Devising a technique for descending the illumination elements of aerial vehicles

Abstract

The object of this study is the process of descending illumination elements equipped with a braking device in the form of two-bladed grills rotating in different directions. The classic parachute method does not provide the necessary speed of descent, it has low illumination parameters and significant drift of illumination elements by side wind. To solve the tasks set, mathematical dependences were obtained for calculating the aerodynamic characteristics of the descent device with the illumination element and its delivery to the ejection point. The drag and lift force coefficients during the flow around the blades of a dual-rotor impeller with different Reynolds numbers were determined by the method of numerical modeling based on the ANSYS CFX software package. The optimal geometric characteristics of the profile satisfying the condition for the necessary speed of descent of the illumination element at the given weight of the descent apparatus were determined. Reasonable requirements for illumination parameters and an improved composition of the flare have been proposed. A mathematical model of the movement of a body of variable mass to the point of ejection of the illumination element was built. The new design of the descent device makes it possible to reduce the speed of descent by 10–15 % and increase the weight of the payload by 20–30 %. The proposed illumination composition provides sufficient illumination of the object for 5 minutes with a light intensity of 2–2,5 million candelas and an average diameter of the illuminated area of 2000–2500 m. The mathematical model of the movement of a variable mass body to the point of the illumination element ejection makes it possible to determine with high accuracy the gun firing settings with illumination ammunition (30–40 % more accurate) and the time of ejection of illumination elements. Results of the current research make it possible to solve the scientific problem of ensuring the maximum efficiency of illuminating the terrain at night