Speaker 1: Welcome to brain Stuff from How Stuff Works Fay brain Stuff.
Speaker 1: It's Christian Sager. When you think about it, airplanes they're
Speaker 1: pretty amazing, right, Despite their weight, these enormous metal contraptions
Speaker 1: can lift hundreds of people into the air, and most
Speaker 1: of the time they can do this safely, if not
Speaker 1: kind of comfortably. Take the Boeing seven forty seven eight,
Speaker 1: for example, it has a maximum takeoff weight of four
Speaker 1: hundred and eighty seven point five tons. Now, for comparison,
Speaker 1: that's about the same weight as almost a hundred and
Speaker 1: forty average sized African elephants. And that's a bunch of
Speaker 1: weight to move. And the engines need a lot of
Speaker 1: fuel to make that happen. But how much fuel do
Speaker 1: they need exactly? Now, Before we can answer that, let's
Speaker 1: ask another question. Why should we care? Well? Fuel efficiency
Speaker 1: and fuel cost is part of how an airline determines
Speaker 1: your ticket prices, So a more efficient airline can theoretically
Speaker 1: result in lower ticket prices for you and me. Let's
Speaker 1: look at a plane on an international trip to see
Speaker 1: how much fuel it uses per person. And since we're
Speaker 1: dealing with a lot of numbers, let's set it up
Speaker 1: this way. I will use US standard measurements, but since
Speaker 1: the rest of the world uses the metric system, I'm
Speaker 1: going to pop those in two. So here we go.
Speaker 1: We're ready for takeoff. A plane like the seven forty
Speaker 1: seven eight can carry around sixty three thousand, thirty four
Speaker 1: gallons of fuel or two hundred thirty eight thousand, six
Speaker 1: hundred and ten leaders, giving it the ability to make
Speaker 1: extremely long flights, so flying from say, l A to
Speaker 1: Australia is no problem as long as it's gassed up. However,
Speaker 1: the plane uses approximately one gallon or four leaders of
Speaker 1: fuel every second, and this means that over the course
Speaker 1: of a ten hour flight, it might burn thirty six
Speaker 1: thousand gallons or a hundred and thirty six thousand, two
Speaker 1: hundred and seventy five liters of fuel, which sounds like
Speaker 1: a lot right now. According to Boeing, this works out
Speaker 1: to approximately five gallons of fuel per mile or nineteen
Speaker 1: leaders per one point five kilometers when the plane is
Speaker 1: in flight, And at first this might sound like the
Speaker 1: plane gets a terrible miles per gallon rating and that's
Speaker 1: not efficient, but let's remember that the seven eight isn't
Speaker 1: the same as something like I don't know a four
Speaker 1: door sedan. It can carry as many as five hundred
Speaker 1: and sixty eight people on a very uncomfortable flight. So
Speaker 1: how does all of that fuel workout per person? Well,
Speaker 1: let's say, for example, that there are five hundred people
Speaker 1: on a plane. So a seven forty seven eight is
Speaker 1: transporting five hundred people one mile using five gallons of
Speaker 1: fuel or again nineteen liters per one point five kilometer. Now,
Speaker 1: this means that the plane is burning about point zero
Speaker 1: one gallons per person per mile or point zero four
Speaker 1: leaders per person per point six kilometers. Now, in other words,
Speaker 1: the plane is getting a hundred miles per gallon per
Speaker 1: person or forty two point five kilometers per leader per person. Now,
Speaker 1: for comparison, your typical car gets around twenty five miles
Speaker 1: per gallon or ten point six kilometers per leader. So
Speaker 1: in this respect, the seven forty seven is actually much
Speaker 1: better than a car carrying one person, and it compares
Speaker 1: favorably even if there are four people in the car. Now,
Speaker 1: of course, this isn't exactly an apples to apples comparison
Speaker 1: for a number of reasons, but still, a hundred miles
Speaker 1: per gallon per person isn't all that bad When you
Speaker 1: consider that the seven forty seven is flying at about
Speaker 1: five hundred and fifty miles per hour. I mean, how
Speaker 1: fuel efficient is your private plane? Check out the brainstuff
Speaker 1: channel on YouTube, and for more on this and thousands
Speaker 1: of other topics, visit how stuff works dot com.