Category FLUID-DYNAMIC LIFT

The task of completing this book was undertake n to fulfil an important technical need, as did the book, “Fluid-Dynamic Drag”. Upon reviewing the available material and notes of the late Dr. Hoerner on the subject of lift, we felt that his valuable and extensive work should be made available to the engineering community.

In working with Dr. Hoerner’s data, we have considered and incorporated recent technological advances and developments. In compiling and completing his work we have attempted to maintain his standards and technical excellence. His notes, completed chapters and extensive library provided the basic material needed to do this, and also have helped to preserve his ideas and expertise. Although considerable work had been done on the subject by Dr. Hoerner extensive studies and analysis were necessary to meld the vast store of material into a complete and useful book.

This book has been written for both the practicing engineer and the student. It is designed so that the physical aspects of the problem can be understood as wed as to provide solutions. The book is not just a collection of data but brings together and integrates the material to form as complete a picture as possible. The many sources of data used are given to provide material for any desired expanded studies.

Many people have cooperated in providing new sources of data for this book, including the many scientists of NA$A. Without their extensive help this book could not have been completed in its present form. We also want to thank Mrs. Hoerner for giving us the opportunity to complete the work of her late husband on the subject and for making available his extensive library, notes and data. Special thanks are also given to Mr. Ralph C. Cooper of the Office of Naval Research for his support in the final consummation of this work.

Although the basic and underlying work of the late Dr. Hoerner on fluid dynamic lift was done over a period of many years, the remaining chapters were written and the final review was completed during the last two years, к is hoped that this book fills an existing technical gap and will be useful over many years as an engineering resource.

Wayne, Pennsylvania

June, 1975 Henry V. Borst

This 1985 second edition differs from the proceeding one as follows: a number of mis­prints and some errors have been eliminated. New material has been added on cascade flow in Chapter II and in Chapter III new data on winglets and endplates. The improve­ments possible in section maximum lift with small changes in the upper surface contour are given in Chapter IV. Also in Chapter XII the theoretical characteristics of ducted fans has been expanded along with the effect of rotation on blade section characteristics.

Wayne, Pennsylvania

April 1985 Henry V. Borst

THE CO-AUTHOR graduated in aeronautical engineering from Rensselaer Polytechnic Institute in Troy, New York. He worked for the Curtiss Wright Corporation on research projects for many years and became Chief of Aerodynamics. During this time advanced work on propulsion systems was done and two new VTOL aircraft were developed, the X-100 and the X-19 for which he holds the basic patent. Later he joined the Vertol Division of the Boeing Company becoming Director of Preliminary Design. During his career he has written many technical papers of aerodynamics. He now heads the Henry V. Borst and Associates of Wayne, Pennsylvania, aeronautical consultants to government and industry.

Between the years of 1945 and 1950, the author consolidated his aerodynamic experience (since 1930) as a researcher, wind-tunnel experimenter, designer and as a pilot (in organizations such as Junkers and Messerschmitt) by writing “Aerodynamic Drag”. After augmenting his knowledge through the numerous publications pouring out after that time, he then wrote and published “Fluid-Dynamic Drag” (1958), second edition 1965. On the basis of this book he was asked by the U. S. Navy’s Office of Naval Research, whether he could and would write a text on “lift”. Thus encouraged and aided by Contract Nonr-3196(00), the author set out writing “Fluid-Dynamic Lift”.

The number of available publications and technical reports dealing with aerodynamic lift, may now be between 10 and 20,000. It soon became obvious that not all of these could be evaluated. To reduce the amount of effort and complexity, the author restricted the subject to subsonic speeds. Even then, it was found impossible to study all of the remaining, say 10,000 sources of information. However, not all of the published information is worth reading. Possibly 50% of it is obsolete, unnecessary, repetitious, and some of it is misleading. If the author did not use all of the useful results available, there is a point of view given as advice by the late Hugo Junkers to his engineers. He told them, when studying and developing something new, not to look up what others had done and found in the same field. New ideas, aspects and conclusions may thus be reached, without interference by premature and/or erroneous judgements by others. The best way of using existing information seems to be to take indisputable facts, and to explain and accept them in spite of conclusions and theoretical indications to the contrary. To be sure, it is the author’s intent to find the “truth” about the many aspects of fluid-dynamic lift. However, as a French research professor (Ourisson, Ecole Normale Superieure in Paris) has said, “the search for truth is influenced by one’s idea of what the truth must be”. In this respect, the author never accepts what theory says it “must” be. Emphasis is placed upon the deviations from theoretical predictions, although any theoretical analysis is gratefully used as soon as it consistently agrees with experimental results. In particular, theory can thus be used to extrapolate available statistical data.

After completion of* this text, the author wishes to thank and/or to acknowledge the help of those, without whom the book could not have been written; among them Cdr. H. B. Keller and Mr. Ralph C. Cooper of the Office of Naval Research, Mr. G. L. Desmond at the Bureau of Weapons, the Office of Scientific Research of the U. S. Air Force, the NACA or NASA (where most of the technical reports came from) and the librarians of the American Institute of Aeronautics and Astronautices.

S. Hardy F. Hoerner

New York City January 1967

THE AUTHOR studied mechanical engineering at the Institute of Technology in Miin- chen (Dipl. Ing.), he earned a degree as Dr.-Ing. in aerodynamics at the Institute of Technology in Braunschweig, and he obtained a degree as Dr.-Ing. habil. from the TH Berlin. He served at one time as research assistant at the Deutsche Versuchsanstalt fur Luftfahrt (DVL, near Berlin), as aerodynamicist in the Fieseler Corporation (working on the first STOL airplane, the "Stork”) and later for a time as head of design aerody­namics in the Junkers A. G. He was then research aerodynamicist at the Messerschmitt A. G. After World War II, the author was invited to come to the United States, where he worked in aerodynamics at Wright Field, Ohio. For some years he has been acting as specialist for aerodynamics and hydrodynamics in the field of naval architecture at Gibbs & Cox, Inc., New York City.