission levels. The considered architectures include a turbo-electric (power controlled and direct driven), hybrid-electric (serial and parallel) and a pure electric concept. Their system weights are determined using today’s technology assumptions. With the help of performance models and flight mission calculations the impact on fuel consumption, CO ${}_{2}$ emissions and aircraft performance is evaluated.
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Fishbach, L. H., and S. Gordon. "NNEPEQ—Chemical Equilibrium Version of the Navy/NASA Engine Program." Journal of Engineering for Gas Turbines and Power 111, no. 1 (January 1, 1989): 114–16. http://dx.doi.org/10.1115/1.3240205.
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The Navy NASA Engine Program, NNEP, developed in 1975, currently is in use at a large number of government agencies, commercial companies, and universities. This computer code has been used extensively to calculate the design and off-design (matched) performance of a broad range of turbine engines, ranging from subsonic turboprops to variable cycle engines for supersonic transports. Recently, there has been increased interest in applications that NNEP was not capable of simulating, namely, high Mach applications, alternate fuels including cryogenics, and cycles such as the gas generator air-turbo-rocket (ATR). In addition, there is interest in cycles employing ejectors such as for military fighters. New engine component models had to be created for incorporation into NNEP, and it was also found necessary to include chemical dissociation effects of high-temperature gases. This paper discusses the incorporation of these extended capabilities of NNEP and illustrates some of the effects of these changes.
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Rea, Francesco, Francesco Amoroso, Rosario Pecora, and Frederic Moens. "Exploitation of a Multifunctional Twistable Wing Trailing-Edge for Performance Improvement of a Turboprop 90-Seats Regional Aircraft." Aerospace 5, no. 4 (November 16, 2018): 122. http://dx.doi.org/10.3390/aerospace5040122.
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Modern transport aircraft wings have reached near-peak levels of energy-efficiency and there is still margin for further relevant improvements. A promising strategy for improving aircraft efficiency is to change the shape of the aircraft wing in flight in order to maximize its aerodynamic performance under all operative conditions. In the present work, this has been developed in the framework of the Clean Sky 2 (REG-IADP) European research project, where the authors focused on the design of a multifunctional twistable trailing-edge for a Natural Laminar Flow (NLF) wing. A multifunctional wing trailing-edge is used to improve aircraft performance during climb and off-design cruise conditions in response to variations in speed, altitude and other flight parameters. The investigation domain of the novel full-scale device covers 5.15 m along the wing span and the 10% of the local wing chord. Concerning the wing trailing-edge, the preliminary structural and kinematic design process of the actuation system is completely addressed: three rotary brushless motors (placed in root, central and tip sections) are required to activate the inner mechanisms enabling different trailing-edge morphing modes. The structural layout of the thin-walled closed-section composite trailing-edge represents a promising concept, meeting both the conflicting requirements of load-carrying capability and shape adaptivity. Actuation system performances and aeroelastic deformations, considering both operative aerodynamic and limit load conditions, prove the potential of the proposed structural concept to be energy efficient and lightweight for real aircraft implementation. Finally, the performance assessment of the outer natural laminar flow (NLF) wing retrofitted with the multifunctional trailing-edge is performed by high-fidelity aerodynamic analyses. For such an NLF wing, this device can improve airplane aerodynamic efficiency during high speed climb conditions.
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Venkataraman, B., and A. B. Palazzolo. "Effects of Wall Flexibility on the Rotordynamic Coefficients of Turbulent Cryogenic Annular Seals." Journal of Tribology 118, no. 3 (July 1, 1996): 509–19. http://dx.doi.org/10.1115/1.2831567.
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A theory for analyzing the effects of elastic deformations of the seal wall on the dynamic characteristics of high pressure cryogenic annular seals under concentric operation is presented. The bulk flow continuity, axial and circumferential momentum, and the energy transport equations are utilized to determine the pressure distribution in the seal. Thermophysical properties of the cryogenic fluid are assumed to be functions of the local pressure and temperature. The wall deformations are obtained using an iso-parametric, axi-symmetric Finite Element formulation of the seal wall. A perturbation analysis is employed to arrive at the first order solution which yields the rotordynamic coefficients. Results obtained for the case of Space Shuttle Main Engine Oxygen Turbopump (SSME-HPOTP) Preburner Seal show a significant impact of seal flexibility on the dynamic coefficients.
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Brown, A. P. "Inflight icing data gathering during routine flight operations — a case study." Aeronautical Journal 105, no. 1051 (September 2001): 501–16. http://dx.doi.org/10.1017/s0001924000017942.
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Abstract For the purpose of the design and certification of inflight icing protection systems for transport and general aviation aircraft, the eventual re-definition/expansion of the icing environment of FAR 25/JAR 25, Appendix C is under consideration. Such a re-definition will be aided by gathering as much inflight icing event data as reasonably possible, from widely-different geographic locations. The results of a 12-month pilot programme of icing event data gathering are presented. Using non-instrumented turboprop aircraft flying upon mid-altitude routine air transport operations, the programme has gathered observational data from across the British Isles and central France. By observing a number of metrics, notably windscreen lower-corner ice impingement limits, against an opposing corner vortex-flow, supported by wing leading edge impingement limits, the observed icing events have been classified as ‘small’, ‘medium’ or ‘large’ droplet. Using the guidance of droplet trajectory modelling, MVD values for the three droplet size bins have been conjectured to be 15, 40 and 80mm. Hence, the ‘large’ droplet category would be in exceedance of FAR/JAR 25, Appendix C. Data sets of 117 winter-season and 55 summer-season icing events have been statistically analysed. As defined above, the data sets include 11 winter and five summer large droplet icing encounters. Icing events included ‘sandpaper’ icing from short-duration ‘large’ droplets, and a singular ridge formation icing event in ‘large’ droplet. The frequency of ‘large’ droplet icing events amounted to 1 in 20 flight hours in winter and 1 in 35 flight hours in summer. These figures reflect ‘large’ droplet icing encounter probabilities perhaps substantially greater than previously considered. The ‘large’ droplet events were quite localised, mean scale-size being about 6nm.
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Лось, Олександр Васильович, and Віктор Іванович Рябков. "НОВЕ ПОКОЛІННЯ ВІТЧИЗНЯНИХ ВІЙСЬКОВО-ТРАНСПОРТНИХ ЛІТАКІВ." Aerospace technic and technology, no. 4 (August 28, 2020): 5–11. http://dx.doi.org/10.32620/aktt.2020.4.01.
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According to European experts, only the USA and Ukraine can produce a full line of military transport aircraft of all weight categories (light, medium, and heavy).At the time of the creation of the “State comprehensive program for the development of the aviation industry of Ukraine until 2020” Ukraine had:- light transport aircraft An-32 with a carrying capacity of 6.7 tons and a range of 2500 km;- operational and tactical military passenger aircraft (MPA) with a carrying capacity of 30 tons and a range with a full load of 4300 km;- regional passenger aircraft Аn-148-100В (An-148-100V) with a maximum payload of 9.0 tons and a range of 2600 km.Through the efforts of the entire Antonov Company team, prototypes have been designed, manufactured, and partly tested such modifications as An-132D, An-178, and An-188, the implementation of which is based on the use of the new “Methodology for Designing Military Transport Aircraft Modifications, Taking into Account Profound Changes in the Wing and in the Power Plant”.Given the scientific provisions of this "Methodology ...":- based on the An-32 aircraft, a modification of the light aircraft MTA An-132D with a carrying capacity of 9.1 tons, with an increased range of up to 2400 km and with a fuel efficiency index higher than that of the base model, has been created through profound changes in the power plant, i.e. using PW150 engines and an increase in fuel mass by one and a half times;- based on the An-148 passenger aircraft, by means of profound changes both in the wing geometry and in the power plant, a modification of the mid-range military transport An-178 aircraft has been created with a carrying capacity of 18 tons and a range with a maximum load of 1.200 km, which provides a niche to this modification not occupied by competitors;- ensuring the complete superiority of the An-188 modification among analog competitors is also based on the profound changes: replacement the D27 turboprop engine for a turbofan CFM LEAP-1Ain the power plant; the use of a discrete geometric twist of the local wing chords, which ensured the aircraft range of 3200 km with a payload of 47 tons and significantly increased its combat readiness due to the use of turbofan engines.A comparative assessment of these military transport aircraft with their basic models shows that the team of the Antonov Company has honorably implemented the “State comprehensive program for the development of the aviation industry of Ukraine until 2020” in part of the creation of a new generation of military transport aircraft that is competitive in all technical and economic parameters.
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Тиняков, Дмитрий Васильевич, and Виктор Иванович Рябков. "МЕТОД ПОПЕРЕДНЬОГО ФОРМУВАННЯ ОСНОВНИХ ПАРАМЕТРІВ ПІД ЧАС ГЛИБОКИХ МОДІФІКАЦІЙНИХ ЗМІН У ЛІТАКАХ ТРАНСПОРТНОЇ КАТЕГОРІЇ." Aerospace technic and technology, no. 7 (November 10, 2018): 62–67. http://dx.doi.org/10.32620/aktt.2018.7.09.
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The method of a preliminary development of main performances during deep variation in variants of a transport category aircraft, that is, when changing a wing area and a powerplant output, has been proposed. The main performance of any aircraft on the stage of its modifying is takeoff mass to, its value depends on structural members’ masses, in which modifications changes are present. The method is based on the com-parative evaluation of take-off mass increments of a basic aircraft and it’s variant. That allows qualitatively and quantitatively to evaluate the specific value of the take-off mass increment of an airplane variant depending on engineering and economical requirements changes. Also, it is obvious that changes in the combination of performances their changes in the process of an aircraft variant creation, move the solution of an existence equation at new point, which corresponds to a new takeoff mass. The analysis of the method was implemented on the example of the regional passenger aircraft variant with two turboprop engines. The method of a preliminary development of main performances of a transport category aircraft subject to deep modification, i.e. when changing a wing area or a powerplant output, is proposed. The mathematical model for the estimation of the takeoff mass increment, depending on requirement groups realized in modifications, is developed by using the models of calculation of required mass (due to change of modification) and available mass (constant for a base variant). Statistical equations for the preliminary estimation of a takeoff mass increment, that create the relationship between the constituent masses and the takeoff mass for a regional aircraft, are used. For middle-range and long-range airplanes an adjustment is needed. The proposed method and the mathematical models allow at a preliminary designing stage of an airplane variant not only typical required quantitative change in structure, but the necessary changes of a wing area and a powerplant output to satisfy the required engineering and economical requirements, which aircraft and air-lines’ markets dictate.
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Лось, Александр Васильевич, Владимир Федорович Шмырев, and Виктор Иванович Рябков. "ДОСТИЖЕНИЕ ПРЕИМУЩЕСТВА Ан-188 СРЕДИ ОПЕРАТИВНО–ТАКТИЧЕСКИХ ВОЕННО-ТРАНСПОРТНЫХ САМОЛЕТОВ." Aerospace technic and technology, no. 8 (August 31, 2020): 5–11. http://dx.doi.org/10.32620/aktt.2020.8.01.
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In the "Antonov" Company, a unique medium-sized tactical military transport aircraft An-12 and An-70 have been created. Based on the Аn-12 basic version, several modifications have been developed, which operate in many countries around the world.To replace this aircraft has been created the An-70 with a higher capacity and hourly capacity, which on some key parameters outperforms the competition-analogs: American C-130J-30, West-European A400M, and Japanese C-2.However, the range with the maximum capacity is worse for Аn-77 compared to the A400M, but cruising speed and combat readiness – for C-2.For the most complete implementation of tactical tasks:– transportation of personnel, equipment, goods, and means of procurement;– delivery of military units, equipment, and cargo in the interests of peacekeeping or counter-terrorism operations;– transportation of troops, arms, military equipment and material resources of strategic direction;– delivery of units and formations of the airborne forces and ground forces in the areas of military purpose;– provision of the relocation of aviation units and formations, and provision of superiority at range with maximum load, at cruising speed and combat readiness the team of the “Antonov” Company created the An-188 – the medium-sized tactical aircraft with short takeoff and landing, which provides execution of a series of tasks, not available even for C-2.At the initial stage of designing this modification scientific principles the "Design techniques of modifications of the MTA taking into account the profound changes in the wing and the power plant" were used. The most important modification change in An-188 is the replacement of the D-27 turboprop engine for СFM LЕАР-1A turbofan engine, which increased the capacity and combat readiness of modification.Another important modification change was the use of discrete geometric twist of the wing local chord, bringing its shape in plan view to elliptical one and has brought a reduction in induced drag for a given lift force. This solution provided an increase in the range of up to 3200 km.Such profound modification changes in the power plant and the geometry of the wing have contributed to the complete superiority of the An-188 in the class of operational-tactical MTA.In combination with An-132D and An-178 modification, the An-188 can be considered as a unified system of support for the troops with military transport planes.
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San Andre´s, Luis. "Bulk-Flow Analysis of Hybrid Thrust Bearings for Process Fluid Applications." Journal of Tribology 122, no. 1 (June 10, 1999): 170–80. http://dx.doi.org/10.1115/1.555340.
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Advanced cryogenic fluid turbopumps are very compact, operate at extremely high shaft speeds, and require hybrid (hydrostatic/hydrodynamic) radial and thrust fluid film bearings for accurate rotor positioning. Sound design and reliable operation of fluid film thrust bearings also allows for unshrouded impellers with a significant increase in the turbopump mechanical efficiency. A bulk-flow analysis for prediction of the static load performance and dynamic force coefficients of high speed, angled injection orifice-compensated, hybrid (hydrostatic/hydrodynamic) thrust bearings is presented. The model accounts for the bulk-flow mass, momentum and thermal energy transport, and includes flow turbulence and fluid inertia (advection and centrifugal) effects on the bearing film lands and recesses. The performance of a refrigerant hybrid thrust bearing for an oil-free air conditioning equipment is evaluated at two operating speeds and pressure differentials. The computed results are presented in dimensionless form to evidence consistent trends in the bearing performance characteristics. As the applied axial load increases, the bearing film thickness and flow rate decrease while the recess pressure increases. The axial stiffness coefficient shows a maximum for a certain intermediate load while the damping coefficient steadily increases with load. The computed results show the significance of centrifugal fluid inertia at low recess pressures (i.e. low loads) and high rotational speeds, and which can lead to film starvation at the bearing inner radius and subambient pressures just downstream of the bearing recess edge. [S0742-4787(00)02201-3]
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Redkin, A. V., Yu A. Yaloza, and I. E. Kovalev. "Reliability assessment of convertible aircraft with hybrid propulsion system and multirotor lifting system." Civil Aviation High Technologies 23, no. 5 (October 28, 2020): 76–96. http://dx.doi.org/10.26467/2079-0619-2020-23-5-76-96.
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Projects and experimental models of innovative concepts of VTOL aircraft with a hybrid propulsion system are attracting great interest and investment inflow all over the world. In this regard, when developing new concepts, it is important to understand how much better they will be than the currently operated rotorcraft and convertible aircraft in terms of reliability and flight safety, to be able to use them for passenger transportation in the future. In addition, when designing and choosing the optimal layout, it is necessary to know the contribution of each element and unit to the reliability of the aircraft as a whole in order to meet the requirements. To calculate the reliability indicators, the method of structural diagrams was chosen, and the calculation methodology was developed. The general classification of modern innovative concepts of convertible aircraft is considered, schematic diagram of hybrid propulsion system and its main parameters are determined. The article discusses the influence of the number of lifting rotor groups and their location on the possibility to continue the flight in hover mode in case of failure of one rotor group, the necessary power reserve of lifting electric motors is determined to ensure the given safety condition. In accordance with the adopted structural diagram, the main functional groups of the hybrid propulsion system of convertible aircraft operating in different flight modes are determined. The basic modes of a typical flight profile of a convertible aircraft are considered, time intervals characteristic for each mode are set. For each flight mode, a structural scheme of reliability of functional groups of a hybrid propulsion system is constructed, having a serial or parallel connection of elements, depending on their influence on the consequences of failure, the equation for calculating the probability of fail-free operation is derived. For lifting rotor groups, a combination of critical failures of more than one group is considered, and the equation is composed to calculate the probability of a catastrophic event in hover mode. Based on the obtained equations, the resulting calculation of the probability of fail-free operation, the probability of failure per flight hour for each flight mode was carried out separately and in total for the entire flight. Thus, for all flight modes, the probabilities of a catastrophic and emergency event, as well as a difficult situation in flight, are considered. A comprehensive analysis of the obtained results of reliability indicators calculation for convertible aircraft with six lifting rotors and two turboprop engines made it possible to conclude that it meets the requirements of the 25th part of aviation regulations for transport aircraft. A good potential margin of up to 10-2 was determined for the probability of a catastrophic failure in take-off, landing and transitional modes. The elements and subsystems that are critical for fail-free operation are identified, and ways to improve their reliability and the aircraft as a whole are proposed.
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Богоявленский, А., and A. Bogoyavlenskiy. "Ensuring the uniformity of measurements of parameters of vibration during the technical operation of aircraft." World of measurement, June 25, 2016, 6–14. http://dx.doi.org/10.35400/1813-8667-2016-02-6-14.
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In this article we are talking about how to ensure the unity of measurements of vibration parameters in the technical operation of aircraft. In air transport, the main controlled parameters of vibration in flight are vibration speed, vibration acceleration or vibration overload. They are particularly informative for aircraft with turboprop engines, as well as helicopters, which – because of the design features-the vibration is much higher than on aircraft with turbojet engines.
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Mani, Karthik V., Angelo Cervone, and Jean-Pierre Hickey. "Turbulence Modeling of Cavitating Flows in Liquid Rocket Turbopumps." Journal of Fluids Engineering 139, no. 1 (September 14, 2016). http://dx.doi.org/10.1115/1.4034096.
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An accurate prediction of the performance characteristics of cavitating cryogenic turbopump inducers is essential for an increased reliance on numerical simulations in the early turbopump design stages of liquid rocket engines (LRE). This work focuses on the sensitivities related to the choice of turbulence models on the cavitation prediction in flow setups relevant to cryogenic turbopump inducers. To isolate the influence of the turbulence closure models for Reynolds-Averaged Navier–Stokes (RANS) equations, four canonical problems are abstracted and studied individually to separately consider cavitation occurring in flows with a bluff body pressure drop, adverse pressure gradient, blade passage contraction, and rotation. The choice of turbulence model plays a significant role in the prediction of the phase distribution in the flow. It was found that the sensitivity to the closure model depends on the choice of cavitation model itself; the barotropic equation of state (BES) cavitation models are far more sensitive to the turbulence closure than the transport-based models. The sensitivity of the turbulence model is also strongly dependent on the type of flow. For bounded cavitation flows (blade passage), stark variations in the cavitation topology are observed based on the selection of the turbulence model. For unbounded problems, the spread in the results due to the choice of turbulence models is similar to noncavitating, single-phase flow cases.
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Hosseini, Saeed, Mohammad Ali Vaziri-Zanjani, and Hamid Reza Ovesy. "Conceptual design and analysis of an affordable truss-braced wing regional jet aircraft." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, May 6, 2020, 095441002092306. http://dx.doi.org/10.1177/0954410020923060.
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A regional, turbofan-powered, 72-passenger, transport aircraft with very high aspect ratio truss-braced wings is developed with an affordable methodology from an existing 52 passenger, conventional twin-turboprop aircraft. At first, the ration behind the selection of the truss-braced wing configuration is discussed. Next, the methodologies for the sizing, weight, aerodynamics, performance, and cost analysis are presented and validated against existing regional aircraft. The variant configurations and their design features are then discussed. Finally, sensitivity analysis is carried out to investigate the effects of the wing aspect ratio and engine bypass ratio on the aircraft weight, aerodynamics, and cost. It has been found that the penalties associated with the wing weight will prevent the acceptable realization of the high aspect ratio wing benefits, but when it is combined with the very high bypass ratio engines, a 17% reduction in the mission fuel weight is achieved. In contrast, the cost analysis has revealed that the application of higher aspect ratio wings in the truss-braced wing configuration may increase the development and maintenance costs. Consequently, with aspect ratios higher than 24, eventually, these costs may outperform the associated fuel cost reductions.
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Bicsák, György, Áprád Veress, Máté Erdősi, and Vítězslav Hanzal. "Introduction of a Cost Effective Method for Analysing Engine Intake Ice Removal Device for Small Aircraft." Periodica Polytechnica Transportation Engineering, January 24, 2018. http://dx.doi.org/10.3311/pptr.11491.
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As the need for personal air transport increases significantly, new aircraft and/or its components are required to be designed and developed together with expectations for guarantying the high level flight safety. Since smaller aircraft manufacturers don’t have the infrastructural and experimental resources for complex investigations, analysis of engine components with especial care for the behaviour of particle separation components in the inlet air duct for example, smarter, more efficient solutions have to be developed. CFD software gives an opportunity to simulate the trajectories of different type of particles, such as hailstones, dust, or even liquid water droplets. Hence, in this study an upper-wing type, two engines thrusted, small turboprop aircraft’s integrated engine air intake device has been analysed, to prove the effectivity of the aircraft performance in the considered raining and icing conditions. The flow field has been discretized with a detailed, hybrid mesh using hexa elements at the simpler parts, and tetra elements, where the geometry is more complex. Inflation layers have been inserted on the wall-type surfaces, with especial care to the problematic parts, where the y+ number is predictably higher. The inlet boundary conditions of the model have been extracted from a larger, complex pre-simulation, performed in a previous study. Standard Reynolds Averaged Navier-Stokes equations have been considered with Shear Stress Transport turbulence model. Solid (ice) and liquid particles have been defined, and their trajectories are investigated by using fully coupled model. The interaction of the wall-fluid particle has been taken into consideration.
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Petrov, A. V., Y. G. Stepanov, and M. V. Shmakov. "Development of a Technique and Method of Testing Aircraft Models with Turboprop Engine Simulators in a Small-scale Wind Tunnel - Results of Tests." Acta Polytechnica 44, no. 2 (January 2, 2004). http://dx.doi.org/10.14311/530.
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This report presents the results of experimental investigations into the interaction between the propellers (Ps) and the airframe of a twin-engine, twin-boom light transport aircraft with a Π-shaped tail. An analysis was performed of the forces and moments acting on the aircraft with rotating Ps. The main features of the methodology for windtunnel testing of an aircraft model with running Ps in TsAGI’s T-102 wind tunnel are outlined.The effect of 6-blade Ps slipstreams on the longitudinal and lateral aerodynamic characteristics as well as the effectiveness of the control surfaces was studied on the aircraft model in cruise and takeoff/landing configurations. The tests were conducted at flow velocities of V∞ = 20 to 50 m/s in the ranges of angles of attack α = -6 to 20 deg, sideslip angles of β = -16 to 16 deg and blade loading coefficient of B 0 to 2.8. For the aircraft of unusual layout studied, an increase in blowing intensity is shown to result in decreasing longitudinal static stability and significant asymmetry of the directional stability characteristics associated with the interaction between the Ps slipstreams of the same (left-hand) rotation and the empennage.