Reality Check for Hyperloop
With the latest news that the Alberta government was interested in the Transpod Hyperloop, we felt it was time for an update on our previous story.
What are some of the critical problems in trying to make hyperloop become a reality?
It’s easy to destroy this system by making a small dent in the tube. Yes, it’s one inch thick steel, but there are easily attainable ways to dent one-inch steel. When you hit a small bump protruding inside the tube while going at 1,000 km/h nothing good can possibly happen regardless of capsule suspension design. As proposed the system is impossible to secure - Clem Tillier
The whole thing about hard vacuum versus partial vacuum is academic This is a 99.9% vacuum. In a sudden decompression the passengers cannot survive, regardless of whether oxygen masks are available. This is unlike an airliner where there is always sufficient residual pressure and oxygen to survive even the worst-case decompression event. - Clem Tillier
Due to changes in temperature, the steel would change in structure. In bridges there are expansion joints to allow it to expand and shrink without compromising the structural integrity. The Hyperloop will require thermal expansion joints to function. Installing the joints on bridges is easy enough, however, they do not need to maintain a seal holding back billions of kilograms of force.
Phil Mason predicts
the Hyperloop will require a joint every 100 meters. Over the entire
distance, it would accumulate 6000 moving vacuum seals - all of which
are a significant point of failure."A failure on any one of them would
be disastrous to everyone inside" Phil Mason - The Hyperloop Busted Video.
A proposed Hyperloop of 600 km with a diameter of about two meters, will maintain a surface area of about four million meters squared. Given one square meter will experience 10,000 kg of force, the Hyperloop will have to endure nearly 40 billion kilograms of force over its entire surface.
A small compromise in the structure of the tube would
result in a catastrophic implosion. If the tube became punctured,
external air would tear into the tube, shredding it apart as it
violently rushes in to fill the void. - Interesting Engineering - June 29th, 2017
exits in some form are required for the hyperloop. There are always
emergencies that could occur in the tube and people must be evacuated.
However, designing an emergency exit system that both accommodates
sufficient safety and acceptable costs is complex. What emergencies are
critical and to what emergencies the system needs to be designed, is
A hyperloop has never been built and operated before, so practical experience and data is not readily available. It is hard to determine what is acceptable in terms of safety. Hyperloop Connected - Challenges for the Hyperloop, May 16, 2019
G-Force and Illness
Elon Musk's planned route is designed to limit lateral G-forces to a maximum of 0.5 Gs.
to James Powell PhD that’s a problem: "In all our tests, we found
people started to feel nauseous when you went above 0.2 lateral Gs." The
closest comparison would be roller coasters, which usually top out
around half a G — but the Hyperloop wouldn't just peak at 0.5; it would
stay there for the duration of the curve. The result would be well short
of blackout, which most studies peg around 4.7 lateral Gs, but it would
make the Hyperloop challenging for the faint of stomach. A sick
passenger might be less catastrophic than a crash but, given the tight
passenger compartments, the results could still be fairly traumatic. - The Verge
the UK’s planned High Speed 2 as a benchmark, high speed rail capacity
can be nearly 20 000 passengers per hour per direction, assuming 18
trains/h over a double track alignment, each with 1 100 seats. If a
Hyperloop pod had 50 seats for example, then to match HS2’s capacity 400
pods would need to depart every hour at a 9 sec headway. Assuming the
same number of seconds to alight from a Hyperloop pod as a train, 23
tubes would be needed to match HS2’s throughput. Railway Gazette - Gareth Dennis 14 March 2018
Hyperloop Technology Needed That Does Not Exist
Hyperloop High Speed Switches
- In the hyperloop network all hubs are connected with links. The
technological development of high speeds switches is in its infancy and
feasibility needs to be proven.
There is no technology to master the airlock system that will allow
pods to move into and out of the tube without wrecking that vacuum, then
spending the time and energy pumping all the air back out.
- Big enough to propel a full-scale vacuum train do not exist There are
no turbomolecular pumps big enough to propel a full-scale vacuum train
at supersonic speeds. However, it is with good reason. Engineering a
case that can withstand the force of a blade traveling at hypersonic
speeds with the force of 10 full-size locomotives is preposterous
according to an article from Interesting Engineering in 2017.