Theory of Propellers III is a comprehensive guide to the design and operation of propellers. The book is written by the Langley Aeronautical Laboratory and is based on decades of research and experimentation. It provides a theoretical basis for the design of propellers and includes numerical values for two-blade and four-blade designs. This book is an important resource for anyone interested in aerodynamics or aviation. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.