Up
In Disney/Pixar’s newest animated adventure film UP, Carl Fredricksen attaches helium balloons to his house to take him and young wilderness explorer Russell on the adventure of a lifetime in South America.
But could this actually be done in real life? How would you steer the house to get it there, and how many balloons would it take to lift a house and make it fly?
There is a sport called cluster ballooning where people can strap themselves to helium balloons and fly. The ‘pilots’ drop the weights they are carrying, to rise higher, and can reach as high as 6,000 meters (20,000 feet)! However, 900 - 1500 meters (3000 - 5000 feet) is the more common altitude.
Steering is a bit difficult as the cluster balloons move in whatever direction the wind carries them, but since the wind directions that exist at different altitudes vary, some manoeuvring is possible by controlling the altitude.
This means that steering the house in the right direction could be possible by throwing out heavy things, perhaps a grandfather clock or that home gym that you used twice and is now relegated to the spare room.
How many balloons would it take to lift the house?
There are different estimates on this. A website called The Wired Science Blog contacted a company that moves houses and came up with the following calculation.
They estimated Carl Fredricksen’s house would weigh about 50,000 kg (100,000 pounds). The balloons would be filled with helium, which is lighter than air, and therefore creates an upward thrust.
To be more precise, air weighs about 1.20 grams per litre (0.078 pounds per cubic foot), and helium weighs just 0.18 grams per litre (0.011 pounds per cubic foot); creating an upward force of 1.02 grams per litre (0.067 pounds per cubic foot).
So if you divide 50,000 kg (100,000 pounds) by 1.02 grams per litre (0.067 pounds per cubic foot), you end up with the conclusion that it would take about 49,020 litres (1,492,537 cubic feet) of helium to lift the house.
The cluster ballooners use balloons that range in size from 91 to 213 cm (3 to 7 feet) when they fly, and depending on the mix of sizes, they need anywhere from 50 to 150 balloons to carry them. The balloons used by Mr. Fredricksen in UP are smaller, so using balloons 91 cm (3 feet) in diameter that together carry 49,020 litres (1,492,537 cubic feet) of helium would add up to about 106,000 balloons.
However, regular party balloons are even smaller than 91 cm (3 feet) in diameter, so Pixar estimate it would take many more of them. "We’re not physicists but one of our technical directors calculated that it would take 20 to 30 million balloons to actually lift Carl’s house," says Steve May, the film’s supervising technical director.
In the end the creative team ended up using 10,297 balloons for most of the floating scenes in the film, and 20,622 when the house actually lifts off.
So, to lift your house with helium balloons as portrayed in UP, you would need between 100,000 to 30 million, depending upon the size of the balloons.
Preparing for the journey
Before you and your house heads off to South America, you might want to look into some other small details. Such as what the local authorities think of you making your home into an aircraft, flying it over densely populated areas, dropping home gyms from several thousand feet to steer it etc.
While you get that sorted you can check out UP, released in cinemas on the 9th of October, for some adventure inspiration as well as plenty of laughs. The film is also released in Disney Digital 3-Dä, to give you a fully 3 dimensional look at how to make it all work.
Up is released 9th October
Tagged in Pixar