Inititial Note: This might not be the right board for this threa, but I think it is the closest one.
Up until very recently, I have thought that the largest flying creatures on Earth don't exceed a mass of around 10kg (~18lb). Albatrosses apparently have a mass somewhere in that ballpark. I knew about the prehistoric flying reptiles called Pterosaurs and their huge wing spans, but I always recalled some, as it turns out erroneous, information that although heavier than Albatrosses, the Pterosaurs too were not as heavy as humans and might range from say 20-40kg (36-72lb). This seemed to be the biomechanical limit on the weight of flying creatures.
Apparently, however, Pterosaurs were much heavier than that. The article I link states that Quetzalcoatlus could have weighted between 250lb and 550lb and had a wingspan of 36 feet! This is obviously much heavier, not to mention larger, than the average human. Going by mass, this would indicate that a category "Large" creature might be able to fly. Going by size (wingspan), it would indicate that category "Gargantuan" creature might be able to fly.
I remember some that the High Level Campaigns book in back in 2E AD&D stated that on a non-magical world creatures larger than a certain size cannot fly. I don't have the book in front of me, but I think the size category in question was "Small" or in that ballpark. Sometimes reality is more amazing than fantasy!
So, what does this say about Dragons? Well, 3.5E D&D Draconomicon does provide their sizes and masses and these are much, much larger than those of the Pterosaurs. That means we are most likely back to ' it's fantasy' or 'it's magic' as an explanation for dragon-flight, but the biomechanics of realistic flight of massive creatures is still something that is interesting to think about! And although the dragons may be too big, the range of fantasy creatures that could 'realistically' fly without magic or suspension of disbelief has just grown much bigger!
Final Note: Obviously, airplanes can fly and some of them have a mass in excess of 150 metric tonnes. Here, however, we are talking about biological systems and biomechanical limits of flight, which are likely to differ substantially from actual physical limits of flight of machines.
Scientific American Magazine - May 14, 2009
How Giant Pterosaurs Took Flight
Biomechanics suggests that a giraffe-size pterosaur could have jumped from all fours to get off the ground
By Stuart FoxFor almost a century, scientists struggled to explain how the extinct reptiles called pterosaurs managed to get off the ground. In regard to the smaller pterosaurs, bird models sufficed; flapping from standstill or a running start could work. But for the larger pterosaurs, some of which had a 26-foot wingspan and weighed 200 pounds, scientists could not find a bird model that explained takeoff.
That is because they did not take off like birds, thinks Michael Habib, who studies functional anatomy and evolution at Johns Hopkins University. After analyzing the biomechanics of the creatures, Habib proposes that pterosaurs took flight by using all four limbs to make a standing jump into the sky, not by running on their two hind limbs or jumping off a height, as more widely assumed.
“I started as a bird researcher,” Habib says. “I became interested in mechanical limits in flying animals, and that naturally leads to pterosaurs.”
And pterosaurs such as Quetzalcoatlus sit firmly on the far end of those limits. Even with its birdlike hollow bones, Quetzalcoatlus weighed between 250 and 550 pounds and had about a 36-foot wingspan. By comparison, an albatross weighs about 18 pounds and has an 11-foot wingspan. It had to take off somehow, but no one had a good guess how.
By analyzing the shape of the pterosaur arm bones, Habib calculated that the forelimbs could withstand stresses far greater than those encountered during flight. But why evolve reinforced wings if they would never experience high stress? Habib then made the connection between the quadrupedal gait of the large pterosaurs and the jumping quadrupedal takeoff he had seen in vampire bats. If the large pterosaurs used all four limbs to get off the ground, that would explain both the superstrong forelimbs and solve the mystery of pterosaur takeoff.
But just because an animal could do something does not mean it did, and some paleontologists remain unconvinced that Habib’s data actually explain how pterosaurs got off the ground. “When I read the manuscript, my first reaction was, ‘Hmm, that’s odd.’ But if you work on pterosaurs, you get used to odd things anyway,” remarks David Unwin, a paleontologist at the University of Leicester in England and author of the book The Pterosaurs: From Deep Time. “Large and giant pterosaurs pose a problem,” he explains, “because the flying speed they need to achieve is quite high, 30 or 40 miles per hour, and I have a hard time understanding how they get that fast from a standing jump.”
Paleontologist Kevin Padian of the University of California, Berkeley, also questions some of Habib’s conclusions. Padian says he believes the smaller pterosaurs (some were the size of sparrows) were bipedal and thus took off with two legs, not four. He also does not think Habib has covered every kind of relevant bone stress.
The divide between the pterosaur researcher and the researcher looking at pterosaurs is fairly common in this area of paleontology. According to both Unwin and Habib, pterosaurs, with their improbable size and ability to fly, draw in biomechanics experts more focused on physics than prehistoric biology. “Because of the bizarre nature of pterosaurs, they’ve attracted attention from outside paleontology,” Unwin says. “So we’ve had a disproportionate number of people come in from outside paleontology, lots of people ready to have a go at the aerodynamics who are not pterosaur researchers first.”
Still, all agree that Habib brings up interesting points, and they are not just for biomechanics. Showing that the large pterosaurs could take off without having to jump off a cliff expands the range of places they could have lived, raising all kinds of questions about the ecology of large pterosaurs. Says Padian: “Every time we think we’ve figured them out, they throw us another curve.”
This story was originally published with the title "Leapin' Lizards"
From Scientific American: http://www.sciam.com/article.cfm?id=how-pterosaurs-first-took-flight
There was an interesting discovery channel show on dragons that was presented in a "if they were real, this is how they did it" sort of way (I don't know when discovery became more about psuedoscience and myth than actual science, but I digress). They posited in that show that dragons generated methane (I think) gas to both aid in flight and help them generate their fiery breath weapons (they ate certain rocks and use them like flint and steel in their mouths to create a spark while exhaling the gas). I am still not convinced that they lift from the gas they could hold would have been enough to make the wingspan to weight thing work, but it was interesting none-the-less.
Yeah, dragons the size of those in D&D could fly but they would have WAY bigger wings and their musculature would make them look significantly different than we see in the books.
Sean Mahoney.
That program sounds like it might be based on the book The Flight of Dragons by Peter Dickinson, which made similar suggestions. It's quite an entertaining discussion on the subject, if you can get hold of a copy. It's been a while since I read it, but I vividly remember the dinner plates and bricks illustrations explaining the mass to required lift problem.
One question: are we talking about true, powered flight (such as what a songbird achieves), or are we working with anything that gets you off the ground, e.g. gliding? The structural differences between the two might be important.
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I'm sure the Draconomicon covers this, but if you're looking to make things real world accurate, why bother playing a fantasy setting in the first place? I'd be more concerned about the existance of giant arthropods given that fantasy settings are assumed to have modern Earth-like oxygen levels. That, and the existence of magic. :)
I too saw the TV program in question and enjoyed it as fluff -on par with the alien life series they did. Patrick Stewart narrated IIRC.
Lots of D&D creatures are impossible. (Without magic goes without saying, so assume my argument below involves an antimagic field to cut out blatantly impossible things like breathing fire.)
Giants aren't outright impossible, but would need to be built like elephants, not scaled-up people.
Dragons, Rocs, and other big flyers are impossible unless you can dramatically increase the power output of their muscles or make them out of balsa wood (without weakening them.)
Fire Elementals have nothing to burn.
Anything with a meaningful burrow speed is impossible.
Even without magic, the 'mundane' physics of the game world are different from those of our own. They have to be.
Perhaps they rely on dynamic stall, like bumblebees. And methane ... and magic ... and quantum physics ... and peanut butter ... and
Due to the size and caloric needs of a dragon, I think they'd use crunchy. Smooth peanut butter wouldn't do the trick. Hard peanut chunks would burn better. That's their secret.
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Perhaps they rely on dynamic stall, like bumblebees. And methane ... and magic ... and quantum physics ... and peanut butter ... and
How Quetzaquoatl Flies: let me tell you about this dream I had...A black snake moving through the morning grass, unfurled coarse black feather wings from its body (they came from nowhere). Fully streatched the forward leading edge feathers pulled forward from the Feathers on the trailing edge to reveal a band of coloured skin - it literally emmited the light of a rainbow. Then without flapping it simply absorbed the light of the Sun and lifted off the ground and glided away.
'It shouldn't be able to get airborne.'
'You're right there.'
'If it's built like swamp dragons, it should weigh about twenty tons. Twenty tons! It's impossible. It's all down to weight and wingspan ratios, you see.'
'I saw it drop off the tower like a swallow.'
'I know. It should have torn its wings off and left a bloody great hole in the ground,' said Lady Ramkin firmly. 'You can't muck about with aerodynamics. You can't just scale up from small to big and leave it at that, you see. It's all a matter of muscle power and lifting surfaces.'
'I knew there was something wrong,' said Vimes, brightening up.
-- Terry Pratchett, Guards! Guards!
A large big lizard-like creature with wings, red scales, and burning breath is waiting outside. It told me it will answer all your questions when you go outside and ask them to its face.
It says silly questions give it the hiccups.
Verisimilitude!
To address the OP, Quetzalcoatlus would be a large creature by 3.5 size standards.
That would be in keeping with historical depictions of dragons. Most dragons in real world legends were no bigger than a large bear. In fact, some of the smallest dragons were the most dangerous because of the poisonous bite or breath.
Now, for modern dragons, most would be too big to fly without some form of magical effect or unusual aspect of the world.
Lots of D&D creatures are impossible. (Without magic goes without saying, so assume my argument below involves an antimagic field to cut out blatantly impossible things like breathing fire.)
Giants aren't outright impossible, but would need to be built like elephants, not scaled-up people.
Dragons, Rocs, and other big flyers are impossible unless you can dramatically increase the power output of their muscles or make them out of balsa wood (without weakening them.)
Fire Elementals have nothing to burn.
Anything with a meaningful burrow speed is impossible.
Even without magic, the 'mundane' physics of the game world are different from those of our own. They have to be.
You forgot a few other things, unexplained by magic or even different physics, like:
Small longspears are, by definition, smaller than medium longspears, yet they still provide a 10' reach.
Tiny maces/hammers, etc, shouldn't hurt you to any serious degree, but they still do.
A horse can't move at full speed down a 5' wide tunnel; it has to "squeeze", even though it is not 5' across.
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Perhaps they rely on dynamic stall, like bumblebees. And methane ... and magic ... and quantum physics ... and peanut butter ... andHow Quetzaquoatl Flies: let me tell you about this dream I had...A black snake moving through the morning grass, unfurled coarse black feather wings from its body (they came from nowhere). Fully streatched the forward leading edge feathers pulled forward from the Feathers on the trailing edge to reveal a band of coloured skin - it literally emmited the light of a rainbow. Then without flapping it simply absorbed the light of the Sun and lifted off the ground and glided away.
Photovolition. You can get 'spontaneous' lift with light (as in not-heavy) polymers. The polymers are organic-based.
The bigger the flier, the bigger the wings need to be. House fly wings aren't even as long as they are, while seabird wings are maybe 1.5 to 2 times their body length. A Large dragon's wings would have to be...I dunno, 48' long. A Colossal dragon's would have to be...basically so big that they'd snap like twigs under their own weight.
Oh yeah, and larger bones are weaker than smaller bones so a Colossal dragon skeleton would look something like the Michelan Dragon.
Dragons and other flying creatures have a supernatural ability that they can use at will as a free action:
Magi-scientifi-flight (Su): You are able to warp the laws of magic and science to make yourself fly. No one knows how. Elminster and Steven Hawking got together and tried to figure it out once, but the problem was so complex that they gave up and went to Branson.
If you see this ability being used and attempt to identify it, you become helpless for 10 minutes as your grasp of reality is ripped from your mind. If you try a second time, you're just too stupid to live and the powers that be remove you from existence. Period. Really, you're not supposed to think about stuff like this.
Dragons and other flying creatures have a supernatural ability that they can use at will as a free action:
It's an (Ex), not (Su), but yeah, pretty much.
OT: Dan,
Nope. Canadian, eh.
I don't get this one. When you say tiny, how tiny are you talking? A one pound, well balanced hammer is quite heavy enough to break your bones and crush your skull.
Tiny maces/hammers, etc, shouldn't hurt you to any serious degree, but they still do.
Yes, in the hands of a human, who would actually have the physical capability of doing so. Picture the type of light hammer you'd expect a pixie to wield one-handed. Now imagine that pixie being able to put enough momentum behind such a hammer to actually do some serious damage to you. Silly, isn't it?
Bludgeoning weapons rely on two things: weight and force, with the latter being the more important of the two. Real warhammers and maces worked because all that force was being applied to a relatively small surface area. The fantasy "Thor-style" warhammers work because they're big blocks of stone or metal that batter the heck out of you. Bludgeoning weapons below a certain size become ineffective. The only reason a sling bullet does damage is due to the speed with which it is released. Put a sling bullet on the end of a stick and hit someone with it, and they'll laugh at you. Try to hit them hard enough to do damage, and you'll likely just annoy your target and break the stick.
Although if a six inch tall person flew up to my face and whipped a good roundhouse into my temple with a two inch long hammer, I might actually notice that.
Tiny creatures will exploit their size and manuverability in their fighting styles, just the same as giant creatures will exploit their mass and power. A pixie may fly at a speed of 30, same as a medium humanoid walk speed, but when they put that same speed of 30 into every hit they make, much like sparrows or other small birds, those impacts could add up, especially as the tiny weapons slip through gaps in the armor.
Although, to be fair, it certainly makes a solid case for the Armor as DR variant from Unearthed Arcana.
Although if a six inch tall person flew up to my face and whipped a good roundhouse into my temple with a two inch long hammer, I might actually notice that.
Tiny creatures will exploit their size and manuverability in their fighting styles, just the same as giant creatures will exploit their mass and power. A pixie may fly at a speed of 30, same as a medium humanoid walk speed, but when they put that same speed of 30 into every hit they make, much like sparrows or other small birds, those impacts could add up, especially as the tiny weapons slip through gaps in the armor.
Although, to be fair, it certainly makes a solid case for the Armor as DR variant from Unearthed Arcana.
Good point, though it goes back again to velocity. I'd be willing to allow for flyby hits by pixies being very effective. If they're just hovering in front of a character, swinging, then my suspension of disbelief begins to fail.
I've never really taken a close look at the armor DR rules in UA. I might have to give them a better perusal.