Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Hyperloop lets you travel on a resonant acoustic wave?

conscienceofanentrepreneur.blogspot.com

Post reply on HN
Print view View original

41–50 of 93 posts

Re: Hyperloop lets you travel on a resonant acoustic wave?

#41

Post by deletes »

speeq wrote: post #8

"Elon Musks final invention will be a time machine. It will only work once before exploding. Before entering it, Elon will turn around and tell us he has done his duty and given us many gifts, and now we must use those gifts to advance mankind. He hopes great things for us. We beg for him to stay and aid us further. He smiles sadly, He looks at us with his tired but happy eyes, shakes his head, and steps into the mac…

Since he would be rather old when going back in time, wouldn't he rather pass his knowledge to his younger self and then iterate the process to obtain the ultimate laws of the universe.

Re: Hyperloop lets you travel on a resonant acoustic wave?

#42

Post by niels_olson »

As a surfer, let me volunteer that it's a bit like a highway onramp: you want to match speed exactly when the front arrives. Tiny adjustments in speed, pitch, yaw, roll, and center of gravity make the difference between making it, falling off the back, and getting eaten.

Mistiming your drop leads to bad outcomes that are directly proportional to the kinetic energy of the wave and are inversely proportional to the depth of the water. This is huge kinetic energy with a distance to the wall of, probably, microns. I want to see how this thing works, but oh, Nelly, what a wipe-out!

Re: Hyperloop lets you travel on a resonant acoustic wave?

#44

Post by moocowduckquack »

bjornsing wrote: post #29
lnanek2 wrote: post #25

Earlier quoted context omitted.

I don't think there is any distinction. He's just reblogging. He did link the original at least.

Not so, I felt it with my own gut! Another difference is in Charles' model you would have to travel at the speed of sound. Due to the shape not being a perfect line airflow will have to be supersonic somewhere over the surface of the craft. That's generally not good for energy efficient travel. My "design" allows for the capsule traveling at subsonic speeds.

I suspect that design by gut is not necessarily a reliable approach to this.

Re: Hyperloop lets you travel on a resonant acoustic wave?

#45

Post by foobarqux »

moomin wrote: post #27

Not to be funny, but it seems like every other day has another "hyperloop uses acoustic waves" article. It's a good guess, but it doesn't even contain new speculation (another article went into detailed theorising about how cars would accelerate and decelerate). Seriously, until we have a solid info, or even a new guess, can we lay off Hyperloop?

I wouldn't mind the article if it contained some kind of real analysis as to feasibility from a physics and engineering perspective. That type of analysis would be interesting independent of hyperloop.

Re: Hyperloop lets you travel on a resonant acoustic wave?

#48

Post by [deleted] »

jessriedel wrote: post #19

I can't figure out how the OP proposal differs from Charles Alexander's. Low frequency (long wavelength) waves travel around the tube at the speed of sound. By traveling at the same speed, and correctly choosing a point along the wavefront, one can take advantage of significantly reduced apparent drag. It's implicit in Alexander's suggestion that either (a) the total length of the loop is an integer multiple of the w…

[deleted]

Re: Hyperloop lets you travel on a resonant acoustic wave?

#49

Post by rorrr2 »

dkrich wrote: post #37
dhughes wrote: post #10

6,437km/h (4,000mph) to zero is going to be one hell of a stop.

Yeah, where did you get those numbers? The distance from SF to LA is about 380 miles, and the speed of sound is about 760 mph. Whether or not the principles of sound movement are involved in Musk's plan, the speed is roughly equivalent if we're talking traveling back and forth in half an hour. Still a jolt, but you're talking about six times that.

Either way, pretty much any accident will result in everyone's death.

Car accidents at 50 MPH result in 80% death.

760 MPH is much much much more, considering the amount of energy needed to be dispersed grows quadratically (E = 0.5 * m * v^2)

Re: Hyperloop lets you travel on a resonant acoustic wave?

#50

Post by PaulHoule »

foobarqux wrote: post #45
moomin wrote: post #27

Not to be funny, but it seems like every other day has another "hyperloop uses acoustic waves" article. It's a good guess, but it doesn't even contain new speculation (another article went into detailed theorising about how cars would accelerate and decelerate). Seriously, until we have a solid info, or even a new guess, can we lay off Hyperloop?

I wouldn't mind the article if it contained some kind of real analysis as to feasibility from a physics and engineering perspective. That type of analysis would be interesting independent of hyperloop.

Worst of all this article is just a rip-off (a paraphrasing) of another article. He is kind enough to point to the original article, but he isn't adding anything new, just putting the old wine in new bottles.
Post reply on HN