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Overbanked turns (was: the SDC coaster for 2013)
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Victor Canfield
Jul 23, 2012, 11:01:30 AM7/23/12
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On Jul 10, 1:01 am, dalloff.gcfn....@sbcglobal.net (Dave Althoff Jr.) wrote:
> On another matter, I have not ridden the Texas Giant, either in its
> original or in its Iron Horse configuration. But it features an
overbanked
> curve, an element that has proven to be a spectacular failure
> on wood coasters in the past (Mean Streak and Son of Beast being two
> particularly egregious examples). When Summers/Dinn tried it, and even
> worse when Stengel and RCCA did it, the mistake was in taking it too
> high, so that the train lost too much energy before reaching the
> midpoint of the curve. It was particularly bad on Son of Beast, where
> the back of the train threatened to stall out on the overbanked curve.
> The trouble is that when the train is moving so slowly and the track is
> superelevated that high, gravity is going to overcome the train's
> angular acceleration on the curve, causing the train to literally fall
> off of the outside rail. The proper solution is to run the train faster
> through the curve, so that it can stay "stuck" to the outside rail all
> the way through the curve. Has RMC solved this problem with their
> overbanks?
Isn't that the definition of an overbanked curve, one on which the train
is going too slowly to stay on the outside rail? The transition between
a traditional (underbanked) curve and an overbanked one could be
problematic, at the point where the train falls from the outside to the
inside rail.
Meta: Sorry about the new thread, but messages expire from my news
server after about a week, and google is having trouble, at the moment,
sending posts.
> On another matter, I have not ridden the Texas Giant, either in its
> original or in its Iron Horse configuration. But it features an
overbanked
> curve, an element that has proven to be a spectacular failure
> on wood coasters in the past (Mean Streak and Son of Beast being two
> particularly egregious examples). When Summers/Dinn tried it, and even
> worse when Stengel and RCCA did it, the mistake was in taking it too
> high, so that the train lost too much energy before reaching the
> midpoint of the curve. It was particularly bad on Son of Beast, where
> the back of the train threatened to stall out on the overbanked curve.
> The trouble is that when the train is moving so slowly and the track is
> superelevated that high, gravity is going to overcome the train's
> angular acceleration on the curve, causing the train to literally fall
> off of the outside rail. The proper solution is to run the train faster
> through the curve, so that it can stay "stuck" to the outside rail all
> the way through the curve. Has RMC solved this problem with their
> overbanks?
Isn't that the definition of an overbanked curve, one on which the train
is going too slowly to stay on the outside rail? The transition between
a traditional (underbanked) curve and an overbanked one could be
problematic, at the point where the train falls from the outside to the
inside rail.
Meta: Sorry about the new thread, but messages expire from my news
server after about a week, and google is having trouble, at the moment,
sending posts.
tyl...@gmail.com
Jul 23, 2012, 5:57:14 PM7/23/12
to
Typically the way I've seen it used is a turn with banking past 90 degrees, but not part of a traditional inversion. First time I can remember it being thrown around was to describe the first turnaround on Millennium Force.
Dave Althoff Jr.
Jul 23, 2012, 10:07:23 PM7/23/12
to
Okay, collected gang of Internet coaster experts, let's discuss:
Is it an overbank because the banking exceeds that required for the
vehicle speed going through the curve, or are we now redefining
overbanked curves to those that exceed 90 degrees of superelevation?
In this particular case, isn't the issue that the track is going past 90
degrees, but we have seen that done on high speed coasters where the
train is moving fast enough that the outside rail isn't really even an
issue; the curve banking allows a tighter turn and keeps the resolved
force vector pointing straight "down" (talking patron coordinate space
here; I know Victor knows what that means... 8-) ). If that is the
case, then the overbank becomes more of a visual element than a
mechanical one, and it would actually work..
> Meta: Sorry about the new thread, but messages expire from my news
> server after about a week, and google is having trouble, at the moment,
> sending posts.
really understand what a "thread" is, and why it matters to a news
server... 8-)
-- Dave Althoff, Jr.
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Wolf
Jul 24, 2012, 12:32:45 AM7/24/12
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"Dave Althoff Jr." <dalloff....@sbcglobal.net> wrote in message
news:jul00r$b77$1...@dont-email.me...
much banking for the train."
--
|\-/|
<0 0>
=(o)=
-Wolf
news:jul00r$b77$1...@dont-email.me...
> Victor Canfield <va...@psu.edu> wrote:
>> On Jul 10, 1:01 am, dalloff.gcfn....@sbcglobal.net (Dave Althoff Jr.)
>> wrote:
>> Isn't that the definition of an overbanked curve, one on which the train
>> is going too slowly to stay on the outside rail? The transition between
>> a traditional (underbanked) curve and an overbanked one could be
>> problematic, at the point where the train falls from the outside to the
>> inside rail.
>
> Now that's something that I suspect is open to some debate.
>
> Okay, collected gang of Internet coaster experts, let's discuss:
> Is it an overbank because the banking exceeds that required for the
> vehicle speed going through the curve, or are we now redefining
> overbanked curves to those that exceed 90 degrees of superelevation?
You're the only person here I know who uses "overbank" in the sense of "too
>> On Jul 10, 1:01 am, dalloff.gcfn....@sbcglobal.net (Dave Althoff Jr.)
>> wrote:
>> Isn't that the definition of an overbanked curve, one on which the train
>> is going too slowly to stay on the outside rail? The transition between
>> a traditional (underbanked) curve and an overbanked one could be
>> problematic, at the point where the train falls from the outside to the
>> inside rail.
>
> Now that's something that I suspect is open to some debate.
>
> Okay, collected gang of Internet coaster experts, let's discuss:
> Is it an overbank because the banking exceeds that required for the
> vehicle speed going through the curve, or are we now redefining
> overbanked curves to those that exceed 90 degrees of superelevation?
much banking for the train."
--
|\-/|
<0 0>
=(o)=
-Wolf
thalt...@verizon.net
Jul 24, 2012, 8:37:44 AM7/24/12
to
I
On Tuesday, July 24, 2012 12:32:45 AM UTC-4, Wolf wrote:
> "Dave Althoff Jr." <dalloff....@sbcglobal.net> wrote in message
> news:jul00r$b77$1...@dont-email.me...
> > Victor Canfield <va...@psu.edu> wrote:
> >> On Jul 10, 1:01 am, dalloff.gcfn....@sbcglobal.net (Dave Althoff Jr.)
> >> wrote:
>
> >> Isn't that the definition of an overbanked curve, one on which the train
> >> is going too slowly to stay on the outside rail? The transition between
> >> a traditional (underbanked) curve and an overbanked one could be
> >> problematic, at the point where the train falls from the outside to the
> >> inside rail.
> >
> > Now that's something that I suspect is open to some debate.
> >
> > Okay, collected gang of Internet coaster experts, let's discuss:
> > Is it an overbank because the banking exceeds that required for the
> > vehicle speed going through the curve, or are we now redefining
> > overbanked curves to those that exceed 90 degrees of superelevation?
>
> You're the only person here I know who uses "overbank" in the sense of "too
> much banking for the train."
>
> --
> |\-/|
> <0 0>
> =(o)=
> -Wolf
I would define overbanking as anything greater than equilibrium, i.e the point at which the resultant of gravity and centrifugal forces are perpendicular to the plane of the track. At equilibrium the train would tend not to hug either rail, and the smallest irregularity in the track could cause the train to hunt or ricochet back and forth between the rails. What I dislike about most of the new wood coasters being built today is the tendency to bank the turns at or close to equilibrium all but eliminating centrifugal forces. I much prefer fast curves with little or no banking that throw you around. In my view it contributes to what makes a wild, seemingly out of control ride experience.
Tom Halterman
On Tuesday, July 24, 2012 12:32:45 AM UTC-4, Wolf wrote:
> "Dave Althoff Jr." <dalloff....@sbcglobal.net> wrote in message
> news:jul00r$b77$1...@dont-email.me...
> > Victor Canfield <va...@psu.edu> wrote:
> >> On Jul 10, 1:01 am, dalloff.gcfn....@sbcglobal.net (Dave Althoff Jr.)
> >> wrote:
>
> >> Isn't that the definition of an overbanked curve, one on which the train
> >> is going too slowly to stay on the outside rail? The transition between
> >> a traditional (underbanked) curve and an overbanked one could be
> >> problematic, at the point where the train falls from the outside to the
> >> inside rail.
> >
> > Now that's something that I suspect is open to some debate.
> >
> > Okay, collected gang of Internet coaster experts, let's discuss:
> > Is it an overbank because the banking exceeds that required for the
> > vehicle speed going through the curve, or are we now redefining
> > overbanked curves to those that exceed 90 degrees of superelevation?
>
> You're the only person here I know who uses "overbank" in the sense of "too
> much banking for the train."
>
> --
> |\-/|
> <0 0>
> =(o)=
> -Wolf
I would define overbanking as anything greater than equilibrium, i.e the point at which the resultant of gravity and centrifugal forces are perpendicular to the plane of the track. At equilibrium the train would tend not to hug either rail, and the smallest irregularity in the track could cause the train to hunt or ricochet back and forth between the rails. What I dislike about most of the new wood coasters being built today is the tendency to bank the turns at or close to equilibrium all but eliminating centrifugal forces. I much prefer fast curves with little or no banking that throw you around. In my view it contributes to what makes a wild, seemingly out of control ride experience.
Tom Halterman
Dave Althoff Jr.
Jul 31, 2012, 12:55:52 AM7/31/12
to
Back in 1991, Mean Streak was advertised as having "overbanked turns"
and nothing on that ride goes past about 50 degrees. I think the meaning
of the term actually changed in 2000 when Millennium Force opened with
three curves that are past 90 degrees
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