Official SpaceX Hyperloop Pod Competition

[Memphis]

45 minutes ago, DocM said:

Again, chemical truck tanks are not hyperloop runs and neither are railroad tracks.  

 

Your railway  mass/mile numbers are also off - 228,800 is for only one rail and it takes 2 rails per track. Rails can also run up to 155 lbs/yard, and many rights of way have 2-3 tracks.

 

 

They are similar in their design, unless you think they are going to put allot more steel in the hyper loop they are fairly identical, what makes you think it will be stronger? Yeah, you got me on that rail bit, but it doesn't exactly change much given that you keep moving the bar on the tubing used for the hyper loop we are still talking an absolute minimum of 3.5 times the steel and that's not including the fact that these tubes are much smaller in diameter than the hyper loop will be unless you want to make a mode of travel were a person needing to pee cant stand up to get to these facilities. You analogy of having 2 - 3 tracks is also flawed as the hyperloop must have two sets of tubes or its a one way and fairly useless. Again, Doc, answer the original questions put to you. Basically, "put up or shut up".

Edited April 13, 2017 by sidroc

[SALSN]

32 minutes ago, sidroc said:

fairly identical

What does that even mean?! :-P

They look kind of similar but one is designed to hold liquid, one is designed to hold vacuum, guess which one will not hold vacuum?!?
You can not use the failure of one thing to demonstrate a different thing will also fail, since they are not the same thing! Even if they kind of look alike!
 

 

40 minutes ago, sidroc said:

"put up or shut up"

This is EXACTLY what hyperloop is doing!

[DocM]

And he's assuming the tubes will be made of steel. That may not be the case.  Just sayin'.

 

As to another of Thunderf00t's supposed points; thermal expansion and buckling.

 

He's clearly unfamiliar with railroads. Continuously welded rail with no expansion joints has been around a while, and it's done by heating the rails to 40°C or so and keeping the rails under tension during installation. In hot weather the tension relaxes a bit, but the rails stay true.

 

Alternative 2: use materials with a lower coefficient of thermal expansion. These exist in the form of tailored composite tubes with a CTE of zero. Use NO-NA composites (no oven-no autoclave) and tube segments could be constructed on-site.

 

[Memphis]

48 minutes ago, SALSN said:

What does that even mean?! :-P

They look kind of similar but one is designed to hold liquid, one is designed to hold vacuum, guess which one will not hold vacuum?!?
You can not use the failure of one thing to demonstrate a different thing will also fail, since they are not the same thing! Even if they kind of look alike!
 

 

This is EXACTLY what hyperloop is doing!

 

The tanker trucks are indeed made to withstand a vacuum as much as possible to help prevent damage if it is pumped without opening the air intake by accident, otherwise it would implode allot quicker.

 

 

Yeah, they're finally welding some tubes together. Lets see them perform test runs over a long period of time.

Edited April 13, 2017 by sidroc

[Memphis]

42 minutes ago, DocM said:

And he's assuming the tubes will be made of steel. That may not be the case.  Just sayin'.

 

As to another of Thunderf00t's supposed points; thermal expansion and buckling.

 

He's clearly unfamiliar with railroads. Continuously welded rail with no expansion joints has been around a while, and it's done by heating the rails to 40°C or so and keeping the rails under tension during installation. In hot weather the tension relaxes a bit, but the rails stay true.

 

Alternative 2: use materials with a lower coefficient of thermal expansion. These exist in the form of tailored composite tubes with a CTE of zero. Use NO-NA composites (no oven-no autoclave) and tube segments could be constructed on-site.

 

Yeah, I am assuming that because its what Hyperloop One has stated, unless you have another source? again, your unable to cite a source saying they might make it out of something else yet I can cite sources showing they are using steel. Also, I only noted the amount of steel used to compare rail, actual rail itself cannot be compared, while oil and gas pipelines can be compared. Kind of funny that you seriously think you can compare rail expansion joints with joints used in tubes. Find a oil and gas pipelines without expansion joints, lets see it. Pipelines uses Teflon coated sliders, expansion loops, etc. try showing how that could be done and maintain the integrity of a vacuum. As usual Docm, you say things that could use a citation and cite nothing at all. I think your grasp of how this could work is deluded by your interest in technology advancement.

 

 

Edited April 13, 2017 by sidroc

[+Zagadka Subscriber²]

Thunderf00t has some points. Science is about studying and demonstrating. I'm sure he would be happy if/when it can work. So would I. Research on. But be realistic about results, and openly discussing how it is failing is a step in finding what does work.

[Memphis]

Thunderf00t has some points. Science is about studying and demonstrating. I'm sure he would be happy if/when it can work. So would I. Research on. But be realistic about results, and openly discussing how it is failing is a step in finding what does work.

I will happily eat my words and make use of a hyperloop if it works. I think everyone would.

[SALSN]

1 hour ago, sidroc said:

The tanker trucks are indeed made to withstand a vacuum as much as possible to help prevent damage if it is pumped without opening the air intake by accident, otherwise it would implode allot quicker.

Okay, so they can take some under pressure, it is STILL apples to oranges.
Do you seriously believe it is impossible to make a tube that can withstand vacuum? Even if you throw a rock at it?

[Memphis]

Okay, so they can take some under pressure, it is STILL apples to oranges.
Do you seriously believe it is impossible to make a tube that can withstand vacuum? Even if you throw a rock at it?

No, and I also don't believe its impossible to make to make a faster than light drive so long as its warping the space to get around the physics. Never mind the ridiculous fuel requirements or missing technology but its possible, so there [emoji1] .

[SALSN]

Well going just the speed of light requires infinite energy unless you have 0 mass.

Anyway, creating a tube that can withstand one atmosphere is a lot easier than getting infinite energy, and it has been done, even with tubes that can stand lots and lots of atmospheres.

So why is you keep seeing it as some sort of enormous hurdle? Sure they will make it as thin as possible, but obviously not too thin, so I really don't see how this can be a point of contention?!?

[Memphis]

Well going just the speed of light requires infinite energy unless you have 0 mass.

Anyway, creating a tube that can withstand one atmosphere is a lot easier than getting infinite energy, and it has been done, even with tubes that can stand lots and lots of atmospheres.
So why is you keep seeing it as some sort of enormous hurdle? Sure they will make it as thin as possible, but obviously not too thin, so I really don't see how this can be a point of contention?!?

Not if space is being warped so the ship is not moving at the speed of light but riding a warped bubble or wave if you will. Physics says this can happen, but its impractical and probably never will be done. Keep acting like its no big deal and I will wait for a rational scientific response with citations from the hyperloop one team.

[flyingskippy]

Like talking sense into an anti-vaxer.... 

[Memphis]

Like talking sense into an anti-vaxer.... 

Interesting comparison, their is hundreds of criticisms that coupd be shown to an anti vaxer to explain why they are wrong with peer reviewed source for all of them. All studied and tested unlike this. this is not so clear cut and it is obviouse by the lack of citations from hyperloop one or other credible sources. No matter, its funny that you say this instead of this a citation at me.

[FloatingFatMan]

10 hours ago, SALSN said:

Well going just the speed of light requires infinite energy unless you have 0 mass.

Anyway, creating a tube that can withstand one atmosphere is a lot easier than getting infinite energy, and it has been done, even with tubes that can stand lots and lots of atmospheres.

So why is you keep seeing it as some sort of enormous hurdle? Sure they will make it as thin as possible, but obviously not too thin, so I really don't see how this can be a point of contention?!?

Actually, no one has make a vacuum tube as long as the Hyperloop will need to be. Therefore at this point, we don't fully know exactly what stresses it will come under.

 

Also, yes they could use other materials than steel for the tube, but that will drastically increase the cost.

[IsItPluggedIn]

Hyperloop one, is a private company they are not going to come out and tell people how their tech works. Its no like Boeing comes out and tells everybody how their new jet engine works or rocket engine works. People understand this technology but they themselves dont release details specs on their design. This is not a statement to say trust them its just saying that they will not openly tell everybody how they overcome the technical challengers.

 

It would be easier to get this information from some of the competition teams as they are university groups, but most of them are working on the trains and not the track. Im not sure if they are openly sharing information either as it is a competition.

 

It is currently a time thing, there is currently a push on hyperloop, im sure they will get further than they are now, but im not 100% sure they willl actually build any of them or if the costs will just be too high. Kind of reminds me of electric cars back in the day.

[DocM]

The largest current Hyperloop chamber is the 1 mile x 6 foot test track outside of SpaceX's headquarters in Hawthorne, built for the competition. HyperLoop One's track is slightly shorter at 0.932 mile.

 

 

[FloatingFatMan]

I would like to see a full scale diameter test track TBH.  Prove they can built it, and have it be safe, at actual sizes.

[SALSN]

15 hours ago, sidroc said:

Not if space is being warped so the ship is not moving at the speed of light but riding a warped bubble or wave if you will. Physics says this can happen, but its impractical and probably never will be done. Keep acting like its no big deal and I will wait for a rational scientific response with citations from the hyperloop one team.

If space is being warped the ship is going faster than light locally, it is manipulating space around it, to change the distance it has to travel. And as far as I understand this requires negative energy, something that has not been demonstrated to exist, So I would rather say known that physics says this might be a possibility, rather than this being outright possible.
Something that is absolutely possible is many atmospheres of overpressure in a tube, you could look up a submarine if you really don't believe me. Obviously I have no access to hyperloop one internal communication and documentation, but luckily I don't need that to demonstrate my point.

 

7 hours ago, FloatingFatMan said:

Actually, no one has make a vacuum tube as long as the Hyperloop will need to be. Therefore at this point, we don't fully know exactly what stresses it will come under.

 

Also, yes they could use other materials than steel for the tube, but that will drastically increase the cost.

If you make a vacuum chamber 100 meters long or 10 km, I really don't think that is going to change the stresses significantly.

[FloatingFatMan]

33 minutes ago, SALSN said:

If you make a vacuum chamber 100 meters long or 10 km, I really don't think that is going to change the stresses significantly.

How many vacuum chambers 100 meters long have you seen outside of a lab environment, at the side of the road, exposed to the elements and other uncontrollable external factors?

 

[DocM]

Two. One at Hawthorne and one at Hyperloop One. 

 

If you want to go with reverse cases, pressurized vessels operating in a vacuum or near vacuum, every aircraft that hits the stratosphere and ISS. They face similar radial stress and material durability issues, just in the opposite direction. In both cases the pressure per area is still only one atmosphere, plus or minus a fraction of an atmosphere. 

 

Care to guess how many cylindrical structures carry a radial load of tens of atmospheres?  A lot.

[IsItPluggedIn]

Im not 100% on this, but why does it matter how long it is with the pressure? More internal volume increases the pressure but it is negated by the increase in external surface area. if the tube gets bigger ie rounder then the pressure will increase but not if it get longer.

 

Expansion is still an issue. What is the effect of the low pressure on temperature?

[DocM]

Expansion can be handled by pre-stretching, heating the tubes and putting them under tension during assembly. On reheating the tension reduces without linear expansion.

 

That or you can make some tubes out of Invar*, an iron-nickel alloy which exhibits very little or even a negative coefficient of thermal expansion (Fe 65%, Ni 35%). There are also composites with this property. Tubes made with negative expansion materials could make them useful as expansion compensation segments.

 

* Charles Édouard Guillaume won the 1920 Nobel Prize in Physics for its discovery.

 

Edited April 14, 2017 by DocM

[DocM]

Hyperloop Pod Competition II will take over the weekend of August 25-27th, 2017. This time the scoring will be based on speed.

[SALSN]

On 14/4/2017 at 11:57 PM, IsItPluggedIn said:

Im not 100% on this, but why does it matter how long it is with the pressure? More internal volume increases the pressure but it is negated by the increase in external surface area. if the tube gets bigger ie rounder then the pressure will increase but not if it get longer.

 

Expansion is still an issue. What is the effect of the low pressure on temperature?

That was exactly what I was getting at, it does not really matter.

 

 

On 14/4/2017 at 5:36 PM, FloatingFatMan said:

How many vacuum chambers 100 meters long have you seen outside of a lab environment, at the side of the road, exposed to the elements and other uncontrollable external factors?

Apart from what DocM mentions there are multiple submarines longer than 100 m, and while technically not vacuum chambers, they can take a lot of differential pressure, and a lot of beating by the elements.

[FloatingFatMan]

Just now, SALSN said:

Apart from what DocM mentions there are multiple submarines longer than 100 m, and while technically not vacuum chambers, they can take a lot of differential pressure, and a lot of beating by the elements.

And cost hundreds of millions of dollars to build...

 

The point of Hyperloop is that it's meant to be cheap and practical... Using alternative materials, or submarine strength construction is neither cheap nor practical.  Even just using steel, you're talking monstrous amounts of material needed to construct a loop between 2 cities.

 

Also, remember... That's LOOP, so to travel 350 miles you need over 700 miles of actual track, plus all the infrastructure to support and protect that loop. How the hell is that ever supposed to be cheaper than a slower train?