Teen build R5800 death ray that can boil concrete

[Pbartender]

make the water tank of a ceramic that can withstand the focused eneergy

So instead it cracks under the heat differential?

No, really, for that sort of power generation, you're better off having a much wider spot of steady, even heat, than a tightly focused point of extremely high heat.

Now, solar welding, on the other hand...

 

[Scott DeWar]

I was watching the smoke reveal the focus path of the parabolic reflector and it would be myguess you can adjust the position to where you want for the focal dispersion.

though the solar welder idea looks like it would have merit.

 

[Umbran]

I was watching the smoke reveal the focus path of the parabolic reflector and it would be myguess you can adjust the position to where you want for the focal dispersion.

Yes - which is exactly what they do for solar steam turbines.

(Here for an example image)

I was arguing against having such a concentrated point, not against using a parabolic reflector, in general. Of course, if you don't actually need it so perfectly focused, you can use a not-really-parabolic reflector that's cheaper to make, and get the same end results.

I'll say again - the kid didn't do anything technically new there.

though the solar welder idea looks like it would have merit.

With a parabolic reflector, you have the problem that the focal point at which you do your welding is fixed - for a given position of the sun, and a given reflector, you get the maximum heat at only one point in space - if you move the reflector, you lose the heat. You'd have to move the piece you're welding, rather than the welding tool, which is sub-optimal, especially for large construction.

 

[Janx]

yeah, thats not new, other than "on youtube" its been done before.

The tons of mirrors was cool, adding more in a rebuild will probably just yield the same thing but hotter. Which it looks like the original was hot enough.

making each mirror independently auto-track the sun and the target and building an array out of that would give you actual range and duration of burn in a more useful fashion.

Which is what the mythbusters were attempting to do with humans holding the mirrrors.

telescopes can have motors to make them track a point, so that technology can be used on the array itself to track the sun.

What's needed from there is a way to make each mirror shift its angle to reflect the sun optimally to a target, thus always keeping it aligned.

Once you have that, distance isn't a problem given how much energy is in the beam after travelling all the way from the sun and through our atmosphere.

I would suspec the big solar arrays in the desert do this, but the challenge is to come up with a comparable but portable mechanism for the wagon array.

 

[MarkB]

"Unfortunately, the R5800 was completely destroyed in a burning shed on December 13, 2010."

Do you think he left the curtains open?

 

[Umbran]

The tons of mirrors was cool, adding more in a rebuild will probably just yield the same thing but hotter. Which it looks like the original was hot enough.

Adding more mirrors on the same size dish gets you something closer to a continuous mirrored surface, and thus more fine focus.

What's needed from there is a way to make each mirror shift its angle to reflect the sun optimally to a target, thus always keeping it aligned.

Large, multi-mirror telescopes already have this technology, used for slightly different purpose (removing distortion that comes from the atmosphere.

Once you have that, distance isn't a problem given how much energy is in the beam after travelling all the way from the sun and through our atmosphere.

Oh, distance always matters. The parabolic shape is, as I recall, the most perfect one for focusing light from a distant object onto a point, and the parabolic dish has a natural focal point. By making the surface out of many small adaptive mirrors, you can move some away from that focal point without losing a whole lot of the energy, but it isn't like you can aim at something a mile off and expect to burn a hole through it - the farther you are from the natural focal point of the parabola, the less energy you'll be able to deliver.

I would suspec the big solar arrays in the desert do this, but the challenge is to come up with a comparable but portable mechanism for the wagon array.

It is what the big arrays in the dessert do, yes. But making it small and portable and forking for thousands of mirrors isn't a typical shed in the back yard kind of project.

And, even if you did do it - your welder would only work on sunny days.

 

[Pbartender]

And, even if you did do it - your welder would only work on sunny days.

It's always sunny in space...

 

[Joker]

It's always sunny in space...

The Russians constructing nukes on the far side of the Moon disagree with you.

 

[Scott DeWar]

The russians did what?

 

[Janx]

Oh, distance always matters. The parabolic shape is, as I recall, the most perfect one for focusing light from a distant object onto a point, and the parabolic dish has a natural focal point. By making the surface out of many small adaptive mirrors, you can move some away from that focal point without losing a whole lot of the energy, but it isn't like you can aim at something a mile off and expect to burn a hole through it - the farther you are from the natural focal point of the parabola, the less energy you'll be able to deliver.

well, my theory was, if you had the mirrors that could pivot, they'd always be angled to bounce the sun onto the target.

This might be akin (though not technically correct) to having the mirrors on a dish that could flex, becoming flatter or deeper (thus changing the focal point.

the fixed mirrors on a fixed parabola is what gives it a fixed range, which is why distance matters for it.

For a rig with flexi-mounted mirrors, it could change the focal point, thus distance doesn't matter (to the extent they can all be kept aligned)

I got a rough idea on how to keep 1 row or mirrors aligned on a target. But making a larger array of rows with this feature and keeping it portable is trickier.

one random idea:
get a sturdy ring and stretch cloth over it. Then mount the mirrors on that.

Then pull the center of the cloth back, which would cause a curve to form in the material.

I think one of the mythbusters deathray episodes had somebody with something similar. Though there it was like mylar, stretched over a drum, and vacuum presure or something caused it to curve inward, forming an adjustable disk.

I also wonder about the burning of the shed that housed the death ray. Seems a little coincidental that fire making device burns up in a fire. I suspect the kid did something stupid.