Characteristics of Ground Effects of an Unmanned Aerial Vehicle with Medium-aspect-ratio Flying Wings during Take-Off

摘要

With the continuous development of large and heavy-duty unmanned aerial vehicles (UAVs), take-off and landing technology has become a key link restricting its development. In the analysis of take-off and landing performances of UAVs, ground effect is one of the factors that have to be taken into consideration [1,2]. Ground effect refers to the nonlinear complex flow field relationships between the aircraft, the atmosphere, and the ground surface during take-off and landing. The large scale of UAVs with medium-aspect-ratio flying wing configurations strengthens the interaction of UAVs with the ground when taking off: this influences the longitudinal aerodynamic characteristics of UAVs. When the take-off height of UAVs with flying wing configurations is different, the ground effects vary correspondingly, so elevator deflection and take-off velocity of UAVs have to be adjusted according to the changes in ground effect. For UAVs with flying wing configurations that are difficult to be controlled in the longitudinal direction, ground effects exert significant influences on manipulation design for safe take-off, therefore, in view of UAVs with medium-aspect-ratio flying wing configurations, it is necessary to study the characteristics of ground effect during take-off and find accurate relationships between longitudinal aerodynamic characteristics with height from the ground, take-off velocity, and angle of attack.