Physical–chemical study of light fuels and of lubricants in Aeronautics. (M. Moutte, La Technique Aeronautique, Sept.–Oct., 1926, pp. 279-281 and 305-319) (8.51/5096 France)

Systematic tests of fuels in an engine on the test bench were commenced in 1917, in conjunction with a systematic determination of physical properties, and as far as possible of chemical composition. It was found that homogeneity, volatility and high latent heat of evaporisation were the most desirable qualities. In agreement with Ricardo, the aromatic compounds of hydrogen are found to be the least amenable to propagation of explosion, then the saturated cyclic compounds, and lastly the saturated acyclic compounds. In identifying fuels use is made of characteristic curves of distillation:—

Temperature—Volume Distilled, Density;—Volume Distilled.

Temperature—Density, Temperature—Solubility.

Temperature of distillation plotted against critical temperature of solubility in aniline gives highly characteristic differences, and is considered a fundamental method. Optical methods are also used for approximate quantitative determination. The formation of clouds of condensed drops affords another method of determination. The mechanical conditions were also examined:—Variation of inlet pressure, condensation, centrifugal separation.