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When I came across this hilarious and awesome way of transportation I thought "why is no one rollerblading through the woods anymore?". I am pretty sure there are more fantastic but forgotten inventions out there, or new ones like these water bikes.

For my setting I searched for means of transportation especially independent of fuel. Recreational benefits are not excluded. Also, like the example with the mono-blades, they should allow the user to cross remote terrain either on land or by water, or both. Walked out paths exist, but not asphalt roads. In either way, it needs to be a twist on our commonly known transportation methods, or a new one, with the promise to actually work and not just "rollerblades on a horse".

Our landscape is placed inside a space settlement (O'Neill cylinder) with a total area of about 900 km2, serving as a nature conservation area with strict restrictions. There are all kinds of landscapes, ranging from mountains, forests, swamps, lakes, plains, beaches, in a temperate climate. Anything futuristic is allowed, but as said, no fuel, and if you can make use of the setting you get a cookie. Your answer can either be an existing invention or your own. It could function for either children, single people or groups, and it can include existing animals.

So. What other human-powered transportion methods do or could exist, besides the commonly known?

Edit: No, food is (of course) not considered a fuel in this scenario. That would be illogical. While food is, technically speaking, a fuel, "fuel free transportation" implies that one does not have to use energy beside human energy, because the device is to be operated by humans. How could humans operate anything without food. "I want to ride my fuel free bike, so I guess I'm not eating anything today"?!

Edit 2: Anyone who continuous to nitpick on "food is a fuel" is missing the point on purpose and can blame themselves for not getting a cookie.

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    $\begingroup$ Can you please give a more precise definition of what you mean by fuel? Technically the food a person eats which gives them the energy to walk counts as fuel in a sense. Most people don't consider capacitors to be fuel even though electrical energy is stored in them. Flywheels are purely kinetic energy storage devices. So, what do you mean by fuel? $\endgroup$ – Mathaddict Oct 15 at 15:17
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    $\begingroup$ I'm seconding Mathaddict's question. The fuel is called "food" instead of "gasoline" but it is still a fuel and the conversion of this fuel into energy still results in pollutants and waste products. $\endgroup$ – krb Oct 15 at 16:16
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    $\begingroup$ Okay, so you've changed the title of the question - are you now looking for only human-powered? Because there are plenty of fuel-free alternatives that don't require human labor - solar being the most obvious in a space station, but also nuclear (which technically requires fuel, but a single fuel rod can last for decades or even centuries, so it's not like you have to keep replenishing it.) Wind, hydro, and geo power don't work so well in space, but you could beam up such power from the planet to power things on the station via a powerful laser. $\endgroup$ – Darrel Hoffman Oct 16 at 14:39
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    $\begingroup$ Are the properties of the environment negotiable? If gravity is significantly less than 1g, and/or if the air pressure is significantly higher than on Earth, then human-powered flight becomes feasible. The coriolis force will add some interest too, by making it easier to fly in one direction than the other. $\endgroup$ – Nathaniel Oct 16 at 20:19
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    $\begingroup$ Can't add an answer because its locked but I think of: i.postimg.cc/Qt0cRdZX/… $\endgroup$ – leetbacoon Oct 17 at 5:15

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A unique mode of transport that would only work in an O'Niell cylinder would be a giant swing, suspended from an axle in the middle. Grab the swing, run as fast as you can, take your feet off the ground and you'll continue to move until air resistance slows you down.

The obvious draw-backs are that it only works for travel around the circumference (east and west), there may be problems passing trees and tall buildings, and there would be a lot of air-resistance on the kilometres long rope.

You could imagine a super-thin rope with a peddle-powered propeller contraption on the end, that would allow you to 'fly' without having to generate lift. This would be as fast and efficient as a bicycle on a super-smooth road. Add a rudder and you could steer around obstacles.

However I think it would work best when used as a barge or crane for transporting large heavy cargo. Much like one horse could pull a 50-ton barge along a canal, you could load tons of cargo onto a swing, push it to gradually accelerate it up to walking speed and then allow it to coast for miles.

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    $\begingroup$ Wow. Instant giant cookie! This is an amazing idea with so many ways to play this out. Of course they would need some engineering, but "only the sky is the limit" on this one. As an attraction, or for many people if made several meters long or as a kind of air boat. And that's just what immediately came to mind. $\endgroup$ – Backup Plan Oct 16 at 9:39
  • $\begingroup$ Presumably, you'd also have to continually climb the rope, or have a mechanism to draw it up at the correct rate. $\endgroup$ – Harabeck Oct 16 at 14:10
  • $\begingroup$ @Harabeck - why would you need to do that? All points on the surface would be the same distance from the centre. $\endgroup$ – Robin Bennett Oct 16 at 14:14
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    $\begingroup$ @RobinBennett Mmm, I was thinking about travel along the axis, but you specified the opposite. Don't mind me. $\endgroup$ – Harabeck Oct 16 at 14:17
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    $\begingroup$ If I recall correctly, there would be a constant breeze as friction with the ground pulls the air along, meaning there is always a wind counter-spinwards which gets stronger relative to the ground the "higher" one goes. Thus the air-resistance problem is one of the suspension rope being constantly pushed counter-spinwards. Perhaps this could be exploited as a method of propulsion but the details would depend on the size of the cylinder and speed of rotation. The bigger struggle might be getting it to stop or slow down instead of always racing off counter-spinward. $\endgroup$ – pluckedkiwi Oct 17 at 14:24
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Being sensible (alas!). The most obvious form of non-powered transportation inside an O'Neill cylinder would be the bicycle. It's non-polluting and healthy too. Why go past the obvious. A well-established and mature technology.

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    $\begingroup$ Well, sure. Mountainbikes mostly, I assume, since there are no paved roads. But I am searching for transportation besides the regular ones :) $\endgroup$ – Backup Plan Oct 15 at 11:48
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    $\begingroup$ To a4android and anyone upvoting: you seem not to like when things differ from the norm. But this is what this question is about. To explore what else is out there. Not what is best. And you know, it's for a story, not "your daily commute to work". It is not supposed to be most sensible, but fun. $\endgroup$ – Backup Plan Oct 16 at 8:57
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    $\begingroup$ @user28434 That seems a bit nitpicky. If that the item is sometimes discarded/wrecked into a river makes it polluting, then everything is "polluting". $\endgroup$ – Harabeck Oct 16 at 14:07
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    $\begingroup$ "Any path a human being can walk on, a bicycle will go." That statement is pushing it a bit, but bicycles are still the #1 device in this situation. Even if OP wants silly or fun answers, bicycles just need to be mentioned. Any Q&A about human powered transportation which doesn't mention bikes is missing out. $\endgroup$ – Loduwijk Oct 16 at 17:59
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    $\begingroup$ @Loduwijk Well I grant you that. And while I agree with the answer being sensible, my intention is to push people to think a bit further, and not just clap their hands and say "that's it, best answer given". It's specified in the question to give common transportation a twist. I don't see a twist in using bikes. $\endgroup$ – Backup Plan Oct 17 at 7:49
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If we don't count food as fuel, how about plain old wings?

Climb far enough up one of the end walls, and the gravity gets low enough for people to fly on their own muscle power (potentially aided by thermal convection). Don't worry about the air getting too thin; with the gravity dropping off, there'll be breathable air all the way to the center of any reasonably sized O'Neill cylinder -- at the center, there's zero gravity!

So, you make yourself a pair of flappy wings, climb to the axis, lock the wings out, and launch. Build them so you can flap with the big muscles in your legs, of course. If you don't want to go all the way to the other axis point, just drop down a little and, when the gravity gets too high to maintain your altitude, actuate the latch that locks the wings in a gliding position and glide -- and potentially land anywhere on the interior surface.

If the inside gravity is kept a bit below Earth normal, and the air pressure is kept a bit higher, it's even possible take off from level ground with wings of this sort -- I've seen calculations suggesting that on the Moon, you could fly this way in about 1.5 atmospheres.

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    $\begingroup$ You'd almost certainly keep a space habitat at lower pressures to slow down leaks and reduce the strain on your habitat's skin. $\endgroup$ – Harabeck Oct 15 at 20:10
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    $\begingroup$ Of course food is not fuel. It's food. And speaking of, here is your cookie. $\endgroup$ – Backup Plan Oct 15 at 21:56
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    $\begingroup$ IIRC, someone does exactly this in "Rendezvous with Rama" - flying near the centre in near-zero-g, to reach the far end of the cylinder. $\endgroup$ – Robin Bennett Oct 16 at 9:48
  • $\begingroup$ @RobinBennett I never read Rendezvous, but Clarke did certainly do this in one of the later Space Odyssey books (3001 if I recall correctly). There someone flew around a zero- or low-grav space-station on an artificial dragon. $\endgroup$ – Tonny Oct 16 at 11:00
  • $\begingroup$ I first read the "wings in high pressure on the Moon" in the 1970s, probably in Analog but don't recall the author or title of the story. Might be a question there... $\endgroup$ – Zeiss Ikon Oct 16 at 11:18
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I think using some futuristic version of powerstriders would be pretty interesting. They already look pretty scifi as is, but you could imagine a fair amount of upgrades to make them more practical.

To start with, it would be cool if they could be retracted, maybe stored behind the wearer's calf, with the blade folded in some manner. Perhaps the blade is made of a material with asjustable rigidity to allow this.

Adding different "soles" to the stilts for different terrain could also be practical. Sharp studs like on soccer shoes could help adherence on damp soil, whereas ridged rubber could give better adherence on rocky terrain. Maybe they even come with a mountain climbing setting.

If they are retractable, maybe they are also adjustable, so that they can serve as just plain stilts for wading through swamps or other shallow bodies of water.

These are however quite energy consuming if I remember correctly, so they wouldn't be best suited for long distance travel.


For long distances, you could install a system of zip lines that would only require large poles to depart from and netting to land safely. It is possible to pull yourself along one, but I believe that it's quite strenuous on the arms.

Hang gliders and para gliders are two different heaver than air, non motorised crafts that can allow for fairly long distance travel without any prior installations. However, sustained flight requires thermals for lift, which I don't think you'd get in an O'Neill cylinder. You also need an adequate landing zone, for safety reasons.

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    $\begingroup$ Zip lines, para gliders, etc. are not fuel free. The fuel consumption occurs before they are used, when the person and any equipment are transported up to the high spot from which they launch. $\endgroup$ – krb Oct 15 at 16:19
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    $\begingroup$ @krb in that case I can't imagine any transport that's truly fuel free. Walking you say? Ah, but that burns calories! Letting yourself roll down a hill? But how did you get up to the top of the hill? $\endgroup$ – Whitehot Oct 15 at 17:13
  • $\begingroup$ I like the zip lines and the powerstriders, well and the gliders too. It's not making use of the setting in it's literal sense but you get a cookie because these ideas would all work out. Good stuff. $\endgroup$ – Backup Plan Oct 16 at 9:10
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    $\begingroup$ I'm not sure how the zip lines would work traversing the circumference of the cylinder. You certainly couldn't zip directly across, but a series of smaller runs might work. @krb OP edited to add that human "fuel" (food) doesn't count... so if they manually climb, that's a moot point. $\endgroup$ – Doktor J Oct 16 at 15:52
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    $\begingroup$ @DoktorJ see Robin Bennett's suggestion for a circumference vehicle - it could work well in conjunction with a series of zip lines :) $\endgroup$ – Whitehot Oct 16 at 16:32
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You could have a pedaled aircraft (such as used to cross the English Channel). The more you pedal it up in the air, the less the 'gravity' will be, so you mainly have to expend energy when taking off.

A small pedal-powered airship could also be useful. You wouldn't need as much energy to get it up as a heavier-than-air aircraft, and it will quickly reach an altitude where the air is so thin that it stops rising. You would need to anchor it when it is parked, however.

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Leverage the angular momentum of the O'Neill cylinder, itself. When one is standing on the surface of such a cylinder and drops his ice tea, it is not his own feet that get the bath, but the person next to him. In fact, the dropped beverage (aside from being a travesty in lost deliciousness) is attempting to move in a straight line while the person who dropped it is following a curve. That causes the path of the dropped beverage to appear curved from the perspective of those riding in the cylinder.

To make use of this, simply have a series of conveyor belts that simply wrp the cylinder at different levels. One level simply loops in place. A second spirals "clockwise" to allow transit to one end of the cylinder. The third level spirals the other direction to allow transit to the other end. If the conveyors move on frictionless rollers (while not being frictionless themselves), so much the better. This gets full movement capabilities at only the cost of keeping the cylinder rotating.

For a more complex approach, have two concentric cylinders rotating at different speeds (the inner having a greater angular momentum to simulate a similar gravity level as the outer, but possibly a different level for reasons that might be considered necessary in story). Radial movement would be as simple as transitioning to the other cylinder for a time. Lateral movement can be achieved by capturing the rotational differences and transferring the differential rotational energy into lateral conveyance of any type. There would be more energy involved in keeping the cylinders rotating at their prescribed speeds but transit would be "free".

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    $\begingroup$ Very nice, here is your cookie! Appreciate the effort you made [insert thumbs up]. $\endgroup$ – Backup Plan Oct 15 at 19:30
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    $\begingroup$ "That causes the path of the dropped beverage to appear curved from the perspective of those riding in the cylinder." Such a force on an inhabited station would be hardly noticeable. If it was, it would make people sick. "This gets full movement capabilities at only the cost of keeping the cylinder rotating." No way. They'd have to be normal conveyor belts. Maybe the first time rotation started they'd take time to spin up with the habitat, but spin up they would, just like all the air inside. $\endgroup$ – Harabeck Oct 15 at 20:07
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Parabolic Tunnels

There has been some research into the idea of a tunnel in the shape of a parabola underground, where the momentum the vehicle gains dropping to the bottom of the tunnel is enough (or nearly so) to get it back up to the top on the other side of the parabola. You'd have to deal with friction, of course, so some sort of maglev would be required, though it could be simple static magnets if you can make them strong enough. Articles I've read quoted 1 hour from New York to London as a possibility with this method.

The major difficulty of course is digging a tunnel deep enough into the Earth's crust. And of course there's a limit to how far a single parabolic tunnel can travel before its bottom would sink below the crust. Point is, it gets you from A to B using almost nothing but gravity and momentum. (Elon Musk may already be looking into this, not sure if the Boring Company is doing parabolic designs or not...)

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  • $\begingroup$ would be cool with some plots of courses in a rotating station. $\endgroup$ – ths Oct 15 at 19:21
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    $\begingroup$ I don't see that working within an O'Neill cylinder, considering the limited space and the gravity shifting from lowest in centre to highest on the surface. Maybe worth to make into a separate question. $\endgroup$ – Backup Plan Oct 15 at 22:02
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    $\begingroup$ @BackupPlan The route could be attached to the outside of the cylinder. Then it has the added benefit of easily maintaining a vacuum to reduce drag and improve travel ability, though then you would need to protect yourself with a suit or in a capsule. If the capsule was a perfect, smooth metal sphere, it could roll instead of using maglev, making the design simpler and also a less common idea, fitting your question criteria great. $\endgroup$ – Loduwijk Oct 16 at 18:14
  • $\begingroup$ @Loduwijk Yes, outside makes more sense, using existing vaccuum. I'm not sure about the gravity outside the cylinder working out as needed, though. And would the tunnel be attached around the circumference, or twisted about the cylinders length? $\endgroup$ – Backup Plan Oct 17 at 7:59
  • $\begingroup$ 1) The artificial gravity outside should be even greater than it is inside. 2) I was thinking around the circumference, but you could probably do it either way. I think this is one of the better ideas, as it sounds both realistically plausible and a fun and unexpected twist. But there are multiple great answers! You will have a hard time marking only 1 as accepted, and you have plenty of great ideas here. $\endgroup$ – Loduwijk Oct 17 at 16:45
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Horses were actually really quite good at what they did.

We abandoned horses as a method of transit mostly because they weren't as fast and their effective operational range (for a reasonable timescale) was therefor generally quite a bit lower.

Additionally, there are space/infrastructure concerns that scale poorly as a function of population density - They fit less gracefully into an urban environment, as they need room to run when they are not being used as transit.

The environment you describe is small enough to be crossed on horseback in a reasonable time, has plenty of open space, and sounds like it has low population density - horses would be an excellent fit. As an added bonus, you have no real need of spending manpower or resources on maintaining roadways, as the horse is an extremely effective all terrain vehicle.

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    $\begingroup$ Horse upkeep and cleanup is a considerable amount of work, plus medical care and, in the long term, breeding. Not to mention getting them into space in the first place. But if they're part of the biodiversity mission you might have them there anyway ... $\endgroup$ – pjc50 Oct 16 at 8:30
  • $\begingroup$ Future humans might have evolved a belief that horseback riding is animal cruelty. If they're environmentally conscious enough to want fuel free transport, they might also care about the suffering inflicted on living things to support their life. $\endgroup$ – Muuski Oct 16 at 20:00
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    $\begingroup$ @Muuski I don't want to get into an ideological debate with you on this one, so let me just say that domestication has not been generally considered to be cruelty and that humanity as a whole has shown no significant signs of moving in this direction for the past 10,000 years. So a likely premise, this is not. $\endgroup$ – Iron Gremlin Oct 17 at 20:33
  • $\begingroup$ @Iron Gremlin I'll agree not to get into a debate, however, many vegans seem to disagree with your assessment. $\endgroup$ – Muuski Oct 17 at 21:07
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I bet, at childhood you did a trick with a balloon: first inflate it, then release it :) So it hops over the room loosing the air pressure inside until deflated.

So why we can't create such a transportation method? You sit on a chair with, let say, small wings and attached balloon. Prerequisite: the balloon is inflated. Once opening a vent, you start moving (and this is your pilot skill to adjust the trajectory to desired one, he-he). Once the balloon is deflated, you're grounding down, closing the vent, inflating the balloon back (using old-school mechanic pump, let say, leg-driven one). Repeat the deflation hops until you're done from point A to point B. We can name it "sky golf" or something like that, what do you think?

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    $\begingroup$ Very impractical, but it would be hilarious to see and it sounds like much fun if it worked. Great answer. $\endgroup$ – Loduwijk Oct 16 at 18:15
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    $\begingroup$ I just want it to make that pbtpbtpbt noise as it flies by. $\endgroup$ – Muuski Oct 16 at 19:51
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If you are looking for something human powered, practical, suitably futuristic and still mostly unknown, look no further than the Shweeb:

enter image description here.

Using a network of multi-level rails and remote-controlled switches, trunk lines and branches can be built to achieve any density you require. The low weight of the rails and the pods lend themselves really well for commuting between vast skyscrapers and for the occasional steep slopes electrical motors can be built either into the pods or into the rails themselves. As a bonus, these motors can act as generators as well when the pods are going downhill.

Controlling the switches can be either done manually via remotes inside the pods or optionally the user can enter a pod at an end terminal, specify their destination and a routing algorithm sets the switches at the proper time just before the pod swooshes by.

For improved speed and efficiency multiple pods can travel close to each other in trains, reducing air resistance, and if outfitted with proper bumpers or towers, the stronger travelers can assist the weaker ones (or even move cargo pods). How's that for a post-scarcity, neo-communist utopy?

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Hamster balls the size of humans!

They can also traverse water!

https://www.youtube.com/watch?v=tg7i30pXARQ

And be bouncy enough for the jumping trick!

And, if pressurized, could be used for the occasional EVA!

Every family needs one! Or several!

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Since the cylinder has artificial gravity, there is one "human powered" transportation method that uses the variable gravity of the cylinder.

The person simply climbs to the spin axis, either at the end cap, or raised platforms spaced along the cylinder, and then while in the zero g zone, aims along the spin axis and pushes off as hard as possible. They wear a "wingsuit" so they can scull through the air while in the zero G zone, and also to provide the means of a controlled descent through the air as they drift into lower "altitudes" from the spin center and become subject to the spin gravity.

A skilled user could presumably travel several kilometers in the spin axis and then make a controlled glide to their destination on the ground.

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For some reason, everyone seems to forget exactly what an O'Neill cylinder actually is. It's a spinning tube, that uses the fact that it must apply a force to you to accelerate you in a circle; this force is what simulates gravity.

The cylinder can only apply artificial gravity if you're in contact with it...

If you're not touching it, then you'll be floating in space as per any other space station; with this metal can spinning around you.

As such, jump (hard enough - springs may be required) in roughly the right direction, and float your way there. Sure you have to adjust the jump direction to account for the fact the ground is spinning.

Far less effort than a bike.

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    $\begingroup$ Don't forget the body's own inertia. You're going to keep moving in a fairly straight line as the inner surface of the cylinder moves in a circular path. If you jump straight up you retain your inertia and come down about where you started. Jump counter to spin and you'd get a slight increase in distance, etc. You'd have to completely neutralize your motion relative to the axis of rotation to float, at which point the moving air will push you towards the surface. $\endgroup$ – Corey Oct 16 at 3:08
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    $\begingroup$ It would make a difference if one runs or bikes in the same or against the direction of rotation. The latter allows the rider to jump long distances. An arm-powered winged suit will allow the rider to propel him/herself with little effort from one point to another. As with conventional flight, landing needs practice, as you must adjust your speed to the rotation. $\endgroup$ – Christmas Snow Oct 16 at 5:24
  • $\begingroup$ @Corey correct - hence why "jumping" won't cut it, but like I said, something to launch you. The speed you launch though really won't need to be very significant. As for the moving air - absolutely it'll be a factor; but then you'll have the same story with even a bike... There's nothing stopping someone making multiple jumps to get to their destination. $\endgroup$ – UKMonkey Oct 16 at 18:05
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    $\begingroup$ I was thinking something very similar when reading other answers. There is no magical gravity in the center space. But despite that oversight, the other answers do mostly work anyway. But because of the actual physics of it, if we are being realistic, keep in mind that simply touching the outer wall does not cause you to suddenly be grounded normally... it will be moving relative to you, and it needs to accelerate you to its speed. Depending on that speed, you might scrape along the ground a bit before coming to rest. What fun though, just jump toward the other end of the cylinder! $\endgroup$ – Loduwijk Oct 16 at 18:21
  • $\begingroup$ Your answer reads like you can just push off and immediately come to rest while the cylinder rotates under you, and that's just not so. Run the numbers. In order to 'float' you'd have to jump hard enough to reduce your own inertia relative to the axis of rotation to almost zero. You're going to need something a little better than just springs, you'll need rockets. The only way this is going to work is if the rotation of the cylinder is very slow. $\endgroup$ – Corey Oct 16 at 21:52
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A climbing rope mechanism, if it's a cylinder then you tie both ends to and have a crank like mechanism that when rotated have a platform climb up the rope, seeing how a straight line is the shortest distance between two point you will reach the other end faster then walking around the cylinder & as a bonus you don't waste ground space that can be used for building\farming\etc.

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  • $\begingroup$ Highly recommended addition you should edit in as another paragraph: "Added bonus: when you get to the center, you will feel weightless and can push off to fly to the other end of the cylinder." $\endgroup$ – Loduwijk Oct 17 at 16:27
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Instead of using the power of humans, passively use the power of the O'Neill Cylinder itself.

At least, use an inevitable feature of the O'Neill Cylinder design: Wind.

Instead of horse drawn wagons, you'd have sailing wagons barrelling down your dusty dirt roads. Most of the daily traffic would go with the wind, anti-spinward, but it doesn't take much to learn how to tack like sailing ships do, allowing you to go in any direction you choose, including spinward.

You can even have sailing wagon races along your plains, and "X-Treme" land sailing competitions in any rocky terrain with bicycle- or tricycle-like vehicles.

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SIMPLE ANSWER...... A BICYCLE.

VARIANT ANSWER...... A Recumbent Bicycle.

Note. Water on many alien worlds is as hard as iron because it is frozen and you said 'by land' and 'by water'.

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(Not quite sure on the physics here.)

I think if you have a river that loops around the habitat, it will end up with a constant flow, because the water has inertia and will act against the movement of the station. You can then get in a boat to travel antispinward (I think?) without needing to row. (This is basically the conveyor belt answer, but water is easier to come by.)

The energy actually comes from increased drag on the station, but there's no energy needed at the point of use, and any nature reserve needs rivers anyway.

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    $\begingroup$ The water would not flow just because the station is spinning. It would spin with the station. The water having higher inertia just means that it would slosh more than the air if the rate of spin changed suddenly. $\endgroup$ – Harabeck Oct 15 at 21:23
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    $\begingroup$ The "water conveyer" will only work when the station starts spinning. As time goes by, it will 'catch up', and become stationary with respect to the "ground". $\endgroup$ – Chronocidal Oct 16 at 15:56
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    $\begingroup$ Though the water will accelerate over time in an attempt to match the cylinder wall speed, I doubt it would do so perfectly. The water surface speed should lag behind the water bottom speed. The deeper the water, the more I would expect this to be the case. Depending on what that difference is, this transport mode may still be useful, especially if you don't mind travelling slowly. @Chronocidal $\endgroup$ – Loduwijk Oct 16 at 18:25
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    $\begingroup$ The water won't accelerate over time, it will accelerate as it is delivered to the station. The cylinder was probably spinning before any people started living there, to test it and so on, and then all of the supplies were delivered with the people. Thus accelerating during the docking process. $\endgroup$ – Muuski Oct 16 at 20:06
  • $\begingroup$ Not to mention that the station needs to be spinning in order to keep the river in its bed. $\endgroup$ – Phlarx Oct 16 at 21:47
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I think you have some basic misconceptions about what "fuel-free" should mean (food is fuel! etc.), but the question is an interesting one. If your goal is to allow transportation without needing large portable energy supplies that would be unsafe or impractical, human-powered transportation is an option, but will significantly impact nutritional needs for keeping everyone fed.

An alternate perspective that might be interesting is reducing or eliminating energy consumption per unit distance traveled. Fundamentally, you only need energy to accelerate/decelerate. The reason we need to spend energy per unit distance traveled is all a matter of friction and wind resistance. If you setup a system of vaccum tubes/tunnels with very-low-friction pods/vehicles inside, then essentially the only energy expenditure for travel via them is maintaining the system and some minimal amount of acceleration/deceleration proportional to the speed you want to travel at.

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  • $\begingroup$ Why the downvote? This was written before some edits that clarify, and may not be as relevant anymore, but that's all I can figure..? $\endgroup$ – R.. Oct 16 at 20:15
  • $\begingroup$ "Fundamentally, you only need energy to accelerate/decelerate" - and overcome resistive forces. Infact; you'll find that almost all energy we use in transport ends up going against either friction or air resistance. Also, if you acknowledge that your answer is bad because the question wasn't clear - then you should use the comments section to clarify before you answer or just delete the answer. $\endgroup$ – UKMonkey Oct 16 at 20:30
  • $\begingroup$ @UKMonkey: That's exactly what I said in my answer. $\endgroup$ – R.. Oct 16 at 20:32
  • $\begingroup$ Plus, part of the decceleration can be regenerative. You could envisage to engineer a system where a pod arriving at a dock needing to decellerate will use its momentum to acccelerate a pod departing the dock. You'd save even more energy expenditure. Of course this would only be usefull in the "busy" docking stations (hubs) where you wouldn't have to wait long for another user to accelerate/decellerate you. $\endgroup$ – Hoki Oct 17 at 10:11
  • $\begingroup$ For low usage end points (to your house), the pod is slowed down by the docking station but part of these energy is retrieved, either mechanically (you compress a long spring when you arrive at the dock, latch it, then the spring gives you assitance to start your journey on the next morning), or electrically (to power the TV in your house or again give you a assitive impulse on the next trip. $\endgroup$ – Hoki Oct 17 at 10:13

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