typodupeerror

## Comment Re:Watts is not energy (Score 1)262

There's no 4.6 anything. A 15 second braking of a 6 ton vehicle from 160mph to a stop dissipates 1MW (1,000 kilo Watts) on average. The vehicle energy at 160mph is 15MJ (15,000,000 Joules). The energy at 1000mph is 0.6GJ (600,000,000 Joules). The 4.6 is someone's figment of imagination.

## Comment Re:Stronger? (Score 1)262

It wouldn't solve anything, because you have no clue about mechanics of such composite assemblies. Just forget it. There is no rotor issue. Remember that the article doesn't mention any issues at all. They managed to shatter a carbon disk that wasn't designed for the job. Big deal. There are no other problems at all. It's just sensationalism and innuendo. Get over it.

## Comment Re:Stronger? (Score 1)262

So, to anyone dumb enough to propose regen braking: take a good look at the size and weight of a 1MW generator, even a small duty cycle one, even water-cooled.

## Comment Re:Stronger? (Score 1)262

Let's get some perspective.

A well-loaded SUV doing pedal-to-the-metal ABS emergency braking from 100mph on dry pavement with summer tires can easily hit 1MW total braking power.
A passenger car doing some only mildly distracted late braking in city traffic easily pulls off 50kW braking power.
An old grandma's scooter can easily exceed 5kW of braking power in city traffic.

The 4.6kW figure is a typo, and anyone who takes it on face value is silly. I don't know where the heck it came from. A 6 ton vehicle doing 15 second braking from 160mph to stop needs to dissipate 1MW.

All figures are average power per vehicle, not per brake. Uneven braking will produce higher peak power.

## Comment Re:Stronger? (Score 1)262

So, let me think. A simple chunk of metal that heats itself by friction, vs. a generator and a bunch of resistor coils. Yes, I thought so. Proposing regen braking for this project is insane. BTW, who the heck told you that heating is a problem? Disc brakes work just fine. On my wife's car, on dry pavement, I can hit 1MW of braking power for a second or two, no biggie. Braking a 6 ton vehicle from 160mph is no problem for disc brakes. Let me repeat: braking is not a problem at all. It's the survivability of a brake disc that wasn't necessarily designed for operation in enterprise hard drive spindle type of a job. A major problem with off-the-shelf brake discs in this application is fatigue cracking. They have various holes and radii that are not designed for the hard drive spindle operation called for here. The whole article is IMHO a big fat decoy, most likely an inadvertent one - due to ignorance, not malice.

## Comment Re:Killowatts are power, not energy (Score 1)262

Do you really need to write like an american teenager?

brakes, not breaks
braking, not breaking
their, not there

Sheesh :)

## Comment Re:Killowatts are power, not energy (Score 1)262

The hard part is going to be making the brakes survive spinning at 10,000rpm, not dissipating the energy from slowing down.

Finally someone who gets it :) But that's not even the hard part. The hard part is making a much larger diameter wheel that will survive this. The brake disc is, comparably speaking, peanuts.

## Comment Re:Killowatts are power, not energy (Score 1)262

"There are 100 ways I can think of for stopping a car without having brake disks."

You miss the forest for the trees. The article is just mumbo-jumbo. The wheel itself is a much larger diameter metal structure, subject to much larger stresses. Since the wheel isn't a problem, seemingly, then the friction disc brake isn't either. Remember that the disc brake doesn't have to operate at 1000mph, and doesn't have to endure the high centrifugal forces while being hot. Operation at 160mph is peanuts. Why did they goof and go with carbon discs I don't know, but the brakes aren't an issue at all. If the wheel survives, a similarly constructed brake disc will, too. The entire reason for having a separate braking disc and not using the wheel itself is the wear. The wheel has much larger diameter than the brake disc, so any braking wear on its circumference would require wheel rebalancing. That's an expensive, time consuming operation, since the wheel has to be balanced better than a hard drive spindle is balanced.

## Comment Re:Killowatts are power, not energy (Score 2)262

Of course if you actually looked at what you propose you'd realize that any inductive system still needs to use bulky rotors. It's the rotor's survivability that is the problem. The fact that it's a friction brake is rather inconsequential here. It's not the braking that is the problem. It's mere survivability of a disc brake at rotational speeds of an enterprise hard drive.

## Comment Re:Killowatts are power, not energy (Score 1)262

They do, although they are not really called cars anymore. The problem isn't 160MPH nor 6 tonnes. The problem is that the brakes have to survive "storage" (not braking) at 10kRPM, since the car will be going ~1000mph at some point. Everyone is focusing at the low speed or relatively forgettable weight. Those are not the problems, even my "little" Volvo XC90, when loaded, weighs about 2.5 tonnes, and I'm sure its brakes would survive slowing it down from 160MPH with a 3 ton brakeless trailer attached to it. Meh. But I don't really know if the front brake discs would survive being spun up to 10kRPM.

## Comment Re:What surveillance equipment? (Score 1)304

A Piston console with a bit of external storage is probably all one needs. It'd be physically very, very small.

## Comment Re:USA, the land of freedom (Score 1)304

It's much easier than it was in the year 2000, as far as I can tell. There are quite a few products at the local dollar store that are, in fact, made in the U.S.A. Same goes for home improvement stores - I've started to find U.S.-made tools.

## Comment Re:Complex rules == easily gamed systems (Score 1)143

Assuming that you have an internet connection and a networked printer at those locations, something like eFax would make much more sense. Or just set up your own Asterisk at some central location, use a T-38 VOIP provider, and send the print jobs to printers "out there".

## Comment Re:Teensy 3.1 is cooler (Score 1)138

Heck, I don't even know who would need solder paste without actually using a laser-cut stencil and, you know, actually printing the paste like it was meant to be - in quantity? What's the point? You don't even need or want a fine-tipped soldering iron. For reflowing anything with leads, you in fact want a nice 3mm-5mm wide, short tip with good thermal conductivity. You don't need solder paste, you do need a flux pen .

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