CLOSE
Original image
iStock

The Science Behind Why Airplane Wings Wobble in Turbulence

Original image
iStock

Experiencing turbulence on a flight is worrying enough, so it certainly doesn’t help to look outside your window and see the plane’s wing bouncing up and down like it’s made of plastic. After observing such oscillation on a recent flight, one WIRED writer decided to dig deeper into the physics behind the phenomenon.  

By analyzing a video he shot using his iPhone, he was able to determine that the wing of the Boeing 737 he was aboard reached an oscillation amplitude of 10 centimeters (nearly 4 inches). The amount of time it took for the wing to move from one minimum position to the next was about 0.3 seconds. 

While all that wobbliness may seem like cause for panic, the flexibility of a plane’s wings is actually a sign of safety. The Federal Aviation Administration requires that all airplanes are able to withstand 150 percent of the maximum expected load for 4 seconds. According to CBS MoneyWatch, that means a plane’s wings can survive turbulence 50 percent stronger than the worst that’s ever been encountered before breaking. In order to absorb all that force, the wings are built like giant springs. If they were rigid and unyielding, it would take a lot less wind power for them to snap off—not something you want happening at 30,000 feet.

As for why the wings respond to turbulence by bouncing up and down, it’s simply a matter of physics. If an aircraft is flying at a constant speed and altitude, the net force pushing it up and down would amount to zero. If the plane moves into an area with higher air density (or experiences a similar atmospheric change), this results in more lift than there was before. This causes the plane to temporarily accelerate upward, and the wings to bend up farther. When the plane moves back to a place with lower air density the lift is reduced, causing the wings to bend back down. Sudden changes in lift force, which is what goes on during periods of turbulence, are what bring about the oscillation. 

So next time you see your plane’s wing wobbling during a bumpy flight, remember that it’s just a product of basic physics. And if that doesn’t do much to comfort you, maybe try shutting the window shade. 

[h/t: WIRED]

Original image
arrow
History
How the Wright Brothers' Plane Compares to the World's Largest Aircraft
Original image

The Wright brothers famously built the world’s first powered, heavier-than-air, controllable aircraft. But while the siblings revolutionized the field of aviation, their early plane looks tiny—and dare we say quaint-looking—when compared to the aerial giants that came after it.

In Tech Insider’s video below, you can see how the Wright brothers’ flyer stacks up against the scale of other aircrafts. You'll notice that size doesn't always guarantee a successful journey. The Hughes H-4 Hercules—the largest flying boat ever made—never made it past the prototype stage, performing only one brief flight in 1947. And the Hindenburg, which was 804 feet long and could fit 80 Olympic swimming pools, famously exploded on May 6, 1937.

Today’s longest commercial airliner is the Boeing 747-8, which measures 251 feet from nose to tail. While slightly shorter (238 feet), the Airbus A380 is certified to hold more people than any other plane in the air—a total of 850 passengers. That record won't last long, though: In a few years, the Stratolaunch carrier—the widest aircraft ever built—will dwarf its contemporaries when it takes to the skies in 2019. Built to launch rockets into orbit, its wingspan is about the size of a football field, even bigger than that of the Hughes H-4 Hercules.

Still, what the Wright brothers’ plane lacked in size, it made up for in ingenuity. Without it, these other giants may never have existed.

[h/t: Tech Insider]

Original image
iStock
arrow
technology
Microsoft’s Autonomous Gliders Stay in the Air by Mimicking Birds of Prey
Original image
iStock

When designing different ways for vehicles to move, engineers will often look to nature. Animals have had millions of years to evolve locomotion methods that get them where they’re going fast without burning a ton of energy. Now, researchers at Microsoft have chosen the hawk, a master of energy-efficient air travel, as the model for their new autonomous gliders.

As Co.Design reports, the tech company’s “infinite soaring machine” can move through the skies without generating its own propulsion. Instead, it seeks out warms streams of air to provide the upward push, much like a hawk does.

While riding air currents doesn't take up a lot of energy, it does require some sophisticated artificial intelligence. As a substitute for millennia of animal instinct, Microsoft “trained” its glider to fly by plugging it into a video game-like simulator that showed hawks in flight. By repeatedly subjecting the technology to these virtual experiments, researchers eventually developed algorithms capable of recreating the scenes in the real world.

Using onboard sensors, the sailplane can independently navigate the skies without a motor. The gliders are no more than a few feet long, which means they don’t serve much of a practical purpose outside of research. But the aircraft’s simple design is exactly what makes them appealing to engineers.

With less hardware to worry about, they can focus on refining AI software which can be used in different types of autonomous vehicles in the future. And by testing AI navigation in the air instead of on the road, Microsoft gives themselves a much bigger test track to work with.

You can watch the infinite soaring machine take to the skies in the video below.

[h/t Co.Design]

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios