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Spiroid wingtip devices (WD) offer a promising way of improving the lift drag ratio of UAVs, but may on the other hand lead to negative aerodynamic interference of the wing with the WD and deterioration of the aerodynamic characteristics as compared to a wing without the WD. Determining the influence of the geometric parameters of a spiroid WD on aerodynamic wing characteristics, however, remains an understudied field. In our study, we investigated the influence of the following geometrical parameters on wing aerodynamic characteristics with WD: area, radius, camber angle, constriction, and pitch of the spiroid. We found that the positive effect of the WD is present at a relative radius > 0.05, as well as with an increase in the lift coefficient C L as a result of an increase in the proportion of inductive resistance. For example, with the Reynolds number Re = 2.1×105 for a rectangular wing with an aspect ratio θ = 5.12 equipped with a spiroid WD with =0.15 the quality gain is almost 10% at C L = 0.5, and at C L = 0.7 is almost 20% and at C L = 0.7 – almost 20% compared to a wing without WD. Moreover, we found that a change in the camber angle WD θ provides an increase in the derivative of the lift coefficient with respect to the angle of attack in the range from θ = 0° to θ = 130°. By changing the camber angle, it is possible to increase the lift drag ratio of the layout up to 7.5% at θ = 90° compared to θ = 0° at the Reynolds number Re = 2.1×105. From the point of view of ensuring maximum lift drag ratio and minimum inductive drag, the angle θ = 90° is the most beneficial.
Igor F. Kravchenko; Vasyl V. Loginov; Yevgene O. Ukrainets; Pavlo A. Hlushchenko. Aerodynamic Characteristics of a Straight Wing with a Spiroid Wingtip Device. Transactions on Aerospace Research 2021, 2021, 46 -62.
AMA StyleIgor F. Kravchenko, Vasyl V. Loginov, Yevgene O. Ukrainets, Pavlo A. Hlushchenko. Aerodynamic Characteristics of a Straight Wing with a Spiroid Wingtip Device. Transactions on Aerospace Research. 2021; 2021 (2):46-62.
Chicago/Turabian StyleIgor F. Kravchenko; Vasyl V. Loginov; Yevgene O. Ukrainets; Pavlo A. Hlushchenko. 2021. "Aerodynamic Characteristics of a Straight Wing with a Spiroid Wingtip Device." Transactions on Aerospace Research 2021, no. 2: 46-62.
Self-oscillations are one of the common problems in the complex automatic system, that can occur due to the features of the workflow and the design of the governor. The development of digital control systems has made it possible to damp self-oscillations by applying complex control laws. However, for hydromechanical systems, such way is unacceptable due to the design complexity and the governor cost. The objective of this work is to determine the parameters of the hydromechanical free turbine speed controller, ensuring the absence of self-oscillations during ground tests of the turboshaft engine with a hydraulic dynamometer. The TV3-117VM engine (Ukraine) with the NR-3VM regulator pump (Ukraine) was selected as the object of the study. However, self-oscillations can also occur in any modifications of the TV3-117 engine with any NR-3 regulator pump. The results of the research may be of interest to engineers and scientists who investigate the dynamics of automatic control systems for similar engines. The paper analyses the nonlinear features of the empirical characteristics of the FTSC leading to self-oscillations of the engine speed. The authors propose the mathematical model of the automatic control system dynamics, which takes into account all the features of the engine and regulator pump. It is shown that the load characteristics of the water brake and the helicopter main rotor can differ significantly. Research of the dynamic characteristics of the TV3-117VM engine was carried out. The analysis showed a good agreement between the calculation results and the field test results, and made it possible to determine the parameters of the controller, which lead to self-oscillations during test. Two cases are considered. The first case includes ground tests of the engine with a water brake; the second case—flight tests of the engine as part of the helicopter’s power plant. The data obtained make it possible to develop recommendations for adjusting the hydromechanical governor without testing it on the engine.
Oleksandr Lytviak; Vasyl Loginov; Sergii Komar; Yevhen Martseniuk. Self-Oscillations of The Free Turbine Speed in Testing Turboshaft Engine with Hydraulic Dynamometer. Aerospace 2021, 8, 114 .
AMA StyleOleksandr Lytviak, Vasyl Loginov, Sergii Komar, Yevhen Martseniuk. Self-Oscillations of The Free Turbine Speed in Testing Turboshaft Engine with Hydraulic Dynamometer. Aerospace. 2021; 8 (4):114.
Chicago/Turabian StyleOleksandr Lytviak; Vasyl Loginov; Sergii Komar; Yevhen Martseniuk. 2021. "Self-Oscillations of The Free Turbine Speed in Testing Turboshaft Engine with Hydraulic Dynamometer." Aerospace 8, no. 4: 114.
Vasyl Loginov; Yevgeniy Ukrainets; Igor Kravchenko; Аlexandr Yelansky. Analysis and selection of the parametric profile of a powerplant engine for a light trainer aircraft. Eastern-European Journal of Enterprise Technologies 2019, 1, 59 -68.
AMA StyleVasyl Loginov, Yevgeniy Ukrainets, Igor Kravchenko, Аlexandr Yelansky. Analysis and selection of the parametric profile of a powerplant engine for a light trainer aircraft. Eastern-European Journal of Enterprise Technologies. 2019; 1 (1):59-68.
Chicago/Turabian StyleVasyl Loginov; Yevgeniy Ukrainets; Igor Kravchenko; Аlexandr Yelansky. 2019. "Analysis and selection of the parametric profile of a powerplant engine for a light trainer aircraft." Eastern-European Journal of Enterprise Technologies 1, no. 1: 59-68.