Introduction
Aviation has always been associated with cutting-edge innovation, international activities, and experience, and therefore the global and rapid development of technology and other events of a global scale is reflected in it in the first place. For example, we can cite the consequences of the pandemic that affected the aircraft industry and civil aviation (Dube, Nhamo & Chikodzi, 2021). These restrictions allowed focusing on the environmental issues of the technology, as well as returning to the restoration of work (Gössling, 2020). In addition, an innovative approach can also be traced in the aircraft industry, where hybrid power plants that include an electric element are trendy (Dean, Wroblewski & Ansell, 2018). The leading manufacturers of aircraft engines are currently paying increased attention to creating hybrid power plants, which combine a heat engine (piston or gas turbine) and an electric motor (Gesell, Wolters & Plohr, 2019). This combination can significantly increase the fuel efficiency of the aircraft, reduce harmful emissions and increase operating efficiency (Rings et al., 2019). This paper discusses the main trends associated with the future of this technology, as well as current developments in this area.
The Context
A hybrid propulsion system is a symbiosis of heat and electric engines. Piston or gas turbine is used as heat. In an aviation hybrid power plant, the electrical part is connected during takeoff and landing of the aircraft, while the central part of the flight occurs due to the heat engine alone. A hybrid power plant is considered one of the most promising areas for the development of modern engine building (Ruscio, J. P., et al., 2021). The electrification of power plants is indeed opening up new opportunities for aviation, not only in terms of environmental requirements, which are now being talked about so much. In the future, the use of a hybrid power plant can increase the reliability and functionality of single-engine platforms, the reliability, and speed of helicopters, for passenger aviation, solve the problem of noise in populated areas where small runways are located within the city and improve takeoff and landing characteristics.
The development of hybrid power plants and their integration into aircraft for various purposes is one of the most pressing trends in the development of the aircraft engine market: the combination of a hybrid heat engine and an electric motor can partially solve the main problems of modern aviation (Finger, Bil & Braun, 2020). World experience shows that practically all major manufacturers of power plants for aviation are, to one degree or another, working on the creation of hybrid power plants. In particular, the American company Pratt & Whitney, in mid-July 2021, enlisted the support of the Canadian government for the first flight of a turboprop hybrid aircraft engine: it is expected to reduce harmful emissions into the atmosphere significantly (Finger, Braun & Bil, 2018). At the same time, significant fuel savings are expected, which, if hybrid power plants are integrated into regional turboprop passenger and transport aircraft, can amount to up to 30% (Dahal et al., 2021). The American corporation United Technologies Corporation also develops hybrid aircraft engines and their installation on various aircraft. In particular, the corporation presented “Project 804” – a demonstrator of the light turboprop Dash 8 aircraft of the Canadian company Bombardier, which has a 2 MW hybrid power plant instead of one of the engines (Ismagilov et al., 2020). The sample is currently undergoing a series of tests.
It is noteworthy that the most critical declared goal of “Project 804” is to reduce fuel consumption and increase the economic efficiency of transportation. According to the company, the aircraft, equipped with a GSU, will allow it to carry from 30 to 50 passengers at a distance of 200 to 250 nautical miles (370–463 km) and fly within one hour (Finger et al., 2020). In early June 2021, the British company Rolls-Royce began testing the first components of its hybrid power plant based on the AE2100 for aviation. Its total capacity will be 2.5 MW. The timing of the creation of the AE2100 has not been specified, but Rolls-Royce has repeatedly announced its intention to significantly reduce emissions of harmful substances by 2030 (Amerini et al., 2021). The development of the hybrid power plant will likely be completed by this period. Previously, the development of this installation was carried out by Rolls-Royce in cooperation with the European concern Airbus, but in April 2020, the joint project was closed, and the British company continued to develop this installation independently (Sziroczak et al., 2020). The French Safran group is actively developing a hybrid propulsion system for helicopters and commercial aircraft. It is assumed that at the turn of the 2040s and 2050s, these power plants will dominate the company’s portfolio of orders. Safran’s helicopter hybrid powertrain completed its first test in July 2018, with a sample output of 100 kW.
The American corporation General Electric is developing similar TriFan technology for light passenger and transport aircraft in collaboration with XTI. Its capacity will be about 1 MW, maximum capacity – about 1.4 thousand hp. When mounted on a lightweight Denali aircraft from Cessna Catalyst, it can carry up to four people at a range of up to 1,600 nautical miles at speeds up to 285 knots (Madonna, Giangrande & Galea, 2018). The work is in an active stage; it is expected that the finished sample of the GSU will be created by the beginning of the 2030s (Wheeler et al., 2021). Chinese engine manufacturers are also developing a hybrid aircraft engine, but at the moment, it is not known about the creation of any demonstrators or ready-made samples.
The use of hybrid power plants for aircraft will reduce fuel consumption by 70%, significantly reduce harmful emissions, and significantly reduce maintenance and repair costs. In general, hybrid and electric propulsion systems make it possible to create aircraft with fundamentally new architectures that provide ultra-short takeoff and landing. In this regard, this study’s importance is vital in the framework of aviation technology, as it can lead to new results. This study aims to identify the main innovative directions and orientations that contribute to the development of hybrid power plants. The research objectives are to define an ethical research framework that typically reflects the environmental responsibilities of manufacturing companies. In addition, the tasks include: determining the research methodology based on the information provided on modern developments, the correlation of such developments with the leading international plans regarding the emission of aviation units, and the increase in the volume of traffic.
Several reasons dictate the need to study this topic. First, the global climate situation requires a reduction in atmospheric emissions. In this regard, the transition to electric motors can contribute to the requirements of environmental responsibility, which are becoming more serious every year. Secondly, the design capacity and reduction of maintenance and repair costs in this innovative development will improve the economic performance of the production. In a pandemic, in aviation, as one of the hardest-hit areas, such improvements will be decisive for some companies. In this regard, the importance of this study is obvious.
Methodology
The study is supposed to use a mixed methodological approach with the method of online questionnaires. The mixed approach implies, first of all, the search for qualitative causes and determinants that are influencing now and may influence the future trends in the development of hybrid power plants. Then, using an online survey, quantitative data will be obtained, which can be analyzed following the qualitative characteristics of the determinants. The result will be a more concrete picture, considering a relatively wide range of problems and trends (Basias & Pollalis, 2018). In this approach, this is an advantage over the use of methods of the same type or mono methods, which can give a detailed but one-sided assessment of the question. Qualitative analysis and its interpretation with the help of quantitative results of online questionnaires make it possible to partially neutralize the risks of disinformation obtained from open sources, which will immediately affect the analysis of the correlation of results (Saunders, Lewis, and Thornhill, 2019). Finally, another advantage of this method is triangulation – the possibility of multiple points of view on a question, which is achieved through the multitude of available opinions in the questionnaire and relevant information in open sources.
It should be borne in mind that the development of these technologies is often classified for several reasons—first, the race of scientific discoveries in some countries, which is political, matters. Secondly, the pioneers who launched the project first can receive a significant economic advantage (Chen et al., 2018). As a result, online surveys should be conducted among non-interested parties, the number of participants in which is noticeably decreasing. However, many researchers from research institutes have publicly available results (Wang, Xu & Huang, 2017). In this regard, the online questionnaire will include the results and responses of data from researchers who are more impartial, scientifically able to assess future prospects.
The questionnaire itself will include determining the estimated time frame in current developments, the use of appropriate technologies, the effectiveness of achieving the effect, the positive dynamics of changes in the indicators of traffic volume, speed, emissions of aircraft units. Consideration should also be given to the expected reduction in greenhouse gas emissions, which is consistent with environmental responsibility and broad environmental policy programs (Becken & Mackey, 2017). As a result, with a sufficiently large sample, a quantitative equivalent will be obtained to assess the future trends of hybrid power plants. In parallel and above, a qualitative analysis was carried out using information available from open sources. The final step in this methodology will be to use the search for correlations between the qualitative and quantitative indicators of questionnaires and information in order to draw appropriate conclusions and make more specific predictions about future trends in the development of hybrid propulsion systems.
Ethical Implications
One of the main functions of this study is to identify possible risks to the environment. Even in the case of a significant scientific breakthrough that can increase traffic volumes while reducing emissions, the environmental side of the issue should be studied before production. However, these risks are associated with the content of this research, while the following problems may threaten the form of research. First, it is the unreliability of information in open sources. This difficulty is solved by conducting an additional quantitative analysis of an online survey of interested but unbiased persons in this matter. Secondly, most of the relevant information on developments and plans is classified due to the tremendous political and economic interest in obtaining possible information. In this study, such data is not used, which does not violate the ethical norms of copyright.
Since it is aviation, due to more stringent requirements for the creation of technology, the locomotive of the development of hybrid power plants, which can also be used inland transport and in the navy, this study will be helpful in other areas of production. In this regard, the importance of adhering to ethical standards, both in the form of research and in environmental management, is increasing significantly. Risk minimization is achieved on this issue will be achieved through appropriate questions in the online questionnaire, which will take into account and control activities following the requirements of environmental responsibility.
Conclusion
World practice suggests that almost all major manufacturers of power plants for aviation are, to one degree or another, working on the creation of a GSU. These include the American companies Pratt & Whitney and the United Technologies Corporation, the British Rolls-Royce, and the French Safran group of companies. Of course, Chinese engine manufacturers are also developing a hybrid aircraft engine, but the latter does not provide available information on this issue. This technological development must be accompanied by environmental responsibility, which will be highlighted in this study. Finally, using a methodology that considers the qualitative and quantitative aspects of the issue will allow a more detailed assessment of future trends in the development of the subject of research.
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