Elon Musk said it was nearly impossible to get injured in his system. Which means that any aircraft travel is out, because all it takes is an engine failure to kill everyone on board.
The safety reason is a big reason why I'm going with the underground tubes between LA and SF.
Engine failure doesn't kill people, because you can typically glide to a landing. Speculatively, if you got your glide ratio perfect and launched high enough, you might not need an engine to get between LA and SF.
But yeah, flight is comparatively one of the safest ways to travel. But, in principle, it is still quite risky. A lot has to go right for an aircraft to successfully take off, fly, and land. Air speed must be maintained, the engines must remain mechanically sound, landing gear must be operating correctly, hydraulics on the wing and tail flaps must be operating, the pilot must be competent and alert. Countless systems must be working correctly. Any one of these things going wrong can result in mass casualties. Statistically our standards of operation are so high that flight is effectively safer than the automobile or trains or even lightning, as the article points out. But 1 in 12 million is still far from the effective 100% safety that Musk is promising for hyperloop.
That would be one hell of a glide ratio. A little research on Wikipedia tells me that modern sailplanes get a glide ratio of something like 50:1. It's roughly 350 miles from LA to SF, so you're looking at launching from about 37,000 ft. This sounds doable, but I don't know if it really works like that. Can they keep the same glide ratio at that altitude? What about weather conditions? What about Elon's claim of 30 minutes for the trip?
To be fair, if he's comparing to human-driven cars, every mode of transport is "nearly impossible" to get injured in. That clause doesn't really constrain anything.
I don't think it can be underground, since Musk said it would cost $6 billion to build. Also, the plan is to build something similar for east-west coast travel, and underground would be even less possible.
The other consideration aside from cost is that seismic activity, even minor, can skew a tunnel. (Edit: for deep tunnels, that is. I have no idea about tunnels right below the surface.) That's bad news at high speed. I've given the tunnel approach some thought.[1]
And I keep hearing people trying to apply Hyperloop to coast-to-coast travel, but I don't recall Elon every saying anything about that long of a distance. In fact I recall him specifically talking about "the right city pairs", which implies some kind of distance limit.
I do wonder if there's something specific about LA to SF that enables the low low cost Elon's suggesting. Like the fact that they share a coastline with the Pacific Ocean.
The $6 billion cost seems too good to be true for any transportation system that would require significant land acquisition. California is set to spend some $60 billion on a train between these cities, and most of that cost is for right-of-way.
The construction cost alone for building a tunnel underground would be in the several billion dollars. I don't think it will be underground. At least not most of it.
This doesn't work for an electric aircraft, or many normal public transport methods as they are all focused on batching people up into large groups (planes, trains, etc).
Also, Elon has called Hyperloop 'another type of transport', i.e. nothing like we already use, whereas I would say this idea is just an aircraft with a new type of launch system; not as different as Elon suggests it will be.
However I agree that getting the land to build a tunnel on the surface (or a track of any sort) would cost a lot of money, and tunnels below the surface would be too costly as well.
Although I think lots of people are converging on the idea, sound waves, evacuated tunnels, all that sort of stuff, I think everyone so far has missed the big detail or breakthrough that makes it feasible, after all, these techniques have been known for a long time, just not been taken advantage of because they aren't practical.
> This doesn't work for an electric aircraft, or many normal public transport methods as they are all focused on batching people up into large groups (planes, trains, etc).
True, but as the batch size gets smaller, so does the interval between vehicles. "one every minute, on the minute" is not much different from "It leaves when you arrive". This may not work for aircraft, but it certainly would for automated light rail systems.
> Also, Elon has called Hyperloop 'another type of transport', i.e. nothing like we already use, whereas I would say this idea is just an aircraft with a new type of launch system; not as different as Elon suggests it will be.
I'll stick to my reasoning [1], firmly grounded in poesy, and proclaim this the strongest counterargument (slightly rephrased): Elon is simply too proud to call such a system a 'fifth mode of transportation'.
I'll re-issue my prediction: an STP hydrogen tunnel with elecromagnetic levitation (my favorite being Inductrack, known for its passive failsafe) and propulsion, and wheels for low speeds, makes a lot more economic sense than an evacuated tunnel. Much less drag, much higher speed of sound.
The other things that any modern engineer would never do that an 1870's railroad technician somewhere built into SOP, like mixed speed segments, frequent braked unbanked turns, single-tracking, and manual signalling / switching and grade crossings, will also be consciously avoided; the FRA regulations are built on making operating under such principles safer. Applying modern real-time at-speed routing to rail is something the PRT guys have been dreaming about for decades - the money and organizational will just hasn't been there to make it happen at a scale sufficient to make it cheap enough to justify.
Sounds like an insane fire hazard. With large volumes of hydrogen and breathable air in close proximity, otherwise minor failures would be catastrophic.
After ruling out underground tubes, electric aircraft and coast-to-coast travel, teleportation seems to be the only option left. And I haven't really expected that.
One of my takes on it is that it has to be some sort of land/underground interconnection between cities.
My reasoning behind this is that he is open sourcing the designs. My guess behind this is that if it is a ground based system that requires right of way/property access etc. then there is tons of transaction costs & government regulation that would prevent copy cats from destroying the first mover's capital investments that would normally be protected via IP law.
If it didn't have these high transaction costs associated with it, then any actor could come and undercut your system after the tech behind the open source designs becomes cheaper. Traditionally this would be protected because of IP laws. However, he's dismissing this route & letting anyone up to the challenge take on the construction challenge with him. I'm guessing this is likely because the government won't eminent domain/allow/permit etc. extra routes between SF & LA etc. if there's already a hyperloop.
Interesting idea, but I don't think it is realistic as air travel, even from a launch tube, I suspect would be under the rules if the FAA, which I'm sure would still require the security ....uhhhh, stuff (?) that we currently have to deal with, so really a very limited benefit.
Plus, if then hyper loop can run along/beside the California aquaduct, I think that would solve the issue of terrain and land purchase. If elon can convince the gov't that the hyper loop would secure the passageway, they might go for that.
About the land access concern, in France we had the aerotrain which was developped as an alternative to high speed train but did not survive the conventional railroad lobbies. There is still 60 km of test track south of Paris. The track is 10 m above the ground and is built using pillars every 20 m. It has been there for more than 40 years for it's considered too expensive to dismantle for actual very limited annoyment, more limited than high voltage power lines for example. However, land is flat there and mostly non urban.
Keeping a passenger aircraft at constant speed of 600 mph is not realistic with the current (or near-future) battery technology, even if the initial kinetic energy comes "for free".
May be it's a rocket. You just stand in a small rocket vertically, like those used in the military and cost about 3-4 million each. You get launched to 10-15 miles height making a gravity turn at some point. After that it takes a relatively small burn to secure a nice trajectory that lands you 500 miles away. I imagine it's a vertical pipe 1 mile high and you stay on your feet the whole journey with about 5g being accelerated in the pipe until you reach the proper delta-v. Then you land with parachute on cushions or grasshopper-style. Worst case may be an electric propeller.
I remember a similar project from the French TV news. The airplanes were ultralight drones (no pilot and only as many passenger as taxis). I can't find the source.
I guess Elon Musk does know about stuff like "right of way". Also you might experience difficulties to launch something into the air from an evacuated tube...
He didn't say the tube were going to be evacuated did he ?
If you are going to put something in the air, evacuationg th lauchpad seem to be a bit pointless.
why is everyone taking this thing so seriously? correct me if I'm wrong but it seems so vague as to not deserve the current hype, regardless of who Musk is
It's a lot more fun to imagine it won't be a massive, Segway-level disappointment; plus he has a history of making big promises and delivering. Also, I think humanity is just ready for teleportation technology, now.
The safety reason is a big reason why I'm going with the underground tubes between LA and SF.