NACELLE STRAKE DESIGN FOR A SHORT TAKE-OFF AND LANDING CONFIGURATION WITH TURBOPROPS

The scope of the presentation is to discuss the integration effects of turboprop nacelles on a high-lift wing with an internally blowing plain flap system with Reynolds-Averaged-Navier-Stokes computations. It is shown that the resulting nacelle vortices can significantly reduce the maximum angle of attack and maximum lift coefficient at zero thrust conditions. In order to limit the negative impact, an inboard nacelle strake was designed with the aim of maximizing the lift coefficient of the landing configuration at zero thrust. To reach this goal, a sensitivity study on basic geometric strake parameters was carried out. The best nacelle strake is able to improve the maximum lift coefficient by 17 lift counts and the maximum angle of attack by three degrees. The study also revealed further potential of improvement due to an outboard strake. Using an outboard strake, which is not properly designed but simply mirrored from the inboard one leads to an additional improvement of 13 lift counts and 4 degrees in maximum angle of attack. Furthermore, it is shown that the installation of an inboard strake does not negatively impact the high-lift performance at a moderate thrust level.