WEBVTT - How Fuel Efficient Is An Airplane?

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<v Speaker 1>Welcome to brain Stuff from How Stuff Works Fay brain Stuff.

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<v Speaker 1>It's Christian Sager. When you think about it, airplanes they're

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<v Speaker 1>pretty amazing, right, Despite their weight, these enormous metal contraptions

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<v Speaker 1>can lift hundreds of people into the air, and most

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<v Speaker 1>of the time they can do this safely, if not

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<v Speaker 1>kind of comfortably. Take the Boeing seven forty seven eight,

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<v Speaker 1>for example, it has a maximum takeoff weight of four

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<v Speaker 1>hundred and eighty seven point five tons. Now, for comparison,

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<v Speaker 1>that's about the same weight as almost a hundred and

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<v Speaker 1>forty average sized African elephants. And that's a bunch of

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<v Speaker 1>weight to move. And the engines need a lot of

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<v Speaker 1>fuel to make that happen. But how much fuel do

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<v Speaker 1>they need exactly? Now, Before we can answer that, let's

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<v Speaker 1>ask another question. Why should we care? Well? Fuel efficiency

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<v Speaker 1>and fuel cost is part of how an airline determines

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<v Speaker 1>your ticket prices, So a more efficient airline can theoretically

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<v Speaker 1>result in lower ticket prices for you and me. Let's

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<v Speaker 1>look at a plane on an international trip to see

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<v Speaker 1>how much fuel it uses per person. And since we're

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<v Speaker 1>dealing with a lot of numbers, let's set it up

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<v Speaker 1>this way. I will use US standard measurements, but since

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<v Speaker 1>the rest of the world uses the metric system, I'm

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<v Speaker 1>going to pop those in two. So here we go.

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<v Speaker 1>We're ready for takeoff. A plane like the seven forty

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<v Speaker 1>seven eight can carry around sixty three thousand, thirty four

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<v Speaker 1>gallons of fuel or two hundred thirty eight thousand, six

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<v Speaker 1>hundred and ten leaders, giving it the ability to make

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<v Speaker 1>extremely long flights, so flying from say, l A to

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<v Speaker 1>Australia is no problem as long as it's gassed up. However,

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<v Speaker 1>the plane uses approximately one gallon or four leaders of

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<v Speaker 1>fuel every second, and this means that over the course

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<v Speaker 1>of a ten hour flight, it might burn thirty six

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<v Speaker 1>thousand gallons or a hundred and thirty six thousand, two

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<v Speaker 1>hundred and seventy five liters of fuel, which sounds like

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<v Speaker 1>a lot right now. According to Boeing, this works out

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<v Speaker 1>to approximately five gallons of fuel per mile or nineteen

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<v Speaker 1>leaders per one point five kilometers when the plane is

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<v Speaker 1>in flight, And at first this might sound like the

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<v Speaker 1>plane gets a terrible miles per gallon rating and that's

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<v Speaker 1>not efficient, but let's remember that the seven eight isn't

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<v Speaker 1>the same as something like I don't know a four

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<v Speaker 1>door sedan. It can carry as many as five hundred

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<v Speaker 1>and sixty eight people on a very uncomfortable flight. So

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<v Speaker 1>how does all of that fuel workout per person? Well,

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<v Speaker 1>let's say, for example, that there are five hundred people

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<v Speaker 1>on a plane. So a seven forty seven eight is

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<v Speaker 1>transporting five hundred people one mile using five gallons of

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<v Speaker 1>fuel or again nineteen liters per one point five kilometer. Now,

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<v Speaker 1>this means that the plane is burning about point zero

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<v Speaker 1>one gallons per person per mile or point zero four

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<v Speaker 1>leaders per person per point six kilometers. Now, in other words,

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<v Speaker 1>the plane is getting a hundred miles per gallon per

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<v Speaker 1>person or forty two point five kilometers per leader per person. Now,

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<v Speaker 1>for comparison, your typical car gets around twenty five miles

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<v Speaker 1>per gallon or ten point six kilometers per leader. So

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<v Speaker 1>in this respect, the seven forty seven is actually much

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<v Speaker 1>better than a car carrying one person, and it compares

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<v Speaker 1>favorably even if there are four people in the car. Now,

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<v Speaker 1>of course, this isn't exactly an apples to apples comparison

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<v Speaker 1>for a number of reasons, but still, a hundred miles

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<v Speaker 1>per gallon per person isn't all that bad When you

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<v Speaker 1>consider that the seven forty seven is flying at about

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<v Speaker 1>five hundred and fifty miles per hour. I mean, how

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<v Speaker 1>fuel efficient is your private plane? Check out the brainstuff

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<v Speaker 1>channel on YouTube, and for more on this and thousands

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<v Speaker 1>of other topics, visit how stuff works dot com.