Originally Posted by dave1993
generally anything that promotes separation improves stall. as mentioned my friend had similar results with a row of tiny vortex generators (angled fins) across the top. the more the merrier. i got kf type stall resistance with a simple strip of triangle cross-section placed just in front of Cl. both resulted in considerably more drag than kf and also lacked its wing strength benefit.
Actually anything that 'prevents' separation improves (as in helps delay) stall. Stall is by definition what happens when you have flow separation on the top surface of the wing, so anything that promotes separation also promotes stall.
Vortex generators and turbulators are both devices specifically designed to prevent separation, not promote it. We speculate that KF steps might have a similar effect at low Re numbers but that's as yet unproven.