h a l f b a k e r yGood ideas at the time.
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First, I must apologize for this idea. Not that it's a bad idea, just that it is utterly useless.
It's an idea I had thirty years ago, and back then the future was very different. We were going to see huge space stations with lots of open areas. Back then, this idea was going to be wonderful - in
about a century and a half.
But, that future died, and our future space stations shrank. I still had this idea in my head, though... but now my memory is getting bad. Maybe I'll lose it completely. So, I'm plunking the idea down here, in celebration of what might have been.
***********
We're on a space station. It's a big place. It has to be, so we can have a full self-contained sustainable ecosystem. So getting around can be a hassle sometimes. You can always get somewhere by walking - we do spin the arcologies for gravity - but that is, by definition, taking "the long way around." So, when you're in a weightless area, you want - the Spaceman's Broom.
It gets its name from the witches' brooms of the past, as will become obvious. The body of the vehicle is a lightweight, rigid tube, of about the size of one's wrist. Teeing out to the sides are rotating handgrips, like a motorcycle's throttle; with clutch levers, both sides. About (by definition) a cubit aft of those grips, a pair of cupped, padded elbow rests. A little farther aft, a loop for attaching the waist strap.
Yet farther down the tube, a very bicycle-like pair of pedals are mounted on a crank through the tube. No chain-ring, though - the crank has bevel gears inside the tube, which drive shafts going to both ends of the tube. At those ends, there are cage-enclosed pedal-powered propellors.
The hand grips turn the prop-heads - the right hand grip causes the front prop to arc up and down, while the left controls the left and right motion of the rear prop. Power is applied equally to the two fans, unless you yank the clutch on one of them.
Grab your broom, strap on, push off, and start pedalling. It'll take you a while to get going, and you better remember that - 'cause it'll take you just as long to slow down.
O'Neill Habitat
http://en.wikipedia.org/wiki/Island_Three
Big, cylindrical, in space, big. [bungston, Dec 13 2010]
[link]
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//Not that it's a bad idea, just that it is utterly useless.// |
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Is anyone else looking at this and thinking [marked-for-tagline]? |
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//a very bicycle-like pair of pedals// |
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Yes, it does sound like a kind of zero-gravity bicycle. |
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1/6 G holidays to the moon may very well happen sometime. This will provide an expensive opportunity for 1/6 G sex; flapping wing flying (in a sealed aerodrome), and of course plenty of Spacemen's Brooms. |
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So your idea is not useless, just well before its time. |
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Agree with [Ling] You had Swanwick (with his compressed air
"broomsticks") beat by around 7 years. These are better,
though, cause they ought to retard bone demineralization. |
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//Is anyone else looking at this and thinking [marked-
for-tagline]?// |
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This would work underwater better than it would work in air at 0 G. |
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flipper(s): then it would actually look broom'ish instead of odd-thing-on-a-pole. |
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Actually, I think a trailing rudder panel might be necessary - otherwise, you'd have no control inputs at all if you weren't pedaling. And since a single panel rudder would only allow you to steer in-plane, you might need to split the panel, and operate the two segments individually so you could roll to the plane you wish to steer in. |
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Then, like with flippers, it'd look properly broom-like. |
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There's a sci-fi short story featuring pedal powered personal space craft, which compete in a Tour de Systeme race on a course around the solar system. Pedalling provides power to an ion drive engine. I haven't found it on the web; it may be too obscure. The long time required for accelerating at both ends of the trip is discussed. |
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I guess [lurch]'s idea is the indoors equivalent. |
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I bunned only if it can be used by Spacey Women, too!!! |
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The concept of a broomstick as a personal interstation transport craft pre-dates thirty years ago. (earliest similar concept I know of is in Heinlein's "Space Cadet" ~1948). |
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I haven't seen something for intrastation transport using fans, but I suspect stability and line of thrust would be difficult to maintain. |
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And why do you need a transport at all? In micro-g, you push off one wall and you're going to reach the other, a lot more efficiently than the pedaling will get you there. |
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See what I mean? You're probably thinking of a space station with no dimension more than a few hundred meters. |
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Imagine doing your "push off" manuver when your destination is five miles away. Within a hundred meters or so, air resistance brings you to a stop, and you're marooned out in the middle of the air. Now what do you propose? |
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Also, re: //Spacey Women// - the broom works more efficiently when you're close to having the front and back props driving along the same line. However, that's not possible, as the driver's mass is hanging outside that line. The front prop then has to "nod downward" far enough that the torque of the (front fan/Center of Gravity) couple is equal & opposite of (rear fan/CoG). So, it's an advantage to have the Center of Gravity nearer to being in-line, and not too far forward or aft. The, ah, female design better fits these criteria. (And looks better, too, IMHO ;) |
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I think a single panel rudder which could rotate circumferentially could steer. If the panel rotates to be horizontal it would be up and down. If vertical, left and right. Various angles produce various combinations of up/down and left/right. |
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Alternatively instead of rotating the panel, give the rudder dimension: a square of thin blades would work. Would a circle work as well as a square? |
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About the only design that has that sort of distance is an O'Neil type habitat, and every single concept for one of those I've seen has a tram or transport along that axis. |
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Human power is going to be horribly slow, simply because of conservation of momentum (pushed air mass relative to body mass). |
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"ought to retard bone demineralization" |
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Is there some manner in which you can bring the upper body muscles into the propulsive efforts game, instead of just using it for manipulating controls? |
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Could you incorporate another crank system, with the clutches and steering still on the crank handles but set up as "clutch and steer by wire" so that you don't need linkage headaches? |
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This way you could get a more full body workout. |
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//O'Neil type habitat// McKendree went a lot bigger than O'Neill; my favorites (and what I had in mind) were somewhere in between. (Mass drivers and Martian sand, baby!) That leaves a *lot* of potential non-axis destinations. |
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/Human power is going to be horribly slow/ |
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I can see how someone with thin spindly legs and an enormous belly audibly sloshing with beer might think that. Not to say that _you_ have any of those characteristics, [MechE]. |
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Where are the pyrotechnics, we ask. |
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//we ask// --- you would. |
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I wouldn't build such a habitat in the same *universe* with a Borg "civil"ization. |
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Which, come to think of it, may explain where all the possibilities went... |
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[bungston] Have you noticed my other comments where I mention repeatedly that I am a cyclist commuter? |
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Bikes work well because the propelling force is very efficiently transferred to the reacting medium (the road). This idea is much more closely related to a paddle(pedal) boat, which are much slower and much less efficient. |
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And [lurch] a McKendree is just an O'Neil scaled up for modern materials. The only zero-g corridor remains along the long axis. |
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//McKendree is just an O'Neil scaled up// exactly. And even in an O'Neill, your axial tram is two and a half miles from the surface, which is basically a helluva long way to walk. |
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[MechE] - I will try to make it simple: this idea will *not* work in environments where the environment makes it *not* work. |
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The environment for which this idea was envisioned has these important characteristics:
1. Big
2. Zero gravity
3. 1 & 2 are together
4. Full atmospheric pressure.
5. Non-rotating. |
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(You'll notice that lets out O'Neill and all of his buddies; there were some under- or un-published designs which were doable with very low-quality glass. Please - just consider it a given; if I had to post one, just the intro would be longer than the Compleat Works of Vernon) |
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If you ramped it up through enough gear steps you might be able to get some hellish rpm out of it - it may not be as underpowered as you think. |
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It would be fun to bench test a prototype. Your own personal wind tunnel ride. |
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No need, these things will just fly off the shelves ... |
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My primary point is that it won't work in "big". It's to
inefficient. It might work in "just big enough", that is in the
sweet spot where a push off won't get you across but
significant power isn't required. But the first pass there is
something more akin to a crank and release pogo stick. |
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How would you quantify such a device's power on the bench? Have an athlete crank it up and measure the wind output, then do some fancy maths? |
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[normzone] Load cell. Or set it on an ice-skating rink (or,
better, air-hockey table), and use a spring scale to measure
horizontal force (or use a balance with a cable and pulley
arrangement). |
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[MechE] I reread the idea, and I still don't see where it says
these things aren't recreational. I mean, sailing, swimming,
surfing, hang-gliding, unicycling, pogo-sticking ... lots of
modes of transportation are impractical, but practiced
enthusiastically nonetheless. |
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/paddle(pedal) boat, which are much slower and much less efficient/(than a bicycle) |
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I wonder if this is intrinsic to propeller vs wheel, or has to do with the increased friction from passing thru water as opposed to air. Consider a contest between a submerged bicycle pedalled on the substrate (for example on the bottom of a pool) vs the same bike in midwater with wheels turned 90 degrees and fitted with propeller blades. |
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// lots of modes of transportation are impractical, but practiced enthusiastically nonetheless. // |
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Except for travel on the London Underground. |
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/bike wheel fitted with propeller blades/ |
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This would be fun to make. You could make it out of a junker bike and wrap a life preserver around it for neutral buoyancy. You would travel at right angles, though. But you could steer with the front wheel prop. I envision this being devised during a weeklong vacation at the lake. I can smell the algae and taste the beer. |
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Bun only if it comes with a basket in the front and features the background music from the Wizard of Oz. |
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I'll get you, my pretty! AND YOU'RE LITTLE DOG, TOO!' EH HEH HEH HEH!!! |
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