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Coasters to Face G-Force Limits?
jonerik writes "NBC News is reporting that today New Jersey will begin examining the possibility of placing limits on roller coaster G-forces. Pointing out that the G-forces on coasters are considerably greater than even those experienced by astronauts and race car drivers, legislators on both the state and national levels want to start reining in coaster G-forces which have been blamed for a number of injuries and deaths over the past few years. Pansies. Why do they think people ride roller coasters to begin with?"
This site on Amusement Park Accident Reports was a bit of an eye opener.
there have been a number of deaths (actually, usually at least one every summer)
I don't know.. according to the report on the congressman's page, there has only been one death ever in NJ, and the victim was medically predisposed. Now I think that's only brain injuries, but this page doesn't list much in NJ either, and most of it is due to people not using the safety bar.
Check your facts before you pass on anecdotes as truth.
"potentially harmful effects of large gravitational fields"
Roller coasters do not generate "gravitational fields." They generate no gravity whatsoever. The do create acceleration forces which cause effects similar to gravity, and we actually know quite a bit about those forces. Fighter pilots regularly undergo forces of up to 9 Gs, and this is an area that the military and NASA have studied extensively. They have things called "centrifuges" which can subject people to very high accelerations. All fighter pilots spend time in the centrifuge learning how to handle high G loads.
As for your cousin, I suspect he had some other nascent condition which the ride exacerbated. The fact is, you're probably more likely to be hit by lightning than to be hurt on an amusement park ride, and no one is saying we should make it a crime to go outside in the rain.
-Vercingetorix
"Necessitas non habet legem." -St. Augustine
i'm not so sure how complete that site is for accidents. I remember I was back at Great Adventure back in the late 1980's.. hrm I was in middle school so it had to be like 87-88. A girl let the ride 'lightning loops' restraints close behind her, and was ejected from the ride mid loop. She died from that and its not listed anywhere on that site. Also stories are on the news a lot about the Boardwalk rides like one 'wild mouse' roller coaster that had a 60 degree climb or so and the climbing mechanism broke and people went down and hit a car behind them causing some horrible G forces i'd assume, but I ride roller coasters a LOT myself and I say leave the G's alone..
Space launches have steadily reduced their peak G forces over the years. During the Mercury and Gemini programs, the Astronauts were exposed to as much G force as modern jet fighters do in a dogfight, and for as long. The heavier Saturn launch system of Apollo was gentler, and the Space shuttle is very tame by comparison. Russian cosmonauts still get a better (in roler-coaster terms) ride than their American counterparts.
Given how tame the shuttle is, maybe it's technically true, if misleading, to say that roler coasters give the rider more G that an Astronaut experiences. (They did after all say "astronaut", not "cosmonaut") A space shuttle jockey, just barely goes over 3G. Some roler coasters may peak at 5. But here's the difference: The shuttle sustains the 3G for the entire duration of the post-SRB-separation boost. That's several minutes of continuous burn. I doubt whether any roler coaster ever peaks over 3G for more than 2 or 3 seconds at a time, if that.
The physiological risks associated with high G are not determined by the magnitude of the G alone, but mainly by other factors:
The duration that high G is sustained. Long duration deprives the brain of blood long enough to cause very bad things to happen. No real risk there on roler coasters.
The onset-rate. How suddenly the G force starts and stops. High onset rates cause all kinds of problems, including back and neck problems, inner ear problems, and even brain dammage in extreme cases. Once again, no issue in a well-designed roler coaster.
Head movement. High G forces, especially combined with high onset rates, are aggrivated by sudden head rotation. This can be a problem even if the G forces are only momentary. Inner ear problems can result. Roller-coaster designers have little control over this factor, so perhaps it is a real concern.
Negative G. (Negative means the blood rushes to your head). High negative G can cause all kinds of problems, including burst blood vessels in the eyes. I've personally never heard of a roler coaster that goes beyond about -0.5G or so, and even then for less than a second, so I doubt that this is an issue.
Sudden transitions from positive to negative, or vice-verca. All the bad things associated with high positive G are accentuated if it immediately follows a period of negative. And vice verca if negative follows a period of positive. This will become a real issue if roler coasters ever start exploring the negative regime. Frankly, I doubt that they will. The average rider views positive G's as exhilirating fun, but would find negative to be obnoxious and uncomfortable.
Frankly, I'm much more worried about the structural design and maintenence of the coaster than the G-profile. But then, I've flown to WAY higher positive and negative G forces than either roler coaster or space shuttle experience, and I know the breathing techniques, and I know to keep my head relatively still. Roler coasters all seem really disappointing to me.
<quote> Wednesday, June 17, 1987 - A 19-year-old girl was killed after falling from the Lightnin' Loops shuttle loop roller coaster ride at Six Flags Great Adventure theme park in Jackson Township, New Jersey. An investigation by the State Labor Department concluded that the ride itself was operating properly, but that the ride operator started the ride without having made sure that all of the passengers were secured by the safety harnesses. The Department's Office of Safety Compliance further concluded that the accident would not have occurred had proper procedures been followed. The park was found to be in violation of the Carnival/Amusement Ride Safety Act and was subsequently charged with the maximum state fines of $1,000. The ride was reopened on Saturday, October 10, 1987, with the permission of the Labor Department, but was eventually dismantled and no longer operates at Great Adventure.</quote>
78% of all statistics are made up on the spot.
The Viper (a relatively new steel coaster) at Six Flags Great Adventure is horrible in terms of comfort. The ride isn't that exciting and thanks to the design of the shoulder restraints most of the ride experience is liken to being repeatedly punched in the ear.
Your comment kind of simplifies the human bodies ability to withstand G forces. I just finished watching a whole program on the Discover Channel about crash testing and the effects of certain forces on the human body, so obviously I'm now a certified expert. Moving right along the program just reinforced what common sense would tell anyone who has been in any kind of accident: it's not just how hard you hit, it's how you hit, what position you're in when you hit, how many times you hit and the angle that you hit at.
The numbers you mentioned sound a bit off from what the program was stating in terms of what the human body could safely endure. They showed a man traveling at some thing like 630mph decelerate to zero in about a tenth of second, which worked out to roughly 45Gs horizontally. His lung(s?) collapsed and his retinas temporarily detached. He eventually recovered and managed to live another 45 years but its still not what I would consider a fun day at an amusement park.
The program also went on to state that the human body can only survive 15Gs of momentary force vertically before the spinal damage occurs. I wonder what 6Gs of sudden momentary lateral force would do to someone's neck.
It would also seem that human anatomy would play a big role in what forces and change in forces the human body could survive without damage. A person sitting perfectly upright may be able to survive a 6G load in one direction, but what happens when they are subjected to the same force with their body and head are shifted to one side from the previous 4G turn or loop? I sure as hell don't know, I doubt New Jersey state legislators know either.
Rider operators do not want to kill customers, just momentarily make customers think they are going to die. There are so many variables in play that any legislation that tries to "make these rides safer" is going to fail hopelessly. I'm all for making ride operators/builders prove that their machines are minimally dangerous but to put blanket limitations on them just doesn't seem to do anyone much good.
-- Button up, your ignorance is showing
Not to have their bodies exposed to more forces and danger than most astronauts ever experience
From the original post:
the G-forces on coasters are considerably greater than even those experienced by astronauts and race car drivers...
I flew military jets for 9 years, and I think these comparisons are crap. When people used to ask me how jets compared to roller coasters, I would tell them that the two experiences are totally different. It's a matter of scale. Sustaining 4G or more for even 10 seconds, let alone 30 or 60 seconds or more, is an experience that simply cannot be reproduced by any rollercoaster that can fit in a theme park. The effects of the sustained G are DRAMATICALLY different than the one or two second hits (or three or four...whatever) felt on a high performance rollercoaster.
I recently road with my brother on a rollercoaster that I considered to be quite exciting, with corkscrews and consecutive loops, and when it was over he asked me how many G's he thought we had pulled. Based on the sensations I had felt (compared to my years in jets) I guessed 1.5-2. I was surprised to see a brochure later that claimed the ride pulled 6G. The two or three second hits just didn't have time to register.
Another example: a person using an ejection seat pulls an ongodly amount of G -- something like 30 or 60, although the actual number escapes me. Obviously this is enough to kill a man, but the brief time period involved make it survivable. I've known people who ejected and were able to walk around with no problem immediately afterward.
The point is that comparisons to astronauts and race car drivers is misleading. The maximum G must be examined only in conjunction with the period of time over which the G occurs. Brief hits DO NOT COMPARE to sustained G. Maybe rides should be limited and maybe they shouldn't, but the forces faced by astronauts are not part of the debate.
Evil is the money of root.
Yeah - and people who get stoned are really good drivers, too, I suppose?
Well, for some value of really good - see this for details.
Here is a paragraph from the report referenced:
In this context, positive and negative Gs are relative to the body orientation: positive Gs are directed from head to feet; negative Gs are directed from feet to head.
In physics, there may be no difference between positive and negative Gs, but there are definite physiological differences in how the body reacts to positive and negative Gs, and how much the body can tolerate in each direction. Like the previous poster said, negative Gs cause increased blood pressure in the head, which can lead to bursting blood vessels. Contrariwise, positive Gs cause decreased blood pressure (and flow) to the head, and can eventually cause blackouts.