The lift coefficient for a flat plate at low angles of attack is obtained experimentally for various aspect ratios (AR
¼ 1, 2, 4, 8) and moderate Reynolds numbers (Re ¼ 40 103 to Re ¼ 200 103). The variation of the lift
coefficient with the angle of attack in the pre-stall region is consistent with a linear slope approximation. We
consider that this slope is a function of both the aspect ratio and Reynolds number. In this research, we provide a
correlation that can predict the lift slope value with an average error of less than 5%. This correlation captures the
idea of Prandtl’s finite wing theory and extends its application for any Reynolds number. The same correlation is
tested against other literature experiments providing very accurate results even outside our range of measured AR
and Re.
