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