1955

This propulsion wind tunnel (PWT) at Arnold AFB was the first large-scale facility for testing jet and rocket engines in simulated high-speed flight conditions. It has a unique combination of transonic (1955) and supersonic (1960) wind tunnels using a common 236,000 horsepower drive, the world's largest when built. It can achieve air speeds up to Mach 4.75 at altitudes up to 150,000 feet in its 16-foot square, removable test sections. Design engineers were Lief J. Sverdrup, John R. Parcel, Brice Smith, and Walter Cook, of Sverdrup and Parcel, St.

This is one of the three original 60-ton vessels by which the basic oxygen process (BOP) of steel making was introduced into this country from Austria, where it was invented. It heralded the first new technology in fifty years to become the basis of a major process for steel production throughout the world. In this process, a water-cooled lance injected a jet of high-purity oxygen into the bath of molten iron. Various chemical reactions produced a quality low-nitrogen steel at a ton-per-hour rate nearly three times that of the open hearth furnace.