Understanding Aerodynamics: Arguing from the Real Physics (Aerospace Series)

Too often aerodynamics has been treated as applied mathematics. This is akin to force the learning of English by committing to memory English grammar rules that the vast majority of native speakers never think about. This has an effect of discouraging anyone but the most unusual students. This book, along with Ed Obert's Aerodynamic design of transport airplane, published in 2009, are important and refreshing in that both are highly informative but not math heavy. Obert's book is one of experience. McLean's book, however, tackles the theory of aerodynamics from a physical point of view. It enhances your understanding of the fundamentals, which is a necessary part of an aerodynamicist's know-how. Only by combining a strong background in theory and all-around experience can an aerodynamicist hope to function in today's highly competitive aircraft manufacturing business. I sincerely recommend this book to people who have long lost hope in a pure mathematical and lifeless approach.

Understanding Aerodynamics is a new approach at explaining why various aerodynamic characteristics take place. Most aerodynamics textbooks use experimental data and theoretical developments to explain aerodynamics, but there are very few equations or theories developed here. The basis is an understanding of the physical mechanisms that lead to lift and drag, which is a refreshing and important contribution. The downside is that the author tends to throw out many classic theories because they can't explain all details of aerodynamics: my response to that is to quote the well-used statement "all theories are wrong, but some are useful." Just because a theory isn't perfect (and none of them are) doesn't mean the theory can't be useful and important. What the author should concentrate on, perhaps, is that we should never confuse our theories with reality, and I think that is an important contribution.

This book is definitely not a light read, but the information is written in a way that makes aerodynamics quite understandable even to a non-scientist. So many of the concepts are new to me, even as someone who has loved aviation all his life, flies airplanes and volunteers at an aviation museum.

This book, for an aero engineering student, will feel like a light read. Purchase this and put it on your shelf. You will enjoy its coverage of the fundamentals and find yourself referencing it from time to time to clarify things. I don't personally know the author but my colleagues at Boeing speak to his knowledge in the field of aerodynamics. Cited this text several times in my MS thesis.

The author did an excellent job balancing the dry mathematical theory with descriptive dialog aiding in the grasp of very complex theories in aerodynamic physics.

excellence in reaching back to me to rectify any issue

Doug McLean’s Understanding Aerodynamics is presented as a corrective to common misconceptions about lift, circulation, pressure, and the physical interpretation of aerodynamic forces. In that role, it has some value. The book is clearly the product of some professional experience, and it contains a few thoughtful observations about how aerodynamic explanations are often oversimplified. However, its larger intellectual posture is deeply problematic. The book too often gives the impression that most conventional explanations of aerodynamics are wrong, incomplete, confused, or misleading, and that the reader must therefore pass through McLean’s own interpretive framework to understand what is “really” happening. This is an extraordinary rhetorical burden, and the book does not justify it. The central weakness of the book is not merely that it is qualitative. Many excellent aerodynamic texts contain qualitative interpretation. The weakness is that McLean repeatedly treats standard aerodynamic concepts as if they require rescue from misunderstanding, when in fact classical aerodynamics already provides a coherent, mutually consistent framework. Pressure forces, circulation, vorticity, downwash, momentum balance, boundary conditions, and energy considerations are not competing explanations of lift. They are different representations of the same physical system. A mature aerodynamics text should help students organize these viewpoints into a unified theoretical structure. McLean’s book does the opposite: it relitigates them in a way that can make long-since-settled ideas appear unsettled. This is a serious pedagogical flaw. Students do not need to be told repeatedly that the usual explanations are wrong unless they are also given a clear, disciplined replacement. They need to learn how to calculate, predict, and interpret aerodynamic behavior from governing equations, boundary conditions, approximations, and validated models. They need to understand potential flow, the Kutta condition, thin-airfoil theory, finite-wing theory, boundary layers, separation, compressibility, and viscous/inviscid interaction in an ordered way. McLean’s book is instead dominated by explanatory commentary. It is a book about how to think about aerodynamics, but it is not effective at teaching aerodynamics as an analytical discipline. These problems in his book become especially acute in the treatment of lift. McLean is right to reject simplistic popular explanations, such as the equal-transit-time fallacy or naive Bernoulli arguments that ignore the origin of the velocity field. But correcting bad explanations is not the same thing as establishing a superior pedagogy. The classical frameworks already reconcile the pressure field, circulation, vorticity, and downward momentum imparted to the flow. These are not separate causal mechanisms that McLean believes require endless philosophical sorting. A pressure distribution produces a force on the airfoil; the associated flow field contains circulation; the wake contains vorticity; the far field reflects momentum flux. These statements are simultaneously true. The difficulty is not that classical aerodynamics is conceptually defective. The difficulty is that poor teaching sometimes presents only one projection of the physics and mistakes it for the whole. McLean’s book persistently attacks what it presents as poor teaching, but it leaves the reader with the impression that the discipline itself is riddled with conceptual ambiguity. That is perversely misleading. Aerodynamics is not a collection of quasi-competing stories about lift. It is a predictive continuum-mechanics discipline with well-defined approximations. Potential-flow theory has limitations, but within those limitations it is powerful. Thin-airfoil theory is idealized, but it gives correct first-order results. Lifting-line theory is approximate, but it captures the essential physics of finite-span wings. Boundary-layer theory is asymptotic, but it explains skin friction, separation tendencies, and viscous corrections. Compressibility corrections are limited but not arbitrary. A good textbook should clarify the range of validity of each model. McLean too often frames the subject in terms of the inadequacy of explanations rather than the power and proper use of the models. One of the most troubling aspects of McLean’s Understanding Aerodynamics is its severe treatment of earlier aerodynamic thinkers, including figures of the stature of W. R. Sears. The book’s corrective posture may be defensible when aimed at popular misconceptions, such as the equal-transit-time fallacy or naive Bernoulli explanations. It is much less defensible when extended toward pioneers of theoretical aerodynamics, whose work helped establish the very framework within which modern aerodynamic reasoning takes place. Sears was not a casual expositor of lift. He belonged to the generation that developed and refined the analytical foundations of airfoil theory, unsteady aerodynamics, lifting-surface theory, and aerodynamic interpretation. To treat such figures as though they were trapped in conceptual confusion is not merely severe; it is historically disproportionate. There is also a danger in the book’s tone of exceptionalism. The cumulative effect is that nearly everyone else, except McLean, seems to have misunderstood lift, or at least explained it so poorly that a corrective interpretation is needed. That stance may be rhetorically effective, but it is intellectually risky. It encourages the reader to distrust standard explanations before mastering them. This is not how technical understanding is built. Students should first learn the canonical structure of the subject, then its limitations, and finally where common explanations fail. McLean inverts that order. The result is a book that is better at criticizing explanations than at constructing competence. It may help an experienced aerodynamicist reflect on language, causality, and interpretation, but it is not a reliable primary text for students learning the subject. It does not provide sufficient systematic derivation, quantitative development, worked examples, or engineering methodology. It explains around the subject rather than through it. For a mature reader, this may be stimulating. For a student, it can be destabilizing. One of the most serious inadequacies is that the book can blur the difference between a misleading popular explanation and a valid theoretical abstraction. For example, a crude Bernoulli-only explanation of lift is indeed inadequate if it does not explain why the velocity over the upper surface is greater. But Bernoulli’s equation itself is not the problem. Likewise, circulation is not a fiction merely because it is not directly visible as a solid-body rotation around the airfoil. The Kutta-Joukowski theorem is not deficient because it requires interpretation. Momentum balance is not a rival to pressure integration. These are all legitimate and mutually compatible elements of aerodynamic theory. Treating them as if they must be repeatedly defended against misunderstanding risks confusing the epistemic status of the theory itself. A stronger teaching text would say plainly that lift can be obtained by integrating the pressure and shear stresses over the body; in many practical aerodynamic cases, pressure dominates. The pressure field is determined by the velocity field and boundary conditions. For attached flow over an airfoil, the Kutta condition selects the physically relevant circulation. The circulation changes the velocity field, which in turn changes the pressure distribution, producing lift. For a finite wing, trailing vorticity and downwash appear, modifying the effective angle of attack and producing induced drag. The same force can also be interpreted through momentum balance in a sufficiently large control volume. These are not contradictions. They are the same physics viewed at different levels. That kind of structured explanation is what students need. McLean’s extended critique of misunderstandings does not consistently provide it. Instead, the book can become a conceptual labyrinth in which every ordinary explanation needs qualification, every simplified statement is suspect, and every familiar teaching device risks being treated as a misconception. That approach may appeal to readers who enjoy philosophical dissection, but it is not necessarily good aerodynamics pedagogy. The book’s inadequacy, then, is not that McLean lacks insight. He plainly has insight. The inadequacy is that insight is not the same as structure. A textbook must do more than correct misconceptions. It must build a usable framework. It must tell the student what to calculate, why the calculation is valid, what assumptions are being made, what the limiting cases are, and how the result connects to physical interpretation. By that standard, Understanding Aerodynamics is incomplete and, in some respects, counterproductive. The harshest criticism is this. The book risks replacing bad simplifications with excessive complication. It rightly objects to simplistic stories, but it does not replace them with a clear hierarchy of models. It makes aerodynamics seem more mysterious than it is. Classical aerodynamics is subtle, but it is not incoherent. It contains idealizations, but they are purposeful. It has multiple equivalent interpretations, but that is a strength, not a defect. McLean’s book treats the multiplicity of viewpoints as a source of confusion rather than as evidence of a robust theoretical framework. For that reason, the book should not be used as a foundational aerodynamics text. It is best regarded as a supplementary interpretive essay for readers who already know the classical theory and can distinguish between valid critique, semantic overcorrection, and genuine physical clarification. Used too early, it may leave students with the false impression that the standard subject is a minefield of conceptual errors. Used carefully, it may provoke useful discussion. But provocation is not pedagogy, and critique is not a substitute for theory. In summary, McLean’s Understanding Aerodynamics is useful only within severe limits. It is strongest when exposing genuinely poor popular explanations of lift. It is weakest when its corrective posture becomes so dominant that the reader is led to believe that the broader aerodynamic tradition is fundamentally confused. The book is thoughtful, but not sufficiently systematic; insightful, but not sufficiently constructive; corrective, but severely overcorrective. Its main defect is that it spends too much time telling the reader why ordinary explanations are inadequate and too little time building the analytical machinery that makes aerodynamics a predictive engineering science. A fair conclusion would be: McLean’s book is not wrong because it criticizes bad explanations of lift. It is inadequate because it elevates that criticism into a governing method. The result is a book that makes aerodynamics appear more conceptually confused than it really is. Classical aerodynamics does not need to be rescued from itself. It needs to be taught clearly, with its assumptions, equations, limitations, and physical interpretations kept in proper order. On that standard, Understanding Aerodynamics falls well short.

Not as easy to grasp as he makes it,on his you tube,

great book

Nice to get a fresh review of Aerodynamics, lots of subject to consider and lot's of things to go back and review from even top authors on the subject.

Excellent !

As someone who spent Decades running Wind Tunnel and computational Research the Author provides a profound Explanation on every Topic discussed in the Book. Text is easy readable and immersive for someone truly interested in Aerodynamics.

The recipient of this gift was very pleased with the content. It is a great book written by a very knowledgeable person. As purchaser of this book in hardcover I was disappointed that upon opening the front cover full to write an message (its a present) on the inside, the binding split and ripped a bit. definitely not worth the 90€! Go with the softcover. Otherwise a great present, well received.