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Taking several notable real life inspirations from the animal kingdom I like to design a realistic Dragon towering any creature ever lived but has a nasty habit of generating sonic boom every where in its wake. What are the prerequisites my Dragon have to evolve in order to attain supersonic flight?

I think it's must have close to a mammal blood circulation to supply ample oxygen to its already effective muscular system and is warm blooded like a cheetahs to give it energy for sudden rush of adrenaline, a crocodiles eyelids to cover it eyes, and so on. My concern is that this colossal winged breast would be too heavy and its skeletal structure have to be augmented naturally through evolution but I have no clues how any animal can survive unhurt after performing such a earth shattering feat any ideas? No tech pls and absolutely no thunderpants!

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    $\begingroup$ In addition to a dragon already being implausible; the speed of sound is 3 times higher than the speed of a peregrine falcon in full dive and that's the fastest known avian in the world. $\endgroup$ – Erik Jun 8 '15 at 13:10
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    $\begingroup$ The fuel for the jet propulsion could be released from special glands and be natural. $\endgroup$ – MedwedianPresident Jun 8 '15 at 14:00
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    $\begingroup$ Magical Enhancements allowed, or does it need to be 100% natural? $\endgroup$ – Dan Smolinske Jun 8 '15 at 14:35
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    $\begingroup$ "a realistic Dragon towering any creature ever lived" This sounds like a tall order. Blue whales have been known to weigh 190,000 kg, African elephants 10,000 kg, and male adult giraffes stand up to about six meters tall. All of these species are around in our world today. You are going to have an awfully hard time getting either of those off the ground in a believable, naturally evolved manner. $\endgroup$ – a CVn Jun 8 '15 at 15:36
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    $\begingroup$ "I know dragons are supposed to breathe fire, but doesn't it come out the other end?" $\endgroup$ – hildred Jun 9 '15 at 2:29
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Dragons would need to have a reason to be supersonic in order to evolve to do so.

Being able to fly at supersonic speeds will have incredibly high metabolic and structural costs for the dragon. In order for one to evolve these traits, we need to answer the following question: why do supersonic dragons produce more offspring than non-supersonic dragons?

If supersonic flight doesn't get more food, or more mates, dragons won't evolve it. Similar non-supersonic dragons would outcompete the supersonic ones, since they would require far less food.

In nature, nothing else flies supersonic, and supersonic flight won't be worth its calories if its used to catch cattle or ponies or other such animals. That's not to say that it couldn't be useful, though. Dragons have projectile weapons, so if dragons mostly fight against other dragons, supersonic flight could give them a key edge in dogfighting, especially since the dragon they were closing in on wouldn't be able to hear them coming.

Dragons would need to consume incredibly high caloric density food in order to evolve to be supersonic.

It takes a lot of energy for an aircraft to reach supersonic speeds, probably more than an animal could obtain eating other animals. If dragons fly at supersonic speeds, they'll need to consume something more energetically dense. Something like oil.

If dragons consume oil from naturally occurring sources, they could directly burn this in an internal jet engine in order to achieve supersonic flight.

The Ecology of Dragons

Dragons are large creatures that eat oil. They both extract calories from it, and produce refined fuel which they burn in their engines. These engines resemble a pulse-jet engine, and are primarily comprised of carbon fibers and thermally resistant graphites which the dragons synthesize from their food.

Naturally occurring oil, of course, is rare, and as a result, dragons have become incredibly territorial. They've got large, stiff bodies covered in smooth scales to reduce their drag, and can launch flaming globs of tar at one another mid flight. Large dragons can fly at supersonic speeds, which gives them maneuvering advantages in their aerial fights over oil-rich territory. Because their bodies are stiffened for high speed flight, they can't turn their heads very much, so skill in dogfighting is key for dragons to protect their territories.

These supersonic dogfights, of course, are necessarily short, as the thick scales of graphite that dragons grow on the leading edges of their wings and along their heads slowly ablate during supersonic flight. Dragons prefer to cruise at fast subsonic speeds and use their size and breath weapons to dispatch smaller challengers if possible, rapidly accelerating into the supersonic regime only when absolutely necessary to outmaneuver an opponent. These graphite scales also provide a measure of resistance against the breath weapons of other dragons.

Larger dragons can grow these heat shields faster and thicker than smaller dragons. As this gives the largest of these creatures a major edge in combat, evolution has driven these majestic creatures to grow to truly colossal sizes.

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    $\begingroup$ Good answer. Could you also think up a solution to the enormous thermal effects on leading edges in the drtagon's structure? Maybe large blood vessels in those regions to provide some sort of liquid cooling? $\endgroup$ – Burki Jun 8 '15 at 15:22
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    $\begingroup$ First criterion - the flame comes out the other end. $\endgroup$ – WhatRoughBeast Jun 8 '15 at 19:55
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    $\begingroup$ Partial reason to evolve supersonic flight: no one can hear you coming. $\endgroup$ – RBarryYoung Jun 8 '15 at 23:15
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    $\begingroup$ Naturally occurring oil — whales, rather than petroleum. Maybe big, seamonster whales? $\endgroup$ – mattdm Jun 9 '15 at 10:02
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    $\begingroup$ Another reason for dragons to go supersonic would be if a sonic boom was criteria for sexual selection - the dragons that make more or louder booms have more offspring. $\endgroup$ – Jabe Jun 9 '15 at 14:13
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The real issue behind your dragon problem isn't biological - it's mechanical. The fastest animal on earth is the Peregrine Falcon, which can only reach speeds of 389 KM/H while going at full-dive, which is several magnitudes slower than needed. Simply put, an organic life form could not possibly achieve supersonic speed...

Unless they can make it into space.

Skydiver Felix Baumgartner have been well-documented to have broken the sound barrier simply by falling high enough - 24 miles up to be exact. If your dragon can get itself that high up in the first place, all it would take is falling down, then catching itself before it breaks every bone in its body.

The problems your dragon would face trying to do this are:

  • Getting that high up in the first place
  • Surviving the atmospheric climb without externals
  • Breaking its fall in a non-catastrophic way

Let's get our dragon into space first.

Getting Up Into Space

If your dragon is Titan-levels of large, and you don't mind it leaving a crater behind when it launches into the air, it could simply push itself off the ground and, with a light enough body, accelerate itself up 24 miles high. This would require an enormous amount of energy, but we're not looking to solve the ecosystem problem of a giant dragon - we just want to get it into space.

Another option, that could pair well with the above solution, would be hydrogen gas pockets that allow it to float up into the atmosphere (and would explain where it gets all that fire, if it can breath fire that is). You wouldn't make it all the way up with just hydrogen, but coupled with a good launch, you might just make it high enough.

This would also have to be aided by wings to give them additional thrust(origin of their wings I will get to later) since any momentum that could solely carry them up that far would create a sonic boom on takeoff (Not that this would be necessarily a bad side-effect).

Getting both of these would be evolutionarily unlikely - you would need a strong food chain full of high-caloric prey, coupled with a reason to float and have such strong legs. Fortunately, I have an idea...

Surviving In Space

Your dragon will need to not only survive in the incredibly low-atmosphere of space, but also survive the lack of oxygen involved with being so high in the first place. Evolution-wise, there's one option that might give you both of these at once: Deep sea hibernating ancestors.

Deep sea ancestors on the scale of Giant Squids would give you giant, strong dragons with especially strong legs that would be increasingly strong outside of the high pressures of the ocean, and hibernating beneath the sea, perhaps after feasting on giant squids, would give them a reason to survive without oxygen.

It even suggests a means by which this behavior was evolutionarily chosen for - launching themselves from the sea floor, the faster and stronger dragons, who could also handle the rapid change in pressure, could more easily catch Giant Squid the faster they can go. Some dragons may have even figured out that they can get a better chance of catching them on the return-trip, which would lead them to trying to jump higher and higher, until eventually they evolve the ability to survive breaching the water, then as they move onto land, learn to use their strong legs to leap into space.

Surviving the Drop

This is your biggest challenge - to explain how a dragon that evolved from a sea creature would survive a 24-mile drop. Their initial sheer resistance to pressure (possibly owing to their scales) helps, but they'll need SOME way to catch themselves as they break the sound barrier.

Fortunately, being from the sea gives them one unique feature that could help them with this - Fins, or evolutionarily speaking, evolved wings. Originally used to slow themselves back down after catching a squid, they could use them to catch the air and shift their direction mid-flight, so that their momentum is reduced and redirected in a wholly non-catastrophic, and entirely sound-barrier-breaking way.

There you have it - dragons that leap into space and come crashing down at supersonic speeds, evolved from giant sea-dwelling predators that ate giant squids literally for breakfast.

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  • $\begingroup$ +1 I cannot think of any way for a non-jet powered entity to break the sound barrier besides using gravity to pull them to the ground like this. $\endgroup$ – Cort Ammon Jun 8 '15 at 18:56
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    $\begingroup$ I like the idea of dragons that can move effortlessly between sea, surface, sky, and space. Also, being streamlined for underwater movement would make them look really, really cool. $\endgroup$ – evankh Jun 8 '15 at 19:51
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    $\begingroup$ Never mind the energy, launching your self 24km into the sky with out accelerating while airborne requires you to leave the ground at a minimum of ~686m/s (calculated not taking air resistance into account) which is about twice the speed of sound. You would defiantly require some propulsion on the way up, or you've solved the problem simply by taking off :) $\endgroup$ – Wil Selwood Jun 8 '15 at 20:10
  • $\begingroup$ @WilSelwood That I believe is where their hydrogen sacs would give them some assistance. Though....admittedly they would probably have to make a sonic boom on their way up to even POTENTIALLY make one on their way down, so it's not a non-issue. I've edited in a potential solution. Though if you don't mind suspending disbelief even further, sonic booms on takeoff would not be a bad side-effect. $\endgroup$ – Zibbobz Jun 8 '15 at 20:12
  • $\begingroup$ I was going to comment here but it turned into its own answer. Using a kelp like plant with hydrogen pockets to ride up. Rather than the dragon having rather risky gas sacks of its own. $\endgroup$ – Wil Selwood Jun 8 '15 at 20:38
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Actually I think a smaller dragon would be more likely to achieve these high flight speeds. If for no other reason than it can help them escape larger dragons and can be used as a weapon.

I don't think the dragon could reach these speeds by flapping their wings alone, especially since most dragons would already need magic just to fly because of their size. But if they are very fast and can fly high into the stratosphere, then turn down and dive, they might be able to break the sound barrier with just a little handwavium. This could have come about partly from escaping larger dragons, (fly higher than they can) and then attacking either prey or as another defense against the larger predators.

If it was used as an attack dive they might need reinforced heads and necks, but the sonic boom would really mess up another flying creature or any other creature it passes near.

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I was going to post this as a comment on @Zibbobz's answer, however it kind of grew to being its own answer.

If there was some local fauna which was kind of like kelp. With pockets of hydrogen gas to help hold it's self up. The plant would have evolved this to help them scatter their seeds or pollen over a very large area.

When the dragon wants to go hunting it grabs hold of lots of these. Cuts them free of the ground and floats up, up and away. These plants will have evolved to have very stretchy gas sacks so they can reach higher altitudes. (a normal weather balloon can stretch four times its size during flight1) During the early phase of the flight the dragon takes many deep breaths to oxygenate its blood and then holds its breath once it passes out of the range where it can breath. Whales can hold their breath for up to 90 minutes.

Once the dragon is high enough or the balloon/kelp pops it drops down in a very stream lined shape with its wings folded back. It is still holding its breath. Here it will break the sound barrier. The pray it is falling on will not see or hear it coming. The pray is going to have to give it a huge amount of energy. This has to feed a dragon after all.

As the dragon needs to slow down it first goes from noes down to nose level then slowly expands its wings. Hopefully managing to glide out of the fall before it splatters its self into the ground.

The highly flammable plants may be a problem with this plan. Maybe need to explain that the plants seeds can be activated by fire and thus why they are around fire breathing dragons. We are trying to deal with big dragons, some amount of hand waving is required to deal with the square/cubed law.

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  • $\begingroup$ It's not a bad form of propulsion, though it does break the "unaided" requirement. $\endgroup$ – Zibbobz Jun 8 '15 at 20:41
  • $\begingroup$ True, but its not tech or underpant as the question requested. $\endgroup$ – Wil Selwood Jun 8 '15 at 20:44
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    $\begingroup$ Fair. +1 For some very creative thinking. $\endgroup$ – Zibbobz Jun 8 '15 at 20:44
  • $\begingroup$ Still, with earth athmospheric pressure the falling speed would max out below supersonic speed. Decreasing the air pressure though would it also make easier to reach higher speeds in horizontal flight. $\endgroup$ – Mnementh Jun 9 '15 at 15:07
  • $\begingroup$ Are you sure? Wolfram alpha lists the terminal velocity of a blue whale as 5.2Km/s way way over the sound barrier. wolframalpha.com/input/?i=terminal+velocity+of+an+blue+whale Seeing as he said these things tower over any creature that's ever lived. A blue whale seemed like a reasonable example $\endgroup$ – Wil Selwood Jun 9 '15 at 15:21
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What if the dragons utilize their standard, magically hot fire to modify themselves for supersonic flight?

Arcane knowledge of metallurgy and surgery, passed down through the ages, is used to augment their bones with titanium alloys bathed in dragonfire, strengthening their frames for the ordeal while being hollowed to reduce weight. Scales are reshaped and smoothed to reduce friction, and re-enforced on the leading edge to take the brunt of supersonic flight.

Tanks are added to artificial structures, and the dragons use magic to purify and store enhanced rocket fuel that they then use to literally rocket themselves to supersonic speeds.

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    $\begingroup$ "Steampunk cyborg dragon surgeon" has a pretty nice ring to it. $\endgroup$ – talrnu Jun 8 '15 at 20:59
  • $\begingroup$ To go through such an ordeal just for that ordeal these dragons definitely earns my respect and Wolverine (X-men) should be ashamed of himself for relying on Blackbird to accomplish speed of sound. $\endgroup$ – user6760 Jun 8 '15 at 23:34
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If you are only concerned about the boom and do not necessarily need flight, you could consider different methods of creating a sonic boom.

One scenario that is not so far-fetched and actually might have happened is that dinosaurs with very long tails could have flicked them like a bullwhip, accelerating the tip of their tails to the speed of sound.

Here is an article from '97 about a paleontologist discussing whether it is possible.

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  • $\begingroup$ This isn't an unheard of form of attack even today: Pistol Shrimp quite effectively use sonic weapons underwater, though they are much smaller and have the high viscosity of water working for them - a larger creature like dinosaurs, or dragons, could potentially get a large enough snap to mimic something on a larger, land-based scale. Perhaps by whipping their massive tail as you suggested, or as an alternative, clapping their wings sharply together. $\endgroup$ – Zibbobz Jun 8 '15 at 20:43
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Taking the speed of a perigrine falcon as 1/3rd the speed of sound.

We know that the force of acceleration is proportional to mass.

We know that the force opposing this (air resistance) is proportional to surface area and the square of velocity.

We can rearrange those to say that velocity is proportional to SQRT(mass/surface area).

We can say that mass is proportional to density and wingspan^3.

We can say that surface area is proportional to wingspan^2.

So velocity =k x SQRT(density x wingspan).

We can define density to be density(any animal) = density(peregrine falcon) x y.

using symbols v = p(falcon) x y.

Where y is the density of the animal divided by density of a falcon.

So v = k x SQRT(pyw).

For a peregrine falcon, v = 1/3 speed of sound = 113 m/s. Where; p=1,w =1.

113 = k x SQRT(1).

So k = 1.

For a dragon:

v = 113 SQRT(xw).

Lets set w = 30 meters, and density double that of a falcon, x=2.

v = 113 SQRT(60) = 875 = nearly triple that of sound.

Assuming you have solved the problem of how such a big and heavy animal flies, then getting them to dive much faster than sound is trivial.

The bigger they are, the faster they fall.

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A creature meeting your size, speed, and strength requirements would have to be composed of extremely lightweight tissues, most notably including the skeleton (which must be able to handle the physical stresses of accelerating to supersonic speeds rapidly) and muscles (which must be able to convert the creature's biochemical or magical energies into mechanical energy efficiently, rapidly, and at high volume).

The most "realistic" way I could imagine all of these requirements being satisfied is if your dragon looks like a blimp: a giant sack of air that moves short distances by flapping its wings, and naturally floats in the air because its body density is about equal to the surrounding air density. Such a creature might achieve supersonic speeds by rapidy forcing most of the air in its body cavity through a small opening to create jet propulsion. This would also cause the creature to deflate to a narrow, streamlined shape that's more aerodynamic for long, straight flight paths.

We could go into further technical detail, but as you can see the result is a bit ridiculous. Really what I'm saying is you need a fart dragon.

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  • $\begingroup$ +1 if the lift gas is hydrogen or methane and the blimp dragon has to ignite it to accelerate to supersonic speeds. $\endgroup$ – Thucydides Jun 8 '15 at 22:36
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Well, the big problem here is air resistance. Falling objects top out at a speed of somewhat above 500 km/h because of air resistance. Sound of speed is 1200 km/h. So it would need immense energy to speed up above that limit. Luckily there is an easy way around it: just decrease the air pressure. To get still enough oxygen to support big creatures the percentage of oxygen in the atmosphere has to be increased. But all that are possibilities and would it make easier to achieve higher speeds. Still, most birds reach their highest velocity in dives, so you may want to let the dragon break to supersonic speeds while make an diving attack from a higher flight position.

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  • $\begingroup$ Care to explain the downvote? What is wrong with this answer? $\endgroup$ – Mnementh Jun 10 '15 at 14:07
  • $\begingroup$ This is far too simplistic. There is no standard speed for a falling object. It depends a great deal on density, shape etc. If a dragon was heavy enough, and streamlined enough, there's no reason why it couldn't go supersonic in a dive. I didn't down-vote, but this is probably why you received a down-vote. $\endgroup$ – user1751825 Sep 30 '17 at 22:44
  • $\begingroup$ Mass is irrelevant for falling speeds. Bigger mass means bigger force of gravitational pull, but also bigger momentum. That's why gravitational pull of earth is a constant given as acceleration (9,81 m/s2). Shape is more important, as it influences air resistance. But either way, at some point air resistance cancels out gravitational pull. The best form is similar to a raindrop and the 500 km/h max speed I looked up back then I answered the question. The dragon can produce own acceleration, but the same problem with air resistance. Birds combine fall and flight for reaching high speeds. $\endgroup$ – Mnementh Oct 3 '17 at 19:41
  • $\begingroup$ This is incorrect. Mass is very relevant for falling speed. More specifically density. Think of a polystyrene ball compared to a canon ball. Which will fall faster? A raindrop isn't the fastest object, because water isn't particularly dense. A lead ball will fall much faster than a raindrop. If you look it up, you'll find that density is required to calculate terminal velocity. $\endgroup$ – user1751825 Oct 3 '17 at 22:05
  • $\begingroup$ "A biography by Galileo's pupil Vincenzo Viviani stated that Galileo had dropped balls of the same material, but different masses, from the Leaning Tower of Pisa to demonstrate that their time of descent was independent of their mass." $\endgroup$ – Mnementh Oct 4 '17 at 23:15

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