The Physics of Dragons
I have limited this to the Physics of dragons, since I am not a chemist or biologist. Also, I don’t have clearance from the Dothraki to reveal fine details. Actually, I didn’t watch most of the seasons because of the violence, and I can’t remember names to keep track of people.
Fire breathing dragon legends are present in ancient civilizations, and were created to explain glowing meteorites. It seemed hard to imagine how an animal could develop flammable matter, but in fact, it is a principle source of the greenhouse gas methane. The whole contribution of cows and steers to global warming is that their three stomachs can process grass, and they generate methane, which is CH4, and normally called natural gas. We use that to cook and heat our water and our houses, when it burns. Cows expel natural gas through both as burps and anally.
Methane is colorless and odorless, so a smelly gas mercaptan is added to it so we can smell it. A dragon would have learned when young that when it ground its teeth while burping, it ignited its breath. Fortunately, they were raised by Daenerys Targaryen, Mother of Dragons, and taught good manners. It’s also fortunate that Daenerys is The Unburnt, and can’t be burned by fire. That is harder to explain. The dragons are of course also fireproof, or else they would not have survived.
There is another kind of dragon possible, a pepper spraying one. On the scale of pepper hotness, pepper spray is rated about 1,000. However, there are peppers that rate in the millions. A dragon that can digest those or just spray it out upon eating could easily disable an army, and perhaps even kill some. There are also fire stick plants that if rubbed can cause skin burns. They are a colorful orange and green succulent, popular in Southern California. As a danger to pets, amateur gardeners, and birds, they really should be banned. So, a third possible type of dragon can be imagined. The advantage that dragons have over birds of prey is that they can roast or spice their prey at the same time.
The graphics experts seem to have done believable modeling of how a dragon would fly, sort of like undulating swimming of the thin body. My only doubt is about the support and muscles for the dragon’s wings. The junction with the body of the wings seems too narrow support the broad wings. It is also near the center of the wings, and it is not clear how the forward and rear part of the wings support themselves without stiffness. Birds with large wings have broad shoulder support by bones and muscles at the leading wing edge, like an airplane wing. They get lift from that shape. The dragons wings on Game of Thrones don’t seem to have the structure to do that. Oh, like that’s the only fantasy in Game of Thrones?
None of the types of dragon described above actually matches Drogon in GoT. He seems to belch a tankful of kerosene at once, which also seems to have the power to knock down thick walls. Clearly, there would be singeing blowback to the dragon’s rider on its back. So it is nice that Daenerys is fireproof. Also, fortunately, the dragon could not carry the vast amount of fuel necessary to burn up an entire city. So, no worry.