Americas 14,000mph secret transit system, page 7

Originally posted by Badge01
Yeah, it's not g-force that's a limiter.

Originally posted by Badge01
You'd just accelerate slowly and since there are no sharp turns, presumably, the passengers would never feel the speed.

You're right, the passengers wouldn't feel the speed; however, speed and acceleration are two very different things.

Originally posted by Badge01
With pneumatic tubes and a minimum of complexity, I'd think problems of friction and breakdown would be the real limiters of any such system.

That's why a vacuum would be necessary in the tube. It would take far too much energy to pneumatically "push" the VHST with high pressure air.

Originally posted by Badge01
Also, why be so concerned about G-force. There's no need for rapid acceleration or rapid deceleration is there?

There is if you want to reach a very high speed, and then slow back down, within a limited distance.

Originally posted by Badge01
There's no reason that any such system, however fantastic has to go from Zero to 14,000mph or whatever the top speed is (probably about MACH 3 inside a pneumatic tube, though I have no data) besides doing it gradually.

Again, pneumatics work with air pressure. The system would want a vacuum (lack of air pressure) to reduce friction, and to stifle the sonic boom.

Originally posted by Badge01
The only acceleration that pilots experience, after taking off, or in diving or climbing, is turning.

They certainly feel the acceleration if they hit the afterburners, and one doesn't need to climb, dive, or turn to do that. Anytime they accelerate, or decelerate enough (over a limited distance) they'll feel it; and that "limited distance" is proportional to the change in their rate of speed.

Originally posted by Badge01
In addition, please consider doing some research. The fastest G ever experienced was FORTY-SIX G, that's 46G, in a rocket sled and the test pilot John Stapp lived.

I'd kindly suggest that you do the same.

There's no such thing as "The fastest G ever". Speed and acceleration are two different things.

Then there's Kenny Bräck. He survived a crash where his car recorded 214 g. There are also people who survive gunshot wounds, but it's generally not considered to be a good idea to shoot someone; and make no mistake, g-forces can be quite deadly.

Also, the rocket sled was designed to test aggressive deceleration, simulating a crash/stop, not sustained g-forces over a sizeable amount of time. He may have survived high g-s, but they were of very low magnitude. Once the magnitude of time increases, the rules of human tolerances change quite dramatically.

[edit on 3/25/08 by redmage]