Can dragons from Game of Thrones really fly?  Aeronautical engineering and mathematics say yes

Can dragons from Game of Thrones really fly? Aeronautical engineering and mathematics say yes

Can dragons from Game of Thrones really fly?  Aeronautical engineering and mathematics say yes

The following essay is reprinted with permission from The conversationThe Conversation, an online publication on the latest research.

Lately, like many people, I’ve become fascinated with the lives and loves of the ruling classes of the people of Westeros, where the sometimes charming inhabitants spend a lot of time bickering about who’s in charge. Game of Thrones is very entertaining – but don’t get attached to any of the characters, as the lifespans in their world seem quite variable.

One of the many aspiring rulers – Daenerys Targaryen – spends a fair amount of her time with and occasionally rides dragons. My background as an aeronautical engineer got me thinking about the mythical creatures and I noticed that in order to fly, their world has to work a little differently compared to Earth.

It is possible to estimate the size of a dragon compared to Daenerys who appears to be about 1.6m (5ft 3in) tall with a mass of about 60kg (132lb). The dragon’s body appears to be about four times as long as she is, about five times as deep and about twice as wide, with a tail about the same length and about as thick as her body. Assuming that the density of dragon and woman is about the same, the mass of an adult dragon should be about 44 times that of Daenerys: about 2,600 kg (5,700 lb).

Since everyone in Westeros seems to move the same way we do on Earth, let’s assume the same gravitational pull, bringing the dragon’s weight to 26,000 Newtons (what we’ll call W) at a nominal gravitational acceleration of ten meters per second per second (32 ft/s/s).

If we want to understand the aerodynamics of flying dragons, we need two more pieces of information. First, the wing area. Each wing appears to have a wingspan about twice the length of the dragon’s main body, so let’s approximate the wings as two rectangles measuring 4m by 8m (13 by 26ft), or 64m2 (340ft), which we will mention s.

Second, the deceleration speed, or the slowest the dragon can safely fly before falling from the sky. It would be reasonable to assume that dragons take off and land at about their stall speed, just like airplanes and birds. Judging by the programs, it seems that the dragon’s body length of about 13 meters will pass in about three seconds, bringing the stall speed to about 4.3 m/s or 14 ft/s.

Dragon Aerodynamics

As an engineer, when faced with a problem I usually resort to math, in this case the standard elevator equation of:

which I can rearrange to:-

If we use the standard air density on Earth at sea level of = 1.2 kg/m3, this gives a lift coefficient of 36. That is completely unrealistic.

In comparison, a Rogallo winged microlight aircraft – a small one- or two-seater aircraft consisting of a light frame and a small engine suspended under a textile wing in hang gliding – would have a lift coefficient between 2.2 and 2.7. No doubt evolution modified the dragon wing to be very efficient, but I had to make some assumptions here, so I went for maximum lift coefficient (or CL.max) of 3.5.

Aside from the possibility of magic, this tells us that Westeros’ atmosphere must be much denser than ours. Using the same numbers, we can determine how close:

12 kg/m3, or about 10 times the Earth is normal (we call that 10 bar) sounds uncomfortably high, but it’s actually not that bad. It’s about what a diver would experience at 100 meters depth – perfect survival.

There is empirical evidence to support this. If you watch a few episodes of Game of Thrones, you’ll find that just about anyone can pick up a spear or sword and throw distances that an Olympic javelin thrower would envy. Since the gravitational pull appears roughly equal to ours, this suggests that the thrown weapons generate much more lift than on Earth — consistent with a higher-density atmosphere.

There’s something in the air

What is the mix of gases in this atmosphere, I wondered? The Earth’s atmosphere is 21% oxygen, 78% nitrogen, and 1% various other gases. We know that 21% oxygen is fine—you and I are breathing it right now—while 30% oxygen concentrations make just about anything flammable (besides that, starting to look explosive). This seems pretty likely on Westeros, as anyone who comes close to the slightest sigh of dragon breath seems to catch fire, while it’s noticeable that most locals are paranoid about lighting fires anywhere but a stone castle. Westeros probably has high-density air with about 30% oxygen, but no more.

What of the rest? I’m taking a deliberate guess here that it may not be nitrogen that we’re used to on Earth, but is instead argon — an inert gas that’s the second most abundant gas on Earth after nitrogen. Argon is 42% denser than nitrogen and would allow for a higher density atmosphere at a pressure slightly below 10 bar.

There are two laws regarding gases that can be used here to calculate the behavior of the air mixture of argon and oxygen: Charles’s law to add the components together and Boyle’s law to show what happens as the pressure increases. By applying this I can show that at a pressure of about seven atmospheres, an atmosphere of 70% argon and 30% oxygen has our air density of 12 kg/m3, and dragons can fly. In simple terms – we can have a denser atmosphere if the air is heavier – in this case by replacing the inert nitrogen we have on Earth with the heavier (or rather, denser) argon.

This argon oxygen (or argox) mix will actually be moderately narcotic when inhaled at high pressure. Perhaps this could partly explain the regularly irrational and downright aggressive behavior seen in many residents of Westeros.

So a little basic physics, aerodynamics and some working knowledge of human physiology can tell you a lot about Westeros – where dragons fly, fire is to be feared and the irrational behavior of the people is not necessarily about what they drink, but what they breathe.

This article was originally published on The Conversation. Read the original article.

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