Can any of you show calculations for the G-forces at Texas at 220mph and
230mph and how to calculate it?
--
Olav K. Malmin
remove .spam when replying
> Can any of you show calculations for the G-forces at Texas at 220mph and
> 230mph and how to calculate it?
R = turn radius = 750 feet = 228.6 m
If speed = 220 mph = 98.3 m/s, then centrifugal acceleration = 42.3
m/s^2 = 4.3 G's
If speed = 230 mph = 102.8 m/s, then centrifugal acceleration = 46.2
m/s^2 = 4.7 G's
That's lateral acceleration. When you include vertical (i.e., gravity)
and find the vector resultant, you get combined G's of 4.82 at 230 mph,
and 4.43 at 220 mph.
However, we don't have the differential in speed between the
straightaways and the corners, or how much speed is scrubbed off.
But if we assume that a car is doing 230 through the corners, then
relative to the driver's frame of reference, he is feeling a g-force of
about 2.9 g's pushing him down in his seat, and a g-force of 3.9 pushing
him sideways.
I did some digging and discovered that according to a 1964 NASA
document, humans should be able to withstand 3.0 vertical g's for about
2 minutes before blacking out. This would probably be sustained,
constatnt G's.
According to my calcs, 55% of the distance of the track is corners,
banked at 24 degrees. My guess is they spend 60% of the time in the
corners, about 6.5 to 7 seconds in each corner.
So it would appear that the drivers would be typically be subjected to
6.5 or 7 seconds of about 3.0 vertical G's, with a gap between cycles of
about 4 seconds (on the backstratch) and about 6 seconds on the front
stretch. I don't know enough about physiology to know whether the ***
flow to the upper half of the torso is restored within four second or
not. Also consider thatn these guys are sitting almost flat, so the
*** doesn't have to be pump as far vertically.
Either way, it would appear that the drivers are going through vertical
gravitational loading cycles as follows:
3.0 G's for 6.5 seconds
1.0 G's for 6 sseconds
3.0 G's for 6.5 seconds
1.0 G's for 4 seconds, and so on.
The IRL guys are probably seeing about 2.5 vertical G's for about 7
seconds, with similar gaps along the straights.
My only guess is that that sort of cyling of loads isn't good for either
the heart or the brain.
bp
> > Can any of you show calculations for the G-forces at Texas at 220mph and
> > 230mph and how to calculate it?
> Well, centrifugal acceleration = v^2/r.
> R = turn radius = 750 feet = 228.6 m
> If speed = 220 mph = 98.3 m/s, then centrifugal acceleration = 42.3
> m/s^2 = 4.3 G's
> If speed = 230 mph = 102.8 m/s, then centrifugal acceleration = 46.2
> m/s^2 = 4.7 G's
> That's lateral acceleration. When you include vertical (i.e., gravity)
> and find the vector resultant, you get combined G's of 4.82 at 230 mph,
> and 4.43 at 220 mph.
> However, we don't have the differential in speed between the
> straightaways and the corners, or how much speed is scrubbed off.
> But if we assume that a car is doing 230 through the corners, then
> relative to the driver's frame of reference, he is feeling a g-force of
> about 2.9 g's pushing him down in his seat, and a g-force of 3.9 pushing
> him sideways.
> I did some digging and discovered that according to a 1964 NASA
> document, humans should be able to withstand 3.0 vertical g's for about
> 2 minutes before blacking out. This would probably be sustained,
> constatnt G's.
> According to my calcs, 55% of the distance of the track is corners,
> banked at 24 degrees. My guess is they spend 60% of the time in the
> corners, about 6.5 to 7 seconds in each corner.
> So it would appear that the drivers would be typically be subjected to
> 6.5 or 7 seconds of about 3.0 vertical G's, with a gap between cycles of
> about 4 seconds (on the backstratch) and about 6 seconds on the front
> stretch. I don't know enough about physiology to know whether the ***
> flow to the upper half of the torso is restored within four second or
> not. Also consider thatn these guys are sitting almost flat, so the
> *** doesn't have to be pump as far vertically.
> Either way, it would appear that the drivers are going through vertical
> gravitational loading cycles as follows:
> 3.0 G's for 6.5 seconds
> 1.0 G's for 6 sseconds
> 3.0 G's for 6.5 seconds
> 1.0 G's for 4 seconds, and so on.
> The IRL guys are probably seeing about 2.5 vertical G's for about 7
> seconds, with similar gaps along the straights.
> My only guess is that that sort of cyling of loads isn't good for either
> the heart or the brain.
> bp
I would imagine that this was what was happening to the drivers.
Although the loads weren't especially high, the drivers weren't wearing
g-suits, the loads peaked quickly and were repetitive, and the drivers
simply weren't able to sustain their tolerances. With the IRL guys, the
loads were slightly smaller, and probably just as important, the onset
of peak load was more gradual to the lower speeds going into the
corners.
- Jason
| Can any of you show calculations for the G-forces at Texas at 220mph and
| 230mph and how to calculate it?
|
|
> > Can any of you show calculations for the G-forces at Texas at 220mph and
> > 230mph and how to calculate it?
> Well, centrifugal acceleration = v^2/r.
> R = turn radius = 750 feet = 228.6 m
> If speed = 220 mph = 98.3 m/s, then centrifugal acceleration = 42.3
> m/s^2 = 4.3 G's
> If speed = 230 mph = 102.8 m/s, then centrifugal acceleration = 46.2
> m/s^2 = 4.7 G's
> That's lateral acceleration. When you include vertical (i.e., gravity)
> and find the vector resultant, you get combined G's of 4.82 at 230 mph,
> and 4.43 at 220 mph.
> However, we don't have the differential in speed between the
> straightaways and the corners, or how much speed is scrubbed off.
> But if we assume that a car is doing 230 through the corners, then
> relative to the driver's frame of reference, he is feeling a g-force of
> about 2.9 g's pushing him down in his seat, and a g-force of 3.9 pushing
> him sideways.
> I did some digging and discovered that according to a 1964 NASA
> document, humans should be able to withstand 3.0 vertical g's for about
> 2 minutes before blacking out. This would probably be sustained,
> constatnt G's.
> According to my calcs, 55% of the distance of the track is corners,
> banked at 24 degrees. My guess is they spend 60% of the time in the
> corners, about 6.5 to 7 seconds in each corner.
> So it would appear that the drivers would be typically be subjected to
> 6.5 or 7 seconds of about 3.0 vertical G's, with a gap between cycles of
> about 4 seconds (on the backstratch) and about 6 seconds on the front
> stretch. I don't know enough about physiology to know whether the ***
> flow to the upper half of the torso is restored within four second or
> not. Also consider thatn these guys are sitting almost flat, so the
> *** doesn't have to be pump as far vertically.
> Either way, it would appear that the drivers are going through vertical
> gravitational loading cycles as follows:
> 3.0 G's for 6.5 seconds
> 1.0 G's for 6 sseconds
> 3.0 G's for 6.5 seconds
> 1.0 G's for 4 seconds, and so on.
> The IRL guys are probably seeing about 2.5 vertical G's for about 7
> seconds, with similar gaps along the straights.
> My only guess is that that sort of cyling of loads isn't good for either
> the heart or the brain.
> bp
Also, there are little crystals made of Calcium Carbonate inside your inner
ear. They are normally attached to the tips of hairs in the inner ear. These
determine balance and sense of motion. under high G loads, they can break
off, and float freely around in the fluid. This can cause long term vertigo.
--
Design Supervisor
Development Engineering
Nalge Nunc International
75 Panorama Creek Drive
Rochester, NY 14625
> > Can any of you show calculations for the G-forces at Texas at 220mph and
> > 230mph and how to calculate it?
> Well, centrifugal acceleration = v^2/r.
> R = turn radius = 750 feet = 228.6 m
> If speed = 220 mph = 98.3 m/s, then centrifugal acceleration = 42.3
> m/s^2 = 4.3 G's
> If speed = 230 mph = 102.8 m/s, then centrifugal acceleration = 46.2
> m/s^2 = 4.7 G's
> That's lateral acceleration. When you include vertical (i.e., gravity)
> and find the vector resultant, you get combined G's of 4.82 at 230 mph,
> and 4.43 at 220 mph.
> However, we don't have the differential in speed between the
> straightaways and the corners, or how much speed is scrubbed off.
> But if we assume that a car is doing 230 through the corners, then
> relative to the driver's frame of reference, he is feeling a g-force of
> about 2.9 g's pushing him down in his seat, and a g-force of 3.9 pushing
> him sideways.
> I did some digging and discovered that according to a 1964 NASA
> document, humans should be able to withstand 3.0 vertical g's for about
> 2 minutes before blacking out. This would probably be sustained,
> constatnt G's.
> According to my calcs, 55% of the distance of the track is corners,
> banked at 24 degrees. My guess is they spend 60% of the time in the
> corners, about 6.5 to 7 seconds in each corner.
> So it would appear that the drivers would be typically be subjected to
> 6.5 or 7 seconds of about 3.0 vertical G's, with a gap between cycles of
> about 4 seconds (on the backstratch) and about 6 seconds on the front
> stretch. I don't know enough about physiology to know whether the ***
> flow to the upper half of the torso is restored within four second or
> not. Also consider thatn these guys are sitting almost flat, so the
> *** doesn't have to be pump as far vertically.
> Either way, it would appear that the drivers are going through vertical
> gravitational loading cycles as follows:
> 3.0 G's for 6.5 seconds
> 1.0 G's for 6 sseconds
> 3.0 G's for 6.5 seconds
> 1.0 G's for 4 seconds, and so on.
> The IRL guys are probably seeing about 2.5 vertical G's for about 7
> seconds, with similar gaps along the straights.
> My only guess is that that sort of cyling of loads isn't good for either
> the heart or the brain.
> bp
Seems awfully high to me (for the vertical direction), what's the banking
angle at Texas? If the banking was as high as 20 degrees, you'd need a 7.4g
acceleration along the ground plane to reach this high (unless I'm having a
brain fart right now :-)). I timed the cars through corners at Indy once,
long, long ago. If I remember right, they were pulling roughly 2.8g lateral.
I'd imagine that's pretty scary at 220+ mph!
Todd Wasson
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