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What is the lowest, most basic technology level needed for a human population to be able to develop a reliable flying machine capable of transporting people over medium-short distances (at least a few kilometers)?

Context

I have a setting where the world has no solid surface and is instead made of floating islands. I want to know if humans, given the need to move between islands, would be capable of developing flying machines early enough for the purpose of the setting.

There are no flying creatures capable of transporting humans across islands.

Whatever materials are needed exist in the starting island in their natural raw forms.

Humans are extremely motivated to leave the starting island and are actively working on a way to achieve this.

As for magic, there is an elemental system with seven elements: water, air, fire, wood (and flesh), stone, metal and a special seventh element. Humans can create the first six with the help of the seventh at the expense of their stamina.

For example, a human has a piece of the seventh element that is tuned to fire, they can create fire by channelling their energy through it. Using too much energy and the person passes out there and then. This element can also store energy for large periods of time, meaning it can be charged in preparation for heavy usage.

The specifics are quite a bit more complicated, but suffice to say that it can be used for powering an engine provided that the technology allows building an engine in the first place.

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  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$ – Serban Tanasa Jan 27 '17 at 15:43

12 Answers 12

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In an interesting inversion, Leonardo da Vinci described various powered flying machines and even a parachute in the late 1400's, about 300 years prior to the invention of the hot air balloon.

While Leonardo did not have the power source to actually fly any of his machines (and given his inspiration was bird flight, virtually all of them were ornithopters), close examination of his notebooks by modern researchers reveal he had a fairly detailed understanding of bird flight and his flying machines had subtle features to allow the pilot to manipulate the flying surfaces for control.

enter image description here

One of Leonardo's designs

If Leonardo had assembled the "Great Bird", he would have rapidly discovered that no human being would have the muscular strength to flap the wings (particularly when you realize the most detailed sketches had notations which accurately calculated the size of the "Great Bird's" wingspan to carry an adult human male, and it is much larger than some of the early sketches would seem to indicate). Had it occurred to Leonardo to simply lock the wings in the outstretched position, a fairly aerobatic "hang glider" would have been the result. This would actually be more advanced than the gliders created by pioneers like Otto Lilienthal

enter image description here

Otto Lilienthal hang glider

So assuming there are birds for inspiration and a Leonardo level genius living on the floating island, it is quite possible for a late Renaissance level technology to create hang gliders to begin gliding flight between points.

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  • $\begingroup$ Hang-gliders only work in this case if there are cliffs or mountains on all the islands, which is unlikely. They're not really flying vehicles, just gliding. $\endgroup$ – smci Jan 25 '17 at 8:15
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    $\begingroup$ You can get a glider off the ground by facing it into the wind with a static tether. (It's not often done, because you'd be very much at the mercy of the wind gusting or dying). I can't see why a team of horses couldn't accomplish what these days is usually done with a powered winch. A hang glider could be the first step to a "proper" winged glider, that can climb on thermals. $\endgroup$ – nigel222 Jan 25 '17 at 10:37
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    $\begingroup$ @smci I'm presuming that since these are islands in the sky, each one would have a "shoreline" that dropped into nothingness. I think this probably qualifies as a cliff. The OP doesn't mention if all islands are at the same altitude, but presumably they aren't, and we could also imagine some updrafts as winds approached islands that would provide an altitude boost for the glider. @ nigel222 A glider attached to a tether. So a kite? :D $\endgroup$ – Tim Jan 25 '17 at 14:41
  • $\begingroup$ A hang glider can get a distance:drop ratio of 15, so to get a couple of km, you don't actually need that tall of a hill. $\endgroup$ – derobert Jan 25 '17 at 16:56
  • $\begingroup$ Leonardo Copied It. $\endgroup$ – Suraj Jain Jan 26 '17 at 8:23
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I can't add comments yet, but you could conceivably build a hot air balloon with fairly basic technology (textiles, woodworking for the vessel, rope). Flying paper lanterns existed in China as early as the second or third century CE.

You could then couple this with air or fire (heat) magic and create directional travel by essentially building a rudimentary sailboat and suspending it from one or several hot air balloons. Blow the wind into the sails and boom, flying machine.

Sailing ships have been around for much of human history - there is no reason I can see why a similar civilization on floating sky-islands would not pursue this line of technology in place of wind-powered seafaring vessels.

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    $\begingroup$ In order for balloon making to be practical, you'd pretty much need industrial textile technology so that the material becomes cheap enough. Sails were a major part of ship expense, and a balloon requires more cloth than a ship of antiquity; you can clothe a small army with the materials required for a single balloon. Textiles were horribly labor intensive and thus expensive in antiquity; so the fact they could make a hot air balloon doesn't mean that they could commonly use hot air balloons - unless they can use their magic to power e.g. steam cotton gins and power looms for cheap cloth. $\endgroup$ – Peteris Jan 25 '17 at 3:28
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    $\begingroup$ On a ship, sails work because you're extracting energy and directional control from the difference between wind speed and water speed. On a balloon, they're pointless, because you don't have a speed difference to work with. $\endgroup$ – Mark Jan 25 '17 at 6:38
  • $\begingroup$ @Peteris Exploration suggests a stable socioeconomic state for the inhabitants of a given island. I wasn't thinking of personal vehicles so much as exploratory vehicles commissioned by leadership and funded in such a way so as not to be detrimental to the remaining inhabitants. $\endgroup$ – Chris M. Jan 25 '17 at 13:55
  • $\begingroup$ @Peteris. that's a matter of industrial base, not technological level though $\endgroup$ – Separatrix Jan 25 '17 at 14:13
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    $\begingroup$ @Peteris, but making that much cloth without the power looms is simply bums on seats with hand looms. It can be done. Cost is not technology. The question says they're extremely motivated, which in my mind means they will do it by hand if necessary. If they're not willing to weave, they're not that motivated. $\endgroup$ – Separatrix Jan 25 '17 at 14:22
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The Ring of Fire series postulates dropping a West Virginia town from 2000AD into Thuringia in late 1631, and then tracks the influence of the "uptime" ideas and knowledge on the world of the Thirty Years' War. One of the technologies that was implemented fairly early was the hot-air balloon, so I'd say that if you've gotten to at least late medieval/early renaissance technology, hot air balloons are possible - without magic.

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  • $\begingroup$ The author, Eric Flint, has a background as a historian. Thus he'd know that by the 30-year's war mankind was only about 150 years off from its first manned hot-air balloon flight anyway. I don't believe anything required for that flight was invented in the intervening years (unmanned flights go as far back as 200AD), so there's no reason it couldn't have been done far earlier. $\endgroup$ – T.E.D. Jan 25 '17 at 14:43
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    $\begingroup$ @T.E.D. - I have no doubt you're right - I've read extensive discussions about what was possible and what wasn't over on Baen's Bar - but since the actual action takes place in the 1630s and there hadn't been a lot of discussion of how much earlier it could have been done, I wasn't going to suggest that lesser technology would be enough - as other answers here have pointed out, it does take a certain level of infrastructure as well (for fabric manufacture), and for all I know, that may not have been available before the late 1500s/early 1600s. $\endgroup$ – Jeff Zeitlin Jan 25 '17 at 15:19
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    $\begingroup$ Might be worth linking to that Baen's Bar discussion in your answer (if possible). I know the brothers who made the first flight apparently used sackcloth, lined with paper, with buttons for fasteners(!) and cording for support. None of that would have been unavailable several centuries earlier. What I'm not sure about is what they used for heating. $\endgroup$ – T.E.D. Jan 25 '17 at 15:33
  • $\begingroup$ @T.E.D. - Baen's Bar is membership-only, so even if I posted a link, it wouldn't actually work for someone who isn't a member of the Bar. Not to mention that there are multiple threads on the topic... $\endgroup$ – Jeff Zeitlin Jan 25 '17 at 16:05
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    $\begingroup$ In the 18th century, Pilatre DeRozier launched the first hot air balloon with some farm animals in it. It flew for something like 15 minutes. Dirigibles are not far behind. I think this is a much more viable solution than the accepted answer. $\endgroup$ – user11864 Jan 25 '17 at 18:05
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Kites were first created around 500 BC. Kites big enough to lift people weren't recorded until much later, but I see no reason why a kite big enough to carry a person couldn't have been created earlier. Combined with your air magic to power/control it, and you've got it.


Per your comment: In real life, we don't live on sky islands. We evolved on the ground. The highest points we could reach were trees, mountains or buildings (fun fact: The pyramid of Giza at 481 feet was the tallest manmade structure for 3800 years). Humans invented kites and parachutes long before we invented anything that made them a necessity (like a balloon or a plane) so they were pretty much just novelty items. I mean, I live in a 3rd floor apartment, but even I wouldn't consider buying a parachute!

On the other hand, look at the evolution of birds. Birds didn't start off by being able to soar through the air. They started by gliding from either a great height or a great leap. Humans sought to mimic the characteristics of birds in developing flight (Icarus, Bladud, Sampati, et al). It seems quite reasonable that if humans started at a great height already (an island in the sky), we too would begin our quest by controlling our fall rather than looking for ways to reach into the heavens in the first place. We see things fall all the time in our world. Presumably, trees in your world would also lose leaves or have helicopter seed pods that your humans would look at for inspiration.

What I'm wondering (and its totally unrelated to your question), is would we still create gods that lived "in the heavens" if we evolved in such a world?


Edit #2 So I'm thinking about this more. What is a kite but a leaf on a strand of spider silk? I think if the need arose, kites could have been developed even earlier than 500BCE. I can totally see my tribal chief tying me to a primitive kite (that might fail) and reeling out rope until I reach another island. Once I've gathered enough bananas for him (the bananas on the remote island are obviously better!), I reattach the kite, and he reels me back in to the main island.

Once our village priest starts seeing patterns in the winds, he can create a highway (no pun intended) of kites that can be used to get me from one island to another so I can gather bananas from even more remote islands by island hoping.

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Technology is a product of available resources:

If the floating islands have a ready source of lift, constructing an aircraft is easy. Wait... They are floating islands after all...
There shouldn't be an "if" attached.

What actually keeps the inhabitants of a floating island from using (parts of) the island as aircraft?

If they can break off a piece of the rim of the island, does it float away? Can you sit on such a piece, if it's large enough? Can you hold a piece of seventh element, charged up to the brim and use wind as an impulse drive (point to the back and let the wind blow you forward)?

Required technological level seems to be restricted to maybe iron age mining techniques to break off a piece of an island large enough to carry the number of people you want to transport.

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This is more a question of industrial development than technological development. You can make a perfectly good hot-air balloon using paper (second century AD) or silk (fourth millennium BC). Navigation isn't really a problem, either: for such a short hop, you can just wait until the wind is blowing the right way.

The problem is one of scale: even the smallest hot-air balloons require hundreds of square meters of envelope material. Until your culture has sufficient excess production capacity to handle that, you won't be able to fly.

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Mine the lift-stuff.

I asked the OP for clarification. Here is the response:

https://www.reddit.com/r/corsarius/comments/5oygit/on_the_mechanisms_behind_the_floating_islands/

the core of each island is Active Aether infused rock (with debris and the like encrusted on it). This Active Aether is decaying.

In primitive times, you can go to the edge of the island (maybe under the edge) and knock off rock attached to ropes or nets and weights. Sometimes the rock you knock off will have more Active Aether than dead weight, otherwise the opposite.

High quality "lift rock" (with a higher than average Active Aether density) can then be used as the core of your ships.

As the Gaia field is described as a flow, and gravity still seems to exist, and there is air resistance, you can tack. A thin sheet of high quality lift rock (even pulverized and bagged, or turned into cement to get the ideal shape) may be pushed harder by the Gaia field when facing "flat" against the flow, and less when turned to show a shallower profile.

Throw in sails to resist air, propellers to turn physical effort into push, gravity pulling down, and careful control of such flaps, and you should be able to build an air-ship.

But you want to know how primitive we can get.

In more primitive times, lift-rocks will be found (some will "roll off" the bottom of the world), and with rope, nets and effort could be used to build bridges between floating islands.

Before that, take a small lift rock and some fans. Tie yourself to the lift rock so you are neutral boyency. Add large foot and arm fans and bring lots of food. Fly yourself to another island.

In short, there is a mechanism that keeps the island afloat. Humans would exploit that mechanism to keep themselves afloat, and add propulsion mechanisms to move around.

With the islands floating around, these tactics would be used when islands get close. You'd invade another island or colonize it when you are close by, and hop from island to island over generations. The culture who masters these techniques spreads the furthest.

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Invention is the result of inelegance and a need. Most early inventions are just mimics of nature, or extensions of current tech to a new purpose.

My point is that we didn't develop "stable" flight because we didn't need it. There is absolutely no reason for a human to fly in our world. We invented the reasons, like faster travel, or military superiority. We created the need, then the solution for it.

In your world, if there is a driving force to get from one island to another, then flight becomes less about "oh look that's cool" and more about "I must fly or die".

What I am getting at here is that if there is a real need. Humans will find a way. I imagen in your world flying from island to island would be a lot like taking boats from one country to another. Sure boats seem easier to us, but we had a real need to use boats.

Lets break down the problem into it's parts.

First is navigation. We don't have to worry about that. If you want to fly between two islands you wait on the wind to be blowing that way. If the need is great enough it won't even matter if early flight has a high death rate (boats did for us).

Second is lift or floaty-ness. Because were trying to do this as eary as we can, we need a passive floaty-ness. Craft that depend on generated energy (like jet engines) are out. But that leaves gliders, balloons, sails (parachutes), kites and a few others.

So looking at our own history (and google)

  • Some gliders had success around 1 A.D.
  • Some kites worked around 5000 B.C.
  • Some kites have been recorded "lifting men" around 500 A.D.
  • Around 700 A.D. man carrying kites were used quite a bit in China.
  • Examples of rotary aircraft (helocopters of a sort) exist from around 400 BC
  • Then there are hot air balloons around 300 B.C.

So even in our history we understood, in some way, the basics of flight very early on. If we had a real need to fly, back in 300 B.C. It seems we could have.

I would imagen flight in your world would have started very early as a kite. The first kites lifting 1-2 people, then growing in size to hold tens of people. There is less complex material in a kite. Kites can be made from paper, or from leaves, for example.

Kites have some serious problems though. So I don't think it would take too long to go from kite to balloon. Balloons would seems a natural progression. They can be made from paper, but cloth works better. I would see balloons coming around as an answer to stability of the kite. A little hot air and a lot of paper and you could move 10-20 people. Still risky, but if your choices were move to another island or die from lack of food, you would learn to fly.

I would also expect to see (given magic) the idea of rotary aircraft take off pretty fast. The largest problem with early flying machine designs was the lack of a way to make them work. This and the limited number of tries (once you failed at your manned kite attempt that was pretty much it for you) slowed down progress, but we did have the basics.

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Its all about material science, observation and weather.

You'd need tightly woven, light material - early parachutes were made of silk, and that's a low tech material. You don't actually need to take off - you're already above the ground.

You need lightweight, strong frameworks - aircraft have been made of wood, but bamboo-like material would work.

Now the hard part is design. Someone would have to have observed that birds soared in thermals (rather than looking at flapping), someone needs to have designed aerofoils.

Now here's the hard part - navigation You need to navigate, in 3d, taking into account wind currents, thermals and the like. You drop, grab a thermal, soar, and move towards the destination.

Without modern technology, its tricky. Its not like finding an airfield in a fixed place at fixed altitude.

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Given the ability to use magic... Depending on how powerful air magic is, you may just need enough technology to craft a sturdy hang glider and use air magic just to get yourself off the ground and maintain altitude.

Someone else mentioned the approach of creating a hot air balloon, using fire magic as a substitute for the gas powered heat source.

I would just look up what people use to fly/glide today and deconstruct them to what they are made up of and how they work and figure out which elements can be substituted by magic and less advanced materials.

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The magic angle sounds as if hot air balloons should be availabe. Especially if there is no risk of the bag catching fire. No directional control, but flight should work.

Historically those were 18th century tech, but they could come much earlier.

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Well, the Incans were believed to have used balloons in order to draw the immense Nazca lines in deserts of Peru; about 500 BCE, so stone age tech level?

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    $\begingroup$ Welcome to Worldbuilding! Would you be able to expand upon this answer at all (and maybe provide a link to somewhere taking about these balloons)? Thanks $\endgroup$ – Mithrandir24601 Jan 24 '17 at 22:00
  • $\begingroup$ Jim Woodman demonstrated that a hot air balloon could have been made by any culture with a sufficient textile industry, but the Nazca Lines are also visible from the surrounding foothills. However, Kongming lanterns have been around for over 2000 years so...? $\endgroup$ – Tim Jan 24 '17 at 22:25
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    $\begingroup$ Were beleived by who? The same folks who beleive aliens did it? $\endgroup$ – JDługosz Jan 24 '17 at 23:17

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