How does changing thickness effect airfoil characteristics?

[Joel K. Scholz]

I am designing a plane that I would like to use a JT-88 airfoil on, but want a faster and thinner foil. I am looking at reducing thickness to around 80% of the original. Will this greatly effect the characteristics of this airfoil. It has great lift and is almost stall proof even at low speeds.:confused:

[antani]

Joel,

changing the thickness of the airfoil will give you a different airfoil, i.e. not a JT-88 anymore. The performance can vary quite a bit (how much I can't tell, I am not familiar with that airoifl), even though the airfoil would look "like" the original.
If you know the characteristics of the airfoil you want, I would suggest searching online airfoil databases (UIUC has a rather large one) for an airfoil that matches your requirements (or at least comes close).

[Sparky Paul]

If you observe the characteristics of an airfoil family... NACA 24xx for instance, not much changes with thickness. Slightly more drag, higher alphas, etc, but the basic stuff doesn't alter much.
You can expect a higher speed, and higher stall speed ...

[DLC]

Try Profili2 (www.profili2.com) It will let you change thickness, and other parameters of an airfoil, then compute drag polars, lift coefficient curves, etc. (using Xfoil I believe) and make comparisons.