Does anyone out there remember The Jetsons? It was a futuristic cartoon in which the world was filled with flying cars that could fold into briefcases, talking robot maids, buildings soaring high into the sky and people traveling via speedy capsules. We haven’t made too much progress on a flying car that can fold into a briefcase, but we are significantly closer to the era of traveling in high-speed capsules or pods.
Land and air are the two major factors that influence ground-based transport, especially when it comes to high speeds. The development and success of the Shanghai Maglev trains have demonstrated that the world can do without wheels. Therefore, friction between the ground and the vehicle can be eliminated.
Ground-based transportation has focused on improving the aerodynamics of a frictionless vehicle in the last decade and some new designs have made considerable progress. However, complete elimination of drag (air resistance) has not yet been achieved. This is where the Vactrain concept comes to the forefront.
What is a Vactrain?
A Vactrain or a Vacuum Tube Train is a transportation method based on the concept of magnetic linear movement of an object inside a vacuum tube. Passengers will be seated inside capsules that are connected to each other, which are placed inside a vacuum tube that runs all the way to the next destination. Just like Maglev trains, the magnetization and demagnetization of the railway track will result in the levitation and forward movement of the interconnected capsules.
The stations will also have an air-locking system. The section of the tube in which the train stops will be isolated and filled with air with the help of pumps. This will allow the capsules to be opened, so the passengers can get in and out at their desired destination. During departure, the air will be pumped out, once again restoring the vacuum so the train can move along. The lack of air resistance will allow the trains to function at speeds of 4000-5000 mph.
Let’s not get too excited, as the Vactrain concept is still a few decades away, given that it would require huge financial investments and advanced tunneling technology that we are still lacking. However, a similar concept has been proposed and is in development.
The Hyperloop Capsules
Ever played air hockey in the arcade? Next time you do, take a closer look at the table. You will notice the small pores on the table through which air is let out. A thin layer of air is thus created over the table, which reduces the friction between the puck and the table surface. That’s why the puck moves at such a high speed when you hit it!
Now, the same concept has been applied in the Hyperloop concept train. Unlike the Vactrain, which is designed to run in vacuum, a Hyperloop system will have a thin layer of air along the inner lining of the tube, which will provide an air cushion on which the capsules can move forward. The projected top speed for the Hyperloop is 760mph.
The Hyperloop capsule is designed to have an inlet fan and compressor at the nose. Therefore, if there is any amount of excess air in front of the capsule inside the track tube , it will be sucked in by the inlet fan, similar to what an aircraft engine does. The compressor inside will store this excess air. An outlet will be present under the belly of the capsule that will let out the stored air providing the air cushion, as it does in a hovercraft. The capsule is proposed to be around 7ft in diameter and 2.5m long, accommodating about 14 passengers per capsule. This means that you neither stand properly nor take a bathroom break. Fortunately, it won’t take you too long to reach your destination!
Linear Induction Motor (LIM)
The Hyperloop’s movement will be carried out by linear induction motors (LIM). There are two basic parts to a LIM: the rotor (rotating part) and stator (static part). A normal induction motor will have a stator wrapped around a rotor. When a current is applied, the stators and rotors will develop alternate polarities, thus resulting in the rotor moving on its axis. That’s the same way your ceiling fan works!
This type of linear induction motor will have the stator laid out in the form of a straight track, rather than wrapped around the rotor. When a current is applied, alternating polarities are developed along the track. Thus, the rotor will move forward, rather than rotating about an axis.
Which is faster: Airplanes or High-Speed Capsules?
For aeronautical enthusiasts like me, we’re looking at dark times ahead. The current design of the Hyperloop capsules is looking at top speeds of about 760mph, which is faster than the speediest commercial aircraft today – the Cessna Citation X (700mph). Once fully functional, the Hyperloop capsules will be much faster than the average speed of commercial aircrafts. As the system is still under development, airplanes will still rule for few more decades, but aviation beware… thou reign shall end!!
So, to answer the question, can we travel around the world in 4 hours?
Although it might take a few decades to perfect Hyperloops and perhaps even Vactrains in the further future, the answer is…