With the correct oil friction losses in an engine are reduced to a minimum. This is done by taking into consideration circumstances as engine usage, ambient temperature, time of year and climate, location and engine design. The engine manufacturer usually recommends a certain type of oil to use with regard to different circumstances.
Lubricating oil plays an important part in the life of the engine and during maintenance it will be replaced, on certified aircraft the pilot can only replenish it. Without it the engine would fail within minutes, keeping a watchful eye during flight is therefore important.
Having a basic understanding of engine oil is a must for the professional and private pilot, here we can only scratch on the surface of a very interesting subject.
AeroShell supplies the aviation sector with a number of products, ranging from fuel to piston and turbine engine oil. On these pages we discuss the most common types.
Single Grade Ashless Dispersant Oils.
AeroShell Oils W80, W100 and W120 are ashless dispersant oils specifically developed for aviation piston engines. They combine nonmetallic additives with selected high viscosity index base oils to give exceptional stability, dispersancy and antifoaming performance. No general rule exists for every engine type when choosing the correct grade of oil; however, based on the average ambient outside temperature at engine startup the most common grades are SAE 40, SAE 50 and SAE 60, which equates to AeroShell Oil W80, W100 and W120 respectively.
Traditionally, the choice is associated with climatic zones - AeroShell W80 for cold climate regions (-17 - 21 °C), AeroShell Oil W100 for temperate regions (15 - 30 °C) and AeroShell Oil W120 for warmer climates (above 26 °C).
AeroShell Oils W65, W80, W100 and W120 are produced to meet fully the SAE specification J-1899 (Grades SAE 30, 40, 50 and 60 respectively). Furthermore, they all have military qualification approval and are listed on the Qualified Products List (QPL) issued by the US Navy and on the Technically Acceptable Products List (TAPL) issued by the UK Ministry of Defence. The blending plants employed to manufacture these oils also hold the approval of the specification authorities and this ensures that the high quality standard is always maintained.
Promotes Engine Cleanness. The non-ash forming, polymeric additive was developed to eliminate the harmful combustion chamber deposits that occur during normal operation. High Viscosity Index Base Oils used in AeroShell W oils maintain their viscosity and protect engine components more effectively under the high shear stresses that an engine places on lubricants. Provides Compatibility with other approved aircraft piston engine oils.
Since AeroShell Oils W65, W80, W100 and W120 are fully approved to SAE J-1899 and are listed on the relevant Qualified Products List (QPL), elaborate precautions are not needed when changing from similarly approved aircraft engine oils, as long as these oils are qualified products. AeroShell W Oils are inherently stable in storage. Providing that they have been stored and handled correctly, prolonged storage does not have any effect on their quality, properties or performance.
More info in this AeroShell Piston Engine Oil document.
Table below shows some common specification of these single grade ashless dispersant oils:
|Description Units||AeroShell Oil W80||AeroShell Oil W100||AeroShell Oil W120|
|Visual appearance||clear and bright||clear and bright||clear and bright|
|Density at 15 °C kg/L||0.887||0.889||0.894|
|Viscosity at 100 °C mm2/S||14.5||20.2||24.8|
|Viscosity at 40 °C mm2/S||126||213||288|
|Pour point °C||below -22||below -18||below -18|
|Flash point (COC) °C||above 240||above 260||above 240|
|TAN mg KOH/g||< 0.1||< 0.1||< 0.1|
|SAE J-1966||SAE 40||SAE 50||SAE 60|
|US MIL-L-22851D (obs)||Type III||Type II|
|(British) DERD 2450 (obs)||D-65||D-80||D-100|
|(French) AIR 3570||D-65||D-80||D-100|
|NATO||0-123 (obs)||0-125 (obs)||0-128 (obs)|
|Joint service designation||OMD-160||OMD-250||OMD370|