lughnasadh OP t1_j8ehey4 wrote
Reply to comment by mhornberger in 7 international companies have teamed with the EU to form the International Hyperloop Association, the industry's first trade body. by lughnasadh
>> I don't think Thunderf00t is the last word on what will and won't work
My take on Youtube debunkers is that if a person thinks a Youtuber is the last word on every single area of human knowledge & expertise, above and beyond everyone else in the field, perhaps a 101 course in critical thinking might be an idea.
A Chinese company is approaching the hyperloop idea with a partial vacuum and maglev trains. This seems an approach that might work. Total vacuums seem impractical to implement, but partial vacuums are much easier to engineer.
allenout t1_j8ez07g wrote
Maglev trains already exist though. Why do they need an expensive metal cage around them?
[deleted] t1_j8f1po5 wrote
Because maglevs aren't expensive enough. Got to develop the most expensive train possible.
remek t1_j8jvopm wrote
I am no expert on the topic nor do I defend Hyperloop but having a train going over 500km/h not enclosed in a metal tube makes me feel very uncomfortable for some reason. Perhaps if thing is supposed to go this fast I'd rather have it enclosed (or 10km above my head)
allenout t1_j8lw4g0 wrote
The point of the tube isn't protection, it is there to produce a vacuum.
humanitarianWarlord t1_j8ejwjc wrote
Normally I would agree but thunderf00ts video was pretty compelling and focused specifically on musks version of a hyperloop. Musks loop would never have worked and was frankly kind of insane from a safety and engineering point of view.
lughnasadh OP t1_j8em027 wrote
>>Musks loop
RIP to Musk's Hyperloop, its the past & its best to forget about it, and move on.
I'm especially intrigued by the Polish company Nevomo that is one of these 7. Their approach is mag lev trains on existing rail tracks, they say could achieve speeds of 550 kph (340 mph).
diskowmoskow t1_j8fzedz wrote
This could be huge.
mhornberger t1_j8ei4xr wrote
>Total vacuums seem impractical to implement, but partial vacuums are much easier to engineer.
Yes, people were always reading too much into the 'vac' part. It was always reduced air pressure, not hard vacuum on par with intergalactic space. The analysis is only slightly more substantive than the practice of forming fiercely-held opinions of books based just on their title, such as Dawkins' Selfish Gene or Krauss' A Universe From Nothing.
allenout t1_j8ezuc6 wrote
It's worth mentioning that the partial vacuum you are describing is actually 99% vacuum. Getting a true vacuum is impossible.
mhornberger t1_j8f1oif wrote
> actually 99% vacuum
I'm not sure what "99% vacuum" means in technical terms.
https://brilliant.org/wiki/hyperloop/
>>it is instead proposed that the Hyperloop tube operate at very low pressure: 100 Pascals, about 1/6 the pressure of the atmosphere of Mars [1]. This pressure is one thousand times less than atmospheric pressure at sea level and as a result air resistance is drastically decreased. After initial acceleration, Hyperloop pods can therefore mostly glide without applying any thrust until the deceleration at the end of the journey.
But I've read other proposals with higher, or variable, levels of pressure in the tubes.
https://hyperloopconnected.org/2019/02/variable-tube-pressure-a-new-concept/
The point was never to champion Musk's specific proposal. He didn't invent the idea of vactrains, and his white paper is just one paper.
allenout t1_j8g025f wrote
"Let's take expensive maglev and make it more expensive and dangerous by putting a tube around it so we came make a vacuum, but then let's not actually make a vacuum because that's only on 1 white paper".
king5327 t1_j8g3a59 wrote
A tunnel is a terrible place to have a train, on account of needing enough space around it to pass the air, else you enjoy a pressure bubble at the front of the train. But increasing the cross section of a vacuum tube is a non-negligible nerf to the effectiveness of the vacuum pumps, causing similar drag anyway.
This leads me to believe that even if the technology works perfectly, the numbers alone won't allow for the performance that was promised, unless at extraordinary expense in running the pumps.
Edit: Also, if there are any magnets at all on the car, or along the length of the tunnel, induction is going to be a surprise drag.
Viewing a single comment thread. View all comments