But what of tunneled vehicles propelled by large fans. In a sealed tunnel a single fan could easily propel a steady flow of small personal wind driven vehicles over long distances.

Write4U - 28 July 2011 11:50 PM

But what of tunneled vehicles propelled by large fans. In a sealed tunnel a single fan could easily propel a steady flow of small personal wind driven vehicles over long distances.

Hey, what about a gravity train
or in written form

So what was the big deal in Israel?

There’s nothing particularly surprising about a device that can sail downwind faster than the windspeed. I am astounded that some trained professionals didn’t know this. For hundreds of years people have been using a kind of water pump that can take as its input a stream of flowing water and produce as output two streams: one that is flowing faster, at higher pressure than the original stream, and another that is slower and at lower pressure than the original stream. Thus, you can take water from one reservoir and use it to pump a portion of itself into a higher reservoir.

If we roll down the hill and then up again without any friction, we gain zero energy.  But, who cares about gaining energy! 

Instead, if someone else pushes a wave in the pavement on their way to work and back, and we want to catch that wave of wasted energy, then why can’t we put waste to good use?  Solar panels catch the wasted waves from the Sun, that doesn’t bother the Sun at all.  Tidal generators catch the ripples of water from boats, wind.  Waves of energy pushing hot summer asphalt pavement, emitted from heavy buses that stop at the same spot over and over every twenty minutes, the soften pavement recording trough and crest, why not? 

Hey, what about a gravity train

Sounds more like a “Gravy Train” to me…..

jump_in_the_pit - 29 July 2011 12:14 PM

why not? 

Because it doesn’t work, as I have explained many times.

jump_in_the_pit - 29 July 2011 12:14 PM

Waves of energy pushing hot summer asphalt pavement, emitted from heavy buses that stop at the same spot over and over every twenty minutes, the soften pavement recording trough and crest, why not? 

This can’t be considered a wave can it?
It’s a function of dead weight compression, perhaps compounded by a bit of momentum, but not an actual wave function?

But, since you brought it up can anyone here explain the mechanics of “Wash-Boards” on dirt, and softened asphalt roads?

No, that’s not a wave, because it doesn’t travel under its own energy. So long as the buses keep coming in the same way, the wave just gets bigger.

Washboarding is a result of bouncing by vehicles with powered wheels; so long as a car’s drive wheels can bounce upwards from collision with a bump, it will make washboards. The basic mechanics works like this:

The car is traveling along the road. A drive wheel hits a bump; the wheel bounces upward in response. What goes up must come down, so the wheel comes down a smidge later, but by the time it comes down, it has moved forward a short distance. There it hits the road with more-than-usual force, digging in a little harder and, because it’s a drive wheel, pushing a small amount of dirt backwards, right onto the bump that caused it to bounce earlier. That makes the bump higher and the hole following it a little deeper. But now it’s deeper than the normal road surface, so the road surface in front of it looks like a bump to the wheel, so the wheel bounces up again. And so the process repeats.

All of this is affected by a number of variables: the speed of the car, the strength of its shock absorbers and springs, and its weight. And in fact, hitting a washboard at different speeds results in different behavior—but most of it unpleasant. The one speed affect we can be certain of is this: if you drive slowly enough, the drive wheel doesn’t bounce but instead just roles smoothly up and down the bumps. But that usually takes very slow speeds. And if you’re going uphill, you need to maintain a minimum speed or the engine will stall—which is why washboard roads are worst on slopes.