Author Topic: Elon The Boring Company  (Read 1626401 times)

Offline GORDAP

  • Full Member
  • **
  • Posts: 211
  • St. Petersburg, FL
  • Liked: 133
  • Likes Given: 74
Re: Elon The Boring Company
« Reply #1460 on: 06/24/2018 07:57 pm »
If the transport vehicles can be charged during the short but frequent stops for taking on and off passengers, I wonder if 'supercaps' would be a superior solutions vs batteries.  I think supercaps charge faster than batteries and have better cycle lifetimes, both of which would be important in this use case.  Their drawback is energy density, but with a fairly short and fixed route such as this one, I'd think energy capacity would be much reduced, hence undercutting batteries advantage here.  Thoughts?

Economies of scale are kicking in for batteries.  Vehicles and power storage are doubling the world capacity for this storage technology about annually.  Someday, super-capacitors might have a role, but they don't now.  Why is 'quick' charging an ask?

re: "quick charging"   If charging is sufficiently quick, it could be accomplished during the brief time the vehicle is docked putting off and taking on passengers - eliminating the need to take the vehicle out of service or swap batteries.

Offline AncientU

  • Senior Member
  • *****
  • Posts: 6257
  • Liked: 4164
  • Likes Given: 6078
Re: Elon The Boring Company
« Reply #1461 on: 06/24/2018 08:31 pm »
If the transport vehicles can be charged during the short but frequent stops for taking on and off passengers, I wonder if 'supercaps' would be a superior solutions vs batteries.  I think supercaps charge faster than batteries and have better cycle lifetimes, both of which would be important in this use case.  Their drawback is energy density, but with a fairly short and fixed route such as this one, I'd think energy capacity would be much reduced, hence undercutting batteries advantage here.  Thoughts?

Economies of scale are kicking in for batteries.  Vehicles and power storage are doubling the world capacity for this storage technology about annually.  Someday, super-capacitors might have a role, but they don't now.  Why is 'quick' charging an ask?

re: "quick charging"   If charging is sufficiently quick, it could be accomplished during the brief time the vehicle is docked putting off and taking on passengers - eliminating the need to take the vehicle out of service or swap batteries.

Have you ever ridden a gondola at a ski area?  The load time for a dozen people with skis and poles, wearing the least speedy boots ever invented, is 15-30 seconds*.  Don't think about trains and planes, where boarding is minutes to hours... more like the automated subways at Atlanta or Denver or other airports, but quicker.  Loading times for these automated trains are 30-60 seconds.

Still, the economy of batteries will win over all -- the Chicago Loop pods are slated to have Model X 'skates' which already have 250-300 mile range with old format batteries.


* Big gondola at Mammoth Mountain holds 15 people and departs every 15 seconds from a single load point.
https://www.skiresort.info/ski-resort/mammoth-mountain/ski-lifts/
« Last Edit: 06/24/2018 09:50 pm by AncientU »
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Offline Ludus

  • Full Member
  • ****
  • Posts: 1744
  • Liked: 1255
  • Likes Given: 1017
Re: Elon The Boring Company
« Reply #1462 on: 06/24/2018 11:15 pm »
Any kind of induction charging while still or moving is unlikely, Elon's not a fan on account of the inefficiency of it.

Most likely when the battery gets low, the pod will be automatically routed out of service and then either perform some kind of battery swap with some sort of automated system or simply charge with a supercharger style connection (but one that doesn't require a human to plug in).

The supercharger method will be easier to implement I suspect, though I wouldn't entirely rule out a battery swapping system (depends on whether having extra pods for the supercharging method is more expensive than implementing the battery swap system on fewer pods, I imagine).

I’m inclined to think they’ll work hard to get some sort of moving power transmission (without a hazardous third rail) going. Conditions are much closer to ideal than roads and a lot of teams are trying to do it on roads. The work flow is a lot simpler if the Pods never have to stop to charge or swap batteries. They can use a lot of power. The tunnel system is the most expensive part and the way they can save on tunnel is ludicrous acceleration for the Pods. Every departure a zero to 120 mph in 6 second launch. Slower acceleration means longer on-ramp tunnels.

I’m assuming the passengers shown casually standing and seated sideways haven’t been told about this and are in for a surprise.
« Last Edit: 06/24/2018 11:17 pm by Ludus »

Offline matthewkantar

  • Senior Member
  • *****
  • Posts: 2075
  • Liked: 2506
  • Likes Given: 2211
Re: Elon The Boring Company
« Reply #1463 on: 06/25/2018 03:07 am »
The tunnel system is the most expensive part and the way they can save on tunnel is ludicrous acceleration for the Pods. Every departure a zero to 120 mph in 6 second launch. Slower acceleration means longer on-ramp tunnels.

No need to accelerate hard. Constant gentle accel for half of the trip, constant gentle deceleration for the other half.

Matthew

Offline aero

  • Senior Member
  • *****
  • Posts: 3628
  • 92129
  • Liked: 1145
  • Likes Given: 360
Re: Elon The Boring Company
« Reply #1464 on: 06/25/2018 03:51 am »
The tunnel system is the most expensive part and the way they can save on tunnel is ludicrous acceleration for the Pods. Every departure a zero to 120 mph in 6 second launch. Slower acceleration means longer on-ramp tunnels.

No need to accelerate hard. Constant gentle accel for half of the trip, constant gentle deceleration for the other half.

Matthew

Can't do that with there being multiple cars/pods and multiple points of entry along the tunnel. Tunnel traffic needs to maintain constant and equal speed.

But it seems there might be a way to use gravity to aid acceleration. V=at, so a 6-second drop gives 60 meters/sec, or 134 mph, less friction losses. How deep is the tunnel? Looks like it would need to be 180 meters deep for this to work, so electric powered acceleration would also be necessary. Point is, gravity acceleration wouldn't have such a serious effect on the passengers excepting of course the case where the drop was truly vertical, then freefall could disrupt stomaches.
« Last Edit: 06/25/2018 04:04 am by aero »
Retired, working interesting problems

Offline QuantumG

  • Senior Member
  • *****
  • Posts: 9238
  • Australia
  • Liked: 4477
  • Likes Given: 1108
Re: Elon The Boring Company
« Reply #1465 on: 06/25/2018 06:17 am »
They're called "on ramps", but yeah making them go down instead of up seems like a good idea.
Human spaceflight is basically just LARPing now.

Offline jpo234

  • Senior Member
  • *****
  • Posts: 2021
  • Liked: 2280
  • Likes Given: 2184
Re: Elon The Boring Company
« Reply #1466 on: 06/25/2018 08:56 am »
Regarding boarding: Have you seen this picture? This is what TBC has in mind...
« Last Edit: 06/25/2018 08:57 am by jpo234 »
You want to be inspired by things. You want to wake up in the morning and think the future is going to be great. That's what being a spacefaring civilization is all about. It's about believing in the future and believing the future will be better than the past. And I can't think of anything more exciting than being out there among the stars.

Offline docmordrid

  • Senior Member
  • *****
  • Posts: 6334
  • Michigan
  • Liked: 4207
  • Likes Given: 2
Re: Elon The Boring Company
« Reply #1467 on: 06/25/2018 09:50 am »
Regarding boarding: Have you seen this picture? This is what TBC has in mind...

That's an updated depiction of Chicago's Block 37 boondoggle Super-station, which was partially completed at a cost of $400m for a failed similar project. AIUI, TBC will take it over and finish what they need.

News expose...
« Last Edit: 06/25/2018 09:58 am by docmordrid »
DM

Online edzieba

  • Virtual Realist
  • Senior Member
  • *****
  • Posts: 6104
  • United Kingdom
  • Liked: 9326
  • Likes Given: 39
Re: Elon The Boring Company
« Reply #1468 on: 06/25/2018 12:48 pm »
As for Autopilot, it is currently being used on millions of miles of driving at speeds up to 90 miles per hour. 
An auto safety expert explained to me recently that the fact that these autopilots are programmed to allow the cars to break the speed limit is a sign that their manufacturers are not taking safety seriously. 

 - Ed Kyle
I'd question their credentials as an 'auto safety expert'. Deviating from the mean traffic velocity (i.e. 'the speed everyone else is going at') increases risk of an accident, and almost equally in both directions of deviation. i.e. going 10 under the mean velocity is just as risky as going 10 over. If you insist on travelling at the speed limit when everyone else is going 10-15 over, then YOU are the hazard.
« Last Edit: 06/25/2018 04:00 pm by edzieba »

Offline tater

  • Full Member
  • *
  • Posts: 126
  • NM
  • Liked: 136
  • Likes Given: 262
Re: Elon The Boring Company
« Reply #1469 on: 06/25/2018 12:51 pm »
Going slower than ambient traffic flow is not safe, if traffic is moving 10% faster than the posted limit, the cars need to drive 10% faster.

Offline wannamoonbase

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 5412
  • Denver, CO
    • U.S. Metric Association
  • Liked: 3112
  • Likes Given: 3861
Re: Elon The Boring Company
« Reply #1470 on: 06/25/2018 01:35 pm »
Regarding boarding: Have you seen this picture? This is what TBC has in mind...

That's an updated depiction of Chicago's Block 37 boondoggle Super-station, which was partially completed at a cost of $400m for a failed similar project. AIUI, TBC will take it over and finish what they need.

News expose...

Taking over abandoned or unused facilities is a hallmark of Elon developments.  It makes sense to leverage the value someone else has already sunk into something. 

The Fremont factory, Hawthorne facilities, launch pads, McGregor, all places that existed and were going unused.
Wildly optimistic prediction, Superheavy recovery on IFT-4 or IFT-5

Online edkyle99

  • Expert
  • Senior Member
  • *****
  • Posts: 15391
    • Space Launch Report
  • Liked: 8565
  • Likes Given: 1356
Re: Elon The Boring Company
« Reply #1471 on: 06/25/2018 03:42 pm »
Quote
Deviating from the mean traffic velocity (i.e. 'the sped everyone else is going at') increases risk of an accident, and almost equally in both directions of deviation*. i.e. going 10 under the mean velocity is just as risk as going 10 over. If you insist on travelling at the speed limit when everyone else is going 10-15 over, then YOU are the hazard.
In this future nirvana that the autonomous vehicle crowd wants us all to live in, the controlled traffic will slow down to the speed limit, or near the limit.   

And yes, my understanding is that the "Loop" system will use the Block 37 underground station.  I doubt that we will see elevators bringing the "Skates" down.  There simply isn't enough room for that around the Randolph/State/Washington/Dearborn block.

Here's the story of the station site, which was originally going to support express CTA trains.  This includes some rare photos of the site itself.
https://www.nbcchicago.com/investigations/How-Chicago-Spent-400M-On-a-Subway-Superstation-to-Nowhere-293754431.html

 -  Ed Kyle
« Last Edit: 06/25/2018 03:49 pm by edkyle99 »

Offline RDoc

  • Full Member
  • ****
  • Posts: 516
  • Liked: 123
  • Likes Given: 12
Re: Elon The Boring Company
« Reply #1472 on: 06/26/2018 12:00 am »
[Can't do that with there being multiple cars/pods and multiple points of entry along the tunnel. Tunnel traffic needs to maintain constant and equal speed.

But it seems there might be a way to use gravity to aid acceleration. V=at, so a 6-second drop gives 60 meters/sec, or 134 mph, less friction losses. How deep is the tunnel? Looks like it would need to be 180 meters deep for this to work, so electric powered acceleration would also be necessary. Point is, gravity acceleration wouldn't have such a serious effect on the passengers excepting of course the case where the drop was truly vertical, then freefall could disrupt stomaches.
I really like this idea. The cars exiting the main path go off at full speed onto a ramp that curves up to almost fully vertical, then flop over to horizontal just at the surface. The on ramp is the reverse, the car is tilted forward to almost vertical, drops to gather speed, then the ramp curves back to horizontal just before reentering the main path.

Kind of like a hammerhead turn in an aircraft.

Offline aero

  • Senior Member
  • *****
  • Posts: 3628
  • 92129
  • Liked: 1145
  • Likes Given: 360
Re: Elon The Boring Company
« Reply #1473 on: 06/26/2018 04:14 am »
[Can't do that with there being multiple cars/pods and multiple points of entry along the tunnel. Tunnel traffic needs to maintain constant and equal speed.

But it seems there might be a way to use gravity to aid acceleration. V=at, so a 6-second drop gives 60 meters/sec, or 134 mph, less friction losses. How deep is the tunnel? Looks like it would need to be 180 meters deep for this to work, so electric powered acceleration would also be necessary. Point is, gravity acceleration wouldn't have such a serious effect on the passengers excepting of course the case where the drop was truly vertical, then freefall could disrupt stomaches.
I really like this idea. The cars exiting the main path go off at full speed onto a ramp that curves up to almost fully vertical, then flop over to horizontal just at the surface. The on ramp is the reverse, the car is tilted forward to almost vertical, drops to gather speed, then the ramp curves back to horizontal just before reentering the main path.

Kind of like a hammerhead turn in an aircraft.

You got the idea.

But note that the ramps don't need to go vertical or even near vertical. Discounting friction losses, potential energy converts to kinetic energy per unit of vertical displacement, independently of whether the drop is vertical or on a grade. It's true that the more nearly vertical the ramps, the shorter they would be, and the lower the friction losses would be. But overcoming friction losses is much of what the electric motors do anyway.

The neat thing as I see it is that the cars use gravity to accelerate to cruise, electric energy to maintain steady cruise, and gravity to decelerate to stop giving up only the energy that would otherwise be mostly recovered by regenerative braking. Can anyone come up with a more energy efficient method to accelerate and decelerate the cars?
Retired, working interesting problems

Online JamesH65

  • Full Member
  • ****
  • Posts: 1559
  • Liked: 1739
  • Likes Given: 10
Re: Elon The Boring Company
« Reply #1474 on: 06/26/2018 09:56 am »
Quote
Deviating from the mean traffic velocity (i.e. 'the sped everyone else is going at') increases risk of an accident, and almost equally in both directions of deviation*. i.e. going 10 under the mean velocity is just as risk as going 10 over. If you insist on travelling at the speed limit when everyone else is going 10-15 over, then YOU are the hazard.
In this future nirvana that the autonomous vehicle crowd wants us all to live in, the controlled traffic will slow down to the speed limit, or near the limit.   

Quite, although the speed limit can be changed appropriately. For example in the Uk we have variable speed limits on some motorways. Although the speed is brought lower, the average speed over the section doesn't decrease as much as the speed limit change might imply. It also more fuel efficient (not constant acceleration/braking)

On a fully autonomous system like this, the computer know where everything is, how fast it's going, what failures are happening, and can easily manage very high speeds with large amounts of traffic at high safety levels. In this case, it really ISNT rocket science.

I do not believe the control system is anywhere close to a problem, when compared with all the other stuff they need to do.

Offline Ludus

  • Full Member
  • ****
  • Posts: 1744
  • Liked: 1255
  • Likes Given: 1017
Re: Elon The Boring Company
« Reply #1475 on: 06/26/2018 03:37 pm »
The tunnel system is the most expensive part and the way they can save on tunnel is ludicrous acceleration for the Pods. Every departure a zero to 120 mph in 6 second launch. Slower acceleration means longer on-ramp tunnels.

No need to accelerate hard. Constant gentle accel for half of the trip, constant gentle deceleration for the other half.

Matthew

That would work for a tunnel with only an entry and exit but not the Loop system described which is like an expressway with constant speed main tunnels and entry and exit tunnels to accelerate/decelerate. How fast the pod can accelerate/decelerate determines how long the on/off ramp tunnels need to be, which is a major factor in system cost.

Offline RDoc

  • Full Member
  • ****
  • Posts: 516
  • Liked: 123
  • Likes Given: 12
Re: Elon The Boring Company
« Reply #1476 on: 06/26/2018 10:37 pm »

You got the idea.

But note that the ramps don't need to go vertical or even near vertical. Discounting friction losses, potential energy converts to kinetic energy per unit of vertical displacement, independently of whether the drop is vertical or on a grade. It's true that the more nearly vertical the ramps, the shorter they would be, and the lower the friction losses would be. But overcoming friction losses is much of what the electric motors do anyway.

The neat thing as I see it is that the cars use gravity to accelerate to cruise, electric energy to maintain steady cruise, and gravity to decelerate to stop giving up only the energy that would otherwise be mostly recovered by regenerative braking. Can anyone come up with a more energy efficient method to accelerate and decelerate the cars?

But the lower the slope of the ramps the more space they take at shallow depth, which interferes with things like utilities and also requires a larger entrance, cosine and all that. I suppose they could do a double spiral ramp, up and down, but it still needs more surface space for a larger entrance.

To avoid the weightless effect. the car could accelerate at say .5G going down and brake at the same .5 G going up on nearly vertical ramps. That would also allow shallower tunnels.

There would still need to be occasional elevators or something similar in case the cars had a failure that didn't allow them to run at full speed.

Offline aero

  • Senior Member
  • *****
  • Posts: 3628
  • 92129
  • Liked: 1145
  • Likes Given: 360
Re: Elon The Boring Company
« Reply #1477 on: 06/27/2018 12:22 am »

You got the idea.

But note that the ramps don't need to go vertical or even near vertical. Discounting friction losses, potential energy converts to kinetic energy per unit of vertical displacement, independently of whether the drop is vertical or on a grade. It's true that the more nearly vertical the ramps, the shorter they would be, and the lower the friction losses would be. But overcoming friction losses is much of what the electric motors do anyway.

The neat thing as I see it is that the cars use gravity to accelerate to cruise, electric energy to maintain steady cruise, and gravity to decelerate to stop giving up only the energy that would otherwise be mostly recovered by regenerative braking. Can anyone come up with a more energy efficient method to accelerate and decelerate the cars?

But the lower the slope of the ramps the more space they take at shallow depth, which interferes with things like utilities and also requires a larger entrance, cosine and all that. I suppose they could do a double spiral ramp, up and down, but it still needs more surface space for a larger entrance.

To avoid the weightless effect. the car could accelerate at say .5G going down and brake at the same .5 G going up on nearly vertical ramps. That would also allow shallower tunnels.

There would still need to be occasional elevators or something similar in case the cars had a failure that didn't allow them to run at full speed.

I'm afraid I'll have to leave it to others to optimize the ramp slope .vs. g-forces .vs. ramp surface area .vs. construction cost .vs. commuter acceptance ... the whole scheme.

I know that a 6-degree slope on a roadway is very steep but it seems to me that a much steeper tunnel ramp should be do-able, maybe 30-degrees? Maybe a combination of pod elevators and ramps. The elevator could carry the pod down to below any concern for utilities then the pod could depart the elevator onto the ramp. That would work where the main transit tunnels are deep. Where the main transit tunnels are just below the utilities we're back to the problem of very long ramps and high electrical consumption to accelerate the pods to transit speed.

But does anyone care to plot the g-force perceived by the commuter versus the slope of the ramp - both on-ramp and off-ramp?
Retired, working interesting problems

Offline moreno7798

Re: Elon The Boring Company
« Reply #1478 on: 06/27/2018 12:23 am »
As for Autopilot, it is currently being used on millions of miles of driving at speeds up to 90 miles per hour. 
An auto safety expert explained to me recently that the fact that these autopilots are programmed to allow the cars to break the speed limit is a sign that their manufacturers are not taking safety seriously. 

 - Ed Kyle
I'd question their credentials as an 'auto safety expert'. Deviating from the mean traffic velocity (i.e. 'the speed everyone else is going at') increases risk of an accident, and almost equally in both directions of deviation. i.e. going 10 under the mean velocity is just as risky as going 10 over. If you insist on travelling at the speed limit when everyone else is going 10-15 over, then YOU are the hazard.

Go ahead, good luck making that argument at traffic court.

The way I see it, allowing autopilot to break the speed limit has to do with the fact that humans are not involved therefore a different standard can be applied. As more and more cars adopt the technology, and eventually humans are completely removed from the equation, speed limits will probably be non-existant and the only goal will be how efficient, safely and fast can automated vehicles get you to a destination. Once global transportation accidents go down to something like once or twice every 3-5 years, then the only goal in transportation is efficiency.
The only humans that make no mistakes are the ones that do nothing. The only mistakes that are failures are the ones where nothing is learned.

Offline Lar

  • Fan boy at large
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 13463
  • Saw Gemini live on TV
  • A large LEGO storage facility ... in Michigan
  • Liked: 11864
  • Likes Given: 11086
Re: Elon The Boring Company
« Reply #1479 on: 06/27/2018 06:45 am »
As for Autopilot, it is currently being used on millions of miles of driving at speeds up to 90 miles per hour. 
An auto safety expert explained to me recently that the fact that these autopilots are programmed to allow the cars to break the speed limit is a sign that their manufacturers are not taking safety seriously. 

 - Ed Kyle
I'd question their credentials as an 'auto safety expert'. Deviating from the mean traffic velocity (i.e. 'the speed everyone else is going at') increases risk of an accident, and almost equally in both directions of deviation. i.e. going 10 under the mean velocity is just as risky as going 10 over. If you insist on travelling at the speed limit when everyone else is going 10-15 over, then YOU are the hazard.

Go ahead, good luck making that argument at traffic court.

The way I see it, allowing autopilot to break the speed limit has to do with the fact that humans are not involved therefore a different standard can be applied. As more and more cars adopt the technology, and eventually humans are completely removed from the equation, speed limits will probably be non-existant and the only goal will be how efficient, safely and fast can automated vehicles get you to a destination. Once global transportation accidents go down to something like once or twice every 3-5 years, then the only goal in transportation is efficiency.

Many of my fraternity brothers were Civil Engineers and, to show them up, I took Transportation Engineering, a senior level CE course, and I aced it.  That was a long time ago.. but one of the key first principles we learned is that you engineer a road for a given speed. And then, most people actually go that speed. Because people can perceive what the safe speed is, and only a few crazies exceed it. That speed is known as the design speed.  It's driven by the road engineering standards.

NOT the speed limit.  The speed limit is an artificial imposition, and in many cases, it's deliberately set lower than the design speed as a revenue enhancement mechanism.

So Ed, your pal is all wet.

That said, "good luck making that argument at traffic court" indeed. (I know, I tried, once, when I was much younger).... but then traffic court is designed to get you to pay your fine and move along quietly.

Can we get a bit closer to on topic again?  As a note, if one reviews Ed's postings you'll find a lot of skepticism of a lot of things. He's quite notably good at finding things to critique and be skeptical about relating to SpaceX  (their payload numbers are wrong. Their economics won't work. etc etc etc) and that adds value in that it keeps people honest. But it also can get a bit repetitive. So best to let Ed have his say, because that skepticism adds value.... and then move on talking about what you want to talk about instead of trying to convince Ed he's wrong. Won't work. You'll have more luck in traffic court.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Tags:
 

Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1