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The Science Behind Why Airplane Wings Wobble in Turbulence

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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]

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This Just In
Flights Grounded After World War II Bomb Discovered Near London City Airport
Dan Kitwood, Getty Images
Dan Kitwood, Getty Images

London City Airport grounded all flights on the night of February 11, after a World War II bomb was found in the neighboring River Thames, The Guardian reports.

The half-ton bomb was revealed Sunday morning by development work taking place at the King George V Dock. Following its discovery, police set up a 702-foot exclusion zone around the area, closing local roads and shutting down the London City Airport until further notice. According to the BBC, 261 trips were scheduled to fly in and out of London City Airport on Monday. Some flights are being rerouted to nearby airports, while others have been canceled altogether.

The airport will reopen as soon as the explosive device has been safely removed. For that to happen, the Met police must first wait for the river's tide to recede. Then, once the bomb is exposed, they can dislodge it from the riverbed and tow it to a controlled explosion site.

The docks of London’s East End were some of the most heavily bombed points in the city during World War II. Germany’s Blitz lasted 76 nights, and as the latest unexpected discovery shows, bombs that never detonated are still being cleaned up from parks and rivers more than 75 years later.

[h/t The Guardian]

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History
Why Amelia Earhart Is Remembered as One of History's Most Famous Female Pilots
Fox Photos/Hulton Archive/Getty Images
Fox Photos/Hulton Archive/Getty Images

Amelia Earhart was a legend even before she mysteriously disappeared in 1937 while flying around the world. But the aviator's fame wasn't entirely based on skill alone. As Vox explains, Earhart's reputation eclipsed that of several contemporaries who were equally—if not more—talented than “Lady Lindy." So why did Earhart's name go down in history books instead of theirs?

In addition to her talent and courage, Earhart’s international fame could be chalked up to ceaseless self-promotion and a strategic marriage. It all started in 1928, when socialite Amy Phipps Guest and publishing juggernaut George Putnam handpicked the then-amateur pilot to become the first woman to be flown in a plane across the Atlantic Ocean. Earhart wasn't involved with the actual flight process, but the trip still established her as the new female face of aviation (and introduced her to Putnam, her future husband).

After completing the transatlantic journey, Earhart’s profile rose sky-high as she gave public lectures, wrote an aviation column for Cosmopolitan magazine, performed stunts like flying solo across the Atlantic (a feat that was first achieved by Charles Lindbergh in 1927), and endorsed everything from cigarettes to designer luggage. Her celebrity was ultimately cemented with her marriage to Putnam, who orchestrated savvy promotional opportunities to keep his wife’s name in the paper.

Learn more about Earhart’s rise to fame by watching Vox’s video below.

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