How Could an Elephant Fly?

By Rhys L Griffiths

“But I be done seen about everything, when I see an elephant fly”.

Dumbo taking flight for the first time. Still from 'Dumbo' (1941)

Dumbo taking flight for the first time. Still from ‘Dumbo’ (1941)

Following on from the recent run of Disney science blogs, we at the science made simple office started questioning other fantastical films and the science behind them. The one that instantly came to my mind was Dumbo.

Dumbo was released in 1941 and saw an adorable baby elephant born with abnormally large ears. Despite the other elephants mocking him he put them to use and learns to fly. As magical as all this is, could this actually happen? If an elephant had big enough ears, could it learn to fly?

Aerodynamic Elephants

African Elephant compared to Asian Elephant

African Elephant compared to Asian Elephant

Firstly we should establish which is the most aerodynamic type of elephant. Even though it’s never referred to during the film, chances are Dumbo is an Asian elephant. This is mainly because these were the type of elephants preferably used in circus, as they were easier to train. However, Asian elephants have much smaller ears then African elephants and size of ears must be important when achieving lift.

There are no elephants alive with ears big enough to fly although each type of elephant has different body shape, which can help with being more aerodynamic. The highest point on the body of the Asian elephant is the top of the head but the African elephant is more streamlined as it’s highest point is it’s back. After much debate over which is a bigger factor in flight: weight or shape, I’m going to go with weight. An African adult elephant can weigh 13,000 lbs where as a male Asian elephant can weigh up to 11,000 lbs. A lighter elephant will be easier to get off the ground.  As it’s most likely that Dumbo is an Asian elephant, that’s the kind of elephant we are going to look at.

Getting off the Ground

All rights reserved - Science made simple

All rights reserved – Science made simple

In order to achieve take off, Dumbo will have to travel at high speed.  This could be problematic as the fastest Asian elephants have been recorded running is 15 mph and even then it was more of a saunter then a run. Elephants just don’t like running. They also can’t jump making take off close to impossible. Dumbo manages to achieve flight by jumping off the top of the mock apartment building in the circus, or falling off a cliff; but the moment he begns to slow down then he is going to plummet. It’s estimated that Dumbo’s wingspan is about 10 ft and the chord (width) is roughly 2 ft. To find out the wing area we multiply the wingspan by the chord:

10 x 2 = 20 ft²

A baby Asian elephant weighs roughly 200 lbs when born and can gain 2 or 3 lbs per day until they are one. Following the events of the film my estimation is that Dumbo is a couple of months old before he takes flight, putting his weight just under 500 lbs, for ease I’m going to round to an even 500 lbs. To work out his wing load you would divide his weight by the wingspan:

500 ÷ 20 = 25 lb/ft²

This wing load is just a bit smaller then a Douglas DC-3, a fixed wing propeller driven airliner, which needs to travel in excess of 200mph to achieve lift.

Falling with Style

'Jumbo-Jet' by Spike Milligan

‘Jumbo-Jet’ by Spike Milligan

In order for Dumbo to fly, with his dimensions, he would have to maintain a speed close to 200 mph to stay in the air. In the film he tends to glide rather then soar so to achieve this wing load needs to be similar to a hang glider, which has a wing load 1.3 lb/ft². That would mean, Dumbo’s ears would have to have a wing span of 156.25 feet. Those are some pretty big ears in order to glide, just 20 feet short of a Jumbo Jet’s wingspan. That’s assuming the chord doesn’t change. Ideally for better balance his ears would be located on his back for better balance and weight distribution.

Remember, Dumbo is still a growing elephant. He is only a few months old. If he grew up to be an adult elephant, then how big would his ears have to be in order for him to fly? An adult male Asian elephant weighs roughly 11,000 lbs and stands at 10 ft tall. Assuming the chord is 1/3 the height of the elephant, that puts it roughly at 3.5 ft. In order to glide like a hang glider, the wing span would have to be 1,964 ft. That means that each ear would be just under 300 meters (a little bit shy of the height of a wind turbine). Bearing in mind that an albatross has the largest wingspan of any living bird and that is only 3 meters long, grown up Dumbo would be a force to be reckoned with, on land and in the air.

Big ears, big problems

Mockery isn’t the only problem Dumbo would have to face. Elephants pump blood through their ears to cool themselves down. Dumbo’s big ears would actually be a pretty good cooling system and would stop him suffering from heat stress, however he would have to constantly keep flapping them otherwise he would die from hypothermia. An adult elephant with ears proportionate to Dumbo’s wouldn’t manage well as it would need an incredibly large metabolic rate and would require a large intake of food to compensate for the loss of heat through the ears. Even though Dumbo may survive when among the clouds, he would perish on the ground.

For more Disney science, check out:

The Real life Jungle Book

Genetics of the Aristocats

 

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Posted in Biology, Exploring Science, Physics