Mythical creatures like the mighty, fire-breathing, thank-god-not-real dragons from Lord of the Rings and Game of Thrones to the magical, elegant and cute Hippogriffs from Harry Potter have established dominion over the world of fantasy. Being a profound geek and a scientist (not there yet), I cannot help but wonder whether these awesome creatures could actually fly if they existed. Does the Physics add up?
To answer this question, I am going to apply physics and biology to these fantasy creatures by looking at fantasy genre movies and books, and studying different species of bats and birds and researching on google.
Let’s start by discussing a bit more about flying fantasy creature which is unlike anything we have seen in the natural world in both size and shape.
In the world of fantasy, there are a lot of flying creatures like Griffins, Dragons, Manticores, Chimeras, Bone drakes, Pegasus, Hippogriffs, beholders and Darkmantle. These creatures can be classified into 2 major categories: ones which attain the ability of flight through magic like the beholder and the others which have wings like birds and bats like griffins and dragons.
Overlooking the creatures that fly with magic. Let’s dwell deeper into the physics of bird flight. Through extensive experiments and observations, we have a good idea of how birds, bats, insects and planes fly by generating lift but flight is a result of complex interactions of focus which we have quiet no really understood.
All birds don’t fly the same. The variety of different styles of flight arise from the different size, weight and wing shape of birds. Bigger birds like eagles have a slower wing beat and predominantly use energy-efficient methods like soaring. Whereas smaller birds make use of flapping flight. But there are variations depending on the speed and size of the bird. Some have a bounding flight where the flap for some time and glide for the rest of the time.
So to apply real life physics to mythical creatures, we need to have more specific information on there type of flight as well as the reason for flight (hunting or escaping). Looking at creatures in famous movies like Lord of the Rings and How to Train Your Dragon and TV shows like Game of Thrones and Greek mythology, we can compare most of these mythical creatures with large raptors like hawks and eagles why fly using soaring or sporting flapping depending on what they are doing. Based on all this information the basic question we can ask is: Are the wings, shown in these fantasy worlds, big and strong enough to carry the animal of the ground?
To answer this question, I used the relationship between mass of the bird and wingspan of the bird. The mass and wingspan, as expected, are directly proportional but the relationship isn’t linear so a simple extrapolation of the data to much heavier animals like the Hippogriffs doesn’t work.
Researching further, I found an alternate way is considering the wing area. Two major information of how animals flies can be found using the area:
- Wing Loading: Wing area divided by the body mass of the bird. This calculates the amount of weight that each square centimetre of the wing has to support during flight.
- Aspect Ratio: Wingspan squared divided by the wing area. This is a ratio of how long the wing is versus how wide it is.
If plot a scatter graph of the wing loading verses the aspect ratio for a variety of bird and bat species, you really get an interesting graph. Birds like albatross which soar are clustered near the top left sector of the graph with a high aspect ratio and low wing loading. Adorable birds that can almost fly lie puffins are clustered near the bottom right sector with a low aspect ratio and high wing loading. And African raptors are found to be clustered at the bottom left with a low aspect ratio and low wing loading. From this graph we know 2 things: African birds of prey roughly share the same aspect ratio and wing loading. And when we plot the wing area against the mass we get a straight best fit line making it easy for simple extrapolation of massive and heavy mythological creatures. So after we get the wing area of the mythical animal from simple extrapolation, using the aspect ratio the wingspan can be calculated.
A hippogriff flying like a raptor and with the weight of a large horse (1000 kg), its wingspan would be just under 20 m, much bigger than shown in the movies. The most intriguing and cool thing about these calculations is that using them I calculated that for a human weighing about 70 kgs, I would have a wingspan of almost 5 meters. Which is terrifying but cool.
The problem with the above analysis is that when adding wings to a body, you are increasing the overall mass and therefore bigger wings needed and so on. In these calculations, we excluded the weight of the wing for simplicity. The other problem with mythical creatures like dragons is that they have 4 limbs as well as wings, the musculature (arrangement of muscles) in these animals is beyond me.
Birds rely on pectorals muscles to fly which make up 75% of their total muscle mass. And so where the muscles that power the humongous wings of the griffins and hippogriffs on their back, with the four legs and pecs muscles attached to the limbs, attached is what I cannot understand. The musculature doesn’t make any sense. So the creature we have seen and admired in movies have wings that are too small and don’t have any muscles to power them. The biology and physics make them impossible to exist.
Dwelling deeper into the existence of dragons which resemble bats more than birds. I studied the golden-crowned flying fox from the Philippines. The largest flying bat in the world which weigh up to 1.6 kgs and have a wingspan of 1.8 m. The difference between bats and birds flight is the anatomy. Basically bats fly with their hands. It’s like al the fingers enlarge and create the structure of the wing and the skin covered in hair attached between them is the wing. So in a batwing, you have a complete surface area. You have no air gaps like in feathers and as fingers control every edge of the wing membrane, the wing can be easily controllable, it can change shape and collapse also.
