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Design of an optimized multicopter propeller
Zeman, Petr ; Matějů, Jiří (referee) ; Dvořák, Petr (advisor)
Výdrž a účinnost multicopterů jsou z velké části ovlivněny výběrem pohonného systému, zejména pak vrtulí. Avšak u malých bezpilotních prostředků, které většinu času stráví ve visu (např. multicoptery), pracují vrtule při nízkých Reynoldsových číslech, případně i v režimu odtržení. Tyto problémy a efekty spojené s rotací jsou řešeny pomocí korekcí aerodynamických koeficientů a aplikovány na vírovou teorii. Tento přístup vede k významnému zvýšení přesnosti výpočtu leteckých vrtulí. Nicméně pro nulovou rychlost nabíhajícího proudu mají tyto korekce tendenci nadhodnocovat hodnoty tahu vrtule. Pro snížení výpočetní náročnosti a času nezbytného k získání potřebných aerodynamických vlastností pro různá Reynoldsova a Machova čísla jsou použity neuronové sítě. Celý proces je implementován do prostředí MATLAB (včetně grafického rozhraní, neuronových sítí a adaptivních algoritmů) a validován na pěti různých vrtulích k prokázání, že vypočtené výkony vrtulí se shodují s experimentálními daty. Variační počet byl vybrán jako metoda pro návrh optimalizované vrtule, jelikož s jeho využitím lze navrhnout vrtuli s maximálním tahem pro zadaný výkon. Pro ověření zvoleného přístupu byla navrhnuta optimalizovaná vrtule, jejíž koeficient tahu je vyšší než odpovídající vrtule, se kterou je srovnávána, při zachování stejné hodnoty koeficientu výkonu.
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Simple universal nonlinear longitudinal flight simulation with avoiding of static and dynamic stability derivatives
Matějů, Jiří
This paper shows simple method to simulate nonlinear longitudinal flight dynamic of an aircraft in the most direct way. The method is based on physical principles of an analytical-empiric flight dynamics. Non-linearity, as stall or thrust dependent on velocity, can be included. Static and dynamic stability derivatives are not required but can be computed as an output. The model is applicable for various aircraft conceptions. Higher level model, for example, based on flight tests data, can be modified by low-level analytical methods, e.g. for modification of horizontal tail area. No special simulation software is necessary. The model is compared to linear model and flight test experiment. This model, together with valuable analytical-empiric data, might be applied for fast flight dynamic computations. Model is easily accessible and understandable even with basic knowledge of flight dynamic and computer programming. The main application of the method is conceptual design when high precision is not expected, even if VLM, CFD or flight test data can improve the precision.
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Unmanned aircraft powertrain characterization
Serediuk, Vadym ; Matějů, Jiří (referee) ; Dvořák, Petr (advisor)
The aim of this bachelor thesis is to recommend the most efficient electric propulsion system from the selected ones. The beginning is devoted to research in the field of electric propulsion systems and to description of their main parameters. The theoretical part is followed by a practical one, which is divided into two series of measurements. First, the performance characteristics of various motor-propeller combinations are measured. On the basis of the received data, a comparison of propulsion systems in terms of efficiency is made, the most suitable propeller-motor combination is recommended. The last part is devoted to the measurement and visualization of the airflow velocity field behind the propeller.
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Methodology of temperature measurement behind jet engine
Koutný, Martin ; Koštial, Rostislav (referee) ; Matějů, Jiří (advisor)
This thesis is focused on temperature measurement behind jet engine. The theoretical part introduces chosen ways of temperature measurement. The practical part is divided into design (and later assembly) of the measuring stand, methodology of measurement and the measurement itself. The main outcome are heat maps gained by measuring temperatures behind TJ – 42 jet engine.
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Stability and controllability of the Z-143 airplane with a more powerful engine
Kochtík, Martin ; Matějů, Jiří (referee) ; Daněk, Vladimír (advisor)
The thesis deals with the calculation and evaluation of the flight characteristics of the aeroplane Z 143 with the power unit Lycoming AEIO-580-B1A. The first part of the text focuses on a general description of the aircraft, its geometric characteristics and calculation of mass and aerodynamic characteristics. In terms of flight performance there are compared the values for contemporary model and developmental aircraft with a more powerful engine. Another part of the work deals with the calculation of properties in terms of stability and manageability. In this section regards the determination of the results of the flight characteristics and their assessment of whether they comply. In the end I discuss the individual results and comment the possible recommendations on correction or improvement of these properties.
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Flight Simulator of General Aviation Aircraft
Mamula, Marko ; Koštial, Rostislav (referee) ; Matějů, Jiří (advisor)
This bachelor‘s thesis maps the major and mostly used commercial flight simulator softwares on the market, and points out the main differences in developing the aircraft in each simulator. It focuses on the flight simulator X-Plane and describes how it works with the flight model. The main goal of this thesis is developing a virtual model of an experimental aircraft VUT-061 Turbo and comparing its flight data with the data measured on the actual aircraft. Furthermore it suggests the adequate hardware needed for completing the physical simulator.
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Optimized design of turbine engine intake
Kubo, Michal ; Matějů, Jiří (referee) ; Popela, Robert (advisor)
This master thesis deals with design of a subsonic intake which is used to supply small jet engine integrate into the fuselage of agile small unmanned aerial vehicle (UAV). Some kinds of these intakes are listed in order to inspire and introduce future designers into this part of jet plane design. This thesis contains a small amount of theory about compressible flow, and necessary knowledge which are important to know before the very first attempt to design an intake. Two models were designed in order to prove that the theory listed in this thesis is useful and can be used as a guide in design process of subsonic intakes. Both designs have the same layout. S-duct design with one intake placed on the belly of fuselage was chosen. After CFD analysis of first model it was found that there are huge area with separated flow and vortex. Separated flow leads to big total pressure loss and pressure distortion. While designing the second model the emphasis was to avoid this vortex and improve flow conditions. This optimization was success and the second design have smaller pressure loss in compare to the first design. The difference is more than 50% at fly speed M=0,8.
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Matlab Simulink for Flight Mechanics II module
Černota, Jiří ; Zikmund, Pavel (referee) ; Matějů, Jiří (advisor)
The thesis is about the use of Matlab Simulink software for subject Flight Mechanics II. User interface, which allow computing of aerodynamic derivations and state space matrices, was created. It also provides system for launching simulations of longitudinal aircraft movement in Simulink environment and results visualization. In the last part were suggested examples for practice lessons of the aforementioned subject. These lessons focus on mastering basic block programming and to understand concept of aircraft dynamics and controlling aircraft movement.
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