# How much surface area would a dragon's wings need to let it fly?

The dragon is 350kg, and should be able to fly up to 2.5 km above sea level.

Gravity and atmospheric pressure are normal.

There isn't much of a limit for the muscle's strength and bone resistance, but let it at least be plausible, enough for the creature to be able to flap the proposed wing size and a bit more.

The flight is like that of a bat, able to fly up and down, as well as glide — which will be the main transportation method — up to speeds of 180 km/h.

the wing shape is that of a bat's and if you can add anything to improve efficiency, the better

It would be much appreciated if you showed how you figured out your answers.

• Wow 500kg.. +1, though it must be a really big dragon. Normally, dragons are assumed not be so heavy for their size, flying dragons have reptile a "reptile/birdy" skeleton. I think you'll could get in trouble with square cube law ! worldbuilding.stackexchange.com/search?q=square+cube+law Feb 17, 2022 at 23:30
• You don't give us a lot of information to determine this. Given there are objects weighing more than 500kg that can fly without a wingspan, (sufficiently heavy rockets) I think you need to provide us with more information before this question is really answerable. Feb 17, 2022 at 23:50
• @sphennings it's an animal with wings, not a machine Feb 18, 2022 at 0:38
• Infinitely strong bones and muscles doesn't make sense. You could in theory then have tiny wings beating at an incredible rate with a ridiculously high wing loading. We'd need something more reasonable, and also the sort of maneuverability and speed you'd want. Feb 18, 2022 at 0:48
• Knowing the desired maneuverability is required. Knowing the desired cruise speed and maximum speed is also required. What glide ratio is required? Without that, we could give you the details for a 500kg hummingbird, or a 500kg kite. Feb 18, 2022 at 1:07

For a real life example, consider Quetzalcoatlus Northropi:

Though there's still some debate on the matter, they probably weighed closer to 200kg than 500kg. Some estimates were closer to 500kg but the author cast doubts on the ability of something that heavy to actually get off the ground.

The size probably isn't far off what you need. Compare with a Cessna 152 which has a similar size and weight.

the flight is like that of a bat, for example, able to fly up and down as well as glide and up to speeds of 180-200km/h

Bats, even the biggest ones, are what biologists might refer to as "not very big". Your half-tonne dragon, by comparison, might actually be bigger than any living thing that has ever flown unaided.

What it will do is to leap into the air, and flap for as little time as possible in order to transition to thermal-assisted soaring flight, because continuously muscle powered flight in something that enormous would require an impractical amount of stored energy.

It might be able to reach the lower end of the speed range you're thinking of, but it'll be tricky and would put quite a lot of stress on those big wings. It certainly won't be fluttering about, but you definitely wouldn't want to be on the wrong end of a fast descent by a predator that big that could probably see you from many, many miles away.

the wings are around the shape of these wyvern wings

Wyverns are fantastical, not realistic. If you want something wyvern-shaped to be flying around, then you should probably not think too hard about plausible biomechanics, because you'll be disappointed.

Be sparing with your details, and there's no danger of being unambiguously wrong. Not everything has to be hard scifi!

• thanks! I've also been able to reduce the weight, it is now 350kg Feb 18, 2022 at 10:02
• +1 great example from the past.. I saved that diagram ! Feb 18, 2022 at 10:09

Wing span is easier to calculate so lets do that to give us a baseline.

bats: mass in kg = 0.5088(wingspan in meters)^3.0294

W=\sqrt[3.0294]{\frac{M}{0.5088}} = 8.64 meters

Pterosaurs: mass = 0.681 (wingspan)^2.807

W=\sqrt[2.807]{\frac{M}{0.681}} = 9.24 meters

find wing area requires knowing what kind of flyer it is, wing area varies quite a lot based on the type of flyer, like several orders of magnitude. It ranges from (Mass times gravity)/X with X ranging from 4 to 35 just in bats. 4 for the most maneuverable flier and 35 for the fastest. that comes out to that's 857.5 meters squared to 98 square meters which is far too large of a margin of error meaning the size difference is breaking down the calculation. It will be almost impossible to calculate on such a larger animal without knowing wing structure and flight style. Even then the margin of error will be huge.

1. Is the dragon, fast, maneuverable, or efficient(glider), it can only be ONE.

2. what shape is its wings, as in bird, bat, pterosaur, other?.

One thing to consider is that also means it has a wing beat frequency around one wing beat per 8 seconds at minimum.

https://www.witpress.com/Secure/elibrary/papers/1845640012/1845640012204FU1.pdf

https://www.researchgate.net/figure/Pterosaur-masses-estimated-in-this-study-plotted-against-wingspan_fig3_279618696

https://www.dinosaurtheory.com/flight.html

• efficient, very efficient and tries not to flap very much Feb 20, 2022 at 10:01

Ok, I think I got something it's probably wrong, but it's a start, but I'd like some checking I couldn't really figure out the lift coefficient in Cl x ((air density x velocity^2)/2) x wing area =lift

0.7556979626382 x ((1.112 x 96.04)/2) x 85, this gives us 3430 as minimum lift, or 350 x 9.8

• you do know animal wings are different than plane wings right?
– John
Feb 20, 2022 at 12:53