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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.
EN
In ultralight aviation, a very important engine parameter is the power-to-weight ratio. On the one hand, there is a tendency to minimize the size and weight of engines, and on the other hand, there is a demand to achieve the highest possible power by using supercharging systems. Increasing power brings many benefits, but it also increases temperature in the exhaust system, posing a threat to delicate parts of the ultralight aircraft fuselage. Therefore, it is necessary to control temperature values in the engine exhaust system. This article presents the temperature distribution in the exhaust system of an aircraft engine by the example of a four-cylinder Rotax 912 engine with an electronic fuel injection system. The research was conducted in two stages: measurements were made first for the engine without a turbocharger with an original exhaust system and later for its modified version with an added turbocharger system. The paper presents a comparative analysis of exhaust gas temperatures measured at three points: 30, 180 and 1000 mm from the cylinder head. The tests were conducted for the same preset engine operating conditions at constant speed and manifold air pressure. It has been shown that the exhaust temperature in the exhaust manifold decreases with the distance from the cylinder head. The highest gradient, over three times higher than the gas temperature from 589.9 °C to 192.3 °C, occurred in the manifold with a turbocharger for 2603 RPM and 31 kPa of manifold air pressure. The introduction of turbocharging causes an increase in exhaust gas temperatures before the turbocharger by an average of 12%, with this increase being greater for operating points of higher inlet manifold pressure. Turbocharging also causes a significant decrease in exhaust gas temperatures behind the turbocharger and the silencer because the temperature drops there by an average of 25%.
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