A Laboratory Investigation of the Probable Mechanisms of the Action of an Artificial Thunderstorm Cell on Model Aircraft Radomes

The results of experimental laboratory investigations of possible mechanisms of the impact of lightning and thunderclouds on aircraft radomes and equipment inside them are presented. An artificial thunderstorm cell of negative polarity and model aircraft radomes with lightning diverter strips have been used. Experiments have shown that the discharge processes in a radome model significantly depend on the magnitude of the charge that accumulates on the inner and outer surfaces of the radome shell. It is established that the accumulation of large-magnitude charges of different signs on the outer and/or inner surface of the radome (up to hundreds of µC/m2) shell leads to a multivariance of the mechanisms of development of discharge processes inside the radome model, along its surface, and in the space near it. Significant influence of the “reverse” discharge from the antenna model under the radome on the types of current impulses recorded on the antennas under impact of the artificial thunderstorm cell is established. Peculiarities of the discharge formation in the radome model when using solid and segmented diverter strips for its protection are revealed. Parameters of the current impulses registered on the diverter strips and the antennas have been determined. Based on the conducted research, the possible mechanisms of the impact of thunderclouds and lightning discharges on radio-transparent aircraft radomes and the equipment inside them are considered.

Reinforcement learning-based radar-evasive path planning: a comparative analysis

This paper discusses the utilisation of deep reinforcement learning algorithms to obtain optimal paths for an aircraft to avoid or minimise radar detection and tracking. A modular approach is adopted to formulate the problem, including the aircraft kinematics model, aircraft radar cross-section model and radar tracking model. A virtual environment is designed for single and multiple radar cases to obtain optimal paths. The optimal trajectories are generated through deep reinforcement learning in this study. Specifically, three algorithms, namely deep deterministic policy gradient, trust region policy optimisation and proximal policy optimisation, are used to find optimal paths for five test cases. The comparison is carried out based on six performance indicators. The investigation proves the importance of these reinforcement learning algorithms in optimal path planning. The results indicate that the proximal policy optimisation approach performed better for optimal paths in general.

Sistem Kontrol Pesawat Tanpa Awak Untuk Menentukan Waypoint Berbasis Ardupilot

An unmanned Aerial Vehicle (UAV) is a type of unmanned aerial vehicle which is controlled by a remote system. This type of aircraft is usually controlled by remote control from outside the plane and can also move automatically based on a program that has been programmed on the computer system. In this study, a control system with autopilot and remote control is used. This study aims to apply the ardupilot system to the super heavy model aircraft with a long-range flight mode control system using the Futaba T8J (8 channel) radio control. The results of this study took a flight time of 15.02 minutes with an altitude of 30 meters, a waypoint radius of 20 meters with a speed of 10 m / s.

The Things of Life

This book is a social and cultural history of material objects and spaces during the late socialist era. It traces the biographies of Soviet things, examining how the material world of the late Soviet period influenced Soviet people's gender roles, habitual choices, social trajectories, and imaginary aspirations. Instead of seeing political structures and discursive frameworks as the only mechanisms for shaping Soviet citizens, the book explores how Soviet people used objects and spaces to substantiate their individual and collective selves. In doing so, the author rediscovers what helped Soviet citizens make sense of their selves and the world around them, ranging from space rockets and model aircraft to heritage buildings, and from home gyms to the hallways and basements of post-Stalinist housing. Through these various materialist fascinations, the book considers the ways in which many Soviet people subverted the efforts of the Communist regime to transform them into a rationally organized, disciplined, and easily controllable community. The book argues that late Soviet materiality had an immense impact on the organization of the Soviet historical and spatial imagination. The book's approach also makes clear the ways in which the Soviet self was an integral part of the global experience of modernity rather than simply an outcome of Communist propaganda. Through its focus on materiality and personhood, the book expands our understanding of what made Soviet people and society “Soviet.”

The New Ju-Ju: Ijo Masquerades and the Office of War Information in Second World War Nigeria

In May and June 1943, a photographer with the American Office of War Information (OWI) photographed West African men who he identified as ‘witch doctors’ engaging in masquerade dances dedicated to water spirits. However, rather than the typical aquatic-themed headgear, these ‘witch doctors’ wore model planes – reproductions of British, French, and American aircraft. The photographs and their captions constructed a narrative of a ‘new ju-ju’, in which an indigenous community incorporated model aircraft into their traditional masquerades in order to reflect upon and support the power of Allied armies, which had supplanted their previous notions of spiritual power. However, despite their absurd and over-contrived captions, these photos were never published, demonstrating that the narrative of ‘new ju-ju’ was too complex to fit within the standard propagandistic narrative of widespread Allied support. This fascinating story provides insight into how indigenous communities in Nigeria coped with massive societal changes throughout the Second World War period, reveals the constructed narratives of American wartime propaganda, and, overall, demonstrates the uncontrollable nature of photographs as sources that insist upon revealing distinctive forms of agency and telling their own stories.

Rapid computation of rotary derivatives for subsonic and low transonic flows

Purpose The purpose of this paper is to develop a new approach for rapid computation of subsonic and low-transonic rotary derivatives with the available steady solutions obtained by Euler computational fluid dynamics (CFD) codes. Design/methodology/approach The approach is achieved by the perturbation on the steady-state pressure of Euler CFD codes. The resulting perturbation relation is established at a reference Mach number between rotary derivatives and normal velocity on surface due to angular velocity. The solution of the reference Mach number is generated technically by Prandtl–Glauert compressibility correction based on any Mach number of interest under the assumption of simple strip theory. Rotary derivatives of any Mach number of interest are then inversely predicted by the Prandtl–Glauert rule based on the reference Mach number aforementioned. Findings The resulting method has been verified for three typical different cases of the Basic Finner Reference Projectile, the Standard Dynamics Model Aircraft and the Orion Crew Module. In comparison with the original perturbation method, the performance at subsonic and low-transonic Mach numbers has significantly improved with satisfactory accuracy for most design efforts. Originality/value The approach presented is verified to be an efficient way for computation of subsonic and low-transonic rotary derivatives, which are performed almost at the same time as an accounting solution of steady Euler equations.

Imaginary Machines

This chapter argues that about half of the Nobel Prize winners have engaged primarily in the building of intellectual constructs, imaginary machines, or simply ‘models’. This term should be understood as in ‘model aircraft’. Unlike model aircraft, economic models mostly remain on paper, usually in the form of mathematical equations, but mechanical analogues can be constructed. The Phillips MONIAC hydraulic computer, for instance, simulated the circular flow of money in the economy by means of coloured water in glass pipes, with valves which permitted policy choices to be simulated. Hence, the chapter shows that even economic literature is largely speculative, involving ‘an apparently inconclusive exploration of possible worlds’.