A Post Stall Experimental Study of an Eppler 387 Airfoil at a Reynolds Number of 300,000

Post-stall aerodynamic data is required in the design of Vertical Take Off and Landing (VTOL) aircraft, propellers and wind turbines. However this data is very scarce for low Reynolds number conditions. This study aims to provide low Reynolds number post-stall data for an Eppler 387 (E387) airfoil. It includes lift, drag and moment coefficients at a Reynolds number of 300,000 for -32 deg to 33 deg Angle of Attack (AoA) as well as surface pressure data. The paper investigates the validity of using surface pressure readings to predict lift, drag and moment coefficients in the post-stall regime. This is compared to force measurements as well as wake rake measurements. The method used in this post-stall data investigation is unique and therefore the method will be compared and validated with published sources. It was found that the force and wake rake measurements match the published data better than the surface pressure measurements.