I'm trying to come up with alternate versions of flight for a new animal species. Wikipedia has this to say: "Powered flight has evolved only four times (first in insects, then in pterosaurs, birds and bats). It uses muscular power to generate aerodynamic forces and to replace energy lost to drag. Flapping: moving wings to produce lift and thrust."
What are some wing design ideas that could be completely different from "dragon," "leather," "feathered," or "bug" wings?
Some invertebrates fly by making silk kites and letting the wind take them. From the wiki:
Ballooning, sometimes called kiting, is a process by which spiders, and some other small invertebrates, move through the air by releasing one or more gossamer threads to catch the wind, causing them to become airborne at the mercy of air currents. This is primarily used by spiderlings to disperse; however, larger individuals have been observed doing so as well. The spider climbs to a high point and takes a stance with its abdomen to the sky, releasing fine silk threads from its spinneret until it becomes aloft. Journeys achieved vary from a few metres to hundreds of kilometres. Even atmospheric samples collected from balloons at five kilometres altitude and ships mid-ocean have reported spider landings.
A fictional creature might secrete a kind of silk that can be hardened, or they might use silk to attach leaves or light sticks. Such a contraption might then be shaped into a hang glider. These gliding wings could then be disposed of after use, or they may be reusable.
Spiders build so many complex things such as underwater oxygen reserves, trapdoors, tunnels, bolas etc. Making wings/gliders would not be a large stretch, but rather a refining of what they already do.
The Fairyfly has a different way of "flying" than the way we usually think.
In short: It is the smallest known insect and it is so small that air behaves more like a liquid to it than a gas, so it kind of swims through the air. The strange looking wings are a result of that.
Some alternate flying methods that spring to mind:
The Fan lizard from Avatar features an unfurling spiral-shaped wing that spins it out of harm's way, sort of a cross between a maple tree "helicopter" and a pebble toad. This is a defense mechanism that in no way guarantees its safety, and relies largely on the hope that wherever it ends up is safer than where it was.
The Overlord from the Starcraft games floats like a giant zeppelin. This would be difficult to achieve in an Earth-like atmosphere.
Fixed-wing flight is extremely inefficient from a nature perspective, due to the amount of thrust required to get airborne, but gliding creatures come close. Gliders and birds-of-prey often employ thermals to maintain height; if your world has enough of these, a small gliding creature could reasonably use them to its advantage.
Wikipedia misses one other kind of animal that engages in (longish spurts) of actual powered flight: the flying fish.
Watch the slow motion segment carefully, you can see that the fish dives out of the water (powered take-off), glides for a bit (like a bird), then dunks his tail into the water and wiggles it back and forth to drive himself faster through the air (tail powered flight) and then dives back out of the air and into the water again. Interesting method of propulsion, that.
Aerodynamics of flying fish indicate that they are supreme gliders, doing it as well as some birds. They also make use of ground effect to reduce drag and increase lift. I suspect that if these fish ever evolved a way to breathe air, they could probably fly much longer distances.
There are no macroscopic axles in Earth biology. Phillip J Pullman's "Dark Materials" books included some aliens with symbiotic relationship with a tree with a large hard nut. The aliens put limbs into indentations in the nut, and ride it about like a wheel.
Your world could have helicopters and propeller-style plan creatures, as long as the axle was physically separated from the creature. Doesn't need to be symbiotic... it could be extruded out from the one creature like a pearl or some other process that completely disconnects the hard axle.
What are some wing design ideas that could be completely different from "dragon," "leather," "feathered," or "bug" wings?
Hovercraft wings.
Not very efficient, so you'd need a very light creature to begin with, and a high metabolic rate. But you could have lots of petal-sized wings moving in sync all around the creature's lower body, their net effect a continuous flux of air being sucked around the "equator" and being thrust downwards. Modulating this effect allows flying in any direction, and even hover in place, hummingbird-style.
It's sort of the way some microorganisms move in water, using air instead.
@plutotheplanet touched on it but I think hydrogen sac drifting is potentially viable... bio-electric electrolysis paired with an inflatable membrane. Fish, fowl, and amphibians all exhibit air bladders already, so that half of the equation is proven... bio-electricity is represented already on terran life forms... I think the evolutionary path of something that could combine them is visible.
In the docufiction Alien Planet, there are flying creatures called Skewers that have somehow evolved... ...wait for it....... biological jet engines!
Questionable realism, but definitely unique compared to what you'll find on Earth.
What about an animal that has flight powered using methane gas? :) The cavity of its body expands like a blowfish with methane it produces naturally. If it can float, there are a bunch of ways it can move in a non-traditional manner. Anything that can push against the air, a fold of skin, blowing air through its body, releasing some methane, using leaves clutched in their feet, etc.
There is of course the Grenade Frog. It only moves location once every month, when it inflates the front part of its body using powerful muscles so that it is almost lighter than air at ground pressure, while what would be the equivalent of a large intestine secretes a highly unstable chemical both internally and over its hind legs. This at some point spontaneously detonates, propelling the Grenade Frog's lightened fore up to 5 kilometers from its original location, although winds can affect that dramatically. Lacking a rear, it settles in its new location on its diet of insects, enjoying a habitat almost devoid of natural predators, and grows new hind legs and glands. The Grenade Frog evolved to skip between bodies of water and to avoid its primary natural threat, a sort of slow moving toxic algae.
You could investigate gliding creatures and see if they could evolve into flying creatures. There are some frogs called flying frogs that have aerodynamic feet and kind of "skate" through the air. There are also sugar gliders (image), a type of possum that glide using loose skin between their limbs that is pulled tight by extending their limbs after launching themselves into the air. I'm sure there are many other types of pseudo-flying creatures you could investigate.
The novel "Hothouse" by Brian Aldiss has a lot of unique fauna-flora hybrids that have unusual modes of flight. For example, there are large seed-pods which can move under their own power. In another example, human characters with a certain skillset can summon various hybrid artefacts for their own use, but the ability to control them is rare. Another mode of aerial movement is attaching oneself to the fur of giant spiders which have the ability to soar through the air (up to the moon) on giant silk webs. Whilst there is much which is scientifically inaccurate (or biologically unlikely), it is a good source of alternative designs for flora-faunal modes of flight.
Try looking to the man-made world of aviation and see if there are any designs there that have not been replicated in the biology of organisms on Earth. Helicopter-style flight, for example.
You could imagine a creature with of balloon like sacs (making up the majority of it's body) that would suck in air from the front and sequentially push air out from the bottom of its body. This would be like letting a balloon thrust air out of it (but presumably it would have some sort of fins to help it aim.)
Note: The more sacks that participate in this the less "bouncy" the flight would be (in the same way that more cylinders in a car engine causes it to run "less bumpy.")
If the creature lacked bones (using cartilage or something else lightweight) and was mostly these air sacs I think you could get this working in an earth-like atmosphere; as we have many non-animal examples of things that work this way (compressed air rockets, balloons if they are not tied, etc.) and these work without relying on lightweight gasses and don't rely on "floating."
I imagine in order sustain such a high-energy activity it may have a thin/wide maw like a whale in an insect-infested atmosphere, allowing it's travel/feeding to be the same action.
I say it would "breathe in" from the front that way Newtonian physics are still in your favor (however minor this benefit would be.)
I could also imagine a "hot air balloon" animal, again 95% of it's volume would probably be the travel method. The animal could collect burnable gasses and find some way of creating a spark to light the "spout" for the fire (if it's intelligent this is easy, if this is fully biological it would probably be some other chemicals it slurps up and combines to cause an initial burst of heat or maybe a metal that reacts with the air.)
To feed, given the awkwardness of the animal, it would probably need (again) an insect infested atmosphere and maybe a sticky film that drags the insects it runs into into the "basket" like maw at the bottom of the "Hot air balloon"-like animal.
For another temporary flight variant, I can imagine a Rocket animal; who coats it's "rocket sac" in metal that it mines, then fills itself up with gasses, then launches itself (probably for migratory reasons)
I believe each of these are possible due to using propulsion rather than floatation. They both require a light body and a large amount of energy being pushed out. While they can each be hard to believe would evolve; there are truly astounding things that have evolved on earth.
Fly larva that have virtually no brain and yet build an entire trap that filters food out of the water. Termites that build near-cathedrals. Fungus that infects ants and then bursts in order to spread itself through the colony, and the ants realizing this and sectioning off the infected members. Ants that link into bridges to handle flooding or cut leaves to grow fungus in their hive, of which they eat the fungus (and is nearly the only thing they eat.) Fish that have a light hanging off of their head just to attract fish to eat.
Not to forget creatures that are not single organisms but are made from colonies of polyps that contribute different functions to the whole such as the Portuguese Man o' war. Some of the polyps act as a gas filled 'sail'. It doesn't fly, but I thought the colony as a material an interesting notion and one that may be adapted to winged or balloon flight with a little tweaking. More here: http://rsif.royalsocietypublishing.org/content/6/36/613.short
