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Trimming Surfaces in the Automatic Plane Control Process

Abstract

The directions and speed of development of plane avionics systems are determined by three factors: economical consideration, required safety levels, and optimized working conditions for the pilot. This article presents the concept of a system in which the automatic control and stabilization process is effected because of coordinated deflections of trimming surfaces: the rudder, the elevator, and the ailerons. In particular, this article presents the structure of the system in the longitudinal movement steering channel by way of deflection of the trimmer of the elevator. Furthermore, it discusses the results of numerical model simulations, which are compared to the results obtained during in-flight tests. Additionally, this article specifies general technical requirements for the servomechanisms intended for the system class discussed herein.

Selection of sufficiently large amplification makes control the plane with relatively small deflections of the trimmer. In particular, relationship between the deflection of the elevator and the deflection of trimmer, view of a tail plane and dimensions of the elevator trimmer, the structure and results of the pitch angle control system and simulation are presented in the article.

Open access
A Method of Assessing the Tendency of Aviation Fuels to Generate Thermal Degradation Products Under the Influence of High Temperatures

Abstract

The subject of the article concerns the issues associated with thermal degradation of aviation fuels under high temperature conditions. Due to the intensive development towards increasingly higher thermal loads for both, turbine aviation engines, as well as the used fuels, the issue of thermal stability of the fuel itself is extremely important. In aviation, the fuel, apart from direct participation in energy generation during the combustion process of a fuel-air mixture, also takes part in the heat transfer in many aircraft systems. As a result, requirements in terms of the fuel’s thermal potential are increasingly higher. The standard method for determining the thermal stability of fuel executed on a JFTOT device proves to be insufficient in the context of the appearing issues in current operation. The article presents a non-standard approach to the assessment of aviation fuel thermal degradation with the use of a specialist test rig. The authors believe that the presented methodology and the measurement capabilities of the test rig are valuable supplementary material for the standardized thermal stability test. It allows more thoroughly understanding the phenomena undergoing in the fuel impacted by high temperatures. The article has been prepared within the research project no. 2011/01/D/ST8/06567 funded by the National Science Centre in Poland.

Open access
Energy State Impact on Friction and Wearing in Combustion Engines

Abstract

Friction pairs are designed from elements, where is very difficult to define in unequivocal way all optimal parameters. Research on stability of friction pairs are focused on the surface and the top layer of surface in the parts. The main goal is find new solutions to design and material, thereby achieving one million kilometres of mileage to main repair in the case of internal combustion engines. The biggest structural difficulties are noticeable in friction pairs where we can observe sliding and returning motion, which is also connected with sealing function. Piston – ring – cylinder assembly of combustion engine has many friction pair’s examples, also one of them, which decide about fastness to wear. A typical example of such a pair is first sealing ring – cylinder sleeve, called further in piston – rings – cylinder unit in combustion engine. Engineers are currently seeking an additional factor, which would be unable to gain the reduction of tangential force by reducing the friction coefficient in elements of friction pair during operations. Such a factor may be the surface free energy that results from molecular structure and nature of the bonds between the molecules present in the material. Components of surface free energy determine the tribological properties of the material, which is reflected in the stability of the units. The work aims to show the possibilities and benefits of the application of this new method in order to reduce wearing, which is consistent with the observed trend of technology development.

Open access
Diagnostic Aspects of a Crankshaft Torsional Oscillations Monitoring by IAS Measurement

Abstract

Continuous monitoring of diesel engine performance under its operating is critical for prediction of malfunction development and subsequently functional failure detection. Analysis of Instantaneous Angular Speed (IAS) of the crankshaft is considered as one of non-intrusive and effective method of detection of combustion quality deterioration. The article contains presentation of attempt of monitoring of piston engine’s crankshaft torsional vibrations by measurement of Instantaneous Angular Speed at free, and power output ends of the engine’s crankshaft. The angular speed measurements was done using two optical sensors for reading the IAS, mounted at shaft line’s opposite ends, one at free end of the crankshaft and second at end of generator’s shaft. In the article is presented description of the measurement system and explanation of its mode of work. Experiments were based at two kinds of malfunction possible to be simulated at test bed. First one was simulation of a leak of fuel injection pump, the second one relayed on mounting of sets of injection valves with different nozzles characteristics (spraying nozzle angle), giving different parameters of fuel injection. Presented results of experiment derives from test cycle carried out using laboratory stand of Gdynia Maritime University equipped with 3- cylinder self – ignition engine, powering electric generator.

Open access
Determination of CO2 Emissions for Selected Flight Parameters of a Business Jet Aircraft

Abstract

In the last two decades, there has been observed a noticeable increase in the popularity and availability of air transport services, including regional ones. This intensive development of transport is accompanied by an increase in the adverse impact to the environment, increases noise level, and exhausts emissions, despite the modification and modernization of engines. Determining the emission for regional flights takes into account the specificity of the aircrafts design, such as the size of the aircraft and the performance of the engines. In this article, an attempt was made to determine the CO2 emissions of a business jet flying from Gdansk to Rzeszow. The methodology of the research (the method of calculating emissions based on fuel consumption) and the performance characteristics of the aircraft engines have been described. In the first part of the article, the speed-altitude characteristics of the DGEN-380 engine for different cruise parameters were determined using the virtual engine test bench WESTT CS/B. These characteristics have enabled the engine to match the flight characteristics (altitude, speed). For specific flight parameters, the thrust and fuel consumption were determined. On this basis, for the adopted trajectory and flight time of an aircraft equipped with two DGEN-380 engines, total fuel consumption and CO2 emission factors and values in CRUISE phase was determined with regard to the wind speed and direction. The obtained results were illustrated graphically and discussed.

Open access
Research into the Effects of the Effective Microorganisms Addition on the Engine Oil Viscosity

Abstract

In the article, changes in the properties of oils during operation were characterized. The main reason for this is the continuous aging process of the used oil caused by the interaction of oxygen contained in the air, which reacts relatively easily with hydrocarbons and the oxidation process is accelerated just by high temperature. Then the problem of microorganisms occurring in petroleum products and their effect on the properties of oils and the operation of the internal combustion engine was presented. The next part of the article presents effective microorganisms, i.e. what they are and how they work, in particular, their composition and appropriate development conditions. In addition, some of their specific applications were briefly described. In the next part of the article, the research methodology, applied oil samples with additives of effective microorganisms, both for fresh oil and used oil were described. In addition, the measuring test stand with instrumentation and measuring device was shown. The main part of the article contains the characteristics of dynamic viscosity as a function of temperature for fresh oil and used oil compared with oils with the addition of microorganisms in liquid form and ceramic tubes. The developed graphs enabled analysis of the effect of the addition of microorganisms on oil viscosity as ecological products.

Open access
Physicochemical Properties of Fuel Compositions Obtained from Diesel Fuel and Different Kinds of Fatty Raw Material

Abstract

Increased interest in development of alternative fuels used to power combustion engines is caused by excessive use of fuels obtained from mineral sources. Depletion of resources, political aspects as well as the negative impact on the environment are commonly discussed issues in relation to fossil fuels. On the other hand, biodegradability, lower toxic components emissions and interchangeability with mineral fuels are commonly described benefits related to biodiesel, interpreted as fatty acid methyl esters obtained from fatty raw material. Also the multiplicity of raw materials that can be used for production promotes popularization of the biodiesel. However the variety of raw materials can have significant impact on the number of physicochemical properties of alternative fuels due to the differences in molecular structures forming given type of raw material.

The article presents analysis of properties of different types of biodiesel and its mixtures with diesel according to the outlines presented in the quality standards for mineral and alternative fuels. Alternative fuels were produced in the laboratory setup from swine, poultry, rape and sunflower fatty raw material. Such parameters as: density, kinematic viscosity, flash point, acid value, oxidation stability, cold filter plugging point, sulphur content, water content and total contamination were examined, based on the results, the quality of the biofuels was evaluated. Study confirms that biofuels derived from plant origin fatty raw material present favorable results in the aspect water content, total contamination, acid value and cold flow properties, thus biofuels derived from animal origin raw fatty material presents lower density and sulphur content.

Open access
Jet Aircraft Data Acquisition Systems

Abstract

The article presents systems, which record parameters of flight in modern aircraft F-16, which was delivered to Polish Airforce in 2006. With the current level of technical development of the aviation industry, data acquisition systems are an important element of all aircrafts. These systems are responsible for the flight safety, allow reading and storing the most important flight parameters, and combined with digital control and safety systems allow to counteract dangerous situations, which especially can happen often in the case of military aircraft such as the F-16 due to their combat purpose. Systems records basics parameters of plane and engine, as specific fuel consumption or height of flight provides video and audio recording, and aerial combat assistance. These systems record even failures of a braking system during landing. Thanks to modern technology, and devices like those described in this article, F-16 is one of the best fighters in the world. The amount of data provided by analogue and digital sensors is so large that it requires the partitioning of parameters and use of several basic recorders of the entire system is the unit called DAU, or Data Acquisition Unit, which records the most important flight parameters, such as flight time, engine speed, or altitude.

Open access
Review of Design of High-Pressure Turbine

Abstract

The engine manufacturers adopt new measures in order to further improve the characteristics of a turbine engine. They pose new challenges to reduce a fuel consumption and an emission of pollution to the environment (including noise), but also keeping the highest level of reliability. Based on those considerations, current research in propulsion is conducted.

Modern turbines are characterised by high inlet temperature. This has implications for engine efficiency, which is expressed with a change of mass, cross-section and fuel consumption. In this article, main trends in the development of turbine engines are presented. This analysis was carried out on the basis of Rolls-Royce engine data.

The article presents literature review concerning the analytical methods of high-pressure turbines preliminary design. The aerodynamic design process is highly iterative, multidisciplinary and complex. Due to this, modern gas turbines need sophisticated tools in terms of aerodynamics, mechanical properties and materials.

The article depicts simplified model of real turbine engine. As showed in the article, this model gives only a 10% error level in engine thrust value. The calculations may be used for preliminary engine analyses.

Open access
Analysis of Influence of Legal Requirements on the Design of Electronic Ignition System for Aviation Piston Engine

Abstract

The article is a review of European aviation regulations with respect to their impact on the design of a new electronic ignition system for aircraft engines. The analysis covers the EASA decision on certification specifications as well as recommended means of compliance and related standards on testing and designing electronic subassemblies and their programming. The analysis focuses on the following aspects: design requirements (system configuration), functional requirements (principles of operation), safety (fault tolerance), material requirements (with regard to corrosion and fire resistance of electronic components) and scope of tests for particular component.

The analysis is illustrated by a case of a research and development project to design and implement an ignition system for a piston engine. The engine with its new ignition system was to be offered commercially as a product of a Polish aircraft engine manufacturer.

The article is a review of European aviation regulations with respect to their impact on the design of a new electronic ignition system for aircraft engines. The analysis covers the EASA decision on certification specifications and their programming. It is illustrated by a case of a particular engine re-engineering project

Open access