The journal Aviation is aimed at all researchers looking for information about aviation from history to technology.
New research articles were published in the issue of the VILNIUS TECH scientific journal Aviation (Vol. 27, No. 1). The editor-in-chief of this journal, Professor dr. Gintautas Bureika, presents the main highlights of the new issue and the most prominent themes and relevance of research papers on this issue.
Experimental study of physical-chemical properties of advanced alcohol-to-jet fuels
Anna Yakovlieva, Sergii Boichenko, Vasyl Boshkov, Lukaš Korba, Marián Hocko (Ukraine and Slovakia)
The paper presents an analytical review of technological processes of alternative jet fuel production from alcohols and experimental results on the study of its physical-chemical properties. State-of-the-art in the sphere of civil aviation development within the framework of sustainable development and minimization of transport’s negative impact on the environment is presented. The development and implementation of sustainable aviation fuels are considered the main measure for reaching carbon-neutral growth. Two technologies of alcohol-to-jet fuel production are considered, and possible feedstock and processing pathways are presented. Physical-chemical properties of two kinds of alcohol-to-jet fuels are studied experimentally, as well as the properties of conventional jet fuels blended with alternative ones. It is shown that the physical-chemical properties of jet fuels blended with alcohol-to-jet components containing aromatics are very close to conventional jet fuels. All of the studied fuel blends with alcohol-to-jet components completely satisfy the requirements of specifications. Basing on the received results it is expected that alcohol-to-jet components containing aromatics may be successfully used for blending with conventional jet fuel and used as a drop-in fuel.
A laminar flow, propulsive, jet-flapped concept for electrically powered transport aircraft
Nikolaos Kehayas (Greece)
Friction drag constitutes approximately half of the total drag of subsonic civil transport aircraft at cruise conditions. Several means were examined to control the flow over an aircraft and achieve laminar flow. Here, a new concept for friction drag reduction in the form of integrating the aerodynamics and propulsion of the aircraft is put forward. Engines buried in the wing and at the rear of the fuselage suck the boundary layer of the entire wing and fuselage surface, and then, they use it as intake air and exhaust through ducts. At the wings, the engines exhaust in the form of a jet flap at the trailing edge providing distributed propulsion. By this laminar flow, propulsive concept laminar flow is established over the entire aircraft, resulting in substantial drag reduction. The analysis showed that out of the four electrically powered aircraft versions considered only the combined lift distribution with tailless fuselage is about to be feasible. It was also found that the example aircraft design is inappropriate. It is expected that a design purposely based on the proposed concept would bring electrically powered transport aircraft within the specific energy levels of present batteries
Method of evaluation of military helicopter pilot selection criteria: a novel grey SWARA approach
Salim Kurnaz, Aşkın Özdağoğlu, Murat Kemal Keleş (Turkey)
A helicopter is a very important defence and attack tool for a country’s armed forces (army) (air force). With the rapid progress of technology, the designs of helicopters, and the hardware and software elements in the helicopter have also been renewed and developed in parallel with advanced technology. Therefore, it is expected that the pilots who will use helicopters, which are important flight tools of the armed forces, will also have the qualifications to provide the necessary knowledge, skills, and criteria. The aim of the study is to determine the military helicopter pilot selection criteria and to find the importance levels of these criteria. For this purpose, three main criteria as “Health”, “Psychomotor” and “Education and Training” and thirteen sub-criteria were determined. The weights of the determined criteria were found by the Grey SWARA method, which is a current multi-criteria decision-making tool. According to the results of the analysis, it is found that the most important sub-criteria was “Practical Training”, while the lowest important criteria was the “Height and weight limits” criterion. With this study, the weights of the military helicopter pilot selection criteria were found for the first time with the Grey SWARA method.
A simultaneous path planning and positioning based on the artificial distribution of landmarks in a GNSS-denied environment
Samaneh Elahian, Mohammad-Ali Amiri Atashgah, Bahram Tarverdizadeh (Iran)
In recent years, exploration operations by autonomous robots have been expanding into unknown environments on Earth, under the sea, or even on other planets. This paper proposes the idea of Concurrent Path Planning and Positioning (CPPAP) using artificially distributed landmarks, while no GNSS signal is available. The method encompasses an observability-based direction search algorithm for path planning in parallel with Simultaneous Localization and Mapping (SLAM) for localization. Most of the path planning methods utilize offline algorithms; however, the proposed method determines the robot’s direction of motion in real-time, concurrently with the positioning tasks by the inclusion of the system observability, related to the features’ distribution. Same as in all feature-based SLAMs, features play an important role in the determination of the most observable direction, and hence the direction of the robot’s motion. Moreover, the effectiveness of the distribution of the features and their pattern in the proposed method is investigated. To evaluate the efficiency and accuracy of the CPPAP, outcomes are compared with an existing random SLAM.
Aviation accident and incident forecasting combining occurrence investigation and meteorological data using machine learning
Mauro Caetano (Brazil)
Studies on safety in aviation are necessary for the development of new technologies to forecast and prevent aeronautical accidents and incidents. When predicting these occurrences, the literature frequently considers the internal characteristics of aeronautical operations, such as aircraft telemetry and flight procedures, or external characteristics, such as meteorological conditions, with only a few relationships being identified between the two. In this study, data from 6,188 aeronautical occurrences involving accidents, incidents, and serious incidents, in Brazil between January 2010 and October 2021, as well as meteorological data from two automatic weather stations, totalling more than 2.8 million observations, were investigated using machine learning tools. For data analysis, decision trees, extra trees, Gaussian naive Bayes, gradient boosting, and k-nearest neighbour classifiers with a high identification accuracy of 96.20% were used. Consequently, the developed algorithm can predict occurrences as functions of operational and meteorological patterns. Variables such as maximum take-off weight, aircraft registration and model, and wind direction are among the main forecasters of aeronautical accidents or incidents. This study provides insight into the development of new technologies and measures to prevent such occurrences.
Vibroacoustic soundproofing for helicopter interior
Pavithra Nagaraj, Adham Ahmed Awad Elsayed Elmenshawy, Iyad Alomar (Latvia)
As VIP passengers generally want to fly civil and executive jets where the vibratory and acoustic environment is smoother than on the normal jets. Helicopter interior noise is generated by main and tail rotors, engines, main gearbox, and aerodynamic turbulence (Lu et al., 2018). Because of these sources, the tonal and broadband noise is incredibly high and needs to be reduced. A conventional passive system (soundproofing) is the best way to control the acoustic of the cabin whereas active systems (active vibration and noise control) are not completely reliable or applicable. The design of the soundproofing may be researched by simulation using one of these programs: ANSYS, SOLIDWORKS 2020 and ACOUSTIC analysis Vibroacoustic Monitoring (VAM) approach. The analyses were performed from frequency ranges, 5-10Hz and 0-2000Hz then transformed into frequency velocity domain using Proudman’s equations (Lu et al., 2017). Soundproofed ANSYS models are validated using instantaneous sound pressure levels measured within the helicopter during flight. The acoustic detection method for GAZELLE is also performed successfully in SOLIDWORKS for aluminium alloy and titanium alloy, this proves the relationship between acoustic power levels and material configuration. The noise coefficient responses of interior materials are used as the main index for soundproofing helicopter interiors. The results of this research can be used for the implementation of the VAM approach for soundproofing helicopter interiors.
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