Tuesday, August 9, 2011
Caring For Your Aircraft
Part IV: From selecting the correct grade to changing it at correct intervals, knowing your oil is important
There's much hearsay about engine oil and oil changes in the piston aviation world. It seems everybody has an opinion and advice, though much of it isn't based on fact or comes from old ideas. The oil we use in our airplanes today isn't your grandfather's oil (though many of us miss oil cans), and understanding modern techniques and formulations will help us squeeze more life out of our engines. In the end, isn't that what it's all about?
We were fortunate to talk with Paul Royko, AeroShell's Technical Manager of piston-engine oil, who speaks frequently at aviation events and conferences. Though he won't admit to it, Royko is something of an aviation-oil guru, and his advice is something all pilots can benefit from. AeroShell has been providing oil to aviators since they developed the first ashless dispersant aviation oil in the early 1950s. In the 1960s, Aeroshell made headlines again when they developed their now-famous Turbine Oil 555, which was created especially for the Concorde, and could withstand the high-bearing temperatures and stresses of supersonic flight.
"The best advice I can give to pilots is simple," says Royko, "Pick the proper oil for the conditions you fly in. The other critical thing is to change the oil and filter at the proper intervals, and finally, fly often. Those three simple things will extend the life of your engine and your oil, and will help you catch problems early."
How Oil WorksTo put that advice into practice, it helps to understand the seemingly simple process of how the oil works in your engine. In a cold engine, the oil sits in the oil sump, pulled by gravity to the lowest point in the system. When you start the engine, oil is pulled out of the sump by an engine-driven oil pump. It's sent through the oil filter (or oil screen if you don't have a filter), and proceeds into the crankcase, where it lubricates the critical bearings and other components. Oil travels into the cylinders, where it creates a seal between the piston rings and the smooth walls of the cylinders, allowing compression to occur.
The oil carries away heat through convection as it travels through the engine. Typically, the oil will travel through an oil cooler, where air flow will carry the transferred heat away. Microscopic bits of metal that are the result of friction also will be carried away, and will end up in the oil filter.
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Labels: Aircraft Maintenance, Fuel Hazards, Maintenance, Pilot Resources, Aircraft, Aircraft Ownership, Engines