The Hype behind the Hyperloop

        How the Hyperloop is going to work

Are you dissatisfied with the systems of transportation we have today? Do you feel the need for more speed; yet a safer, cheaper, and weather immune system of transportation? Then the Hyperloop could be your dream come true – or so the brain behind it believes.

Elon Musk, South African born entrepreneur and founder of Paypal, SpaceX and Tesla on 12 August 2013, unveiled the alpha-design white paper for what he calls the ‘Fifth mode’ of transport (alternative land, air, sea, and rail); and I must say it’s pretty interesting – I’m quite optimistic about this project as I’ve had a nearly similar idea in the recent past. So, let’s get down to it already—you would soon be riding the Hyperloop in your imagination!

What is the Hyperloop?

Photo credit: space.com

The Hyperloop is all the hype now in the tech media—and for a good reason. This fifth mode of transportation, as Musk calls it, is a proposed elevated ultra-high speed inter-city transportation capsule that will shuttle passengers at top speeds of 760mph (1,220 km/h).

As futuristic as that may sound, one can't help asking if it’s actually science driven or just another stuff of science fiction—well, I’d say is a combination of both as you’ll soon find out.

Do we actually need a new mode of transportation? It depends on who you ask. Most conservatives may argue they don’t see the need for one. Techies on the other hand could get super-excited over the prospect of one. Either way, the bottom line remains that in offering something new to the general public, it has to be better than what they have already; make it mediocre and it’s bound for failure. Musk actually believes his idea “could revolutionize travel”. With ideals of  “safer, faster, lower cost, more convenient, immune to weather, sustainably self-powering, resistant to Earthquakes, not disruptive to those along the route” mode of transport, as he stated in his company's blog, everyone would agree to this ‘next big thing’.

We’ll decide shortly if the Hyperloop can meet up with these aforementioned ideals.

How would the Hyperloop work?

 The Hyperloop elevated tube design

I’ve spent a great deal of time studying the 57 page design brief wherein Musk detailed the technicalities of the system and even the financial facet of the project.

The Hyperloop design and working principle is really interesting on paper. Basically, it’s a pod (or capsule) that would travel in continuous steel tubes which could be elevated (as pictured above), or underground. According to the design brief, it would carry about 28 passengers at a time and some other version of it could even carry the passengers' cars along with it in the journey.

The tubes will be maintained at a partial vacuum (you’d agree that totally evacuating a 1500km long tube will be overly energy consuming—unfeasible with today’s technology—even though it would allow for faster transportation as air friction is eliminated) thus, reducing air friction and heating. The tubes will have a vast array of solar panels that will power the entire system, thereby eliminating the need for grid supply (that way, it ensures its self-sufficiency). Inside the tubes, the pods are mounted on thin skis made out of a high pressure and heat resistant alloy, Inconel. Air is pumped through tiny holes in the skis to make an air cushion over which the capsule rides -- more like, levitates. Magnetic linear accelerators located at different points along the tube do the job of accelerating and decelerating the pods to appropriate speeds (just as it does for those Maglev trains and the roller coasters in amusement parks). It’s instructive to note here that top speeds will be just below the sound barrier (768mph); this ensures that no sonic boom is heard. The nose (front part) of the pod would have a pair of air jet inlets; an electric turbo compressor will do the job of compressing the air from the inlet and directing it to the skis and the cabin. High tailwinds and a low drag eventually translate to high speeds, with aerodynamic efficiency.

Are these ideas indeed practicable? 

A rendering of the capsule's interior

For the most part, the system's design is realistic—it makes use of already existing technology. But, a closer examination might bring some of the proposed concepts into question. The billionaire brain behind the business says his idea is still open for contributions on how to possibly improve on it though (@elonmusk). It delivers a great deal of its ideals: it’s fast (how about 760mph for a ride!), it’s self-powering in an eco-friendly manner (solar powered), Musk also claims it’ll be cheaper (with tickets costing about $20; and the project itself only $6billion—yes, “only”, when you consider that the US government approved $68billion for a less efficient, by Hyperloop standards, high speed rail). The tubes would also be made seismically safe (resistant to Earthquakes) with similar technologies to those used on such structures as the Golden gates bridge.

Concerns such as: G-forces resulting from fast acceleration to such high speeds, wind shear resulting from unequal wind strengths hitting the top and bottom of the elevated tube causing it to sway, and possible heat damage arising from the compressing and expelling of air mechanism earlier explained, have surfaced.

Tweaks to the system might solve some of the identified problems as we’re about to see:

• The problem of painful G-forces wouldn’t be much of a problem if acceleration is made slower. Also the tubes should be as straight as possible (less lateral acceleration) as steep bends definitely add to those forces.
• It’s uncertain if concrete pillars as proposed by Musk will do the job of carrying tubes elevated about 100ft off the ground.
• All that continuous air compression creates an enormous amount of heat and this could potentially damage the entire machinery. Musk plans on adding water tanks as heat exchanger to capture heat and turn it into steam which would be collected at the next station. But this could add to the weight and decrease efficiency – I for one believe there will be a more elegant solution to this problem than that.

How long before we see it take-off?

Hyperloop capsule with doors open at the station

Sorry to disappoint anyone, but in these austere times, it doesn’t look like governments are ready to gamble on seemingly far-fetched ideas like this one just yet. Elon Musk himself says he is not ready to embark on this project (I mean you can't blame him, he obviously has his hands full with managing his companies; and five children) , although he says with time he may build a small-scale prototype. He also says he would be supportive of anyone who may like to take on the project. Seems like our Hyperloop dreams will have to wait for now.

Fancy word you may wanna know about:

Kantrowitz limit: This is nature’s top speed law for a given tube to pod (capsule) area ratio.

At supersonic speeds or high subsonic speeds, a capsule moving in a tube containing a fluid (air in this case) has a minimum area ratio with the tube which when below that value, the flow is choked as they are now too close.