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| The Hyperloop: BUSTED |
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| amspire:
--- Quote from: nctnico on January 20, 2018, 01:59:47 pm --- Your reasoning sounds much like the scaremongering when steam trains, automobiles and airplanes where introduced. :palm: If you'd reason like that then every airport in the world should have a clearance of a 50km radius and the terminal buildings should be bunkers made from reinforced concrete! --- End quote --- There most definitely are serious safety concerns at an airport. The terminals are a fair way from the landing strips, the landing strips are kilometers long and there usually is a runoff area. All fittings along a landing strip are break-away. The safety has been treated as an engineering problem. Hyperloop will have to do the same, but I haven't seen Hyperloop ever describe what would happen in the accident scenarios I am talking about. I think they are fair issues that have a right to be discussed. They are talking about one carriage every five minutes. That is one carriage every 50km. In a 1000km tube, there can be 20 carriages going at 1000km/h. If any safety system fails there will be an accident, and luckily with physics, we can estimate the energy of that accident. Now if high speed trains ran at full speed in an exposed elevated steel tube, there would definitely also be serious safety questions. Where they do run, safety experts do analyse the whole journey and where a derailment would be a devastation disaster, they force the train to run at a safe speed. Are any high speed train services run at just 5 minutes apart? |
| HalFET:
Heh, 36 000 kg would actually be a partially filled 12 m container, and for 2 GJ half a ton of TNT wouldn't do the job unless you presume perfect detonation... Anyway, amspire, a crashing aeroplane has more kinetic energy, is built out of materials which can be significantly more flammable, and yet the main cause of any fire or explosion is still the fuel and not the materials themselves, so for you to worry about aluminium and steel is rather interesting to say the least... Additionally aluminium is actually harder to set on fire than iron in a pure oxygen atmosphere. (Which I always found interesting.) Additionally your explosives vs. energy released calculation is off. But lets go with your 50 000 kg assumption, have you considered how much of that energy goes into deforming/moving the materials involved? You're acting as if we're dealing with a theoretical immovable tunnel wall with an infinite yield strength and an object slamming into it in a perpendicular fashion. And even then the result is surprisingly less damaging than you'd expect. Remember that test footage of that F4 jet slamming into a concrete wall at 750 km/h? You're looking at something with about 300 MJ of kinetic energy slamming head-on into a concrete wall there, and that took place in less than 100 ms. And yes I know the wall moved during that test, but what they forgot to tell you was that it was placed on air bearings for that test and you could have probably pushed it forwards with a few folks... |
| Someone:
--- Quote from: amspire on January 20, 2018, 03:01:16 pm ---Are any high speed train services run at just 5 minutes apart? --- End quote --- Both TGV and ICE services trunk at those sorts of headways in the fully automated sections, sometimes less. |
| mtdoc:
--- Quote from: nctnico on January 20, 2018, 09:44:27 am --- --- Quote from: EEVblog on January 20, 2018, 07:56:47 am --- --- Quote from: mtdoc on January 20, 2018, 05:09:45 am --- --- Quote from: EEVblog on January 20, 2018, 01:18:49 am --- --- Quote from: mtdoc on January 20, 2018, 12:39:44 am ---Very good point. Even if the hyperloop is never realized as a large scale public transport project (as I suspect will be the case due to financial and political but not technical reasons) --- End quote --- I'm happy to categorically state that practical realities will kill it, even if the financial and political will are there. --- End quote --- You need to be more specific about what you mean by "practical realities". --- End quote --- Sure, the vacuum part. If "HyperLoop" becomes a reality then it will not involve the vacuum part as has been, dare I say it, hyped. Make no mistake, the entire premise of the Hyperloop concept is based on the vacuum to lower to air resistance and lower the maglev power. It has no other "innovation". --- End quote --- First of all you have to define vacuum when it comes to the hyperloop. The amount of energy you can save depends linear on the density of the gas you are travelling through. So at 1/10 of the atmospheric pressure you save 10 times the energy. Some people may not call that a vacuum though. --- End quote --- Exactly. Without specifying what is meant by vacuum, one can continue to move the goalposts on what is meant by successful technical implementation of the hyperloop concept. The original Musk "whitepaper" was only meant to stimulate others to explore the idea of high speed transport in a tube with pressure lower than 1 atm. The various teams inspired to pursue this idea, all have different parts of the basic concept which they've focused on and attempted to optimize, etc. If hyperloops are ever built, who knows what intraluminal pressure will turn out to be optimal to balance the other design considerations (cost, safety, etc)?. Meanwhile Thunderfoot and his fanboys have had many of their half-baked technical criticism's debunked. Some have backtracked from their initial claims of "technically impossible" to now saying that while technically possible, it is just impractical (but without being precise about what they mean by impractical). --- Quote --- However in general IMHO you'd do better to take a more objective approach rather than being the umpteenth armchair nay-sayer. Going through the technical challenges and trying to find the economic angle without prejudice/judgement will result in a much more informative video and not deteriorate your credibility. --- End quote --- Good advice. |
| EEVblog:
Some numbers on MagLev operating energy consumed: http://large.stanford.edu/courses/2010/ph240/ilonidis2/ --- Quote ---Maglev is also a very cheap and efficient mode of transportation. Maglev operating costs will be only 3 cents per passenger mile and 7 cents per ton mile, compared to 15 cents per passenger mile for airplanes and 30 cents per ton mile for intercity trucks. [8] Guideways can last for at least 50 years with a minimal maintenance because there is no mechanical contact and wear. [8] At 480 kilometers per hour, maglev consumes 0.4 megajoules per passenger mile compared to 4 megajoules per passenger mile of oil fuel for a 8.5-kilometers-per-liter (20 miles-per-gallon) auto that carries 1.8 people at 96 kilometers per hour. [8]. It is also interesting to compare the efficiency of maglev trains and conventional high-speed trains. Table 1 shows the energy consumption of the German high-speed maglev Transrapid and the German high-speed train ICE 3, both as functions of speed. Transrapid has better efficiency above 330 kilometers per hour but it is less efficient below 330 kilometers per hour. --- End quote --- This is without the evacuated tube, a.k.a Hyperloop. Seems that most of the cost goes into the new infrastructure required. Hypoerloop will be what, maybe half an order more expensive than normal Maglev? |
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