Hi all Got this Profili program and did a comparison between the NACA 2316 & S8086

Can any one tell me what this chart is telling me !

Kindly
Regards
Erick

It's kinda hard to make out the words on the graphs, but the left one is the Cl vs alpha curve. It plots the coefficient of lift (Cl) at various angles of attack (alpha). More Cl, more lift, but also more drag. The top of the curve, where Cl starts decreasing, is called the stall angle of attack. I think you ran Profili in the inviscid mode, since there isn not a drag curve. There should be an option to run things in viscious mode, this will give you the Cd values; read them the same way Cl is read.

The Cm-alpha graph (coefficient of moment) is also read the same way, but Cm is a different beast entirely. There's another thread that goes into how to use Cm in more detail.

Hope this helps

The Y axis on the left looks like it's Cl/Cd. That would make more sense too with the curve dropping off like that at the stall point.

The part on the right shows the pitching moments relating to the 1/4 chord point. Jumping around zero like it does and only going to low peak values shows that the airfoil is very pitch stable. Not positively stable like a plank flying wing airfoil but these would only need a small stab to be held in control.

As Dan says there should be another option that plots Cl vs Cd for various Reynolds numbers. That tells you more about how the airfoil works at different speeds.