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1

Efficient Positioning of Two Long-Range Passenger Aircraft in Formation Flight

Antczak Adam, Lasek Maciej, Sibilski Krzysztof

Transactions on Aerospace Research

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2022

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Nr 3 (268)

21--31

EN

In today’s world, each airline is forced to look for new savings opportunities. One of the methods may be the use of formation flights in daily flight operations, which may allow a reduction in fuel consumption by several percentages. The paper presents the genesis of how the consideration of such flights and the possibility of their implementation in an airline had started. The leader’s plane generates vortices, which, with the proper alignment of the planes to one another, can reduce the drag on the wingman. However, the wrong position may not only have no positive effect but also may be a threat to stable wingman flight. The article presents a method of using these vortices in such a way as to have a positive impact on the aerodynamics of the wingman. A favourable position in the vertical and horizontal axes will be determined in relation to the vortex generated by the leader’s plane in order to obtain the greatest benefit in reducing fuel consumption. The paper presents an operational analysis of the possibility of maintaining such a distance to obtain profit on fuel but also to ensure the highest level of safety of the flight.

2

Identification of longitudinal aerodynamic characteristics of a strake-wing micro aerial vehicle by using artificial neural networks

Rykaczewski Dariusz, Nowakowski Mirosław, Sibilski Krzysztof, Wróblewski Wiesław, Garbowski Michał

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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Vol. 69, nr 4

art. no. e137508

EN

Appropriate modeling of unsteady aerodynamic characteristics is required for the study of aircraft dynamics and stability analysis, especially at higher angles of attack. The article presents an example of using artificial neural networks to model such characteristics. The effectiveness of this approach was demonstrated on the example of a strake-wing micro aerial vehicle. The neural model of unsteady aerodynamic characteristics was identified from the dynamic test cycles conducted in a water tunnel. The aerodynamic coefficients were modeled as a function of the flow parameters. The article presents neural models of longitudinal aerodynamic coefficients: lift and pitching moment as functions of angles of attack and reduced frequency. The modeled and trained aerodynamic coefficients show good consistency. This method manifests great potential in the construction of aerodynamic models for flight simulation purposes.

3

Methodology for conducting preliminary and state tests of an aerial jet target set

Rykaczewski Dariusz, Jastrzębski Grzegorz, Sibilski Krzysztof, Szczepaniak Paweł

Journal of KONBiN

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2020

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Vol. 50, iss. 1

305--318

EN

The article presents a methodology for the implementation of preliminary and state tests on the example of the project entitled "Jet air targets with a programmable flight route" conducted by the Air Force Institute of Technology. The experience in the field of maneuvering aerial targets has allowed for implementation of an aerial jet target set. The further stages of research necessary to implement the set for operation have been presented. Investigations of the aerial jet targets were carried out based on the regulations in force in the Polish Armed Forces.

PL

W artykule zaprezentowano metodologię badań wstępnych i państwowych na przykładzie projektu pt. ,,Odrzutowe cele powietrzne z programowaną trasa lotu”. Badania prowadzone były przez Instytut Techniczny Wojsk Lotniczych. Doświadczenia w dziedzinie manewrujących celów powietrznych pozwoliły na wdrożenie zestawu tych celów. Przedstawiono kolejne etapy badań niezbędnych do wdrożenia zestawu do eksploatacji. Badania odrzutowych celów powietrznych realizowane były w oparciu o aktualne przepisy obowiązujące w Siłach Zbrojnych RP.

4

Mechanical and structural investigations of wings of selected insect species

Landowski Michał, Kunicka-Kowalska Zuzanna, Sibilski Krzysztof

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 2

199--209

EN

This paper presents research and measurements leading to obtaining the Young’s modulus of wing bearing structures of selected insect species. A small testing machine intended for three-point bending and equipped with instruments registering low forces was constructed for the needs of the experiment. The machine was used to perform numerous bending tests of wings of three species of insects (obtained from a breeding farm): Attacus atlas, Vespa crabro, Libellula Depressa at various air-humidity conditions. Values of the force and displacement obtained in the course of the tests were used to calculate Young’s modulus. In order to do so, it was also necessary to obtain the moment of inertia of the wing cross-section. These values were measured on the basis of the images obtained with a SEM microscope. Obtained results were averaged and presented with a breakdown by air-humidity conditions. It was observed that Young’s modulus decreased with an increase of humidity, hence the calculations of the percentage decrease of this mechanical parameter were performed. Obtained results were compared with the observed structure which was also presented under light microscope. It transpired that the construction of a wing does not only influence the mechanical values but also it influences their susceptibility to the changes occurring in the environment. Thereby, differences between Lepidoptera and Hymenoptera insects were indicated also within the aspect discussed in this paper.

5

Bifurcation anlysis of helicopter non-linear dynamics.

Sibilski Krzysztof

Archive of Mechanical Engineering

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1999

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Vol. XLVI, nr 2

171-192

EN

Non-linear dynamics phenomena have become important for various rotocraft motions. Manoeuvrability of a helicopter in critical flight regimes involves non-linear aerodynamics and inertial coupling. Dynamical systems theory provides a methodology for studying non-linear systems of ordinary defferential equations. Bifurcation theory is a part of that theory which is considering changes in the stability leading to qualitatively defferent responses of the system. These changes are called bifurcations. Several papers can be found in which buffurcation theory has been applied to analyse the equations of motion. In this paper, the author presents a study of the critical flight regimes dynamic of the helicopter. Such dynamics is non-linear and therefore it is evident that bifurcation theory can be used in analysis. The equations of motion used in this investigations assumed an 'individual blade' rotocraft model. Results from dynamical systems theory were used to predict the nature of the instabilities caused by bifurcations and the response of the rotorcraft after a bifurcation was studied.

PL

Równania ruchu śmigłowca są opisane układem silnie nieliniowych równań różniczkowych zwyczajnych. Nieliniowość tych równań pogłębia się w przypadku uwzględnienia nistacjonarności opływu. Teoria bifurkacji bądąca częścią teorii systemów dynamicznych jest doskonałym narzędziem pozwalającym na anlizę nieliniowych zagadnień dynamiki lotu. Szczególnie nadaje się ona do badania zmian stanów stateczności. W pracy przedsatwiono wyniki bifurkacyjnej analizy wybranych granicznych stanów lotu śmigłowca. Do analizy ruchu śmigłowca zastosowano tzw. model 'indywidualnej łopaty'. Przeanalizowano typy występujących bifurkacji i zbadano ruch śmigłowca po wystąpieniu bifurkacji.