Subject:
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Re: Brit-Rail APT (Advanced Passenger Train)
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Newsgroups:
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lugnet.trains
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Date:
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Thu, 31 May 2001 16:44:40 GMT
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Reply-To:
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[cmasi@]nospam[cmasi.chem.tulane.edu]
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Viewed:
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731 times
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James Mathis wrote:
>
> In lugnet.trains, Lawrence Wilkes writes:
> >
> > "James Mathis" <thakius@nmt.edu> wrote in message
> > news:GE5Mwy.49r@lugnet.com...
> > > I've been working on a pendular mechanism to tilt train cars through • curves.
> > > A fun project! :-)
> > >
> > > There are quite a few train sets now that employ some type of pendular • scheme,
> > > now; but, for me the Brit-Rail APT was my first introduction to a tilting
> > > train. (Was it the first to carry ticket-paying passengers?) So, it • seems
> > > appropriate to outfit an APT with my first pendular mechanism.
> >
> >
> > My physics might be completely wrong here, but the APT system was active
> > wasn't it, in that it forced the train to lean into the curve to counteract
> > centrifugal force.
> > Without an active mechanism, wouldn't a tilting Lego train have the opposite
> > effect? i.e. centrifugal force making the train lean out of the curve even
> > more and toppling over even quicker than a non-tilting one?
>
> For a passive tilt mechanism:
> It depends on where the pendular axis is located. If the axis of rotation is
> above the wagon's center of gravity, then the wagon would tilt such that the
> base of the wagon swing out in the curve- a "correct" tilt.
> But, if the axis of rotation is below the center of gravity, then the wagon
> would tilt such that the top of the wagon would swing out in the curve- as you
> mentioned above.
>
> > First prize to whomever manages to squeeze an RCX controlled pneumatic
> > active solution into a Lego train :-)
>
> I'd like to see this, too.
>
> In case you're wondering, my solution is a leveraged "active" pendular system.
>
> later,
> James Mathis
Did you MLCad the pendular mechanism too? If so, I would love to see the file!
I haven't put enough time into shared boogies and tilting mechanisms to ever
solve the problem myself ( I'm too lazy? I concentrate on freight? I'm not good
enough? I don't have the parts? Go ahead pick an excuse for me), so I'd love to
see your solution.
Hmm...I wonder if an active tilting mechanism like [1]
http://homepages.svc.fcj.hvu.nl/brok//legomind/models/trains/leaning.html
would work on a bigger heavier 8-wide model. I wonder if the weight of the model
would force the wheels to go straight and cause the train to either derail or
slow way down.[2]
Chris
1. This page is actual supposed to be shown inside a frame, so your navigation
options will be limited. The "correct" url is
http://homepages.svc.fcj.hvu.nl/brok//legomind/models/index.htm
Pick "Trains" and then "Leaning in the Curves"
2. This question comes from an 8-wider who is willing to acknowledge that there
are disadvantages associated with going 8-wide.
--
See some of my LEGO creations at http://cmasi.chem.tulane.edu/~lego/
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Message is in Reply To:
 | | Re: Brit-Rail APT (Advanced Passenger Train)
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| (...) For a passive tilt mechanism: It depends on where the pendular axis is located. If the axis of rotation is above the wagon's center of gravity, then the wagon would tilt such that the base of the wagon swing out in the curve- a "correct" tilt. (...) (23 years ago, 31-May-01, to lugnet.trains)
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