Collected Works of H. S. Tsien (1938-1956)

Superaerodynamics, Mechanics of Rarefied Gases

Hsue-shen Tsien*

(California Institute of Technology)

Zahm^[1] in 1934 published an article on the aerodynamics of highly rarefied gases, a branch of fluid mechanics which he called superaerodynamics. At that time, however, with the means of propulsion then available, flight at extreme altitudes did not seem to be realizable. Therefore, superaerodynamics has been considered as a subject of academic interest rather than one of practical engineering importance. With the recent perfection of the rocket as a propulsive power plant, the situation is radically changed and there should be no limit to the altitude that can be reached by an aircraft. There are even indications that the optimum flight altitude ...