There are four, very distinct versions of Etkin's book.
Two of these are called 2nd edition, and one of them is called 3d edition. The first edition ( naturally ) carries no explicit edition number on the cover. I think the 2nd edition called "Dynamics of Atmospheric Flight" is the classic. The 3d edition was recently new to me. I feel it is by far the best version.
This is a pleasant textbook on "Stabilty and Control". The cover sports a B-58 Hustler in climbing flight.
This is probably the edition that first established Etkin's reputation as a textbook author.
This is the classic that we all knew and feared. It is a complete overhaul of the first edition. Despite the slightly different title, it is called "the" second edition.
This version spends lavish attention on hypersonic flight around a curved Earth, and at quickly varying atmospheric pressures. This added complexity made it less suitable as an ( undergraduate ) textbook.
In his preface to this "other" second edition, Etkin confesses that he had received much negative feedback on his 1972 second edition as a textbook.
This new edition therefore returns to the text of the first edition, with certain modernizations. Somewhat confusingly, but probably more true to fact Etkin therefore calls this the "second edition", but this time of the first book with the original title. This version deletes the last five chapters of the first edition, and replaces them by two new ones with material taken from the 1972 "second edition".
Relative to the first edition, this new second edition introduces the use of eigenvalues and eigenvectors. Externally, the two "second editions" are very much alike, with black hardcover and metallic lettering spelling out “second edition”. However, internally they are very different.
The 3d edition is a true revision of the 2nd edition of the first book.
This version gives the equations of motion in dimensional form, because it is more suitable for real-time computer simulation, like in flight simulators. The model used is the Boeing 747 this time. The cover shows a double shadow image of that airplane.
The prefaces of the books give a clear account of their development. The 3d editon was co-written by Lloyd Reid, who had grown up with the previous versions, first as a student and later as a staff member. Etkin himself had been retired for eleven years by that time.
I believe that Etkin's 3d edition is as good a place to start as any when learning about aircraft dynamics, and the B747 is a good playground.
Last time I looked, a PDF of the 3d edition was freely available on tnis site, and in several other places :
| Etkin (1995) | Dynamics of Flight, 3d edition |