What are the two main sources of energy for the earth? one of them is the sunwhat are the two main sources of energy for the earth? one of them is the sun follow 3 answers 3 report abuse are you sure you want to delete this answer? yes no

The ratio of lift to drag l/d for a wing or airfoil is an important aerodynamic parameter, indeed, it is a direct measure of the aerodynamic efficiency of the wing. if a wing is pitched through a range of angle of attack, l/d first increases, then goes through a maximum, and then decreases. consider an infinite wing with an naca 2412 airfoil. estimate the maximum value of l/d. assume that the reynolds number is 9x10^6.