I have no math and I must scream

[kinzel]

I'm looking for an idea of what kind of rotation I'd need on a drum with a diameter of about 6 meters to give an object/person on the inside of the drum the feeling of 1/10, 1/3, 1/2, 3/4, 1, and 1.5 g ... is that too hard? Alas, I have no math and I must scream. Said drim to be in a spaceship in orbit, if you care.

Comments

[kalimeg.livejournal.com]

It is supposedly sickening to spin something small. There is a lengthy discussion of this in the novel Boundary by Spoor and Flint. Whirling once a second is more like an amusement park feature than it is like artificial gravity.

[kinzel.livejournal.com]

Is there a reason one must stand? Suppose one was, instead, using the "bottom" of the cylinder as a bunk?

Flat Bunk?

[stick-breaker.livejournal.com]

Flat is relative. if you are in the barrel, a piece of material forming a chord is not flat. The acceleration at the edges is higher than at the middle, therefor the "flat" bunk is actually slopped. if you tried to sleep on it you would slide down hill where the bunk intersected the surface of the cylinder. to actually rest you would want a bunk whose curve was equal to the curvature of the circle at the specific radius. "Flat" would be described as have the same acceleration over the surface.

Stickbreaker.

P.s. since I have already paid for the New Yule book, do I really have to wait for Christmas to get it? ;) This addiction to good story telling is killing me. I can barely survive between my weekly fixes.

[keristor.livejournal.com]

"w=sqrt(geff/r) which gives 1.8 Hz for 9.81 m/s^2 and a 3 meter radius"

Er, that 1.8 is angular velocity in radians per second, so that's 0.29Hz or just over a revolution every 4 seconds. Still fast.

As a table:

 G      Hz     RPM
1/10   0.09    5.5
1/3    0.17   10.0
1/2    0.20   12.2
3/4    0.25   15.0
1      0.29   17.3
1.5    0.35   21.1

I agree that the 'tidal' forces would be rather high at that radius, even being in bed and raising your head would be rather nausea-inducing at 1G.

Numbers

[stick-breaker.livejournal.com]

As you can see a 3 meter diameter barrel has to spin very fast to
create the affect of 1G of acceleration.

And you must also take into consideration the effect below the 'Floor', if there is anything farther from the center of spin than the barrel floor.

stickbreaker

Re: Flat Bunk?

[keristor.livejournal.com]

Alternatively, lie along the axis of the cylinder instead of across it and then you won't get a bent back. But you would still get the Coriolis effects if you lifted your head which would be rather disconcerting if not nauseating. Less effect with lower acceleration, of course, probably not noticable much below 1/3G.

[mbarker.livejournal.com]

Does that depend on habituation? E.g., traveling in a car is often sickening until one's brain learns that the visual and motion sensing (inner ear?) messages are not a problem. For that matter, ice skaters learn to spin -- and apparently ignore the vestibular signals, if I remember the science special I saw where they were doing experiments in spinning chairs with such subjects. So perhaps someone who regularly layed down to exercise/sleep in such a framework would get used to it?

Which probably raises the issue of why one is laying in such a spinning framework? Perhaps to reduce the effects of prolonged zero-g?

Re: Flat Bunk?

[kinzel.livejournal.com]

P.s. since I have already paid for the New Yule book, do I really have to wait for Christmas to get it? ;)

Ummm ... yes. Neither of the stories is finished.

[kalimeg.livejournal.com]

Um. I used to dance and skate and do high-speed whirling. It's not the same at all. Moreover I used to adore rides with high centripetal motion. I doubt one could sleep in such an environment. Later, chemical changes led to that motion being sickening -- so no more rides where I push the boundaries of fast spinning.

Give this one up.

[keristor.livejournal.com]

For many of us travelling in a vehicle not under our ddirect control is always nauseating, no matter how much we do it. It isn't only a visual/motion conflict, blind people get car-sick as well. Indeed, I and many others find that if we can't see it's worse.

Being in control of the vehicle (and even more one's own body) makes it a lot easier to take the movement. In the case of dancers and skaters they deliberately minimise the effects by facing the head in the same direction for as long as possible (except for people in horror movies human heads don't rotate through complete circles, but dancers etc. simulate it so that it almost looks as though they are doing that). Being able to anticipate the movement, and for it to be easily predictable (when I turn the wheel to the left I feel acceleration to the right, etc.) makes it a lot easier to handle.

If one were only lying in the rotating cylinder and only moving to enter and leave then probably there wouldn't be much problem. However, if one were moving around then the Coriolis effects and the change in acceleration would be hard to accustomise, much like inner-ear disorders (I know people who have learned to live with them but none who have eliminated the reaction to sensations). Especially in such as small and quickly-rotating frame of reference the sensations caused by even a small movement would be more than we would expect to handle.