Smoke Oil

Aircraft · 4 min read · Apr 21, 2022
smoke oil

Aerobatic smoke oil helps ground spectators see their overhead action and adds a lot of flair to the air show. It may look like an exotic part of aviation life, but aerobatic fog oil can be purchased off the shelf and even used on RC planes. But what is aerobatic smoke oil? What is its role? Let’s take a closer look at this element, which plays various roles at air shows.

Aerobatic smoke oil is an artificial contrail used primarily at air shows and sometimes for other purposes. It is mainly used for the following reasons:

  • Safety Visibility: Used to provide a controllable smoke plume and allow the spectator to follow the aircraft’s course as it performs maneuvers. The trail it leaves reinforces what the pilot has just achieved. Most importantly, aerobatic smoke oil allows other pilots to see where other aircraft are relative to their position. This is especially important for group operations. All members can follow each other’s tracks.
  • Visibility for maneuvering purposes: The maneuvering point may be a smoke eruption. In specific designs, it leaves a pattern and unique marks in the sky. The smoke spiral triggered by a tight spin set is especially impressive.
  • Skywriting: There is no skywriting without aerobatic smoke oil. Skywriting requires a specially trained aerobatic pilot, as mastering flight is significant. However, Skywriting is very expensive for clients, and more viewers are watching TV and social media, so Skywriting is rarely seen anymore.
  • Cool effects: It also comes in many different colors. If you’ve seen the Air Force Thunderbirds, Navy Blue Angels, and Royal Air Force Red Arrows, you know how much they’ll add to the show. From time to time, skydivers like paratroopers and the Army’s Golden Knights also use some aerobatic smoke oil. These can add a unique flair to the operation of special events and groups.
An acrobatic air show in which differently coloured smoke oil is used: blue, red, and white.

Properties of Smoke oil

  • It consists of fully paraffinic base fluids, which create big billowing and persistent smoke;
  • Due to its low volatility, the product does not cause very dense vapor;
  • Since it does not contain Sulphur and its components, aviation smoke oil is fully compatible with aviation fuels employed in different types of aircraft;
  • Unlike alternative oils used for the same purpose, it does not leave a virtual mess to clean;
  • Easy to handle and will not damage the paint or metal parts of aircraft;
  • Provides environmentally safe, intense, and highly persistent smoke;
  • Eliminates flash and fire risks thanks to its high flash point
  • Fully biodegradable;

It’s easy to see the difference between natural contrails and artificial aerobatic smoke oil. Contrails are thin clouds that form after a jet’s hot engine, but contrails can form behind some piston engines.

Trails are formed from the water vapor left by jet engines and sometimes from the pressure differences that occur when the wing of an airplane cuts through the atmosphere. Meteorologically, they are classified as high clouds. 

Depending on the number of engines in the aircraft and the vortex of air on the tip of the wing, it may take a few minutes or even longer for the contrails to evaporate. The contrails that have been hanging for a while spread and eventually become delicate cirrus clouds. Like contrails in acrobatic flight, contrails depend on many meteorological factors such as temperature, wind, humidity, and other potential obstacles.

Oil composition

This oil is paraffin-based mineral oil. It contains safe chemical additives, depending on the color used by the pilot. Professional aerobatic pilots can be purchased on multi-gallon drums. Still, they can be found in small quantities if you are flying a radio-controlled aircraft or if an amateur aerobatic pilot uses it only occasionally.

Some people can even make it themselves. Consistency is essential when teams use aerobatic fog oil in their formations. Although some might have different colors for a particular formation effect, the pilots use the same kind.

Smoke oil systems and tanks

These systems require careful consideration by pilots and aeronautical engineers. They add weight to an airplane designed for maneuverability and quick turns; not only does the system increase an airplane`s weight, but so does heavy liquid smoke oil. Even military aircraft, such as the F18 Super Hornets used by the Blue Angels, require special retrofitting to allow an appropriate system.

The tanks of these systems must withstand the high G forces of specific maneuver and safe containment as the aircraft performs fast, jolting turns,s which creates a great deal of sloshing. On the jet, the smoke oil system uses a fuel pump to pump liquid from the tank to a nozzle attached to the exhaust port.

When liquid oil comes into contact with the heated exhaust fumes, the oil burns and emits noticeable smoke. Oil distribution is controlled by the pilot in the cockpit using a switch connected to the fuel pump in the aircraft fuel system. Electric pumps are an integral part of the array. Nozzles are located near the turbine outlet in turbine aircraft oil systems to generate flammable mist.

Similar to jet systems, the resulting combustion oil creates bright artificial contrails. The modern air show wouldn’t be possible without this addition, but it’s a relatively recent addition to the lineup. Smoke oil was first used by the Royal Navy’s helicopter demonstration team, Black Cats, at an air show in Farnborough, England, in 1957.

US Navy F18's flying in a formation, all equipped with white smoke oil.

What is smoke oil used now?

For some time, diesel oil was used in aircraft smoke systems. However, it was eventually discovered to affect the bright colors of aerobatic aircraft adversely.

Modern aerobatic oil is biodegradable and non-toxic. Ideally, the oil has a low viscosity and flows quickly and in a smooth line. This reduces wear on the smoke oil system, keeps the intended color pure, and eliminates darkening.

Due to its partial oxidation, ground personnel and pilots know that it must be treated as a potentially dangerous substance. Smoke is formulated to be completely vaporized. The mineral oil used as the base usually contains no additives other than the safe compounds used to create a particular color. Aircraft manufacturers recommend that pilots and crew use only certified oils to maintain the system’s integrity.

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Aeroclass Team
A team of professionals with a deep passion for the aviation industry bringing you the newest and the most striking industry-related news and content.

1 comment

  1. Richard Rowlett says:

    Aug 6, 2022: As I was driving back and forth across the I-90 floating bridge over Lake Washington (Seattle) making six crossings with the windows down and sun roof open during the Blue Angels performance this afternoon which was often very low straight up overhead, I was especially intrigued and surprised by the dense volume of “smoke” from the smoke-oil that settled over the bridge and lake after one particularly low pass of several planes that was so thick as to seriously reduce visibility (especially over the lake!) which had a definite brownish tinge where it was the thickest that smelled very much of diesel as I drove through it. I am curious about the diesel smell and the “dirty” color where it was at its densest since I got the impression that diesel-based smoke oil can affect the plane’s paint coating and is normally no longer used which I would think would probably be the case pertaining to the Blue Angels. Researching this a bit including the very informative article above on this site, I got the impression that the Blue Angels use a paraffin-based mineral oil that is non-toxic which is completely vaporized after mixing, burned, and leaves the exhaust port, but I’m not sure what it’s supposed to smell like, if there is any smell at all. I have seen the Blue Angels perform a number of times over Seattle but usually from a vantage point a bit more distant and in all cases the more distant “smoke-oil” contrails appear mostly white or off-white which then gradually diffuse and fade. This was the first time I’ve ever noted the brownish tinge in this one instance mentioned and caught the whiff of diesel. OMG, these new F18 Super Hornets are super LOUD, far louder than the previous 2019 and before smaller version! Now 4 hours later, my ears are still ringing along with a touch of compromised hearing remaining in my left ear. Still, it was an awesome show, wow!

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