Oil mixture SM-4,5

Oil mixture SM-4,5 (TС 0253-007-39247202-96) – is a mixture of aviation oils MS-8p and MS-20 in a ratio of 75:25 (mass fraction, %). It is applied to turboprop engines like AI-20, AI-24 of the planes.

Petroleum and synthetic oils are used to lubricate these engines. The main lubricants are oil mixtures obtained by mixing at the places of consumption of aviation oils MS-8p and MS-20 in the following ratios (mass fraction, %): 75:25; 50:50; 25:75. The use of MS-8rk oil as a part of oil mixes is allowed. Thanks to application of high-quality MS-8p oil quality of oil mixtures considerably increases. Oil mixtures are prepared and their quality is controlled according to the departmental instruction of the Department of Civil Aviation.

Physical and chemical indicators of SM-4,5

Name of the indicator Norm GOST (TС)
Density at 20°С, kg/m3, not more 860
Kinematic Viscosity, mm2/s:
at 100°С, not less 4,3 - 4,7
Acid number, mg KOH/g, not more 0,05
Content of water-soluble acids and alkalis, mechanical impurity Absence
Temperature, 20°С:
flash point in the closed crucible, not less 138
pour point, °C, not more -35
Coking capacity, %, not more, 0,15
Tribological characteristics on ChShMT at (20±5)°C:
critical loading, N, not less -
wear indicator at axial load of 196 N, not more -