Chances are you’ve noticed by now that jets have spiral shapes on their engine spinners. They do come in several different designs, such as the typhoon, the comma, the swirl etc, and the truth is, that they actually look cool.
But have you ever wondered why there were placed there? I mean, they must have a higher purpose, right? Well, as it turns out, there are two main reasons behind these little white swirls.
Here’s how it goes. (the article continues after the ad)
The first one, has to do with the safety of ground personnel. Even though these enormous engines are incredibly loud, due to the runway’s heavy noises, they may not be obvious to people on the ground. Because engines can suck inside and consume everything that walks in the hazardous area (9 to 15 feet – 2,5 to 4,5m), they have that spiral shapes painted on them so ground crews can tell if they are running and stay away from them. A glance is all it takes.
The second reason is to scare birds. Because we all know that aircraft engines and birds are a bad combination, in flight, these spiral swirls flicker in order to scare birds and keep them away from the engine. That being said, and even though the ‘bird-striking’ prevention is mentioned by both Boeing and Rolls Royce (the leading maker of jet engines), several studies have disputed the effectiveness of spirals for deterring bird impacts. For those interested in learning more about these studies, you can check out this one conducted by Japan’s All Nippon Airways (ANA) or this study by the University of Oslo.
So, now you know why jet engines have spiral shapes. Feel free to spread the (useless) knowledge and impress your friends and family the next time you wait at the gate!
EDIT: Special thanks to AeroSavvy for all their assistance! These guys are doing an amazing work so be sure to check their their website for interesting aviation related articles.