AiMT Volume 13 (2018), Issue 2

Statistics of Ejections in Military Jet Aircraft in Czechoslovakia and the Czech Republic

O. Zavila

The article deals with the statistics of aviation accidents associated with the ejection of the crew in military jet fighter, fighter-trainer and trainer aircraft in the service of Czechoslovakia and the Czech Republic from 1948 until the end of 2016. It presents a unique, previously unpublished comprehensive overview of aviation accidents (disasters, air crashes and damage) in which the crew ejected, as well as a critical analysis of types of events involved, date of their origin, type and version of the aircraft and also the number of killed and rescued crew members. The figures are accompanied by numerous annotations and an overview of still accessible reference and information sources on the subject.

Keywords: Army of the Czech Republic, Czechoslovak People’s Army, ejection, aviation accident, jet fighter, statistics.

Pages: 141–156  [References]   [Download Citation]

State of the Art and Problems of Defeat of Low, Slow and Small Unmanned Aerial Vehicles

A. Dudush, V. Tyutyunnik, I. Trofymov, S. Bortnovs’kiy and S. Bondarenko

The article deals with one of the most intensively developing threats for civilian and military spheres – hostile use of Low, Slow and Small Unmanned Aerial Vehicles (LSS UAVs). The classification of the LSS UAVs is given. The existing threats of using LSS UAVs are divided into three categories. Special attention is paid to the third category of threats, the main feature of which is a high level of training of the operator. Main advantages and drawbacks of LSS UAVs are considered. It is determined that the best strategy is to employ a hierarchy of countermeasures including regulatory countermeasures (prevention, deterrence, denial), passive countermeasures (detection and interruption) and active countermeasures (destruction). State of the art and current problems of possible countermeasures are analysed. The most promising LSS UAVs’ counteraction technologies are described. Most attention is paid to specialized sensors and modern active counteraction means, such as programmable air burst munition and high-energy laser systems.

Keywords: Low, Slow and Small Unmanned Aerial Vehicles (LSS UAVs), LSS UAVs classification, threats categories of using LSS UAVs, advantages and weak sides of LSS UAVs, hierarchy of countermeasures.

Pages: 157–171  [References]   [Download Citation]

Dynamic Lift and Vortex Breakdown during an Unsteady Flow over a Pitching Airfoil

A. Svoboda and D. Rozehnal

Computational fluid dynamics techniques are used to give a detailed insight into unsteady phenomena taking place in the vicinity of a pitching airfoil. The vortex formation and breakdown are analyzed using the time history of pressure distribution, vorticity and injected massless particle trajectories. Different cases of flows are modeled to determine the effect of reduced frequency on unsteady lift. Finally, a comparison of lift coefficients for steady and unsteady cases is provided.

Keywords: unsteady aerodynamics, dynamic lift, vortex, pitching, airfoil, NACA 0012, CFD.

Pages: 173–183  [References]   [Download Citation]

Automatic Evaluation of Spatial Disorientation

P. Frantis and A. Petru

The paper discusses the automated detection of spatial disorientation from recorded flight data. The first part of the paper briefly introduces middle ear function and its influence on spatial disorientation. The specially developed simulator and aerodrome manoeuvre flown by the pilot during the experiment is also mentioned. The second part of the paper analyses the recorded data from experimental flights and proposes an algorithm for the automatic evaluation of spatial disorientation. An example graphical interpretation of the recorded data is provided with a clear explanation of the important parameters. At the end of the paper, the most important conclusions of the work are presented.

Keywords: flight illusion, detection, simulator, spatial disorientation.

Pages: 185–192  [References]   [Download Citation]

Real-time Optimal Control of Multi-wheeled Combat Vehicles – using Artificial Neural Network and Potential Fields

A. Mohamed, M. EI-Gindy, X. Huang, J. Ren and H. Lang

This paper presents a real-time path planning algorithm for autonomous multi-wheeled combat vehicles using Artificial Neural Network (ANN), Artificial Potential Fields (APFs) and optimal control theory. Real-time navigation of autonomous vehicles is a very complex problem and it is crucial for many military operations. This paper proposes an optimal control and ANN approach for a dynamic model of the multi-wheeled combat vehicle to generate the possible optimal paths that cover every part of the workspace.

Consequently, the obtained paths are used to train the proposed ANN model. The trained ANN has the capability to control the movement of combat vehicle in real time from any starting point to the desired goal position within the area of interest. The vehicle path is autonomously generated from the previous vehicle location parameter in terms of lateral velocity, heading angle and yaw rate of the vehicle. APF is proposed for preventing the vehicle from colliding with obstacles in border destination. The effectiveness and efficiency of the proposed approach are demonstrated in the simulation results, which show that the proposed ANN model is capable of navigating the multi-wheeled combat vehicle in real time.

Keywords: real-time, optimal control theory, path planning, autonomous multi-wheeled combat vehicle, Artificial Neural Network, artificial potential fields.

Pages: 193–207  [References]   [Download Citation]