DRAG REDUCTION OF SEPARATE LIFT THRUST (SLT) VERTICAL TAKE-OFF AND LAND (VTOL) COMPONENTS

Abstract

Vertical take-off and land (VTOL) is a new technology in the unmanned aerial vehicle (UAV) field. Separate lift and thrust (SLT) is identified as the most simplistic design of VTOL UAVs. However, during the forward cruising flight phase, the VTOL component of the UAV will increase the drag. Therefore, the objective of this work is to reduce the drag effect on inactive propulsion system. In order to reduce the drag, several motor fairings and aerodynamic shaft samples was designed and the best design was selected. Each sample was simulated using computational fluid dynamics (CFD) simulation to examine the aerodynamic properties of the design. Subsequently, the samples were tested in a wind tunnel facility to measure the resultant drag. Then, the drag reduction of the designs was analysed and compared to the original design. Based on the results, the most effective design combination was selected to replace the off-the-shelf design. The findings from this work show that the V3.0 motor fairing and forward swept aerodynamic shaft design have the highest drag reduction.
The V3.0 motor fairing design has 14.9% drag reduction, while forward swept aerodynamic shaft design has drag reduction up to 25.4%. Therefore, these two designs have been selected to replace the off-the-shelf motor holder and shaft.
Keywords: Unmanned aerial vehicles (UAV); vertical take-off and lift (VTOL); drag; motor fairing;
aerodynamic shaft.

Description