Standard Atmospheric Conditions

ALL aircraft and aero‐engine performance calculations are reduced to an agreed Standard Atmosphere defined by the International Commission on Air Navigation in order that direct comparison between the results can be easily made. But for design purposes, especially the design of radiators, this Standard Atmosphere is neither universally adopted nor suitable. Other most commonly used atmospheric conditions in this country are the Temperate Summer and the Tropical Summer. Some of the properties of these atmospheres are given in various Air Publications issued by the Ministry of Aircraft Production, including It. & M. 1891, and can also be found on p. 179 of the Meteorological Glossary (third edition) issued by the Meteorological Office. Unfortunately, the functions tabulated in these publications are inadequate for practical purposes except in the case of the I.C.A.N, atmosphere where all the commonly used functions are given in “Physical Properties of the Standard Atmosphere” by Messrs Pankhurst and Conn in R. & M. 1891. It is, therefore, proposed to fill up this gap and to give functions commonly used for Temperate Summer and Tropical Summer atmospheres on lines similar to those used in R. & M. 1891.