Reducing aircraft stall speed using retrofit vortex generators

The speed at which firefighting aircraft release their payload is a critical factor in the effectiveness of their use. This paper presents the initial results of an investigation into applying low profile vortex generators to existing Air Tractor AT802F firefighting aircraft as a low-cost retrofit to reduce the stall speed and thus improving their firefighting effectiveness. A CFD analysis was conducted to determine the effect of different vortex generator. This paper presents a baseline CFD model of the unmodified wing, comparing the results to standard airfoil data and the maximum lift coefficient of the real aircraft. The model shows good agreement with the real aircraft, as the maximum lift coefficient found is within 2.5% of the real value. This paper discusses the importance of low speed flight for firefighting and reviews the range of vortex generators designs and arrangement with respect to increasing maximum lift. A qualitative CFD analysis of an airfoil with a pair of vortex generators was conducted, showing the capacity for CFD to show the expected flow characteristics.