1981 Pratt & Whitney Aeronautical Vest-Pocket Handbook (19th Edition). Published by United Technologies, this highly collectible, pocket-sized reference manual was a staple for aerospace engineers, mechanics, and pilots during the early 1980s.

This dense technical guide features extensive data tables, including:Air properties at various altitudesCompressible flow and speed effects (Mach numbers)Essential physical properties & conversion factorsGas turbine mechanics and aircraft propulsion formulas