The Influence of Terrain Obstacle Geometry on Aircraft Suspension System Dynamics

Abstract

This paper presents the measurement method and experimental results of a study investigating the effect of terrain obstacle geometry on the aircraft suspension system dynamics. Three different models of terrain obstacle geometry were tested: rectangular, triangular and semi-circular, each model having the same dimensions of 300×150×50mm. Experiments were conducted using the GOM PONTOS measuring system, which made it possible to perform a dynamic analysis of the suspension system of a Cessna 152 during passing over the above variable-geometry obstacles. All experiments were conducted for three takeoff runs of 1200, 1800 and 2700 millimetres for each terrain obstacle model, respectively. The study investigated the dynamic parameters of three crucial structural elements of the aircraft's suspension system: strut, fuselage and wheel centre, for which accelerations and velocities were measured when the aircraft was passing over the obstacles. The obtained test results indicate that the velocities $v$ of characteristic measurement points related to selected structural elements of the aircraft (fuselage, wheel, strut) vary in the range of 1.1-2.56 m/s when passing through various obstacles with different approach speeds (run-up speed). The acceleration values $\alpha$ change accordingly in the range 20–58 m/s2.