The dragon's weight can be reduced, by a mixture of lighter than air gases, heated air, vacuums etc.

I have done some research, but I forgot the equation, this was for a 6000 kg bird, how large does its wings have to be? Well, around 14.5m x 7m, could you help me? Thanks.

edit, this is in an earthlike enviroment, no magic as such, I would like physics, chemistry and math, if you can, and the wing size can also be divided by two more wings, as that was on a 2 wing bird, and this is in a four winged creature

thank you for your help

  • 1
    $\begingroup$ Is it 14.5 x 7 meters? This seems silly, but in physics, units are quite important ;). $\endgroup$ Dec 19, 2020 at 22:55
  • $\begingroup$ Did you try searching here for questions about dragons flying? For example worldbuilding.stackexchange.com/questions/819/… $\endgroup$
    – Seallussus
    Dec 20, 2020 at 0:44
  • 1
    $\begingroup$ How thick is the atmosphere? If its wing muscles are strong enough, it could probably fly around on Venus $\endgroup$ Dec 20, 2020 at 4:42
  • 1
    $\begingroup$ Does the term "like a lead balloon" have any meaning for you? $\endgroup$
    – jamesqf
    Dec 21, 2020 at 3:53
  • $\begingroup$ there are no vertebrates with four lift generating wings. 4 wings would just get in each others way and add a lot of useless weight. the largest creature to ever fly weighed at most 300kg. this is going to make science based not really possible. $\endgroup$
    – John
    Dec 21, 2020 at 7:01

2 Answers 2


I am not very hopeful about 6750 kilogram (14,881 pound) heavier than air flying creatures on a planet like Earth.

See my answer to the question:


For a discussion of the heaviest possible flying creatures on Earth.

My answer here:


Discusses designing a world with a lower surface gravity and much denser atmosphere than Earth. That would help larger creatures to fly, but there are limits to have far it can be taken and remain plausible.

  • $\begingroup$ yeah the largest creature to ever fly weighed at most 300kg. $\endgroup$
    – John
    Dec 21, 2020 at 7:03
  • $\begingroup$ thank you for your answer, i now realized my mistake $\endgroup$
    – Dexyan
    Dec 22, 2020 at 11:30
  • $\begingroup$ but no, it will be on earth $\endgroup$
    – Dexyan
    Dec 29, 2020 at 14:56
  • $\begingroup$ sites.google.com/site/anthonysgurps/dragon-physics is something i found recently $\endgroup$
    – Dexyan
    Jan 14, 2021 at 20:53

Well, that's going to be a BIG problem.


The largest creature that has ever flown was about 250 kg. Now, while your creature is double its weight, a 250 kg pterosaur still had people questioning the limitations of biological flight.

Indeed, burst-flight performance seems not to intrinsically degrade with increasing size.

So, let's talk wings

While aerodynamically efficient, an albatross's monstrous wings would have tremendous inertial costs when it comes to flapping during take-off. Keep in mind that flapping is an oscillatory motion, unlike the rotation of helicopter blades, or the forward motion of a fixed-wing aircraft.

Thanks to how rotation works, a wing with a length of 5 meters can achieve the same speed at a much lower angular velocity, compared to a shorter wing. Large fliers thus tend to have lower flapping amplitudes.

What you must keep high is the flapping frequency, i.e: how many times does the dragon beat its wings in a given unit of time.

So, high frequency, low-amplitude, this is where another important element comes up:

Square-Cube Law

Muscles scale allometrically, they get extra thick but remain short, which comes at the expense of the range of motion. There's a fixed value of absolute shortening the flight muscles have to achieve to move the wing around, depending on the flapping amplitude, once that's met, they can be as thick as necessary.

There's even more to it, but I'm too tired to add it in right now.

  • $\begingroup$ thank you for your answer, the creature is now 300 kg, but has weight reducing vacuums, although i still am searching for a solution with the hydrogen seeping in, and so the weight is actually 250 kg $\endgroup$
    – Dexyan
    Jan 14, 2021 at 18:33

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