Flammable substance, administered together with air into the combustion engine aircraft for heat in the process of oxidation by atmospheric oxygen (combustion). By T. a. include aviation gasoline and jet fuel. First used in piston engines, the second - in turbojet and turboprop.

Of a set of indicators of the quality of aviation fuel, the most important are the detonation resistance, grain size distribution and chemical stability. Antiknock gasoline determines the suitability for use in engines with a high compression ratio of the working mixture without causing knock, causing high shock loads on the pistons and cylinder head overheating. Fractional composition characterizes volatility of gasoline, which determines its ability to form a working air-fuel mixture, chemical stability - the ability to resist changes in the chemical composition during storage, transport and use.

Aviation gasoline is mainly produced from petroleum fractions by direct distillation, catalytic cracking or reforming without additives or with the addition of high-quality components, ethyl fluid, and various additives. Fractional composition of aviation gasoline is characterized by boiling temperature ranges (40-180 (°) C) and saturated vapor pressures (29-48 kPa).

Classification of aviation gasoline based on their anti-knock properties, expressed in octane in terms of grading. Varieties of domestic aviation gasolines are marked, usually a fraction: the numerator - the octane number or grade to lean, the denominator - grade to a rich mixture, for example B-95/130. Meets marking aviation gasoline and one octane number (for example, B-70). Aviation gasolines are available in three grades: B-95/130, B-91/115 and B-70 (Table 1). Of these varieties are most widely used and aviation gasoline B-91/115 B-95/130.

The main indicators of quality of jet fuels are the mass and volumetric heat of combustion, the thermal stability of the fuel vapor pressure, viscosity at sub-zero temperatures, compatibility with structural and sealing materials, nagarnye and wear. Together these requirements do not meet the aviation gasoline mainly because of low density, high volatility and poor lubricating properties. In connection with this gasoline as the main fuel for turbojet and turboprop not apply.