General > General Technical Chat
The Hyperloop: BUSTED
rs20:
Disclaimer: not trying to defend overall hyperloop practicality. Just devil's advocating.
Haven't been following this thread for a while, but how about simple sliding O-ring seals to allow for expansion? The air in the ISS is "famously" held in by a handful of O-rings: http://nerdist.com/air-pressure-on-the-iss-is-maintained-by-these-two-tiny-o-rings/ (Apologies for the sensationalist headlines.)
Obviously keeping the air out of a hyperloop using O-rings is vastly more expensive than that, but I feel like vacuum on Earth is a less precious commodity than air is 400km up where the ISS is.
TheAmmoniacal:
--- Quote from: rs20 on August 03, 2016, 07:49:29 pm ---Disclaimer: not trying to defend overall hyperloop practicality. Just devil's advocating.
Haven't been following this thread for a while, but how about simple sliding O-ring seals to allow for expansion? The air in the ISS is "famously" held in by a handful of O-rings: http://nerdist.com/air-pressure-on-the-iss-is-maintained-by-these-two-tiny-o-rings/ (Apologies for the sensationalist headlines.)
Obviously keeping the air out of a hyperloop using O-rings is vastly more expensive than that, but I feel like vacuum on Earth is a less precious commodity than air is 400km up where the ISS is.
--- End quote ---
Using an O-ring to maintain the vacuum of the hyperloop would work fine - if it was static system. The problem is that the hyperloop must be flexible, allow for both thermal expansions and boarding/offloading.
rs20:
--- Quote from: TheAmmoniacal on August 03, 2016, 07:54:34 pm ---Using an O-ring to maintain the vacuum of the hyperloop would work fine - if it was static system. The problem is that the hyperloop must be flexible, allow for both thermal expansions and boarding/offloading.
--- End quote ---
That sounds like an orthogonal concern -- I'm just talking about dealing with thermal expansion on the plain parts of the track, away from stations. Longitudinal thermal expansion is handled (I propose) by having O-rings that can slide (think telescoping action, except only 10mm per segment).
stj:
if it is underground the temperature will be stable and the tube can be straight A-B with no turns.
T3sl4co1l:
--- Quote from: Maxlor on August 03, 2016, 07:18:38 pm ---What if the pinpoints were 10km apart instead of 1km? That'd increase the radius 10-fold, which would mean 1/10th of the acceleration, i.e. about 1.52m/s^2. That's about the acceleration you experience in a subway, and I think it'd still be uncomfortable to experience that constantly, with direction switching every 30 seconds. Then again, people put up with riding the subway with its constant starting and stopping, so maybe it'd be ok. However, the sideways motion of the tube would increase by a factor of 10 too, to a whopping 212m. That's quite a bit of land use there. So it'd be both slightly uncomfortable and use an unreasonable amount of land.
So I don't think just allowing thermal expansion is the answer.
--- End quote ---
Note that, by rolling the vehicle, lateral acceleration becomes indistinguishable from (and slightly additional to) normal gravity.
The repeat rate at which the vehicle oscillates (due to a buckled or buckling-induced path) is an interesting figure, though.
Now, what about trains? Because, so... they have 100% continuous steel tracks, and their spacings are exact. The path doesn't shift much, relative to the Earth, even over very long distances; except on very long paths, which can buckle on very hot days.
Everyone seems to be forgetting that the Earth itself expands and contracts, and is not, itself, an infinitely rigid element!
Tim
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version