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Hyperloop Freight is a Joke

pedestrianobservations.wordpress.com

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Re: Hyperloop Freight is a Joke

#141

Post by [deleted] »

D_Alex wrote: post #115
LordHumungous wrote: post #83

Earlier quoted context omitted.

The tolerances on each part must be very tight. If there is a single flaw in one part, the whole vacuum fails. The challenges become exponentially greater as you scale up the diameter of the pipe, since the force on the pipe is proportional to the square of the radius. The LHC had a 50mm diameter pipe, the hyperloop proposes an 8+ foot diameter. You do the math.

When you said that you worked on the LHC for several years - what was your role, and how were you involved with the vacuum system? Because your answers show a serious lack of understanding. First, part tolerances are not a particularly important issue with engineering of high vacuum systems (sealing is effected by compression of gaskets, usually soft stainless steel gaskets for UHV systems). Secondly, the difficultie…

[deleted]

Re: Hyperloop Freight is a Joke

#142

Post by mcguire »

Turing_Machine wrote: post #94

an expert in logistics asked “why do we need to move cargo at 500 mph?“. The problem is one of face. I guess the 18,000 packages per hour that arrive at ANC by jet must also be a matter of "face"? What does this even mean? Edit for clarity: The FedEx terminal at Ted Stevens Anchorage International Airport can handle 13,400 packages per hour. The UPS terminal there handles about 5,000 packages per hour. Virtually all…

Tokyo to Anchorage is roughly 5500km, vs. 600km for LA to San Francisco.

Alternatively, how much cargo does FedEx or UPS fly along the California coast?

Re: Hyperloop Freight is a Joke

#143

Post by mcguire »

spectrum1234 wrote: post #124

I wish this was readable but this guy comes off as extremely arrogant. It was a white paper for godsakes!! Is there an app that ensures I never read anything by this guy again? What is his name so I can avoid in the future? I'm not saying Hyperloop is perfect...its the tone of this jerk.

https://hyperloop-one.com

$141M funding.

Re: Hyperloop Freight is a Joke

#144

Post by Lazare »

taneq wrote: post #135
mypalmike wrote: post #106

Earlier quoted context omitted.

What about one where you feel that, acting in various directions, at every curve, every speed transition, and every elevation change. Because that's the "barf ride" being discussed, not merely getting thrown to the back of your seat during initial acceleration.

That sounds even more fun. :D Although as the poster mentioned below, a passenger service would gradually rotate the passenger compartment to keep the G-forces vertical, a la a banking aircraft, so all you'd likely notice would be feeling heavier for a few seconds.

The "barf ride" comments were the result of calculations which included rotating the passenger compartment.

See https://pedestrianobservations.wordpress.com/2013/08/13/loop... linked from the original article.

Re: Hyperloop Freight is a Joke

#145

Post by abduhl »

D_Alex wrote: post #115
LordHumungous wrote: post #83

Earlier quoted context omitted.

The tolerances on each part must be very tight. If there is a single flaw in one part, the whole vacuum fails. The challenges become exponentially greater as you scale up the diameter of the pipe, since the force on the pipe is proportional to the square of the radius. The LHC had a 50mm diameter pipe, the hyperloop proposes an 8+ foot diameter. You do the math.

When you said that you worked on the LHC for several years - what was your role, and how were you involved with the vacuum system? Because your answers show a serious lack of understanding. First, part tolerances are not a particularly important issue with engineering of high vacuum systems (sealing is effected by compression of gaskets, usually soft stainless steel gaskets for UHV systems). Secondly, the difficultie…

Just FYI - hoop stress as you've quoted it assumes a thin walled cylinder. I haven't worked on the LHC so don't know the dimensions; however, this assumption is really only valid for D/t > 20 or so before solutions diverge at which point the interaction becomes more complex than R/t.

Re: Hyperloop Freight is a Joke

#146

Post by Lazare »

Retric wrote: post #121
sib wrote: post #78

Earlier quoted context omitted.

The issue is not acceleration front/back, which can be dealt with in design and is fairly stable and consistent, but acceleration as much as 0.5G side/side, which is also more intermittent and against which it's difficult to build seats that would protect customers.

Really it's just a question of track design as these are 100% predictable G forces. If you really need to turn you can just roll the cabin and keep these g's directly under you and or slow down apraoching it. Elevators can also quickly have a fairly wide range (0.8 to 1.2) g's and people don't really get sick in them. Highways for example have fairly wide banks which people rarely notice. https://sterlingpearce.files…

That doesn't really solve it; there's limits on how much you can rotate the cabin, and how quickly you can rotate it. Lots of math here: https://pedestrianobservations.wordpress.com/2013/08/13/loop...

Re: Hyperloop Freight is a Joke

#149

Post by [deleted] »

D_Alex wrote: post #115
LordHumungous wrote: post #83

Earlier quoted context omitted.

The tolerances on each part must be very tight. If there is a single flaw in one part, the whole vacuum fails. The challenges become exponentially greater as you scale up the diameter of the pipe, since the force on the pipe is proportional to the square of the radius. The LHC had a 50mm diameter pipe, the hyperloop proposes an 8+ foot diameter. You do the math.

When you said that you worked on the LHC for several years - what was your role, and how were you involved with the vacuum system? Because your answers show a serious lack of understanding. First, part tolerances are not a particularly important issue with engineering of high vacuum systems (sealing is effected by compression of gaskets, usually soft stainless steel gaskets for UHV systems). Secondly, the difficultie…

[deleted]

Re: Hyperloop Freight is a Joke

#150

Post by gji »

D_Alex wrote: post #115
LordHumungous wrote: post #83

Earlier quoted context omitted.

The tolerances on each part must be very tight. If there is a single flaw in one part, the whole vacuum fails. The challenges become exponentially greater as you scale up the diameter of the pipe, since the force on the pipe is proportional to the square of the radius. The LHC had a 50mm diameter pipe, the hyperloop proposes an 8+ foot diameter. You do the math.

When you said that you worked on the LHC for several years - what was your role, and how were you involved with the vacuum system? Because your answers show a serious lack of understanding. First, part tolerances are not a particularly important issue with engineering of high vacuum systems (sealing is effected by compression of gaskets, usually soft stainless steel gaskets for UHV systems). Secondly, the difficultie…

Regarding your first point: from my experience (working on physics experiments that depend on vacuum I doubt UHV experience is relevant here though - at 100 torr you can probably get away with simple o-ring seals. And outgassing doesn't matter: even isopropanol has a vapor pressure of only 40 torr.

Edit: The hyperloop design is at ~1 torr, not 100. Still, I'd imagine outgassing is not a huge issue.

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