Can any one explain how to draw a leading edge circle of an aerofoil.

danny2010

Can any one explain how to draw a leading edge circle of an aerofoil. Where is the center and what is the radius of the leading edge circle

mugaliens

It's not a circle. Most model leading edges made of balsa are parabolas, but some are elliptical. In the real world, they're shaped in accordance with whatever airfoil is being used.

boneh3ad

However, at some point on the LE the radius will be a minimum, at which point you COULD calculate a radius of curvature at that point and draw the radius inward normal to that point and make a circle.

mugaliens

And oops! NACA airfoils do indeed have a "nose circle."

boneh3ad

Right. Nose radius is an incredibly important parameter for certain parts of airfoil design, especially if you are talking supersonic airfoils or airfoils meant to stay laminar as long as possible.

danny2010

Thanx for trying to help me.....but i still have a doubt, where will one plot the center and draw the leading edge circle. !!!

boneh3ad

The center will be one nose radius say from the point of minimum radius of curvature on the LE. It will be in the direction inward normal to the surface at said point.

If you have the airfoil coordinates you can find the radius of curvature at any of those points. If it is a NACA airfoil you can definitely find those coordinates somewhere.