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Influence of oil service life on selected performance parameters of an aircraft piston engine

Trendak Michał, Czarnigowski Jacek

Combustion Engines

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2023

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R. 62, nr 3

78--83

EN

This article presents an analysis of the influence of oil service life on the performance parameters of an air-craft piston engine lubrication system used in an ultralight aircraft. The ageing of oil between oil changes causes a change in its parameters (such as density, viscosity...). These parameters have a strong influence on the level of protection of the lubricated components. Currently, in aircraft, oil changes are carried out according to a time schedule - oil is changed every fixed period (residual life) regardless of its actual condition. The task of this article is to test the possibility of an indirect assessment of oil condition based on analysis of changes in selected parameters of engine lubrication system operation during normal operation. The oil warm-up speed during the pre-start procedure and the dependence of oil pressure on engine speed were assumed for the analysis. The study was conducted on an ultralight rotorcraft during normal operation. Selected first daily flights directly after oil change, and after 17, 32, 50 and 66 hours of operation were analysed. It was shown that the warm-up rate changes in the samples analyzed, but that this change may also be due to factors other than oil operating time. In the case of the oil pressure vs. speed characteristics, different characteristics were shown for different operating time, but no specific dependencies were found.

2

Aircraft piston engine load distribution in steady state operating conditions

Czarnigowski Jacek, Trendak Michał

Combustion Engines

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2023

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R. 62, nr 2

29--35

EN

The article presents the results of statistical analysis of aircraft piston engine operational parameters during normal operating conditions. Test was carried out on ultralight gyroplane Tercel produced by Aviation Artur Trendak equipped with CA 912 ULT piston engine. Research was conducted under normal operating conditions of the autogyro and data was collected from 15 independent tests including a total of 14 flight hours conducted during training flights. Engine and flight parameters were recorded at 9 Hz during each flight using on-board Flight Data Recorded system. The data collected was subjected to statistical analysis to determine the statistical distribution of parameters defining the engine's operating condition. The analysis covered engine speed, intake manifold pressure, oil temperature, head temperature and exhaust gas temperature. The results were presented in the form of histograms showing the characteristic ranges of the parameters in aviation engine operation. An analysis of the rate of change of the analysed parameters was then carried out. This was the basis for defining the engine's steady state. The results showed that the steady state of the engine under these operating conditions accounted for more than 78% of the total engine operating time. A Power Consumption Ratio indicating the load range of the engine was determined for steady states. It was shown that most of the time the motor operates at an average load of between 50% and 80% of the nominal value.

3

Analysis of operating parameters of the aircraft piston engine in real operating conditions

Czarnigowski Jacek, Rękas Daniel, Ścisłowski Karol, Trendak Michał, Skiba Krzysztof

Combustion Engines

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2021

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R. 60, nr 4

83--89

EN

The article presents the results of analysis of operational parameters of piston engine CA 912 ULT which is a propulsion system of ultralight gyroplane Tercel produced by Aviation Artur Trendak. Research was conducted under normal operating conditions of the autogyro and data was collected from 20 independent tests including a total of 28 flight hours, divided into training flights and competition flights. Engine speed, manifold air pressure and temperature, fuel pressure, injection time, and head temperature were recorded at 9 Hz during each flight. Collective results were presented to show the statistical analyses of the individual parameters by determining the mean values, standard deviations and histograms of the distribution of these parameters. Histograms of operating points defined by both engine speed and manifold air pressure were also determined. Analyses of the engine dynamics as a distribution of the rate of change of the engine rotational speed were also carried out. It was shown that the engine operating points are concentrated mainly in the range of idle and power above 50% of nominal power. The most frequent range is 70-80% of nominal power. It was also shown that the dynamics of engine work in real operating conditions is small. It was also shown that the way of use significantly influences the distribution of operating points. During training flights, an increase in the number of take-offs and landings causes an increase in the amount of engine work at take-off and nominal power and at idle.

4

The Species Diversity of Grasslands in the Middle Wieprz Valley (PLH060005) Depending on Meadow Type and Mowing Frequency

Kulik Mariusz, Warda Marianna, Bochniak Andrzej, Stamirowska-Krzaczek Ewa, Turos Przemysław, Dąbrowska-Zielińska Katarzyna, Bzowska-Bakalarz Małgorzata, Bieganowski Andrzej, Trendak Michał

Rocznik Ochrona Środowiska

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2019

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Tom 21, cz. 1

543--555

EN

The studies were conducted on grasslands in the middle Wieprz valley in 2017. The aim of study was to assess the diversity of the species composition of selected grassland, depending on the frequency of mowing. The investigations focused on the meadow vegetation of Molinietalia order, Arrhenatheretalia order, the Molinio-Arrhenatheretea class and Phragmitetea class. The floristic diversity of the grassland communities was determined based on two indices, namely the number of species (SN) and the Shannon-Wiener index H'. In order to detect significant differences between the obtained values of these indexes for the particular grasslands (taking into account the research factors), a variance analysis was carried out, taking into account the Linear Model (LM) for the Shannon-Wiener index and a Generalised Linear Model (GLM) for the number of species on the assumption of the Poisson distribution of this variable. In addition, a Multidimensional principal component analysis (PCA) (Jolliffe 2002) was carried out to detect the variation of the analysed dataset with regard to the values of the ecological indices (Ellenberg et al. 1992). In the grassland under study, the number of species varied depending on the type of meadow and mowing frequency. Meadows with vegetation of the Arrhenatheretalia order had the greatest number of species. Furthermore, the number of species was found to increase with the growing frequency of use. The least numerous communities occurred in rush meadows (Phragmitetea class). A more frequent use of the sward of these communities led to a decreased number of species. Similar trends were observed in the case of the Shannon-Wiener index values. A variance analysis was carried out and its results indicate a significant influence of both research factors (meadow type and cutting frequency) on the floristic diversity of the communities under study. The biggest significant differences were confirmed between meadow vegetation of the Arrhenatheretalia order and Phragmitetea class. The biggest influence of cutting frequency on the increased species diversity occurred in meadows with communities of the Arrhenatheretalia and Molinietalia order. According to a multidimensional principal component analysis (PCA) indications, habitat humidity is the main factor determining the type of meadow community and its species diversity.

PL

Badania fitosocjologiczne przeprowadzono w 2017 roku na użytkach zielonych w dolinie środkowego Wieprza. Dolina Środkowego Wieprza (PHL060005) stanowi mozaikę siedlisk o zróżnicowanym uwilgotnieniu, co sprzyja występowaniu różnorodnych zespołów roślinnych. Celem badań była ocena zróżnicowania składu gatunkowego wybranych użytków zielonych, w zależności od częstotliwości koszenia. Przedmiotem badań była szata roślinna łąk rzędu Molinietalia, Arrhenatheretalia, klasy Molinio-Arrhenatheretea i Phragmitetea. Różnorodność florystyczną badanych zbiorowisk roślinnych oceniono za pomocą dwóch wskaźników, jakimi są liczba gatunków (SN) oraz indeks Shannona-Wienera H'. W celu wykrycia istotnych różnic między uzyskanymi wartościami tych wskaźników dla poszczególnych zbiorowisk (z uwzględnieniem czynników badań) wykonano analizę wariancji z uwzględnieniem modelu liniowego (LM) dla indeksu Shannona-Wienera oraz uogólnionego modelu liniowego (GLM) dla liczebności gatunków przy założeniu rozkładu Poissona tej cechy. Dodatkowo wykonano wielowymiarową analizę głównych składowych PCA (Jolliffe 2002) w celu wykrycia zmienności analizowanego zbioru danych, ze względu na wartości wskaźników ekologicznych (Ellenberg et al. 1992). Na badanych użytkach zielonych, wartość tego parametru wykazywała zróżnicowanie w zależności od typu łąki oraz częstotliwości koszenia. Łąki porośnięte roślinnością rzędu Arrhenatheretalia były najbardziej liczne gatunkowo. Stwierdzono ponadto zwiększanie się liczby gatunków w zbiorowisku wraz z rosnącą częstotliwością użytkowania. Najmniej liczne zbiorowiska występowały na łąkach z roślinnością klasy Phragmitetea. Częstsze użytkowanie runi tych zbiorowisk przyczyniało się do zmniejszenia liczby gatunków. Podobne trendy stwierdzono w przypadku wartości indeksu Shannona-Wienera. Wykonano analizę wariancji, której wyniki świadczą o istotnym wpływie obu uwzględnionych czynników (typ łąki oraz częstotliwość koszenia) na zróżnicowanie florystyczne badanych zbiorowisk. Największe istotne różnice potwierdzono między szatą roślinną rzędu Arrhenatheretalia i klasy Phragmitetea. Największy wpływ częstotliwości koszenia na wzrost różnorodności gatunkowej zaznaczył się na łąkach z roślinnością rzędu Arrhenatheretalia i Molinietalia. Wskazaniem wielowymiarowej analizy głównych składowych PCA jest, że wilgotność siedliska jest tu głównym czynnikiem decydującym o typie szaty roślinnej i jego zróżnicowaniu gatunkowym.