Authors:Ivan Ostroumov, Karen Marais, Nataliia Kuzmenko Pages: 1–10 - 1–10 Abstract: During the crucial phases of take-off, initial climb, approach, and landing where aircraft are close to the ground, Global Navigation Satellite Systems (GNSS) signal strength may not be sufficient to guarantee safe operation, especially in the presence of potential interference, malicious or otherwise, from ground equipment. When the GNSS location is lost, aircraft typically revert to other navigation aids. The most accurate navigation aid is Distance Measuring Equipment (DME). However, whereas GNSS location is triangulated, the navigation equipment on-board aircraft can only measure two DME signals simultaneously. Therefore, location based on DME tends to be accurate only to hundreds of meters, compared to meters for GNSS. A new approach is presented for positioning using multiple DMEs. The approach is based on regression analysis for prediction of DMEs distances in time of measurement. This approach increases positioning accuracy due to availability of multiple DMEs data in the system of navigation equations. Spline functions were used in a regression model in order to achieve the most accurate prediction values. An approach was verified using real flight data and shown the decreasing of navigation system error on value depending on availability and geometry of ground stations locations. PubDate: 2022-03-18 DOI: 10.3846/aviation.2022.16589 Issue No:Vol. 26, No. 1 (2022)
Authors:Parampalli Archana Hebbar, Abhay Anant Pashilkar, Pradipta Biswas Pages: 11–2 - 11–2 Abstract: The authors of this paper investigated applications of eye tracking in transport aircraft design evaluations. Piloted simulations were conducted for a complete flight profile including take-off, cruise and landing flight scenario using the transport aircraft flight simulator at CSIR-National Aerospace Laboratories. Thirty-one simulation experiments were carried out with three pilots/engineers while recording the ocular parameters and the flight data. Simulations were repeated for high workload conditions like flying with degraded visibility and during stall. Pilot’s visual scan behaviour and workload levels were analysed using ocular parameters; while comparing with the statistical deviations from the desired flight path. Conditions for fatigue were also recreated through long duration simulations and signatures for the same from the ocular parameters were assessed. Results from the study found correlation between the statistical inferences obtained from the ocular parameters with those obtained from the flight path deviations. The authors of this paper investigated an evaluator’s console that assists the designers or evaluators for better understanding of pilot’s attentional resource allocation. PubDate: 2022-03-22 DOI: 10.3846/aviation.2022.16398 Issue No:Vol. 26, No. 1 (2022)
Authors:Nihad E. Daidzic Pages: 22–3 - 22–3 Abstract: A mathematical model of free balloon launches in windy conditions is based on the conservation of the linear momentum in horizontal and vertical axes. Linear momentum conservation equations are represented by a set of four nonlinear first-order ODEs. Some ODEs were solved analytically, while the nonlinear Riccati ODE with variable coefficients for the vertical acceleration was solved using numerical ODE solvers. Transient aerodynamic lift and horizontal drag are caused by the slip flow over the balloon envelope. It takes free balloon ten half times to reach 90.9% of the wind velocity in a step function response. A launch condition was developed in terms of the minimum required envelope temperature for which the net aerostatic lift overcomes inert weight of a balloon. Perturbation analysis was used to explore changes in the net aerostatic lift. Simulations were performed to cases with and without envelope distortion and enhanced cooling due to forced convection. Since all balloon takeoffs are performed downwind, obstacle clearance becomes an issue due to rapid loss of aerodynamic lift. Balloons may stop climbing and even start descending shortly after liftoff despite intense heating representing real hazard. PubDate: 2022-03-23 DOI: 10.3846/aviation.2022.16621 Issue No:Vol. 26, No. 1 (2022)
Authors:Hatice Cansu Ayaz Ümütlü, Zeki Kiral Pages: 32–4 - 32–4 Abstract: There are different types of airfoil used in many applications such as energy production, aerospace, mixing of fluid products. Design optimization studies are still being carried out on the airfoil type structures. The airfoil section is the most important factor affecting the quality and efficiency of the performed work. The aim of this study is the optimization of the airfoil shape to generate more lift than the original airfoil shape creates. For this purpose, Bézier curves are used to generate the airfoil polar points, XFOIL is used as a flow solver and MATLAB is used to create optimization codes using the genetic algorithm. The results show that the created optimal airfoil shape produces more lift than the original airfoil shape. In this study, design optimization studies are supported by flow analysis using ANSYS Fluent. PubDate: 2022-03-25 DOI: 10.3846/aviation.2022.16471 Issue No:Vol. 26, No. 1 (2022)
Authors:Surendar Ganesan, Balasubramanian Esakki, Silambarasan Mathiyazhagan, Vikram Pandimuthu Pages: 41–5 - 41–5 Abstract: This article’s incitement interprets Unmanned Amphibious Aerial Vehicle (UAAV)’s conceptual design process in a systematic approach. The UAAV is conceptualised to be an ideal tool for limnologists in water quality assessment. Integration of hovercraft with the multi-rotor system helps collect water samples from remote and inaccessible water bodies. The UAAV flies in multi-rotor mode, subsequently land and glide along the water surface in hovercraft mode. The new and unconventional vehicle configuration makes the conceptual stage a challenging one in the design process. To overcome the challenges and strapped configuration of vehicle design, the Authors used a systematic approach of scenario-based design, morphological matrix, and Pugh’s method in the design process of the “Pahl & Beitz” model to retrieve the best possible UAAV design. The conglomerate design of UAAV is evaluated for its design requirements, and the computational analysis is performed to examine the mechanical strength and flow characteristics of UAAV. The experimental prototype of UAAV demonstrates the competence of flying in the air and hovering in water through field trials. PubDate: 2022-03-30 DOI: 10.3846/aviation.2022.16519 Issue No:Vol. 26, No. 1 (2022)
Authors:Alireza Gharib, Masoud Goharimanesh, Ali Koochi, Mohammad Reza Gharib Pages: 54–6 - 54–6 Abstract: This paper aims to design a reliable filter that can transform the actual motion of a flight simulator maneuver into a logical and understandable movement for its workspace. Motion cueing algorithms are used in scaling maneuvers to improve the user’s perception of real-world motion. As a unique algorithm, the washout-filter algorithm reduces the real motions where the user cannot understand the difference between the actual and simulated maneuvers. To design a proper washout filter, first, apply the inner ear model where humans can feel the motion to design a proper filter. The Otolith and semicircular systems were represented by two parts in this model. Second, an evolutionary theory based on a genetic algorithm is used to design a structure that minimizes human perception error and workspace boundaries. The issue is determining the coefficients in the model in order to create a high-performance flight simulator. The filtering algorithm, based upon the human vestibular model, compares human perception with flight simulator motion knowledge. The findings demonstrate an objective function that minimizes user perception error, and the flight simulator motion range can prepare a reliable washout filter for motion cueing. PubDate: 2022-03-31 DOI: 10.3846/aviation.2022.16570 Issue No:Vol. 26, No. 1 (2022)
Authors:Filip Sklenář, Jiří Matějů Pages: 64–7 - 64–7 Abstract: Problem of pitot tube blocking is persistent because even in the recent past there have been several accidents based on inaccurate information from air speed indicators. This problem was caused by a partial or complete blockage of the total pressure probes. Certain principles of blocking detection are well known. This article describes research into another principle of the gradual blocking detection of the pitot tube with drain holes. Pitot tubes with different blockage ratios were made and tested. A gradual blocking curve was described. The independence of velocity magnitude for the investigated airspeeds was found. This research shows that the drain hole design can be useful for a pitot tube blockage detection. The principle is based on another pitot tube with a larger drain hole area. Airspeed error due to gradual blocking grows faster on the other pitot tube. Gradual blocking of both pitot tubes results in a difference in indicated airspeeds, even at constant speed flight and before full blockage. This airspeed difference can warn a pilot and gives him or her a valuable time to use emergency procedures. PubDate: 2022-04-05 DOI: 10.3846/aviation.2022.15963 Issue No:Vol. 26, No. 1 (2022)
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