Yvan Tondji - Academia.edu (original) (raw)

Papers by Yvan Tondji

INCAS BULLETIN

The increased number of accidents in general aviation due to loss of aircraft control has necessi... more The increased number of accidents in general aviation due to loss of aircraft control has necessitated the development of accurate aerodynamic airplane models. These models should indicate the linear variations of aerodynamic coefficients in steady flight and the highly nonlinear variations of the aerodynamic coefficients due to stall and post-stall conditions. This paper presents a detailed methodology to model the lift, drag, and pitching moment aerodynamic coefficients in the stall regime, using Neural Networks (NN). A system identification technique was used to develop aerodynamic coefficients models from flight data. These data were gathered from a level-D Research Aircraft Flight Simulator (RAFS) that was used to execute the stall maneuvers. Multilayer Perceptrons and Recurrent Neural Networks were used to learn from flight data and find correlations between aerodynamic coefficients and flight parameters. This methodology is employed in here to optimize neural network structur...

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As part of a morphing wing technology project, the flutter analysis of two finite element models ... more As part of a morphing wing technology project, the flutter analysis of two finite element models and the experimental results of a morphing wing demonstrator equipped with aileron are presented. The finite element models are representing a wing section situated at the tip of the wing; the first model corresponds to a traditional aluminium upper surface skin of constant thickness and the second model corresponds to a composite optimized upper surface skin for morphing capabilities. The two models were analyzed for flutter occurrence and effects on the aeroelastic behaviour of the wing were studied by replacing the aluminium upper surface skin of the wing with a specially developed composite version. The morphing wing model with composite upper surface was manufactured and fitted with three accelerometers to record the amplitudes and frequencies during tests at the subsonic wind tunnel facility at the National Research Council. The results presented showed that no aeroelastic phenomen...

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The Aeronautical Journal, 2018

ABSTRACTA new wing-tip concept with morphing upper surface and interchangeable conventional and m... more ABSTRACTA new wing-tip concept with morphing upper surface and interchangeable conventional and morphing ailerons was designed, manufactured, bench and wind-tunnel tested. The development of this wing-tip model was performed in the frame of an international CRIAQ project, and the purpose was to demonstrate the wing upper surface and aileron morphing capabilities in improving the wing-tip aerodynamic performances. During numerical optimisation with ‘in-house’ genetic algorithm software, and during wind-tunnel experimental tests, it was demonstrated that the air-flow laminarity over the wing skin was promoted, and the laminar flow was extended with up to 9% of the chord. Drag coefficient reduction of up to 9% was obtained when the morphing aileron was introduced.

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Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering

A morphing wing can improve the aircraft aerodynamic performance by changing the wing airfoil dep... more A morphing wing can improve the aircraft aerodynamic performance by changing the wing airfoil depending on the flight conditions. In this paper, a new control methodology is presented for a morphing wing demonstrator tested in a subsonic wind tunnel in the open-loop configuration. Actuators integrated inside the wing are used to modify the flexible structure, which is an integral part of the wing. In this project, the actuators are made in-house and controlled with logic control, which is developed within the main frame of this work. The characterization of the flow (laminar or turbulent) over the wing is obtained starting from the pressure signals measured over the flexible part of the wing (upper surface). The signals are acquired by using some pressure sensors (Kulite sensors) incorporated in this flexible part of the wing upper surface. The technique used to collect Kulite pressure data and the post-processing methodology are explained. The recorded pressure data are sometimes s...

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AIAA SCITECH 2022 Forum

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2016 International Conference on Unmanned Aircraft Systems (ICUAS), 2016

This article presents a structural analysis of the Unmanned Aerial System UAS-S4 ETHECATL. The ma... more This article presents a structural analysis of the Unmanned Aerial System UAS-S4 ETHECATL. The mass and the center of gravity position are numerically determined and further experimentally verified using the “pendulum method”. The numerical estimations are computed through Raymer statistical-empirical method coupled with mechanical calculations. The mass of the UAS-S4 component are estimated according to their sizes and the UAS-S4 class, by the means of Raymer statistical equations. The UAS-S4 geometry is also decomposed in several geometrical figures, which centers of gravity are individually computed, weighted, and then arithmetically averaged to find the whole UAS-S4 center of gravity. The mass of the UAS-S4 is experimentally determined using two scales. Its center of gravity coordinates are found using the pendulum method. The equilibrium of the pendulum is studied, by including the UAS-S4, the table used to support it and the additional mass used to unbalance it. To determine t...

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55th AIAA Aerospace Sciences Meeting, 2017

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INCAS BULLETIN

The increased number of accidents in general aviation due to loss of aircraft control has necessi... more The increased number of accidents in general aviation due to loss of aircraft control has necessitated the development of accurate aerodynamic airplane models. These models should indicate the linear variations of aerodynamic coefficients in steady flight and the highly nonlinear variations of the aerodynamic coefficients due to stall and post-stall conditions. This paper presents a detailed methodology to model the lift, drag, and pitching moment aerodynamic coefficients in the stall regime, using Neural Networks (NN). A system identification technique was used to develop aerodynamic coefficients models from flight data. These data were gathered from a level-D Research Aircraft Flight Simulator (RAFS) that was used to execute the stall maneuvers. Multilayer Perceptrons and Recurrent Neural Networks were used to learn from flight data and find correlations between aerodynamic coefficients and flight parameters. This methodology is employed in here to optimize neural network structur...

Bookmarks Related papers MentionsView impact

As part of a morphing wing technology project, the flutter analysis of two finite element models ... more As part of a morphing wing technology project, the flutter analysis of two finite element models and the experimental results of a morphing wing demonstrator equipped with aileron are presented. The finite element models are representing a wing section situated at the tip of the wing; the first model corresponds to a traditional aluminium upper surface skin of constant thickness and the second model corresponds to a composite optimized upper surface skin for morphing capabilities. The two models were analyzed for flutter occurrence and effects on the aeroelastic behaviour of the wing were studied by replacing the aluminium upper surface skin of the wing with a specially developed composite version. The morphing wing model with composite upper surface was manufactured and fitted with three accelerometers to record the amplitudes and frequencies during tests at the subsonic wind tunnel facility at the National Research Council. The results presented showed that no aeroelastic phenomen...

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The Aeronautical Journal, 2018

ABSTRACTA new wing-tip concept with morphing upper surface and interchangeable conventional and m... more ABSTRACTA new wing-tip concept with morphing upper surface and interchangeable conventional and morphing ailerons was designed, manufactured, bench and wind-tunnel tested. The development of this wing-tip model was performed in the frame of an international CRIAQ project, and the purpose was to demonstrate the wing upper surface and aileron morphing capabilities in improving the wing-tip aerodynamic performances. During numerical optimisation with ‘in-house’ genetic algorithm software, and during wind-tunnel experimental tests, it was demonstrated that the air-flow laminarity over the wing skin was promoted, and the laminar flow was extended with up to 9% of the chord. Drag coefficient reduction of up to 9% was obtained when the morphing aileron was introduced.

Bookmarks Related papers MentionsView impact

Bookmarks Related papers MentionsView impact

Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering

A morphing wing can improve the aircraft aerodynamic performance by changing the wing airfoil dep... more A morphing wing can improve the aircraft aerodynamic performance by changing the wing airfoil depending on the flight conditions. In this paper, a new control methodology is presented for a morphing wing demonstrator tested in a subsonic wind tunnel in the open-loop configuration. Actuators integrated inside the wing are used to modify the flexible structure, which is an integral part of the wing. In this project, the actuators are made in-house and controlled with logic control, which is developed within the main frame of this work. The characterization of the flow (laminar or turbulent) over the wing is obtained starting from the pressure signals measured over the flexible part of the wing (upper surface). The signals are acquired by using some pressure sensors (Kulite sensors) incorporated in this flexible part of the wing upper surface. The technique used to collect Kulite pressure data and the post-processing methodology are explained. The recorded pressure data are sometimes s...

Bookmarks Related papers MentionsView impact

AIAA SCITECH 2022 Forum

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2016 International Conference on Unmanned Aircraft Systems (ICUAS), 2016

This article presents a structural analysis of the Unmanned Aerial System UAS-S4 ETHECATL. The ma... more This article presents a structural analysis of the Unmanned Aerial System UAS-S4 ETHECATL. The mass and the center of gravity position are numerically determined and further experimentally verified using the “pendulum method”. The numerical estimations are computed through Raymer statistical-empirical method coupled with mechanical calculations. The mass of the UAS-S4 component are estimated according to their sizes and the UAS-S4 class, by the means of Raymer statistical equations. The UAS-S4 geometry is also decomposed in several geometrical figures, which centers of gravity are individually computed, weighted, and then arithmetically averaged to find the whole UAS-S4 center of gravity. The mass of the UAS-S4 is experimentally determined using two scales. Its center of gravity coordinates are found using the pendulum method. The equilibrium of the pendulum is studied, by including the UAS-S4, the table used to support it and the additional mass used to unbalance it. To determine t...

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55th AIAA Aerospace Sciences Meeting, 2017

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