Often available as a PDF for academic use via Cambridge University Press or through libraries on Archive.org .
Gordon P. Leishman (Former Professor of Aerospace Engineering, University of Maryland) Subject: Rotorcraft Aerodynamics / Helicopter Physics Commonly Sought As: "Leishman PDF," "Principles of Helicopter Aerodynamics PDF top" Often available as a PDF for academic use
Using different shapes along the blade span to handle different airspeeds. Often available as a PDF for academic use