Estimated reading time 5 minutes, 10 seconds.
According to Shell Aviation technologist Dr. Matthew Hudson, it’s time for us to take a closer look at the role lubricants play when it comes to keeping our engines running smoothly.
What are you thinking about when you open the hangar door or climb into the pilot’s seat? Your route? Take-off? Or simply the amount of time you have in the air?
Whatever it is, my guess is that it isn’t lubricants. Yet, oils and greases hold the key to a smoothly running, safe and energy efficient aircraft.
Unsung heroes in your engine
Today’s lubricants count for much more than many people realize when it comes to the well being of an aircraft engine. Their primary function is to reduce friction among a piston engine’s moving parts, but they also perform a number of other roles too.
Lubricants fulfill tasks like flushing out contaminants and preventing dirt particles from sticking together to form sludge. This keeps the engine clean and the pistons running smoothly. High quality lubricants also protect against acid corrosion and overheating by limiting oxidation and aiding heat transfer from the engine to the atmosphere outside. This helps prevent degradation and helps your engine reach its certified time between overhaul (TBO).
All about the base (oil!)
In most cases, understanding the power behind these new benefits means looking no further than the base oil, which provides the bulk of a lubricant’s fluid and the key to determining its viscosity and lubricity. In simple terms, the better the base oil, the better the end product.
The terms, ‘synthetic’ and ‘mineral’ are generally used to refer to lubricants that are created from crude oil (mineral) or chemically by joining up oil molecules to form long-chain polymers (synthetic). At Shell, we believe that the best performance comes from synthetic base oils as they offer a more consistent molecular structure and are free of many unwanted hydrocarbons found in crude oil. This makes them better at reducing friction and more stable when it comes to oxidation.
Adding up
Converting a base oil into a fully-fledged aviation lubricant requires a number of additives too. It’s a bit like adding the right mixers to your favourite cocktail. These additives range from Viscosity Index (VI) improvers that keep the oil at the right thickness at high temperatures to pour point depressants that let it flow correctly when it gets cold. Another form of additive is antifoam technology that stops the lubricant from foaming in your engine, whilst other additives help increase wear resistance and prevent rust or corrosion.
The aim is to develop a product that works effectively in various conditions, including extreme temperatures. In the case of greases, thickener is also added to keep the product as viscose as possible.
Don’t just take our word for it
The good news is that when it comes to choosing the best lubricant, you don’t just have to take Shell’s (or any other company’s) word for it. Instead, the Society of Automotive Engines (SAE) maintains strict testing and quality control requirements for every product released.
To be granted official approval, lubricants must meet the SAE’s criteria and be verified by the US Navy. Beware of anything that doesn’t use the word ‘approved’ as often it will not have achieved the necessary standards. You can also check on the Qualified Products Database by searching ‘J- 1899 QPL’ online.
Fly above the rest
It’s fair to say then, that there’s more to aviation lubricants than meets the eye. Most importantly, it’s now widely accepted that your choice of engine oil can have a significant impact on everything from how much it costs to keep your plane in the air to the way it performs while you’re up there.
Equally, the range of benefits has also never been greater. From enhanced performance and improved energy efficiency to lower maintenance costs, there is now a lubricant for every aircraft and every condition. The key is choosing the right one for your aircraft.
