BudE wrote:

> Folks, not everyone knows as much about this stuff as you guys. What is
> "CD"?

Cd (the d is a subscript on the C) represents the coefficient of drag.
It is a dimensionless value that is related primarily to the shape of an
object and the influence of the shape on the drag of the object. To get
total drag you need a few other parameters such as the frontal area of
the object, etc.

For more than you'll ever probably want to know...

http://www.grc.nasa.gov/WWW/K-12/airplane/dragco.html

Matt