Was It Designed?
The Kingfisher’s Beak
● Traveling at speeds of nearly 200 miles [300 km] an hour, the Japanese bullet train is one of the fastest in the world. In part, it owes its success to a small bird—the kingfisher. Why?
Consider: In pursuit of a tasty meal, the kingfisher can dive into water with very little splash. That fact intrigued Eiji Nakatsu, an engineer who directed test runs of the bullet train. He wondered how the kingfisher adapts so quickly from low-resistance air to high-resistance water. Finding the answer was key to solving a peculiar problem with the bullet train. “When a train rushes into a narrow tunnel at high speed,” Nakatsu explains, “this generates atmospheric pressure waves that gradually grow into waves like tidal waves. These reach the tunnel exit at the speed of sound, generating low-frequency waves that produce a large boom and aerodynamic vibration so intense that residents 400 meters [1,300 feet] away have registered complaints.”
The decision was made to pattern the front end of the bullet train after the kingfisher’s beak. The result? The bullet train now travels 10 percent faster and consumes 15 percent less energy. In addition, the air pressure produced by the train has been reduced by 30 percent. Thus, there is no large boom as the train passes through a tunnel.
What do you think? Did the kingfisher’s beak come about by chance? Or was it designed?
[Picture Credit Lines on page 29]
Kingfisher diving: Woodfall/Photoshot; bullet train: AP Photo/Kyodo