Nice! So a better-looking dragon would have to be broad-chested, thin behind it, maybe with extra wing membrane further back to bring the center of lift back a bit? Or is there a different, better model?

Correct!

Another fix could be the addition of a horizontal tail-plane on the tail; this would provide additional lift further back to counteract the imbalance. However actual aeroplane tails are rigid and make good structural levers, flappy dragon tails most likely won't, and could cause his rear to sag between the wings and tailplane.

Some minor mechanical flaws in your reasoning but I get your drift. (The center of lift should be further back, the circulation as the air flow breaks off creates most of the lift. Also the offset of the COl and the shoulder would create a momentum which keeps the draggy in the horizontal. But he sure needs back muscles of steel to actually keep that pose.

I drew this for someone without a STEM background so I simplified the significant centers somewhat; given that dragons would have ways to vary their surface shapes and weight distribution. And yeah the muscles of steel thing is my main point here; very few dragon designs seem built in such a way to handle any sort of pitching moment around the wing joint, and that sort of posture in flight would be very wasteful in terms of energy as well.
I have notes somewhere on "ornitho-motion"? which I would like to include somewhere in this series. I never got around to finishing the calculations; so many integrals... but I was trying to map the volume of air that my wyvern character would displace with each wingbeat. From which I could find what sort of thrust you can expect from dragon wings. The numbers aren't in dragons' favour anyhow; unless they're all made out of carbon nanotubes or something. \o/

Well from an engineering stand point I fear you are looking at either a gross simplification like rectangular wings etc or a lengthy session of computer assisted finite volume discretisation. Good luck with that. Especially with the instationary nature of flapping motion you are looking at a nightmare of a problem. A close to life solutin of this could be a masters thesis.

Heheh, I never got around to using any computer resources at my uni. And engineering is all about approximations anyway. Despite the fact I could have used a simplified rectangle, the actual path it would carve through the area still comes out with a complex 3d shape, so it's equally as difficult. I did frame by frame sketches; almost an animation, based off birds and bats flight cycles, and record the curves of points of the wing (hand, elbow, digits etc.), http://puu.sh/tkRTQ/6c75e97754.png about sums up my working. XD and then used a webtool to match curves to the vertices; the shape from this is like a rounded cheese wedge.

I split the object into lots of full cubes and determined I'd use multi-level integrals to obtain the area of the rest... half way through z==1 I suddenly realised that I had massively underestimated the challenge I had set myself and my feeble human brain. So I promptly said goodbye to calculus forever and decided to become a furry artist.

Great life decision right there hehe. I am still struggling with all the advanced math stuff, only thesis and numerical processes in the way of my bachelors degree....

You don't even necessarily have to flap to fly. Albatrosses could say a few things about this matter ;)

Yes, this is one way to say it, but it applies to both dragons and wyverns as usually people portray both with a powerful and heavy hind part and quite thick tail.

Whether the creature would adapt the posture you depict depends on the (imaginary) strength of the wing joints and the wing structure. He may be able to hold up his body in line with the wing surfaces, but then of course you arrive to the problem what rigid aircraft face about the issue of the center of mass. If the center is behind, the creature will pitch up into a stall. I dunno whether wingflapping would solve anything here as even if they tried to flap, their hind would still be heavy, pitching them up.

Another typical problem is the lack of some means to control pitch. No tail surfaces, no such control, they would only be able to pitch by displacing their wings (behind or before their center of mass to allow that mass to achieve pitching). This is possible (they aren't rigid), but I don't think it is very optimal. At least birds, bats and pterosaurs all have some surfaces to achieve such control (birds: tail, bats: hind legs and tail, pterosaurs: usually hind legs, various configurations). Possibly it is important so they can use their wing muscles optimally to power their flight (especially in delicate situations like landing).

Why wyverns win for me is mostly the chest, the flight muscles: in a conventional six limbed dragon especially if you want an elegant land carnivore shape, there is very little space for those muscles, even less due to the need to fit the front legs there.

I usually balance my designs with a long and powerful neck, a typical example could be the gold wyvern, which I designed especially with a high aspect ratio wing, optimizing for soaring flight. This is tricky, though. The high aspect ratio wing demands a center of mass very much on the front, which isn't very optimal for land movement. Well, if she used flight to hunt something big, gulped it down into her belly, problem solved. No flying for a while, though, but who wants to fly with a full belly, anyway? :D

Another wicked thing is the legwing, which will have the center of mass right. But that's a very unconventional dragon... "thing".

Then of course the most recent Tani Akri. Broader wings, not the most optimal for soaring, but they are more suited for easier take off and landing (the high aspect ratio wings only generate lift dynamically, so you need the airflow, which isn't necessarily present when you want to take off). Like Dracodare mentioned, it also allows having the center of mass a little farther behind, allowing him moving around more conveniently on ground.

Fun stuff, these designs.

Indeed!

Providing the creature itself has an excellent sense of balance around their wing-joint pivot point; which is totally logical given how they evolved for flight. Tails can be retracted and extended to move the center-of-mass, or curled to induce yaw. Tail planes are for stability or ease of flight, but are not necessarily essential for it.

The nature of flappy wings is that drag is a very minor issue unlike fixed wings, as they produce their own thrust and in glide or at zero thrust can be orientated to produce minimal drag. The main limitation (assuming ultra-strong structure) with self-powered flight is thrust / weight and thus energy as things get bigger. Surface area of wings needs to increase by an order of magnitude, and the volume of air displaced or thrust by two orders (noting here that in a scifi setting it would be perfectly logical to attach jet engines and awesome stuff to dragons to increase their cool factor *cough* help them fly :D ).

With some larger bulkier wyverns or western dragons actually taking off becomes a major barrier too. Small birds can produce enough thrust with a few fast wingbeats to propel them forward and get air flowing over their wings immediately, larger birds (albatrosses, ducks, swans) require a good run up first, like a modern plane. Once in the air they are free to seek thermals and aircurrents to aid the comparatively weak thrust from their wings.Albatrosses are masters of this as you know. :)

Even wihtout the performance requirements of sustained flight dragon wings would not be entirely useless; their large surface area would aid jumps immensely and relieve weight off their legs as they ran, velociraptors are believed to have used their "proto"wings for cornering at speed. I like to imagine big dragons utilising the "ground effect" as well, bounding along the landscape on a cushion of air trapped between their wings and the ground. If you have ever landed a plane you feel it like a slight resistance at touchdown, like the ground is repelling you. It's likely not a realistic use for dragons over sustained flight, due to the speed requirements to harness enough "lift" from the Ground effect, but if you look up "ground-effect vehicles" and the massive Lun Class, it's hard not to imagine a big beast skimming along the ocean like that...

Sorry, I ramble. Love this stuff. ^^p

Wyverns are the beasts! Quadrupedal launch, eh? Only the wyvern can do that! :D

Yes, I might have some slight misconceptions about drag and friction on wings. The hawk may be a good example, a decent soarer with rather broad wings. Awesome stuff... In the cheetaan sci-fi I have a bioengineered "creature" which has EHD incorporated in the upper (bare, no feathers) wing surface, but if you have any other idea, you may apply: if it contains no moving parts, it might be possible for biological creatures (a rocket based thruster I think is more possible than a regular jet engine). Maybe even the respiratory system could be adapted to form a sort of (weak) jet engine. Somebody somewhere even sketched up a fart propelled dragon :p (its a pity I lost the image, well, kind of a rocket engine, methane combustion)

I know about ground-effect vehicles, interesting concepts, I just didn't really consider it for dragons as a land environment isn't especially favorable for this tech. It however could be nice for an aquatic dragon design allowing him to travel fast.

Did you ever fly, by the way? (I didn't, just that you mentioned "If I have ever landed a plane") I mean like you were in control, of course :)

I was learning to fly but I have yet to get my license. :C

One currently researched topic of plasma actuators, basically an electrically charged wing, that ionises the air around it allowing it to be redirected with magnetic or electric fields into laminar flow in situations where it would otherwise become turbulent. It is just as awesome as it sounds, as in the coming years we could realistically be having planes flying over at night with glowing blue wings! :D
There are plenty of organisms irl that take advantage of static charge; eels, rays most likely more that we haven't observed enough, it would be easy to imagine dragon designs taking advantage of this phenomenon too. And the glow of plasma around their wings in flight is something that NEEDS to be depicted...

In terms of adapted respiratory function; I believe the Ikran from JC's Avatar; has massive ram-air-intake nostrils right near its lungs to supply the creature's accelerated metabolism for flying. I always thought that was pretty cool.

Wow, I didn't even knew that the EHD / Ionocraft idea was actually deployed in this manner! Great find! If you read a bit about the thing, you might find claims that it is more efficient than conventional jet engines. I imagined it to be used for generating thrust (not just flight control), by the entire wing surfaces. In the cheetaan sci-fi it fits well as I imagine those creatures to power their body by electricity, not by "burning" (oxidizing) in every cell (contrary to how our biology does it, blood carrying oxigen everywhere), but of course uses of electricity occur even within our biological systems (such as the eel you mentioned).

The Ikran's idea if you drive it a bit further towards insanity may even become an actual respiratory jet engine, if you make the air flowing in one direction only (the creature having exhausts on its rear portion). The flight muscles can act as compressors, the airflow cools them, while the air itself warms up and expands. The idea is similar to that of a turboprop engine, just that the primary source of thrust this case is wingflapping.

A problem with these (even the Ikran) is that it likely needs more robust lungs as it quickly receives lots of very cold air (a mammal's or probably bird's structure wouldn't like it). The cheetah by the way exploits a similar idea: they have wide air tracts to supply them with oxygen for those short distance bursts. Overheating even seems to be a bigger problem with them than muscular fatigue. Flight is a bit easier for that the muscles needing excessive cooling are right there where the air flows, likely it would be possible to devise such a structure which solves the problem (and would get even more hot air...).

There I think the constraint rather becomes fuel. But in a sci-fi, it would be possible to devise creatures which don't hunt themselves, rather fed with specialized compounds. It would be possible I think to build even a fictional dragon ruled society running by this principle (that is, it doesn't necessarily means that the dragons are engineered, and are just "used", the dragons themselves could very well be their own "engineers").

Learning to fly... Nice, guess you saw and felt things most people won't likely ever experience! (for me, even just sitting on a plane was something wickedly awesome. If you look at my site, the design was especially inspired by a flight)

Yes, EHD thrust can definitely be more efficient; theoretically it's specific impulse is infinite if it uses the atmosphere itself. However the main limitation is thrust per volt supplied, lots of electricity needed for small increases in thrust until it becomes extremely problematic... A better use of EHD would be a Hall effect thruster or "ion drive", which uses fuel as the fluid, the fuel could technically be anything providing you have the energy to ionise it. Spacecraft use xenon gas, but really any gas could be used and mixed with air.

Am I thinking about dragons or space? ><;

Overheating issues I believe could be solved with specialised recirculation of blood from hardworking muscles through the lungs multiple times; as they will be exposed to lots of cold air, cooling the blood and I suppose warming the lungs. Cold air more dense, so it would be more efficient to intake it as cold as possible for maximum O2 transfer. Another cool idea would be to have a second pair of exhaust nostrils behind the lungs which would open on the exhale. And now I think about it this is basically how sharks work, or gills. oO

"Am I thinking about dragons or space?" - Both

In the Cheetaan Legacy story plans I have those, they might be propelled by the ion drives you mention. I prefer the atmosphere EHD where there is atmosphere to use since it doesn't need the creature to carry propellant (which has to be picked up somewhere, which might not be trivial in the "wild"). "Lots of electricity" - rather extremely high voltages for the ionocraft models they use for demos (but there is little current, the only current is the flow of ions, so relatively little energy). It might be possible to create functional things with different structures than the "lifters" which don't need such voltages and driving it on the verge of producing nice flashy burning demolition.

"Another cool idea would be to have a second pair of exhaust nostrils behind the lungs which would open on the exhale." That's what I mentioned with the respiratory jet engine. I have this on a land creature, the cyats of the shiriat, the rear exhausts visible around the hip area. They are long distance runners where this structure is used for better oxygen supply and improving cooling. In the story ideas they live in a harsh desert world, use synthetic food having devolved digestive tracts (the origin is that the planet they live on isn't their original homeworld, rather one with very primitive life to which they fled long ago, so they don't have those species which were meant to feed them in their ecosystem), but that also allowed them to specialize, so they can have energy dense fuel.

To make such a concept a jet engine, maybe the Ikran is a good starting point, designing it so that the chest itself doubles as such an engine (using the heat generated by the muscles). Although maybe it could be rather called an exploit of the Meredith effect, likely there wouldn't be any really significant thrust there, just that the ventilation and cooling won't produce any excess drag (as it is exploited to generate a little thrust to offset it).

Just recalled that there was a documentary in which jet powered flying creatures occurred: Alien Planet, it is a fiction about a hypothetical extrasolar planet with life and its exploration (the creature mostly shows at 44:00 and from 49:00 where they are described). Being from 2005 it is a bit dated, but I think it is interesting to watch at least once, it shows some quite interesting ideas. If you wander around a bit, there are several more current ones incorporating the recent discoveries about exoplanets, there are some fun ideas in those. Such as at 40:00 in this one, land whales on a planet tidally locked to a red dwarf with intense winds. Well, this is quite offtopic here, just if interested in this sort of thing.

I think I saw that show! Did they also show the buoyant creatures inhabiting gas giants and planets with dense atmospheres? I personally find that to be a very believable and intriguing concept in xenobiology, especially considering all the microbes found floating in our comparatively thin atmosphere.

Just sharing a quick find: a running bat, odd sight! Could be useful for wyvern land motion design.

My solution is butt fins and proportions https://www.dropbox.com/s/7ix2z8yc8.....10.21.png?dl=0

Next thing to add: Cheek Canards! :D

for more head maneuverability!

That should work so long he can proper himself. The overall proportions are quite bat-like, but those broad wings have lots of drag (friction) with sub-optimal airfoil for any soaring: like bats, this dragon in the reality would have to be mostly an active flyer, at that the shape would allow him very good maneuverability (assuming it scales up, in the reality there would be severe structural issues at a reasonable "dragon" size). The principle is about the same like biplanes for aerobatics (very short broad wings allowing insane maneuverability) versus sailplanes (optimized for gliding with little descent, allowing the use of thermal columns, winds against hillsides and other natural phenomena to keep themselves in air indefinitely). But you can see this on birds as well, for example the albatross versus a crow. There are some exceptions, like broad winged hawks which might soar, but they are assisted by the feathered nature of those wings (especially the primary reminges on the wingtips).

Just opinions. This is a broad subject if one starts to dig into it.

I think for this dragon the added lift from more wing area far outweighs any issues with drag. And yeah, you do run into scaling issues fairly quickly. Though with my limited understanding of the mechanics of flight (I'm just an ME, not an aero) I've been able to fudge the numbers close enough to reality for dragons up to 60 or so tons. Thats where it starts to get really wacky in calorie consumption and amount of air needed to be displaced per wing beat.

Wing area only gives you lift if you are an active flyer, and that's indeed a problem for wings optimized for soaring. Just look at how an albatross can struggle with taking off, they demand a runway, and even at that they are going downhill, against a breeze which helps them rising. The high aspect ratio wing has little drag (due to that it is thin, little friction), but generates lift by its airfoil, how the air flows around it (higher speed air above, lower pressure, lifting force). That, of course, needs the wing to have some speed relative to the air. But once in air, the little drag permits the albatross to use the power of nature to generate the lift (over the sea they use winds across waves), they need very little energy investment to stay up.

Big flying animals (like the Quetzalcoatlus, a pterosaur which was possibly huge enough to pick up even a human) like soaring especially for this: once in the air, so long they instinctively understand the natural phenomena allowing sailplanes to stay up, it doesn't need energy to stay up. If you are in a hilly region, on a slightly windy day, you may even see hawks or other birds raising in an updraft against the hillside, gentle circles without a wingflap, and in minutes from taking off somewhere in the valley, they are high above the peak.

Dragons if I want to consider them with all seriousness, as a possible flying creature, would I think behave similarly, lifting themselves without much energy. If they have fire breath (or acid or whatever), they don't even need to be very maneuverable as even if their weapon is relatively short range, it is ranged, allowing them to hunt without the need to really consider obstacles during a risky swoop down (similar to sea birds, permitting them to optimize for soaring).

Of course there is another alternative, a dragon which is primarily land oriented, assisted by occasional short flights. I think this fits best most people's ideas of the creature (and most of you portray them in land affairs, at best only showing off their wings... especially the six limbed dragon could pick up someone and gulp him down in flight, yet I don't think I ever saw such portrayed here, for the prey, well, that's even more of an one way situation... That's a frightfully long way down otherwise!). Those would have broad wings (as commonly portrayed) allowing generating lift by flapping, optimized for easy take off and landing (optionally crushing prey) as these are what they mostly use their wings for after traveling short distances.

Sixty tons... How many elephants per hundred kilometers, may I ask? :D

And connecting the wing membrane to your butt keeps the wing inline with the body, nice. Admittedly your design looks very "stable" along all axes, especially with the wings up high and weight low, like a pendulum. C:

Having such logical thought about proportions and aerodynamics along with an idea of dragonic structure closely matching my thoughts makes me want to commission a piece from you all the more!

I love vigorously testing fantasy like this, engineering is just creativity with rules. Sometimes leading to ideas that you wouldn't have thought of without it. :)

And I do aim to break into taking commissions at some point. For now I'm thinking of doing the off trade and request to build my skills up and make sure I can pull off a piece to a commissioner's request.
What sort of piece were you thinking of may I ask? ^^

I am a huge fan of envisioning and elaborating on such ideas; having realism accent the fantasy adds lots of feeling and emotion to things :D

I very much feel like you have lots of potential and skill, and do hope that you get to that point! Still, some of your vorish work is divine, leaving me much in the idea department there, eheh ^^;

I cannot agree more! And thank you for the feedback, there is a lot of feeling and emotion in the concept of vore itself which personally I feel is not addressed as often as is demanded by such a complex wide-ranging field. I'm working to do it justice. ^^p

Can't promise anything, but if you have any ideas for me, let me know. :3

May just throw a note your way, then! Flattered~ C:

I appreciate the amount of thought that went into this. I do like a bit of realism mixed in with my fantasy dragon. I will be keeping this in mind when redesigning my dragon, with a bit of leniency considering this is not my area of expertise. If I were to get too realistic in the design, it would probably end up looking far less attractive than I would wish. Being unsatisfied with my character isn't what I want. Sometimes we artists just have to say "damned be physics", to get a character we can fall in love with. There are likely many characters that wouldn't fly with their current design in real life.

Aye, that's what creativity is all about! \o/

I think that this concept is a good thing for all artists to bear in mind though, as engineer or not, we ALL have a basic understanding of mechanics and how our world works. When these are left out; for example a character standing in a pose where the center of mass would not be supported by the current position of the legs, through our view of the world it "just doesn't look right". Things look better overall when they adhere to our mental model of the world (This doesn't mean uberscientific realism). :3

Fortunately though our subconscious is good at addressing this as we draw, without many artists even considering it, but I feel it helps to be able to explain it to myself as well. ^^p

Fuck it, derg Karlos is non-flyin.

PHYSICS HAS DEFEATED ME

Add moar boosters!

We'll strap some rockets to your hips! X3