Leishman begins with the fundamentals: how a helicopter generates lift. Using , the rotor is modeled as an "actuator disk" that creates a pressure jump to accelerate air downward (induced flow).

J. Gordon Leishman’s Principles of Helicopter Aerodynamics is widely considered the "gold standard" textbook for aerospace engineers, rotorcraft pilots, and students. It bridges the gap between basic fluid mechanics and the complex, unsteady aerodynamic environment unique to rotary-wing aircraft.

On the "retreating side," the blade moves slower relative to the air, requiring a high angle of attack to maintain lift until it eventually stalls.