DonPedro
Re:Hyperloop
on Wednesday August 14, 2013 @04:22PM (#6213974)
This, I thought.
"Maybe guide rails leading up to it"
Re. headroom in Model S: http://www.teslamotorsclub.com/showthread.php/10879-Any-tall...
Not by itself, but maybe in combination with another technology:
http://www.popsci.com/technology/article/2010-11/nasa-engine...
Whatever you were launching would have to move through normal air, not the minimal pressure you have in the Hyperloop tube. It is hard to pass an airlock at supersonic velocities...
Just the simple fact that the Aerotrain was on a track and not in a tube makes all the difference in the world. And I don't get this "look someone proposed something similar before" thing (everything from vacuum tubes to maglev to this thing). These previous inventors failed to get their ideas realised. Now a visionary has his own tweak on things and should have a good shot. Rejoice!
I'll go out on a limb here and wager that SpaceX engineers know the Mach value for various permutations of temperature and air density. But I might be wrong...
I'd rather be stuck in my seat for 35 minutes than to travel to an airport, go through security, check-in, waiting and boarding, fly for 90 minutes and then apply all the logistics in the other end. Your point is valid, but I would contend that the total package is still superior.
Obvious engineering issues for further investigation. I would just point out that fatal failure mechanisms can be pointed out in any transportation system. The acceptance criterion is a sufficiently low fatality rate.
The basic issue the hyperloop overcomes is the energy waste in train transportation, especially at high speeds. This is primarily about aerodynamics, and secondarily about carrying with you the propulsion system. Third, it overcomes the "chunkiness" of the rail system, where passangers needs to be assembled and grouped into train-sized lots for transportation, rather than being able to depart continuously. You get superior energy economics, speed and convenience. I cannot see how that would be disappointing.
They are taking it out at the ends. Assume a fixed point in the middle, and you have some 1000' of movement at either end. That should be feasible, but the tube needs to be designed for very significant longitudinal movement through the pylons, and the design needs to take into account the possible lateral loads on pylons from having to bend the tube away from the geometry it has at the baseline temperature.
No you could not. The steel tube will expand and contract as temperatures change. Along most of the route, that longitudinal movement of the tube will be in the 10s and 100s of feet, which means that the "valley" could be anywhere on the tube according to temperature.