Jet engines play an important role in modern aviation. Featuring an air intake, compressor, combustion chamber and exhaust nozzle, they are the primary means of propulsion for most airplanes.
Jet engines work by sucking air into a combustion chamber where it mixes with fuel. A spark will then ignite the air-fuel combination. This combustion process creates hot, pressurized exhaust gases that shoot out the exhaust nozzle, thereby propelling the airplane forward. If you’ve ever looked at the front of a jet engine, however, you may notice it has a spiral painted on it. What’s the purpose of these spirals exactly?
Overview of Painted Spirals
While not found on all jet engines, many jet engines have a single white spiral painted on them. It’s found directly in the center of a jet engine. As the air intake fan spins to suck in air, the painted spiral will spin with it.
Alternative shapes used for the painted spirals include the following:
- Swirls
- Horseshoes
- Commas
- Hurricanes
- Off-sided balls
- Apostrophes
Why Jet Engines Have a Painted Spiral
Whether it’s a traditional spiral, a swirl, horseshoe, etc., these painted shapes all serve the same purpose: to improve safety by making the spinning fan blades more visible.
As previously mentioned, jet engines have an air intake. Located at the front of a jet engine, the air intake features powerful fan blades that turn to suck in air. Because these blades turn so quickly, they look almost invisible. The painted spiral helps to solve this problem by offering a shape that visibly spins as the fan blades spin.
When the fan blades begin to spin, so will the spiral. And because the spiral is painted white, it’s easy to see. Ground crew members and other people can easily see that the engine is running thanks to the moving white spiral. As a result, they will know to keep their distance from the engine, as spinning fan blades create a powerful suction that can cause serious injury.
Another reason jet engines have a spiral is to deter bird strikes. Bird strikes are a hazard, particularly during takeoffs and landings when airplanes fly at low altitudes. The presence of a painted spiral helps to deter bird strikes by creating a spinning motion that scares away birds.
In Conclusion
The spirals painted on the front of jet engines aren’t for aesthetics. While they look appealing, they serve a functional purpose as well: to enhance visibility and improve safety.
