3 ms·
5000 mph = 134112 meters/m = 3557 rpm at 12m diameter I guess that's not too bad, but still wonder how difficult it is to reliably achieve a precise launch ang
by tomxor 5y ago
5000 mph = 134112 meters/m = 3557 rpm at 12m diameter
I guess that's not too bad, but still wonder how difficult it is to reliably achieve a precise launch angle?
Or are sensors so fast these days that this is easy? Maybe this is just a misplaced instinct from my subconscious fear of stuff hitting me in the head when kids inevitably start playing with centripetal motion using heavy objects.
- kragen 5y agoAt 12 m diameter it would be 82000 gees, eight times the acceleration they're targeting; their render is of a roughly 100-meter-diameter chamber. At 82000 gees rotor integrity becomes probably unmanageable with existing materials. At 100 meters we're talking 420 rpm, 22 radians per second. I don't think the launch angle needs to be precise; if it's off by 10 degrees (175 milliradians) they lose 1.6% of their altitude to cosine error. That would be an error of plus or minus 8 milliseconds, which seems about two orders of magnitude on the easy side of achievable.
- rep_movsd 5y agoTrying to make a 100 meter structure of this kind is madness There are no materials that are stiff enough at that size - not even carbon fiber. The biggest ships engine shafts are literally like pasta and only work because they are mounted on dozens of bearings at regularly spaced intervals.
- kragen 5y agoNot even wrong. Water isn't vacuum. cf. https://news.ycombinator.com/item?id=31036411 https://news.ycombinator.com/item?id=31036411
- freemint 5y agomilliseconds precision triggering of mechanism is trivial. It just means you need a processor which clocks megahertz not kilohertz.