Maximum negative G's?
Larry Stone
is not turning anything up.
What is the maximum negative G's encountered on a roller-coaster (and
where)? I'm having a debate on this with someone in another, non
roller-coaster forum. He says 3 negative G's is routine on
roller-coasters; I say it's much less as 3 negative G's would redefine
"ejector seat" should a restraint ever brake.
Thanks in advance. E-mail copies of replies are appreciated.
--
Larry Stone
la...@stonejongleux.com
http://www.stonejongleux.com/
Adam B
Larry Stone <la...@stonejongleux.com> wrote in message
news:larry-B57670....@news.telocity.com...
> I'm sure this has been asked and answered before but a quick Deja search
> is not turning anything up.
>
> What is the maximum negative G's encountered on a roller-coaster (and
> where)? I'm having a debate on this with someone in another, non
> roller-coaster forum. He says 3 negative G's is routine on
> roller-coasters; I say it's much less as 3 negative G's would redefine
> "ejector seat" should a restraint ever brake.
>
turbo drops do that... I think -3 would kill you if you were restrained in
a seat.
++++ADAM++++
Dave Sandborg
<la...@stonejongleux.com> wrote:
> I'm sure this has been asked and answered before but a quick Deja search
> is not turning anything up.
>
> What is the maximum negative G's encountered on a roller-coaster (and
> where)? I'm having a debate on this with someone in another, non
> roller-coaster forum. He says 3 negative G's is routine on
> roller-coasters; I say it's much less as 3 negative G's would redefine
> "ejector seat" should a restraint ever brake.
>
> Thanks in advance. E-mail copies of replies are appreciated.
Let's put it this way. After one second at -1 G, if you had no
restraints, you'd be 16 feet off your seat.
--
Dave Sandborg
Remove Spam-away to respond via e-mail.
David H.--REMOVE STOPSPAM to reply
Wouldn't air friction cut into that a bit? Or would it be fairly
negligible?
David Hamburger, davi...@bellatlantic.net, Boston, MA
IMPORTANT: Please remove "STOPSPAM" from my address when
replying via e-mail.
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1) Montu 11) Batman (SFGAdv) 1) Shivering Timbers
2) Superman:ROS (SFNE) 12) Incredible Hulk 2) Legend
3) Alpengeist 13) Magnum XL-200 3) Raven
4) Kumba 14) Batman Knight Fl. 4) Boulder Dash
5) Medusa 15) Millennium Force 5) Georgia Cyclone
6) Ice Dueling Dragon 16) Great Nor'Easter 6) Rampage
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9) Raptor 19) Two-Face 9) Texas Giant
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NOTE: only the best of each steel clone is listed.
Wolf
> is not turning anything up.
>
> What is the maximum negative G's encountered on a roller-coaster (and
> where)? I'm having a debate on this with someone in another, non
> roller-coaster forum. He says 3 negative G's is routine on
> roller-coasters; I say it's much less as 3 negative G's would redefine
> "ejector seat" should a restraint ever brake.
-3Gs is highly unusual, and quite possibly fatal.
more than 2 negative Gs is considered dangerous.
--
|\-/|
<0 0>
=(o)=
-Wolf
Wolf
> >restraints, you'd be 16 feet off your seat.
>
> Wouldn't air friction cut into that a bit? Or would it be fairly
> negligible?
At low speed, air resistance is basically negligible.
Dave Sandborg
H.--REMOVE "STOPSPAM" to reply <davidhhh...@bellatlantic.net>
wrote:
> On Wed, 24 Jan 2001 21:00:03 -0500, Dave Sandborg
> <sand...@Spam-away.ix.netcom.com> wrote:
>
> >Let's put it this way. After one second at -1 G, if you had no
> >restraints, you'd be 16 feet off your seat.
>
> Wouldn't air friction cut into that a bit? Or would it be fairly
> negligible?
I'm guessing the -1 G figure would already have included friction in
the calculation.
SROS Backwerdz
Dave Sandborg wrote in message
<250120010735311717%sand...@Spam-away.ix.netcom.com>...
_____
It's possible that 5 seconds of -3G can be more dangerous than 1-2 seconds
of -4G. It's how LONG the force is sustained as well as how gradually you
work into and out of it. Check out that whole simple vs. compound curve
thing Jon Smith and I were chewing on in the "Arrow's Future" post.
-Chris
Joe Schwartz
> Let's put it this way. After one second at -1 G, if you had no
> restraints, you'd be 16 feet off your seat.
Yes, but that's a really bizarre way to think of it. The sensation of
negative G's are essentially *caused* by the restraints pushing you down.
If you had no restraints, you'd only feel weightless (0 G) as you floated
out of the train and fell towards the ground.
You feel negative G's only when you are falling downward faster than
gravity alone would make you fall -- or when you are decelerating upward
faster than gravity alone would make you decelerate. In either case, it's
the restraints that apply this extra downward force to your body. Without
the restraints, your body would fall downward (or decelerate upward) at the
speed due to gravity, and you would feel weightless (0 G) until you hit the
ground. Then you would feel pain.
------------------------------------------------------------------
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Dave Sandborg
<j...@joyrides.com> wrote:
> Dave Sandborg <sand...@Spam-away.ix.netcom.com> wrote:
>
> > Let's put it this way. After one second at -1 G, if you had no
> > restraints, you'd be 16 feet off your seat.
>
> Yes, but that's a really bizarre way to think of it. The sensation of
> negative G's are essentially *caused* by the restraints pushing you down.
> If you had no restraints, you'd only feel weightless (0 G) as you floated
> out of the train and fell towards the ground.
True. I'm not thinking of the physiological effects here, so much as
the disaster that would happen if there were a restraint failure. As
extreme as Georgia Cyclone is, it wouldn't throw you 16 feet out of the
car if the lap bar weren't down. The point is that as extreme as we
feel certain coaster are, they aren't near this kind of level.
Wolf
> > negative G's are essentially *caused* by the restraints pushing you
down.
> > If you had no restraints, you'd only feel weightless (0 G) as you
floated
> > out of the train and fell towards the ground.
>
> True. I'm not thinking of the physiological effects here, so much as
> the disaster that would happen if there were a restraint failure. As
> extreme as Georgia Cyclone is, it wouldn't throw you 16 feet out of the
> car if the lap bar weren't down. The point is that as extreme as we
> feel certain coaster are, they aren't near this kind of level.
Some coasters do actually pull miniscule negative Gs.
However, sans restraints, this converts to 1G with a positive initial
vertical velocity. =)
It's the sudden positive Gs at impact that cuase problems.
DJ
than -2 Gs is dangerous, and -3Gs sustained can be fatal.
The only coaster I know of that performs more than -1.5 Gs is Stealth, but
that doesn't quite count, because the force isn't pushing the blood to your
head, which is what makes negative Gs so fatal. The blood rushes into your
head and your blood vessels explode.
Now for POSITIVE Gs, yes. 3 Gs is routine on roller coasters. Ride Viper @
SFMM in the front, and you can feel the Gs in those loops. Also, from what
I've heard, Goliath really pulls the Gs. I wouldn't be surprised if Six
Flags increased the power of that mid course brake to slow it down so not so
many Gs would be pulled.
Now wouldn't THAT piss some people off?
-DJ
"Larry Stone" <la...@stonejongleux.com> wrote in message
news:larry-B57670....@news.telocity.com...
V. Canfield
>
> Negative Gs are very dangerous. -1 G is like hanging upside down. More
> than -2 Gs is dangerous, and -3Gs sustained can be fatal.
>
> The only coaster I know of that performs more than -1.5 Gs is Stealth, but
> that doesn't quite count, because the force isn't pushing the blood to your
> head, which is what makes negative Gs so fatal. The blood rushes into your
> head and your blood vessels explode.
The fact that your head is mostly encased in your skull protects you
from this fate. The pressure inside and outside your blood vessels is
essentially equal, and your blood vessels, fortunately, do not explode.
Your eyes are not quite so well protected, and high sustained negative
Gs can cause retinal bleeding.
The key here is that it is hard to design rollercoasters that impose
sustained negative Gs on their passengers. I suppose that a long high-G
helix would do it, if it were reverse-banked so that the riders's heads
were downward and to the outside of the helix--but why would anyone want
to ride such a ride?
Bruce Jensen
"Wolf" <wrbu...@mtu.edu> wrote:
> Some coasters do actually pull miniscule negative Gs.
I'd guess this is about true; I doubt if the magnitude ever exceeds -1 G
relative to the seat.
Think about it. A tiny bit more than Zero G as you go over the top of
the hill means a nice float; a very little more means a standup or
ejector. Put minus one G upward on those restraints, and you have your
full body weight smashing on the lapbar from the tops of the thigh -
ouch! The strongest negative G I've felt so far over a hilltop is on
S:ROS at SFNE. It is a very hard float, nearly uncomfy on the thighs,
and yet I'm sure I'm not being "thrust upward" from the seat with more
200 lbs. of force. It may be 50 - 100 lbs (.25 to .5 G for me), but
that's probably about it. What makes it so memorable is that it lasts a
while, perhaps a couple of seconds, and so it feels like you'd launch
right out without the lapbars.
Some stand ups in rear seats seem more powerful than this, like
Ghostrider's back seat for example, but perhaps not to the point where
you'd exit the car...the sensation is intense but fairly brief.
--
Best regards,
Bruce Jensen
Sent via Deja.com
http://www.deja.com/
Wolf
>
> I'd guess this is about true; I doubt if the magnitude ever exceeds -1 G
> relative to the seat.
>
> Think about it. A tiny bit more than Zero G as you go over the top of
> the hill means a nice float; a very little more means a standup or
> ejector. Put minus one G upward on those restraints, and you have your
> full body weight smashing on the lapbar from the tops of the thigh -
> ouch! The strongest negative G I've felt so far over a hilltop is on
> S:ROS at SFNE. It is a very hard float, nearly uncomfy on the thighs,
> and yet I'm sure I'm not being "thrust upward" from the seat with more
> 200 lbs. of force. It may be 50 - 100 lbs (.25 to .5 G for me), but
> that's probably about it. What makes it so memorable is that it lasts a
> while, perhaps a couple of seconds, and so it feels like you'd launch
> right out without the lapbars.
I agree. I suspect that Magnum's bunnies are in fact, negative Gs,
especially at night. Ejection-air usually is slightly below 0 Gs. A lot of
floating air time isn't even 0, really.
Wolf
> from this fate. The pressure inside and outside your blood vessels is
> essentially equal, and your blood vessels, fortunately, do not explode.
Unfortunately, forcing blood into your head - serviced by some major
arteries - can cause capillaries to burst, which will lead to a stroke.
The eye thing is referred to as a red-out, and is a major warning sign.
Bruce Jensen
"Wolf" <wrbu...@mtu.edu> wrote:
> I agree. I suspect that Magnum's bunnies are in fact, negative Gs,
> especially at night. Ejection-air usually is slightly below 0 Gs. A
lot of floating air time isn't even 0, really.<
Hmmm - yeah, I see your point...if you do not actually lose contact
with the seat but simply become *almost* weightless, then, yepp,
probably a very small positive G.
Wes Lagattolla
<Killrbyte@_spam_me_and_die_geocities.com> authored the following
post:
>Now for POSITIVE Gs, yes. 3 Gs is routine on roller coasters. Ride Viper @
>SFMM in the front, and you can feel the Gs in those loops. Also, from what
>I've heard, Goliath really pulls the Gs. I wouldn't be surprised if Six
>Flags increased the power of that mid course brake to slow it down so not so
>many Gs would be pulled.
>Now wouldn't THAT piss some people off?
You couldn't increase the power of the mid-course on Goliath. It
already brings you to a complete stop.
=W=
Wes Lagattolla ghostr...@yahoo.com
#1 Wood-GhostRider #1 Steel-Superman: Ride Of Steel
Dave Althoff Jr
: DJ wrote:
: >
: > Negative Gs are very dangerous. -1 G is like hanging upside down. More
: > than -2 Gs is dangerous, and -3Gs sustained can be fatal.
: >
: > The only coaster I know of that performs more than -1.5 Gs is Stealth, but
: > that doesn't quite count, because the force isn't pushing the blood to your
: > head, which is what makes negative Gs so fatal. The blood rushes into your
: > head and your blood vessels explode.
: The fact that your head is mostly encased in your skull protects you
: from this fate. The pressure inside and outside your blood vessels is
: essentially equal, and your blood vessels, fortunately, do not explode.
: Your eyes are not quite so well protected, and high sustained negative
: Gs can cause retinal bleeding.
On the Vekoma coaster, what is the direction of the force applied? The
alleged -x G's is actually what we would normally think of as a "forward"
or "into the restraints" force, rather than a vertical "head to toe"
force, is it not?
--Dave Althoff, Jr.
--
/X\ _ _ _*** Closed for the season ***
/XXX\ /X\ /X\_ _ /X\__ _ _ _____
/XXXXX\ /XXX\ _/XXXX\_ /X\ /XXXXX\ /X\ /X\ /XXXXX
_/XXXXXXX\__/XXXXX\/XXXXXXXX\_/XXX\_/XXXXXXX\__/XXX\_/XXX\_/\_/XXXXXX
A.J. Spaide
-Adrenaline Junky
Excuse me while I kick the sky!
Remove "mma" to respond
DJ
> You couldn't increase the power of the mid-course on Goliath. It
> already brings you to a complete stop.
>
> =W=
>
> Wes Lagattolla ghostr...@yahoo.com
> #1 Wood-GhostRider #1 Steel-Superman: Ride Of Steel
Really? Well, I haven't ridden Goliath yet. I was at SFMM, but it broke
down and they closed it for the day, and I never got to ride. I didn't
remember it going to a complete stop. I was pretty friggin pissed because
that was one of my big hopes for SFMM. As of so far, I have yet to ride a
hyper. The tallest coaster I have ridden is Viper, and that doesn't have
much of a drop.
They'll probably install a trim brake somewhere along the ride then. If the
Gs are as good as what I've heard, there's no way they'll leave it like
that.
I've said it a billion times before and I'll say it again. It SUCKS living
in Portland, OR!!
-DJ
DJ
like you're upside down at the bottom of a hill, which would cause ferocious
negative Gs.
-DJ
"A.J. Spaide" <pli...@aol.commma> wrote in message
news:20010127001134...@ng-fk1.aol.com...
A.J. Spaide
Richard Bonner
> Let's put it this way. After one second at -1 G, if you had no
> restraints, you'd be 16 feet off your seat.
> --
> Dave Sandborg
*** Dave, I haven't taken the time to think hard on tnis one. can
you save me the time and explain this one to me please?
My initial thoughts are: If a rider is experiencing -1G, then isn't the
coaster dropping away at 1G? With gravity acceleration at 32 feet per
second per second, wouldn't the coaster and rider be 64 feet apart after
1 second?
Richard Bonner
Managing Director:
The Coaster Enthusiasts of Canada
www.chebucto.ns.ca/~ak621/CEC/CEC.html
Dave Sandborg
<ak...@chebucto.ns.ca> wrote:
> Dave Sandborg wrote:
>
> > Let's put it this way. After one second at -1 G, if you had no
> > restraints, you'd be 16 feet off your seat.
> > --
> > Dave Sandborg
>
> *** Dave, I haven't taken the time to think hard on tnis one. can
> you save me the time and explain this one to me please?
>
> My initial thoughts are: If a rider is experiencing -1G, then isn't the
> coaster dropping away at 1G? With gravity acceleration at 32 feet per
> second per second, wouldn't the coaster and rider be 64 feet apart after
> 1 second?
OK, I'll try to go through this in detail. Along the way, I'll also
try to explain why I expressed my point about negative G's in the way I
did--the way that puzzled Joe.
First, we should be clear on exactly what a G measurement is. In a
way, "G forces" can really be considered a measure of acceleration,
because they factor out mass, which would have to be taken into account
for an actual force. But it's not precisely acceleration, because 0
G's is experienced in free fall, when the rider is accelerating
downward at 32 ft/s^2 (by the way, Richard, why didn't you use metric
units! :-). And 1 G is experienced at rest, with no acceleration
whatsoever. It's really the difference between the actual acceleration
and free fall acceleration. Why this is the case would take us a bit
far afield, so just take my word for it. There are other complications
(one of which I'll mention below), but for my basic argument, the above
is enough to work with.
So if a coaster car is accelerating at -1 G, it is accelerating
downward at 32 ft/s^2 greater than it would be under free fall. That
is, the train would be accelerating downward at 64 ft/s^2.
Now, if the riders are restrained, they will also be accelerating
downward at the same rate. Hence they'd be experiencing -1 G too. But
I don't want to dwell on that, because it doesn't really get at why I
think coaster designers subject the rider to such extreme negative G's
for any extended period of time. People talk about the physiological
effects of negative G's, but that's not an issue for -1 G. In
physiological terms, that's not really all that extreme. It's the
equivalent of hanging upside down. (My way of talking about G forces
above doesn't quite do it in terms of explaining why this is the case.
That's one of the complications I mentioned above. Take my word on
this one too.) There are two things to recognize about this: 1) It's
not physically dangerous to hang upside down for a long time, but 2)
it's quite uncomfortable to do so. Hence, -1 G would not be
particularly dangerous to a properly restrained rider, but it would not
be particularly *fun* either. "More extreme negative G's are better"
is *not* something that should be taken as axiomatic, even by an
airtime freak such as myself!
This is why I focused on the *unrestrained* rider, because this is
where the danger of even -1 G comes into play. So let's consider that
case. The unrestrained rider will be in free fall. So a coaster train
accelerating at -1 G will be accelerating at -32 ft/s^2 with respect to
that rider. Think of what happens then when an unrestrained rider who
starts out sitting on the seat experiences 1 second of -1 G.
At the beginning of the second, the rider and the train will be moving
together; their relative speed will be 0 ft/s. At the end of the
second, the coaster will be moving downward relative to the rider at 32
ft/s--a direct consequence of the acceleration rate.
Does this mean that the coaster train will be 32 feet below the rider?
No! These are measurements of relative *speed*, not relative
*position*. In general, to infer position from speed, we'd need to use
calculus. However, this is a relatively simple case--referred to as
the "Mean Speed Theorem"--and it was known well before Newton or
Leibniz invented the calculus.
If you graph the speed in this second, you'll get a line with a
constant slope. I'll represent that in a figure, which you'll need a
monospaced font to see correctly. Also, I'll just forget about putting
the negative sign in; it would be easy to do so if I were so inclined,
but it's not illuminating.
32 ft/s S| /|
P| / |
E| / |
E| / |
D| / |
0 ft/s |/_____|
0 1
s s
e e
c c
TIME
We calculate the distance traveled by taking the area under the line.
Note that the figure is a triangle. The area of a triangle is half the
area of its bounding rectangle. So we multiply 32 ft/s * 1 s, and
divide by 2 to get our distance traveled, 16 feet. This shows that at
the end of the first second of -1 G, an unrestrained rider would be 16
feet above the train.
*This* is why extended strong negative G's are dangerous. It wouldn't
take long for the relative acceleration between rider and car to build
up, if there were a restraint failure. Even a second leads to the
rider being thrown way beyond what you might have expected. This would
be way too dangerous for any coaster designer to allow. It's possible
that some coasters generate such strong negative G's, but if so, only
for a very short instant. Even unrestrained on the Georgia Cyclone,
you would not be tossed this far.
I hope at least some of that came off clearly...
Wolf
> > restraints, you'd be 16 feet off your seat.
> > --
> > Dave Sandborg
>
> *** Dave, I haven't taken the time to think hard on tnis one. can
> you save me the time and explain this one to me please?
>
> My initial thoughts are: If a rider is experiencing -1G, then isn't the
> coaster dropping away at 1G? With gravity acceleration at 32 feet per
> second per second, wouldn't the coaster and rider be 64 feet apart after
> 1 second?
No.
x = VoT + (1/2)A(t)^2
Now, Vo = 0 since you aren't movign away from or towards the train
initially.
A = 32.2ft/(s^2)
so...
x = (1/2)*32.2*1^2 = 16.1ft (4.9m) away from the train after 1 sec.
And yes, the train is dropping away at 1G, although the perception of the
effect is relative and open to interpretation.
Wolf
> way, "G forces" can really be considered a measure of acceleration,
> because they factor out mass, which would have to be taken into account
> for an actual force. But it's not precisely acceleration, because 0
> G's is experienced in free fall, when the rider is accelerating
> downward at 32 ft/s^2 (by the way, Richard, why didn't you use metric
> units! :-). And 1 G is experienced at rest, with no acceleration
> whatsoever. It's really the difference between the actual acceleration
> and free fall acceleration. Why this is the case would take us a bit
> far afield, so just take my word for it. There are other complications
> (one of which I'll mention below), but for my basic argument, the above
> is enough to work with.
>
> So if a coaster car is accelerating at -1 G, it is accelerating
> downward at 32 ft/s^2 greater than it would be under free fall. That
> is, the train would be accelerating downward at 64 ft/s^2.
I do want to make one comment here.
While -1 Gs is 2 fewer Gs than 1G, or normal, it is not like an ejection at
64ft/s^2. If you experience 0Gs, you will not fly away from the train.
Assuming both are level, you will follow exactly the same path, you just
weigh nothing. In 1G, you follow the train's path as well, you just have
weight. This is because the train prevents you (conveniently) from falling
towards the giant gravity well we call Earth.
Tim Long
Dave Sandborg <sand...@Spam-away.ix.netcom.com> wrote in message
news:300120012015560067%sand...@Spam-away.ix.netcom.com...
.
.
.
> *This* is why extended strong negative G's are dangerous. It wouldn't
> take long for the relative acceleration between rider and car to build
> up, if there were a restraint failure. Even a second leads to the
> rider being thrown way beyond what you might have expected. This would
> be way too dangerous for any coaster designer to allow. It's possible
> that some coasters generate such strong negative G's, but if so, only
> for a very short instant.
This is why a woman was ejected on Colosuss at SFMM in the early days. She
was very obese and the ride had only lap bars. She had no 'lap' to speak of,
so the bar was not pushed down very far. The train returned with n-1
passengers. This led to the first reprofiling of Colossus, and the airtime
was never the same.
I consider myself fortunate to have ridden big C. prior to this reprofile!
Still the most negative G's I've experienced on a coaster...
Tim Long
chrisk...@my-deja.com
__
After having ridden "Staplerman: Ride Of Steel" at New England, I
conclude that there can be as many neg-G's as desired, as long as the
duration is not too long(maybe 2-3sec). Those Intamin restraints will
hold an elephant in place!
-SROS BACKWERDZ
Richard Bonner
> In article <956pq9$j3f$2...@News.Dal.Ca>, Richard Bonner wrote:
> > Dave Sandborg wrote:
> >
> > > Let's put it this way. After one second at -1 G, if you had no
> > > restraints, you'd be 16 feet off your seat.
> > > --
> > > Dave Sandborg
> >
> > *** Dave, I haven't taken the time to think hard on tnis one. can
> > you save me the time and explain this one to me please?
> >
> > My initial thoughts are: If a rider is experiencing -1G, then isn't the
> > coaster dropping away at 1G? With gravity acceleration at 32 feet per
> > second per second, wouldn't the coaster and rider be 64 feet apart after
> > 1 second?
> OK, I'll try to go through this in detail.
(Snip)
> because 0 G's is experienced in free fall, when the rider is accelerating
> downward at 32 ft/s^2 (by the way, Richard, why didn't you use metric
> units! :-).
(Snip)
> --
> Dave Sandborg
*** I didn't because your original post used "16 feet" and i didn't want
to confuse the issue for the metric-impaired. (-: