Abstract
Wing design has a critical
importance for sailplanes as well as for all the aircrafts in terms of
aerodynamic performance. One of the important design phases of an
aerodynamically efficient sailplane wing is selection of the appropriate
airfoil. Airfoil selection of a wing design firstly requires performing
aerodynamic performance analyses of different airfoils to compare according to
determined requirements. In this study, numerical investigation of nine
different airfoils was performed with the aim of comparison in terms of
aerodynamic performance of sailplanes by using the general public licensed
computer program XFLR5. Firstly, the airfoils which will be compared were
selected from Eppler, Goettingen, NACA and Wortmann airfoil families. For the
comparison of the airfoils, the two-dimensional analysis validation of the
program was done with experimental data, and the airfoils were analyzed in two
dimensions under the same validated analysis conditions. The analyses were
performed at 2x105 Reynolds number and angle of attacks from -5 to
20 degrees. According to obtained results from the analyses, the airfoils were
compared in terms of determined criteria which are thickness, maximum lift
coefficient and its angle of attack, maximum drag to lift ratio, drag
coefficient at maximum lift condition, pitching moment at zero lift condition and
power factor.