Historical trend in the research and development of aircraft

Results are presented from a study of aircraft design trends undertaken to determine the relationship between research, development, test and evaluation and aircraft mission capability, requirements and objectives. It is shown that while in some cases a performance objective was the primary research driver, research was the driver in the formulation of objectives in others. Among the topics discussed are: (1) speed considerations such as compressibility, propulsion and test techniques; (2) airframe considerations such as swept, delta, trapezoidal and variable-sweep planforms and mission commonality; (3) research aircraft; (4) the recent impact of computer-aided design; (5) Soviet aircraft development approaches and (6) a comparison of Soviet and U.S. military aircraft design trends. Attention is given to experimental and prototype aircraft programs which, although cancelled, anticipated significant subsequent developments.