Estonian Aviation Academy

Tartu, Estonia

Estonian Aviation Academy

Tartu, Estonia
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Mrtens K.,Danmark A/S | Umborg J.,Estonian Aviation Academy
Aviation | Year: 2012

This report deals with the project-based learning used by the communication and navigation systems laboratory in teaching aviation engineers. © 2012 Vilnius Gediminas Technical University (VGTU) Press Technika.

Lauk P.,Tallinn University of Technology | Lauk P.,Estonian Aviation Academy | Unt K.-E.,Estonian Aviation Academy
Aviation | Year: 2015

The effect of miniflaps for increasing the L/D ratio and the lift coefficient has been studied on airliners as well as on UAV-s and wind turbines. For sailplanes the lift when Cl>1.0 is of main interest. As the maximum wing loading of racing sailplanes reaches 60-62kg/m2, it is necessary to achieve a high Cl max (1.7-1.8) in thermals. In this case the decrease in TAS caused by a high Cl max even compensates for the drop of the L/D ratio to a certain extent, as the climb speed will increase when the spiral flight radius diminishes in thermals. To bring the L/D to Cl>1.0, a 2% chord miniflap at a 30° deflection angle was attached to the trailing edge of a Jantar-Standard 3 type sailplane wing (airfoil NN-8). In flight tests it was found that the miniflap increased the sailplane's Cl max to 1.35-1.66, i.e. by 23% (Re 1.0-0.92×106). At the same time the L/D ratio Cl increased by over 1.0. Especially good L/D improvement was noted with Cl at 1.13-1.19. In thermal Cl of 1.57-1.65 the roll control was good. At lower Cl<1.0 values, the miniflap reduced the L/D ratio in comparison with a normal configuration. © 2015 Vilnius Gediminas Technical University (VGTU) Press.

Lauk P.,Estonian Aviation Academy | Rebassa J.H.,Polytechnic University of Catalonia | Kartushinsky A.,Tallinn University of Technology | Tisler S.,Tallinn University of Technology | And 2 more authors.
Proceedings of the Estonian Academy of Sciences | Year: 2016

The work consists in numerical modelling of two-phase flow in porous media. The performance of a vertical cylinder pellets dryer with four lateral jets discharging air to a motionless particulate medium was modelled. The aim was to better understand the mechanism of heat exchange and the effect of different parameters on the fluid going through a particulate medium. The flow was considered non-isothermal and turbulent. The cases were first calculated for a single phase (isothermal and non-isothermal) and then for two phases with changing the particles volume fraction and size. The Boussinesq approach was used to take into account the effect of temperature on the gas velocity, and the k-ε model was applied for the closure of momentum equations. The solution algorithm was built using a scheme of finite differences with the tri-diagonal matrix algorithm. The results show how different variables, such as axial velocity or temperature of lateral jets flow, start with high values in the inlets and merge and collapse further downstream while the flow goes through the medium. The axial velocity drops from the jets up to the end of the system. This drop is higher for larger particles volume fractions. The radial velocity tends to increase from a null value faster for larger particles volume fractions. As the drag increases, the temperature drops faster for larger particles volume fractions and for bigger particles, which can be explained by the higher energy transfer between the flow and the particles. © 2016 Authors.

Latt S.,Tartu Observatory | Latt S.,University of Tartu | Slavinskis A.,Tartu Observatory | Slavinskis A.,University of Tartu | And 105 more authors.
Proceedings of the Estonian Academy of Sciences | Year: 2014

This paper presents the mission analysis, requirements, system design, system level test results, as well as mass and power budgets of a 1-unit CubeSat ESTCube-1 built to perform the first in-orbit demonstration of electric solar wind sail (E-sail) technology. The E-sail is a propellantless propulsion system concept that uses thin charged electrostatic tethers for turning the momentum flux of a natural plasma stream, such as the solar wind, into spacecraft propulsion. ESTCube-1 will deploy and charge a 10 m long tether and measure changes in the satellite spin rate. These changes result from the Coulomb drag interaction with the ionospheric plasma that is moving with respect to the satellite due to the orbital motion of the satellite. The following subsystems have been developed to perform and to support the E-sail experiment: a tether deployment subsystem based on a piezoelectric motor, an attitude determination and control subsystem to provide the centrifugal force for tether deployment, which uses electromagnetic coils to spin up the satellite to one revolution per second with controlled spin axis alignment, an imaging subsystem to verify tether deployment, which is based on a 640 × 480 pixel resolution digital image sensor, an electron gun to keep the tether at a high positive potential, a high voltage source to charge the tether, a command and data handling subsystem, and an electrical power subsystem with high levels of redundancy and fault tolerance to mitigate the risk of mission failure.

Nommik A.,Estonian Aviation Academy | Nommik A.,Tallinn University of Technology | Kukemelk S.,Nordic Aviation Group | Kukemelk S.,Tallinn University of Technology
Aviation | Year: 2016

the gravity model is a method that is used by transportation researchers, airline network planners and analysts to explain how traffic is distributed between city pairs in correlation to the distance or travelling time between them, which as a result indicates the behaviour of travellers or the performance of the transport connection. How ever, the applicability of the model depends on the reliability of the results, which poses a major issue for researches. The major difficulty is to obtain comparable qualitative insights into the key parameters that are selected. This paper presents a possibility study for the use of the gravity model for regional route planning from the scientific point of view and suggests possibilities of gravity model calibration for airline network analysis including alternative methods for estimating the gravity potential of destinations and measurement of the influence of distance on the potential. The focus of the research is the ability to explain and forecast the development of regional air transportation routes in the commercial aviation network when there is a lack of recorded booking demand data. © 2016 Vilnius Gediminas Technical University (VGTU) Press.

Vanker S.,Tallinn University | Enneveer M.,Estonian Aviation Academy | Masak M.,Estonian Aviation Academy
20th International Congress on Sound and Vibration 2013, ICSV 2013 | Year: 2013

This paper aims at studying the problems of aviation noise at Tallinn Airport and implementation of the measures to reduce the noise pollution. At present Tallinn Airport has two stationary noise level monitoring terminals and one mobile terminal for metering and modelling the noise level caused by taking-off and landing aircraft. The research shows that Tallinn Airport has not yet exceeded the noise limits stipulated by the regulations. The area surrounding Tallinn Airport has been divided into four noise zones. Zone 1 where the noise level does not exceed 55 dB is suitable for the majority of the types of buildings, whereas Zone 4 where the noise level exceeds 70 dB and the highest level measured is 105 dB is absolutely unacceptable as a building area. In recent years the number of flights flying over the residential areas of Tallinn has significantly been reduced, i.e. the number of flights taking off from runway 26 and landing on runway 08. In suitable weather conditions the noisy aircraft are directed to land on RWY 26 and take off from RWY 08. After the completion of the military airfield at Ämari in the nearest future, it is going to be possible to transfer the cargo flights, usually made by big and noisy jets, from Tallinn-Ülemiste Airport to Ämari.

Vanker S.,Tallinn University | Enneveer M.,Estonian Aviation Academy | Reppo M.,Tallinn University
18th International Congress on Sound and Vibration 2011, ICSV 2011 | Year: 2011

This paper aims at studying the case of Tallinn Airport in Estonia, with a focus on evaluating the airport noise and its impact on the neighbouring residential districts. Tallinn Airport is located within the city area, and therefore the inhabited areas are also exposed to aviation noise. A peculiarity of air traffic distribution in Tallinn is that only about 18% of take-offs and approaches take place above the city, west of the airport, and 82% above the not densely built-up land east of the airport. As the annual average traffic is relatively sparse in/from western directions, the area exposed to relevant noise input is smaller in the west than in the east. To maintain take-offs and landings from eastern directions as the preferred options is regarded as an appropriate mitigation measure concerning the increasing air traffic. The monitoring system at Tallinn Airport enable operating noise and aircraft noise to be analysed and predicted as a way to differentiate the landing fees for aircraft depending on noise and flight trajectory. By analyzing the survey, conducted in the nearby housing estates of the airport, it turned out that generally the residents do not complain about excessively loud and disturbing noise in their neighborhood.

Kuut A.,Estonian University of Life Sciences | Ritslaid K.,Estonian Aviation Academy | Olt J.,Estonian University of Life Sciences
Agronomy Research | Year: 2011

In recent years the use of ethanol and mixtures thereof as a fuel in internal combustion engine has been studied at Estonian University of Life Sciences. In the course of the research there have occurred new problems and issues to solve. Ethanol fuels in this study include bioethanol produced in farm environment, hereinafter referred to as farmstead ethanol. Farmstead ethanol is simply bioethanol obtained by applying a simpler (cheaper) production method. Such a production process does not adhere to or comply with the requirements set out for potable spirit. The first part of the article provides an overview of the production and properties of ethanol fuel. The second part contains comparative test results, analysis and conclusion concerning the use of ethanol, farmstead ethanol and gasoline (regular fuel) in Otto motor.

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