Very nice! I like the tail/wing design!

Thanks. The wing shape follows the general concept of sailplanes, aiming for good gliding performance which such a large creature would prefer (along with a proper center of mass). This beast at its size might actually be capable of flight :) The tail is just some creative design while serving its purpose in the air.

Interesting. I imagine that, if mythical flying creatures were to exist, they would be as varied as modern birds, wherein you have different wing/body shapes adapted for different environments and ways of life. You would likely see large broad-winged creatures that live similar to that of, say, the Albatross; or short-winged, agile predators, like that of falcons. I would think that, in a desolate, snowy environment, soaring would be the best mode of transportation! Something about the scene reminds me of the comic Arzach, by Mobius...

I checked it a bit by what I found for a quick search, yes, nice art style! Interesting :) For fantasy, the variety is okay, however real world physics doesn't permit scaling that way, probably the most constraining being structural strength. Even the size of soaring creatures have both lower and upper bounds to be efficient, these designs of mine likely approach the upper bound. An interesting related thing is what I read about the Kon-Tiki expedition: Thor Heyerdahl at one point mentions how the old raft design had just the right length. If they made it longer, the waves of a rough sea would have broken it in half (and they were through several heavy storms on that raft), while as it was, it was just so big that it could ascend and descend the great waves smoothly. In the air you have analogous constraints, for sailing the most notable being the thermal columns used for lifting.

With wyverns it might be plausible to get somewhat creative even within real physics constraints. If you design him to be agile on ground, he might be an active flyer who doesn't travel great distances in air. Wyverns and legwings both can launch themselves by their wing muscles (one of the reason why pterosaurs could grow bigger than birds, note that the western dragon can neither use those powerful muscles for launch!), allowing them to take off in poor conditions.

My ideas prefer being and living up in the air for extended periods requiring soaring. In the cheetaan universe setting, the Tani Akri dragons would cross between the poles of the planet across more than ten hundred miles of desert, carried by currents. A hazardous trip, inexperienced dragons might simply get disoriented and lost, and in the heat of the day they could die if they had to land.

The snowy peaks, cold also has its hazards beyond being cold, but it applies to anything high enough. In humid conditions ice could form on the wings, a great danger to aircraft, of course these creatures with their flexible wings are at advantage being capable to break it off by their motions. A smooth webbed wing may even be at advantage here, there is nothing for the ice to attach to, but insulation is a problem (the entire wing have to be kept warm enough so the muscles and tendons within keep functioning). So many many things to consider when putting actual physics in play :)

Certainly! Very few attempt to apply real physics to fantasy or science fiction. I think that isn't exactly a bad thing, especially with comics and movies. Snowpiercer, for example, is awash with scientific impossibilities. However, it wasn't intended to be based in reality.

As a mountaineer, I can attest to the sheer resilience birds have to the cold. The -40 daytime temperatures and 150 MPH winds on Mount Washington don't even stop them. 26,000 feet is the highest man can climb before the body begins to slowly die from lack of oxygen. Birds, on the other hand, can fly well over 35,000 feet - a mile higher than the summit of Everest. Ice only forms on skin when either A: the flesh is frozen solid, or B: liquid water is poured on the skin and allowed to freeze. Typically, at this point, the skin is already frostbitten to the point of being dead. I once read that, after spending a night exposed in a storm at 27,000 feet, Everest mountaineer Beck Weathers' face, hands, and feet looked like porcelain, and that he practically had to chisel himself out of a the snow before descending. Because of their feathers, birds remain above freezing, and thus, ice does not form.

Seabirds like the Albatross live lives similar to the one you described for these dragons. Their 11 foot wingspan is likely to thank for that!

Seems reasonable. With aircraft it is also one method to heat the wing, if it is not below zero, then no ice, but there is an energy cost there. With a feathered cold-blood wing icing might probably happen: the creature might heat the skin sufficiently to prevent it freezing, but the feathers above (as a layer of insulation) might be colder. Other thing is skin-structure, whether it is even susceptible to frost damage. The Tani Akri dragon of the cheetaan universe in particular uses a "bioelectric" concept without blood vessels, which might permit him to maintain a temperature below zero for some body parts (avoiding losing heat by the large wing surfaces would be advantageous to conserve energy, and makes the creature harder to detect by heat).

Even warm-blood creatures might have the aforementioned "trick", it is mentioned here (in the second half). Something alike applied on the wings of a soaring creature may reduce energy loss, but in harsh conditions might expose him the more to the danger of icing.

The Albatross is not that great for the wingspan, rather the wing shape! :) You may also check this site for the pterosaur, which again was likely a soaring creature (the large ones), the wing shape is similar (large wingspan, but thin: the airflow around the airfoil generates the lift, while a long cross-section would generate more drag due to friction: so the real glider doesn't use the wing surface to hold up his mass, rather his velocity, the airflow around the wing, to generate lift). That pterosaur site also describes quadrupedal launch.

Well, I just like fiddling with real world physics concepts. It makes things more fun to have something which might even be possible! (A bit of engineering side: sometimes I toy with the thought of whether it was possible to build a mechanical wingflapping wyvern)

Just recalled a kind of hilarious thing while reading stuff... Somewhere I might still even have that photo.

It is myself. Out in a chill winter hiking in the limestone mountains, visiting some caves in twenty below zero. We don't have such winters since years. Anyway, so I have a beard. It was ridiculous to warm up the batteries to coax the thing to get a shot done. Among things like this or this, I photographed myself, all my beard frozen in solid ice. So given adequate conditions for convergence (that case my exhales), even a quite warm-blooded creature's fur might ice quite badly.

Yeah, I have that same problem happen with ski-masks. The condensation soaks them, and the cold air freezes them. Our mountains, whilst not very tall, are brutally windy. Mount Washington, which has an observatory at the top, has one of the highest wind speeds ever recorded - 231 MPH, or 372 Km/h. It has something to do with the geography, I think. The wind is funneled through the notches and slams directly into the presidential range. A very experienced mountaineer - one who had summited Denali and was training for Everest - got caught in 100+ MPH winds up there two winters ago and froze to death before rescuers could reach her. Alpine grass is the only thing that lives up there. It's granite, so no "real" caves, but there are some pretty impressive boulder fields. Once, I was hiking it in august and found snow and ice in the boulder caves. When the wind blew through them, it felt like I was standing in front of a super cold AC unit (Not that I was complaining; the temperature down in the ravines was in the 90s, as opposed to the summit, where it was in the 40s).

Fur and feathers, I believe, are very breathable, and prevent condensation from building up on the body. People love down jackets for that reason. Around the mouth and nostrils, on the other hand, condensed breath freezes to it.