Frederick Lanchester

Airplane stability and control theory in the modern sense began with Frederick William Lanchester. Lanchester was not really a theoretician but a mechanical engineer who devoted most of his effort to the construction of very innovative motor cars. He performed aeronautical experiments with free-flying gliders. He speculated correctly on the vortex theory of lift and the nature of the vortex wake of a finite wing but was unable to give these ideas a useful mathematical form. His free-flying gliders were inherently stable and exhibited an undulating flight path, which he analyzed correctly in 1897. He misnamed the motion the “phugoid,” intending to call it the “flying” motion; actually he called it the “fleeing” motion, having forgotten that the Greek root already existed in the English word “fugitive.”

Lanchester published two books, Aerodynamics in 1907 and Aerodonetics in 1908, which expressed his views and the results of his experiments. He even talked with Wilbur Wright, evidently to no avail, because Wilbur had no understanding of inherent stability in flight, already demonstrated by Penaud, Langley, and Lanchester on a small scale.