When they open up the StraightDopeland amusement park in suburban Chicago, I’m going to design the Screamin’ Cecil™, the world’s fastest übercoaster. Neither cost, space, available technology, or Illinois building codes are any object.
I want this puppy to go 400 mph. Well, maybe not. But how fast can it go without killing the guests? How fast can a human being travel, in the open air, and still be able to breathe and not have g-forces strong enough to kill them? Let’s assume that I’m not going to give the guests helmets, oxygen masks, pressure suits or anything like that; just their safety harnesses and the open sky. I’d consider giving them goggles, if we start getting into speeds that are survivable but that would cause permanent blindness. I’m assuming that we can alleviate the problem of g-forces by tilting the track downward…
G-forces are only caused by acceleration. The faster you accelerate something the greater the g-forces. Note that acceleration can be speeding up or slowing down or side-to-side. Consider flying in a plane at 580 MPH…you don’t feel a g-force load (except for normal gravity pulling you into your seat).
For positive g-forces I think it is possible to go around 9g or so before blacking out but that’s really pushing it and the person in question needs to actively resist (clenching legs, etc.). I think most people can tolerate 3g or so and maybe 5g would be pushing it for the ubercoaster.
Negative g-forces are harder to resist. I think it only takes -3g for a redout (yes redout…not blackout…everything goes red for you before passing out).
Don’t know how fast you can go and still breathe. Skydivers hit around what…120-180 MPH and they seem to do ok. Just a WAG though.
G-forces are not related to speed. You could be traveling at supersonic speeds and not feel any different G forces than standing still.
There’s a pretty simple solution to the breathing problem, though - it’s possible to design the body of the roller coaster so that while the people on board are technically in an open roller coaster, the air in the sections where the people are is “stuck” to the roller coaster and moves with it.
A more important question would be what wind speed people can be exposed to and survive. That wouldn’t necessarily be the same as what speed an open vehicle they’re traveling in can go at due to the aerodynamics of the vehicle.
There have been a couple instances of people bailing out of airplanes at supersonic speeds and surviving, so the upper limit is pretty high up there. Given the restriction on sonic booms over inhabited areas I think you’ll have to settle for what the laws of man allow rather than the laws of physics. I might also point out that, with one exception that I can think of, these guys all suffered some pretty significant injuries, mostly from the sudden stop at the end of the ride.
Skydivers in the typical “spread eagle” stance generally hit 120 mph, but in other postures can exceed 200 mph, with claims as high as 300 mph.
Roller coasters can reach the 3-5g range in accerlation forces - but personally I find anything much over 2 g’s uncomfortable for any prolonged length of time.
I’d like goggles for this ride, too.
Just to clarify here - are you talking a survivable experience, or one that is gentle enough not to maim?
Well, if you free fall from high altitude, you reach what is called terminal velocity. Its around 120 MPH. Its the speed where a human just falls as fast as he can travel thru the air. His body shape cause drag which limits him to this approximate speed.
At this speed, the skin flaps around the face uncontrollably, eyes will not fucntion without protection and you are still able to breathe however painful it is to scoop air into your nostrils at that speed.
If you situate your body right, you can exceed terminal velocity but you may need a helmet to withstand the forces tearing at your face. A breathing apparatus might be helpful also.
OH, at that speed, water would feel like wet cement so its not survivable to hit anything but air.
Y’might also consider that it’s very possible to travel at extremely high speeds without injury… but to notice, once you’ve stopped, that you’ve gotten mighty windburned…
“Negative g’s” are just g-forces in the “up” direction, therefore making you feel lighter. Imagine “pushing over” in a plane and floating up in your seat. That might be zero g’s. Push over harder, and you get “negative g’s”. About 3 g’s in this direction will force lots of blood up until your head, causing your vision to turn red. It is very uncomfortable, and you can’t really strain against it or relieve it in any way.
As noted, acceleration produces Gs, and a change in direction produces Gs in that direction. The faster you’re going when you do that, the more Gs.
I’d say forget trying for 400 mph without putting these folks in protective gear. The last roller coaster I rode, several weeks ago - whenever the Vegas Dopefest was, was the one at New York, New York. That’s a good ride, but it starts out like most of them - slow, with anticipation building as you clank your way up to the top of the first high point and then… WHOOPEE!!!
Why not make your trademark accelerating the ride from 0-120 mph in 4.0 seconds and then maintaining that throughout a good, modern, twisty, turny, sometimes upside down ride? It’ll be a whole lot easier to do, and will be unusual, and thrilling.
just a thought…if you have slow enough acceleration you could go as fast as you wanted… if it was an open air type thing you could probably only go about 150-200 before bugs and gnats started killing people…
If it was indoors…I guess you could go right up to the point where people started getting burned by the air…
Remember, this is a roller coaster so its not how much can 90% of the population survive 90% of the time. Its what 99.99999% of the population can do without any medical complications (include made up medical conditions) 99.99% of the time. Lawsuits really put a damper on business.
As has been noted, 120 mph is pretty much the lowest possible terminal velocity (i.e. that achieved when falling in the max drag position). Substantially higher terminal velocities are possible (e.g. when falling head-first).
Skin flaps, but not excessively. Eyes function properly, though you’ll be blinking and produce lots of tears without eye protection. Breathing is pretty close to normal - no pain at all.
Helmet is useful, but probably not essential. Breathing apparatus completely unnecessary.