Page:Aerial Flight - Volume 1 - Aerodynamics - Frederick Lanchester - 1906.djvu/10

vi demonstration. It soon became evident that there were considerable lacunae, and these were filled by subsequent investigations, the scope of the work being greatly extended. Finally it was decided to make the publication a complete treatise on Aerial Flight, the main classification being as follows:—

Vol. I. Aerodynamics, relating to the theory of aerodynamic support and the resistance of bodies in motion in a fluid.

Vol. II. Aerodonetics or Aerodromics, dealing with the forms of natural flight path, with the questions of equilibrium and stability in flight, and with the phenomenon of "soaring."

So far as has been found possible the work has been modelled on non-mathematical lines. The commonly distinctive feature of a modern mathematical treatise, in any branch of physics, is that the investigation of any problem is initially conducted on the widest and most comprehensive basis, equations being first obtained in their most general form, the simpler and more obvious cases being allowed to follow naturally, the greater including the less. The reader who is only moderately equipped with mathematical knowledge is thus frequently at a loss to comprehend the initial stages of the argument, and so has no great chance of fully appreciating the conclusions.

It is impossible, in connection with the present subject, to avoid the frequent use of mathematical reasoning, and occasionally the non-mathematical reader may find himself out of his depth. The author has endeavoured to minimise any difficulty on this score by dealing initially with the simpler cases and afterwards working up to the more general solutions; and further by the careful statement of all propositions apart from mathematical expression, and by the re-statement of conclusions in non-mathematical language. Wherever appropriate, numerical examples are given in order to more completely elucidate the methods employed and the results attained.