I’m not sure if you’ve heard, but planes are neat. And how could they not be? You sit down, and in less than a day, you can be on the other side of the world. That’s also before you get into the specifics of the engineering that goes into making them fly, the design differences between various types of planes and how each one is actually flown. If you’ve spent much time waiting at the airport, you’ve probably noticed the odd spiral patterns painted on jet engines, too. Are those just fun little designs, or is there more going on there? Turns out, it’s the latter.
In fact, as our friends over at Simple Flying explained, not only are there good reasons for the spiral designs, they also aren’t exactly new. These spirals date back to at least World War II, and the reason they’re still in use has everything to do with safety. Specifically, they exist to help keep people from getting sucked into jet engines while they’re running. Since the turbines used in jet engines spin quickly, it’s hard for the human eye to actually see whether they’re on or off. And while you can usually hear them while they’re running, the people who work around planes wear ear protection to prevent hearing loss and can’t always tell. So by adding a spiral pattern to the front of the jet engine, workers can more easily tell when an engine is on and make sure they avoid getting sucked in.
Spiral designs improve safety
The spiral designs on jet engines don’t just inform workers that the engines are active and dangerous, though. They also help with another safety issue — bird strikes. Bird strikes don’t usually cause planes to crash, and even if a bird does get sucked in, commercial jets are designed to keep flying even without one of their engines. But the damage they cause is still expensive. One study cited by Simple Flying estimated they cost the U.S. about $400 million every year, while globally the total annual cost is more like $1.2 billion.
So, in an attempt to reduce the number of bird strikes the airlines have to pay to repair, manufacturers hope the spinning spiral designs will make the engines easier for birds to spot and therefore avoid. As Rolls-Royce put it in a brochure back in 2004, “Our aerospace engines have swirls painted onto their spinners in order to indicate when the engine is rotating while on the ground. In flight these swirls flicker as the engine rotates at high speed, scaring birds and allowing them to fly clear of the engine.”
Whether or not the spiral designs actually reduce bird strikes is murky at best, but hey, it certainly can’t hurt. And if it does help, no one’s going to complain about fewer bird strikes, are they?
