Pressure distribution on wings in reversed flow

The series of pressure distribution measurements at three test sections on NACA airfoils 2212 and M6 within 170 to 210 angles of attack in reversed flow proved to be largely independent of the profile form. In contradiction to the pressure distribution in normal flow considerable negative pressure from the upper surface spills over onto the lower surface, and vice versa, even in the zone of sound flow. The results are presented as chord-wise pressure and load distribution. The spanwise lift distribution and the total lift coefficients of the wing obtained by integration manifest approximate agreement with the behavior of a diagonally disposed flat plate. By consideration of the ground effect (represented by a flat wall) the lower surface of the wing shows an increase in the low pressure.