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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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The Secret to a More Pleasant Flight? Urinals
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Even if you can deal with the lack of legroom, privacy, and decent meal options on airplanes, your patience may start to wear thin when it comes time to pee. Being stuck waiting in long bathroom lines on planes may feel like one of life's unavoidable annoyances, but according to WIRED, there's a way to make the experience more tolerable. The secret involves urinals and a bit of math.

At last month's Crystal Cabin Awards, a competition that recognizes innovation in aircraft interiors, Zodiac Aerospace introduced the Durinal, a two-urinal plane bathroom that takes the place of one toilet. Replacing a bathroom that serves all passengers with one that's made for only half the population may seem like a quick way to make the long-line problem worse, but there's some logic behind the proposed solution.

As Wouter Rogiest, a mathematician at Ghent University in Belgium, tells WIRED, gender-neutral bathroom lines are shortest when men have the option to head straight for a urinal. That's because it's quicker to use a urinal than a stall, and when men opt for the urinal, it frees up stalls for women. When he drew up an equation looking at hypothetical bathroom wait times at a concert, he found that a ratio of 14 toilets to eight urinals produced the most desirable wait times: one minute, 27 seconds for women and slightly under a minute for men. On a commercial plane, this ratio would come out to one or two Durinals per six conventional bathrooms.

Rogiest's concert equation isn't a perfect stand-in for airplane scenarios, so a more specific study would be needed before airlines could consider installing urinals. Unfortunately, if bathrooms with urinals do show up on airplanes, you can expect the spaces to be just as tight as they are now.

[h/t WIRED]

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United Airlines Has Gotten Rid of Tomato Juice, and Customers Are Freaking Out
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Lovers of tomato juice are a small camp, but a vocal one. And they're furious that United Airlines has replaced their beloved Mott's tomato juice with Mr. and Mrs. T Bloody Mary Mix on all flights under four hours, which includes most of its domestic runs. United said these changes are part of efforts to “streamline” its food service, the Chicago Business Journal reports.

The stealth substitution has fueled a rebellion among loyal tomato juice fans, as The Week points out.

There is some truth to the claim that tomato juice tastes better on flights. One study revealed that the noise level on an airplane affects our perception of taste, making savory or umami flavors more delicious. Another industry-funded study said the air pressure and humidity levels make bolder drinks seem more appealing.

Premium and economy passengers flying United can also say goodbye to Sprite Zero, Jim Beam, Courvoisier, and Amaretto, which were cut from the menu. And although airlines are not exactly known for their cuisine to begin with, passengers will likely start to see a difference in the types of meals being offered. The Chicago Business Journal writes:

"The reduction in food being offered in many instances in first-class and business-class cabins is not insignificant. Hot breakfasts are being replaced on some routes with only fruit plates and muffins, and more substantial lunches are being switched out for wraps and chocolate slabs."

The airline has said it is "monitoring customer feedback."

[h/t The Week]

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