[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 483: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 112: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 112: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 112: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 112: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 112: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/functions.php on line 4688: Cannot modify header information - headers already sent by (output started at [ROOT]/includes/functions.php:3823)
[phpBB Debug] PHP Warning: in file [ROOT]/includes/functions.php on line 4690: Cannot modify header information - headers already sent by (output started at [ROOT]/includes/functions.php:3823)
[phpBB Debug] PHP Warning: in file [ROOT]/includes/functions.php on line 4691: Cannot modify header information - headers already sent by (output started at [ROOT]/includes/functions.php:3823)
[phpBB Debug] PHP Warning: in file [ROOT]/includes/functions.php on line 4692: Cannot modify header information - headers already sent by (output started at [ROOT]/includes/functions.php:3823)
- View topic - What happens when the Rolling Roads get to the rollers?
View unanswered posts | View active topics It is currently Sat Feb 17, 2018 5:14 pm



Reply to topic  [ 26 posts ]  Go to page Previous  1, 2, 3  Next
What happens when the Rolling Roads get to the rollers? 
Author Message

Joined: Mon Jan 12, 2009 8:27 pm
Posts: 56
Post Re: What happens when the Rolling Roads get to the rollers?
I've just re-read it, which was what prompted the question, and the one that was the primary focus of the story was a 20-strip road: 5-100mph in 5mph increments.

Which means that, topologically, there is no rational way to design it so that you can build things on the strips that I can see: those strips have to get to the end, and either turn 180 degrees in the pitch axis, under a roller and go back, or in some fashion turn 180 degrees in the yaw axis, and go back on the other side -- which would most easily be done by using 2 rollers at 45 degrees to the direction of travel and 90 degrees to one another.

And the reference Ed is looking for is to Methuselah's Children, which I chanced to read immediately afterwards.

And, finally: "Look! Topic drift!"


Fri Feb 27, 2009 6:00 pm
Profile
PITA Bred
User avatar

Joined: Wed Apr 09, 2008 12:17 pm
Posts: 2402
Location: The Quiet Earth
Post Re: What happens when the Rolling Roads get to the rollers?
I contend that the design issues are soluble using a flat-plate model that pivots around, say, a one mile radius at each end. I can sketch a workable model easily.

Whether or not the various issues of practicality are soluble... well, let's chalk it up as a story facilitating MacGuffin. :)

_________________
"Hier stehe ich. Ich kann nicht anders." - Luther
In the end, I found Heinlein is finite. Thus, finite analysis is needed.


Fri Feb 27, 2009 7:22 pm
Profile

Joined: Mon Jan 12, 2009 8:27 pm
Posts: 56
Post Re: What happens when the Rolling Roads get to the rollers?
Is there a mathematician in the house? :-)

I know that the question is "what's the centripetal force generated, measured in G's of lateral acceleration, by an object describing a 1 mi radius curve at 100 mph" (or possibly more; it depends on the design of the plates), but I don't have the math to figure it out off hand; I suspect strongly that it's a pretty substantial fraction of a full G, unbanked; that seems pretty high to me.

Beamjockey: you're a rocket scientist; what's the answer here? :-)


Fri Feb 27, 2009 9:47 pm
Profile
NitroForum Oldster
User avatar

Joined: Thu Jun 19, 2008 3:57 pm
Posts: 152
Post Re: What happens when the Rolling Roads get to the rollers?
The Rolling Roads certainly would be an engineering wonder. What this reminds me of is London Bridge of centuries ago. How often today do we see any structure on a bridge, except the occasional toll booth right at the end? Yet London Bridge was a busy and important city street, with houses and businesses over the River Thames. If anyone were to develop an equivalent structure today, it certainly would be a financial and bureaucratic nightmare, as well as an engineering wonder ....

_________________
http://www.Troynovant.com/ - recurrent inspiration


Sat Feb 28, 2009 10:41 am
Profile WWW
PITA Bred
User avatar

Joined: Wed Apr 09, 2008 12:17 pm
Posts: 2402
Location: The Quiet Earth
Post Re: What happens when the Rolling Roads get to the rollers?


Sat Feb 28, 2009 12:25 pm
Profile
Heinlein Nexus
User avatar

Joined: Thu Apr 10, 2008 8:10 am
Posts: 2236
Location: Pacific NorthWest
Post Re: What happens when the Rolling Roads get to the rollers?


Sat Feb 28, 2009 12:44 pm
Profile WWW
PITA Bred
User avatar

Joined: Wed Apr 09, 2008 12:17 pm
Posts: 2402
Location: The Quiet Earth
Post Re: What happens when the Rolling Roads get to the rollers?


Sat Feb 28, 2009 1:16 pm
Profile
Centennial Attendee
User avatar

Joined: Thu Apr 10, 2008 10:46 am
Posts: 545
Location: Aurora, IL, USA, Terra
Post Re: What happens when the Rolling Roads get to the rollers?

_________________
Bill Higgins
bill.higgins@gt.org
http://beamjockey.livejournal.com


Sun Mar 01, 2009 12:56 pm
Profile WWW
Heinlein Nexus
User avatar

Joined: Thu Apr 10, 2008 8:10 am
Posts: 2236
Location: Pacific NorthWest
Post Re: What happens when the Rolling Roads get to the rollers?


Sun Mar 01, 2009 4:03 pm
Profile WWW
PITA Bred
User avatar

Joined: Wed Apr 09, 2008 12:17 pm
Posts: 2402
Location: The Quiet Earth
Post Re: What happens when the Rolling Roads get to the rollers?
I am darned. :lol:

Remember that the drive comes from many, many points along the road, not from some single source like a propeller or push link. Heinlein implies that there are drive rollers every, what, few hundred yards? By distributing the drive force and the power requirements (including heat dissipation) it becomes much more practical. Don't try to make the calculations as if it's a single-point drive or concentrated force.

RAH also noted that it can take hours to restart a strip, so I think he'd thought it through that the 100mph strip would need to be spun up very slowly, and perhaps even "train" style where some parts start ahead of others and then pull the slower sections along.

It's still a complete ridiculous monstrosity. For one thing, it requires this massive installation to run at full speed even when traffic is very light, the complete opposite of our individual-vehicle model.


Sun Mar 01, 2009 4:11 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 26 posts ]  Go to page Previous  1, 2, 3  Next

Who is online

Users browsing this forum: Bing [Bot] and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by STSoftware for PTF