Simulation reconstruction of the pilot ejection process using the K-36DM ejection seat

The article discusses the method of reconstructing the ejection process. Measurement data were obtained during field tests on an actual object. These data served as the basis for validating the mathematical model of the seat-pilot system’s motion. This model describes the spatial motion of the K-36DM ejection seat. The article includes a description of the mathematical model and a comparison of the measured motion parameters with the calculation results. It also presents computed parameters that were not recorded during the tests. Particular attention was paid to the reconstruction of the flight trajectory and seat rotation and the determination of the G-forces acting on the pilot. The primary objective of the research was to develop a mathematical model of the pilot ejection process using the K-36DM ejection seat. In addition to classical equations of motion, such as linear motion of the seat along the guide rails and motion of the seat along the rails with rotation around the lower pair of rollers, the model also considered the free motion of the seat-autopilot system, taking into account the forces acting on the seat-autopilot system. In this work, four phases of the chair movement were modeled, i.e. phase 1: After activation of the first pyrotechnic charge, the seat moves in a straight line along the guide rails until the two upper pairs of rollers disengage from the rails; phase 2: The seat continues moving along the guide rails using the lower pair of rollers until it exits the cockpit. Simultaneously, the seat begins to rotate relative to this pair of rollers; phase 3: The seat moves through the air; initially, it is propelled by the second pyrotechnic charge, providing the necessary flight altitude; phase 4: The pilot separates from the seat and descends under a parachute.