I read that Boeing ran all the hydraulic lines along the trailing edge of the wing rather than the leading edge
Entirely possible, but that would have had nothing to do with the accident. It was the *tail* engine that threw a compressor disc, and severed the hydraulic lines where they ran through the tail.
The less obvious lesson of that disaster is to have multiple ways to let the operator know what's going on. The pilot lost some sensors and instruments when the engine peeled off.
I'm not sure what flight you're talking about. When you lose all hydraulic controls, you notice instantly. The engine didn't peel off, it essentially exploded. The only way they could steer the aircraft was by differential throttle inputs to the left and right engines. That anyone survived at all, let alone something like half the people on board, was purely because of the skill of the folks who were on the aircraft that day.
Look, Tom's hardware used to be a useful site. It's not anymore. Stop posting their paginated ad-cancer garbage until they realize that so long as they make their stuff intentionally difficult to read, people won't read it.
Huh? All the uranium centrifuge operations I'm familiar with use uranium hexafluoride gas. You dissolve the actual uranium in nitric acid, generating uranyl nitrate in solution. You extract the nitrate from the solvent, treat it with ammonia, reduce it to uranium dioxide with hydrogen, treat it again with hydrofluoric acid (UF4 now) and and oxidize it with fluorine gas to produce UF6, which is a gas at much, much lower temperatures and pressures than pure uranium.
Why on earth would you boil the stuff? You've have to keep it hot in the centrifuges.
The idea was never to coat the walls in lithium. The idea is that neutrons that escape the vessel will be trapped in a surrounding *blanket* of lithium. Lithium *inside* the reactor vessel would do nobody any good.
Residental power in the US is ~220 at the pole, brought into the house that way, and split into ~110VAC circuits
There's nothing you can touch in a US house that's going to be at 220V to ground. Two legs are brought in, along with a neutral, and the two legs are 180 degrees out of phase with respect to each other. So if you want 220V, like for a dryer or a stove, you take both legs, and you have 220V between them, but each one is only 110V wrt ground.
And it's not 110 at the pole, either. It's 110 when it comes out of the transformer, the line voltage at the pole is usually around 3 kV.
The likelyhood of it being a comercially viable energy source is very high.
No, I don't think it is, and I don't think anyone can say that with any certainty.
I tend to class problems in three general ways:
1. Theoretical problems: We're not sure if this is even *possible*. e.g. FTL travel 2. Materials problems: We think this is possible, but we don't know what to build it out of. e.g. a space elevator. 3. Engineering problems: We know this can work, we know how to make it, we just have to work out the nuts and bolts. e.g. The Manhattan project.
Depending on the particular scheme in mind, commercial fusion is all three.
1. There are a wide variety of fusion schemes (the various aneutronic cycles, all cycles in thermal non-equilibrium), that are simply theoretically impossible to generate net energy from. Even plain old D-T fusion is *theoretically* hard; sure, we know it's possible, but getting it to proceed at a rate sufficient for useful net energy extraction might just be intractable. 2. What do you build the reactor vessel out of? You need something that can survive the 300-500 displacements *per atom* that it will experience from neutron collisions over the lifetime of the reactor. No such material is known; ITER will generate only one hundredth of that sort of neutron flux, so it can't even adequately explore the issue. There's another test facility intended to do that, but it's doesn't even exist on blueprints yet. Again, proper materials just might not exist, so you might have to replace the reactor vessel inner surface every few years, which dramatically increases the costs of the scheme and makes it much less viable commercially. 3. Everything else, and there's a lot of it, sits here. And there are some pretty big engineering problems as well, but yeah, those aren't show-stoppers. How do you get the energy out? How do you turn a flood of 14 MeV neutrons into electricity?
It's not theoretically 0, it's really actually 0. It's a macroscopic manifestation of a quantum-level effect. In high-temperature superconductors, there is a finite resistance, but in 'classical' superconductors, it's really zero: current flows with no applied voltage.
The problem with superconductors as a transmission line isn't so much the temperature (although that is a problem). It's not even the materials properties (high-temperature superconductors are basically ceramics. They're brittle and not very strong, which means they aren't very useful as wires). It's the fact that, in addition to a critical temperature Tc above which they don't superconduct, superconductors also have a critical magnetic field and a critical current density. Exceed any of those, and they stop being superconductors, which can lead to some quite catastrophic failures. High-temperature superconductors have much higher critical field strengths than low-temperature ones, and higher critical current densities, but you can't just run all the current you want through them and expect them to not blow up/melt/spontaneously disassemble.
I think you could take care of inductive and capacitive losses by going to DC.
This is, in fact, what is done for long-haul lines. The disadvantage if that you need to convert at either end, but as the transmission line length increases, there comes a point where it's more cost-effective to do that than it is to run AC and lose efficiency charging and discharging a big capacitor 60 times a second. And thyristors have gotten a lot cheaper. You also avoid corona discharge, dielectric losses, and so forth. But you've still got to have at least a couple of hundred miles of transmission line to make it worth it, so you only see it in the longer runs (or underwater, where the capacitive losses are much higher.)
Fusion produces orders of magnitude more neutrons.
In a fission plant, excess neutrons are bad. You want the pile to be barely critical, a stable, but not runaway, chain reaction. So you actually don't have a lot of neutrons flying out of the pile. You moderate the ones you do produce, and use them to fission additional fuel atoms.
But in a D-T fusion scheme, the bulk of the liberated energy is produced in the form of a very energetic 14 megaelectron-volt neutron. And this neutron doesn't participate in additional reactions, DT fusion isn't a chain-reaction process like fission is. The neutron will leave the plasma. Heck, ideally, that's how you get energy out of the reactor, by trapping that neutron in a surrounding blanket, causing that blanket to heat up so you can use that heat to boil water. Every single D-T fusion generates one of these neutrons, so the neutron flux will be many many times that of a fission plant.
But that's not an issue because of "radioactive waste." The wastes we're concerned about from fission aren't neutrons, they're from fission fragments and decay daughters. Some of those might emit neutrons themselves, but really, that's not the primary concern; neutron-induced radioactivity is actually pretty short-lived.
The reasons neutrons are a concern in a fusion plant is that continuous high-energy neutron bombardment does very bad things to all known materials that you might want to build a reactor vessel out of. When a neutron strikes an atom, it displaces it within the crystal lattice. If that happens once, no big deal, but in a commercial fusion reactor, the reactor vessel will experience 300 to 500 displacements per atom over the lifetime of the device. That means that, right now, we don't even know what to build one of these things out of. Austinitic steels start to swell, crack, and degrade after only about 30dpa, and the very best candidate materials we know of can only handle about 150; those might be acceptable, if the cost of changing the inner wall out isn't too high, but we just don't know.
And ITER won't even begin to explore those issues. ITER's flux will only generate 3 displacements per atom.
Fusion is very very hard. My money says that we'll never use commercial fusion power.
After you get over the initial "thrill" of a force-feedback experience
And it's not like it's any kind of credible feedback, anyway. There's an unbalanced weight that spins around, and it's either on, or it's off. That's not feedback anymore than a light going on would be feedback.
I mean, I've done the following:
Driven a car; driven a truck; flown in a CH-47 helicopter; gone skiing; gone mountain biking; gone sailing; ridden a jet-ski; ridden a dirt bike; driven a 3-wheeler; fired guns; set off high explosives.
In none of those things have I ever experienced anything that's even vaguely similar to the sensation of a rumble pack rumbling. It seriously might as well be beeping at me for all the 'feedback' it's providing.
Wow, does their motion-sensing controller seem like a horrible idea.
First, they dismissed the Revolution controller as a gimmick. That's fine, their prerogative to do so and all that. But then shutting up about it for a while and announcing "Hey guys, our controller does that gimmick also!" makes it sound like a last-minute hack rather that the product of a conscious and reasoned set of design priorities.
Second, the Wii controller was designed from the ground up to "sense movement, allowing the player to move an onscreen avatar 'naturally'." The shape, the button placement, the flying dongle, all are part of that design. Sony seems to have just taken their standard two-handed controller and added motion sensors to it. I can't even imagine how you'd grab that controller and move it to swing a sword or aim and gun and have it seem 'natural.'
The 2-second delay is normally a little thing called "autofocus".
Nope. That shutter delay with point-and-shoot digital cameras is due to the fact that the CCD is forced to do double-duty to get the live preview on the LCD viewfinder. When you hit the shutter release, it needs to switch modes, and get ready to capture shutter-speed's worth of incoming light.
DSLRs have autofocus as well, and when you press the shutter release, there's no lag. It just takes the picture, because you weren't already using the CCD to feed an LCD so you can compose the shot.
P&S cameras are getting better in this regard, however. But the lag that's there, isn't there because of autofocus.
Gasoline engines are restricted by the tolerances of their mechanical parts
Well, so's an electric drivetrain. The big difference is the torque curve. An internal combustion engine at 0 rpm stalls out, providing absolutely 0 torque, so you need some way to couple non-rotating parts (red light!) to an engine that has to idle at some minimum rpms. And then the engine delivers more torque as you spin it up.
Electric motors deliver their maximum torque at 0 rpm, and then it drops off as mechanical friction starts acting as a parasite. And since you don't need to worry about mating non-rotating to rotating parts, your drivetrain can be more efficient overall, since you can get out some of the lossy linkages.
You're right. This is nothing new. I saw a video online of an all-electric car beating a Ferrari off the line years and years ago (And not just beating, dominating). But at the end of the quarter-mile it needed a recharge. There are a lot more obstacles to electric cars replacing IC cars than just performance.
Since a turboshaft is just a turbojet with these extra components
No, that's a gross oversimplification. The bypass ratio of a high-thrust jet engine and that of a high-torque helicopter engine are entirely different, and you don't change that significantly with the described modifications. He's still got an engine designed to produce a lot of shaft horsepower, and you don't get a lot of thrust out of that just because you remove the shaft.
I mean, come on. He doesn't have the engine actually hooked up to any gears to turn the wheels. He just has it mounted on the back of the car, and he's relying on the engine thrust to push the car along.
Trouble is that that kind of engine isn't designed to do that. It's a T-58 engine, a turboshaft engine off of a helicopter. While the engine on a jet is designed to shoot lots of hot air out the back, producing thrust to drive the jet forward, turboshafts are designed to, well, turn a shaft, to turn a rotor blade. In other words, they're torquey, not thrusty, and helicopters don't go fast because of the engine exhaust, they go fast because of the rotor.
I was looking to buy a (ex-Soviet) MiG 15 or MiG 17 jet engine.
He'd have been far better off doing that. The engine off a MiG-17 develops 6,000 ft-lbs of thrust.
I mean, look what kind of performance he gets with his 1500-horsepower jet engine:
He said that a jet-boosted run will "pin the speedometer and that's at 140." He thinks that when it hits 160 mph -- he hasn't seen that... yet -
140? My 300-horsepower Mustang GT is perfectly capable of hitting 140, and would probably do 160 if a governor doesn't kick in. 1500-horsepower is the power of the gas turbine in an M-1 tank; if he had this thing hooked into the drive wheels, he'd go like a bat out of hell. But as it is, all he's doing is making a lot of noise.
Which I mean is fun and all, but fundamentally, he doesn't have a jet-powered car. He's got a car with a jet engine in the trunk.
According to our latest poll, at time of writing 74% of Whitedust readers believe that Wal-Mart have manipulated Wiki.
A purported *security* company thinks this is valid evidentiary support? "The lurkers support me in email" is even lamer in the real world than it is on Usenet.
Sorry, but all your saying is you might (if you are lucky) survive the first ball bearing.
Nope. What I am saying is that there are ways to deal with ball bearings in LEO. Your assertion that it's not possible to armor against the energy levels involved is nonsense. In fact, for the energies involved actual penetration levels are very low; the impactor vaporizes in very short order, creating a wide, shallow crater, so several inches of steel over the vulnerable bits on the frontal side of a satellite would actually serve to protect against a number of impacts. And I think you seriously underestimate how many ball bearings you'd need to put up there to reliably score repeated hits against anything in LEO.
And again, yes, I'm aware that having to launch that much additional mass would drastically increase launch costs. If we could get the same intel at a lower cost or greater reliability with things-other-than-satellites, fine, we'd do that.
They fact is they are a limited number of useful orbits for any particular target area on the earth.
"Useful" is not a binary condition. There are orbits that are more useful than others, but for a given location on the surface there are a large number of orbits that can put a satellite over the horizon above it at regular intervals.
There is a reason they want lasers to take out 'enemy' satellites... if avoids creating debris
Um...no. That's not at all certain. Maybe you can just cook off the solar arrays or antennas, but by and large lasers damage targets via plain old delivery of mechanical force in the form of shear stress. Hit a propellant tank, and you're definitely going to create debris.
The advantage to a laser lies chiefly in the fact that if the satellite's over the horizon, you can hit it, and keep hitting it until it's destroyed.
And it'd probably be good against ball bearings, too.
Wrong. The test "failed" in that the military didn't get all the data they were looking for. The test succeeeded in that it *actually disabled the satellite*. I mean, since you're so quick with the Wikipedia links, I'd have thought you'd have clicked through to MIRACL from the page you linked to:
In 1997, amid much controversy, MIRACL was tested against a US Air Force satellite in orbit. The satellite was disabled but the Air Force did not get the data from the satellite it had hoped for.
It didn't destroy the satellite, but they also weren't firing at full-power.
Seriously, are you actually claiming that you can't propagate EM waves through a medium once the strength of the E field becomes greater than the dielectric strength of the medium? Are you *high*? Who taught you EM theory? Seawater has a dielectric strength of essentially zero, what with all those dissolved ions, and high-power lasers propagate through it just fine.
Blooming is a problem. But what causes it is *energy density*. When you get more than about a megajoule/cm2, that's when you start losing energy to blooming. But you don't have to build "lots of little lasers" to prevent that. What's far easier, and what is actually done by people who, you know, build these things, is to use shorter laser pulses or wider beams/lasing cavities/mirrors. Keep the pulse short enough, and blooming doesn't have time to start. Widen the beam enough, and you keep things below that critical density.
Saying "You can't do this because of blooming" is like saying "You can't fly faster than the speed of sound because of friction!" It's a problem, a loss of efficiency, you need to take it into account when you build. But it's not a show-stopper like you're claiming. THEL, which isn't an ASAT platform but is instead a point-defense against short-range threats, has had considerable success shooting down things like missiles and artillery shells without being stopped by blooming.
You can't armour against anything travelling at those velocities except in science fiction.
Utter nonsense. LEO requires an orbital velocity of about 8km/s. So double that for your opposite-direction impact. Call density of steel about 8g/cc, call the ball bearings.6875" diameter, that's a mass of 22 grams, that's an impact energy of 2.815 megajoules.
Yes, we can in fact armor against those energies. That's about 600 grams of TNT. But not quite, because it won't penetrate anywhere near as well as 600 grams of high explosive formed into a shaped charge. Even several inches of steel plate would serve well; like I said, it's certainly not as good as not having to deal with the problem (higher costs to orbit, lower lifetime, higher chance of occasional total failure, etc), but to claim there's no solution possible is asinine.
'Cheap' satellites that survive for a fraction of a second is just a silly idea
I said fraction of an orbit, not fraction of a second. I'm pretty sure if anyone tries launching enough ball-bearings to so saturate LEO that nothing could survive for longer than a fraction of a second, we'd notice.
And once you get beyond LEO, space is big. Really, really big. Having to put satellites into higher orbits would, again, not be as desirable as not having to, but it's certainly not insurmountably difficult, either.
You cannot generate a laser beam powerfull enough to destroy a satellite from the ground. IF you tried you would just make a lot of plasma in the air above your laser.
You. Are. Fucking. High. Learn2physics, kthx.
Here in the real world, the one in which people actually understand electromagnetic propagation through a medium, MIRACL, a megawatt-class deuterium-fluoride chemical laser, successfully disabled a satellite in orbit almost 10 years ago.
Slashdot Mirror
I read that Boeing ran all the hydraulic lines along the trailing edge of the wing rather than the leading edge
Entirely possible, but that would have had nothing to do with the accident. It was the *tail* engine that threw a compressor disc, and severed the hydraulic lines where they ran through the tail.
The less obvious lesson of that disaster is to have multiple ways to let the operator know what's going on. The pilot lost some sensors and instruments when the engine peeled off.
I'm not sure what flight you're talking about. When you lose all hydraulic controls, you notice instantly. The engine didn't peel off, it essentially exploded. The only way they could steer the aircraft was by differential throttle inputs to the left and right engines. That anyone survived at all, let alone something like half the people on board, was purely because of the skill of the folks who were on the aircraft that day.
40 pages?
Fourty. Fucking. Pages?
Look, Tom's hardware used to be a useful site. It's not anymore. Stop posting their paginated ad-cancer garbage until they realize that so long as they make their stuff intentionally difficult to read, people won't read it.
They're not trying to legislate away social problems. They're trying to protect their monopoly.
Remember, kids! Gambling is wrong, unless it generates revenue for the state!
Boiling uranium?
Huh? All the uranium centrifuge operations I'm familiar with use uranium hexafluoride gas. You dissolve the actual uranium in nitric acid, generating uranyl nitrate in solution. You extract the nitrate from the solvent, treat it with ammonia, reduce it to uranium dioxide with hydrogen, treat it again with hydrofluoric acid (UF4 now) and and oxidize it with fluorine gas to produce UF6, which is a gas at much, much lower temperatures and pressures than pure uranium.
Why on earth would you boil the stuff? You've have to keep it hot in the centrifuges.
The idea was never to coat the walls in lithium. The idea is that neutrons that escape the vessel will be trapped in a surrounding *blanket* of lithium. Lithium *inside* the reactor vessel would do nobody any good.
Residental power in the US is ~220 at the pole, brought into the house that way, and split into ~110VAC circuits
There's nothing you can touch in a US house that's going to be at 220V to ground. Two legs are brought in, along with a neutral, and the two legs are 180 degrees out of phase with respect to each other. So if you want 220V, like for a dryer or a stove, you take both legs, and you have 220V between them, but each one is only 110V wrt ground.
And it's not 110 at the pole, either. It's 110 when it comes out of the transformer, the line voltage at the pole is usually around 3 kV.
The likelyhood of it being a comercially viable energy source is very high.
No, I don't think it is, and I don't think anyone can say that with any certainty.
I tend to class problems in three general ways:
1. Theoretical problems: We're not sure if this is even *possible*. e.g. FTL travel
2. Materials problems: We think this is possible, but we don't know what to build it out of. e.g. a space elevator.
3. Engineering problems: We know this can work, we know how to make it, we just have to work out the nuts and bolts. e.g. The Manhattan project.
Depending on the particular scheme in mind, commercial fusion is all three.
1. There are a wide variety of fusion schemes (the various aneutronic cycles, all cycles in thermal non-equilibrium), that are simply theoretically impossible to generate net energy from. Even plain old D-T fusion is *theoretically* hard; sure, we know it's possible, but getting it to proceed at a rate sufficient for useful net energy extraction might just be intractable.
2. What do you build the reactor vessel out of? You need something that can survive the 300-500 displacements *per atom* that it will experience from neutron collisions over the lifetime of the reactor. No such material is known; ITER will generate only one hundredth of that sort of neutron flux, so it can't even adequately explore the issue. There's another test facility intended to do that, but it's doesn't even exist on blueprints yet. Again, proper materials just might not exist, so you might have to replace the reactor vessel inner surface every few years, which dramatically increases the costs of the scheme and makes it much less viable commercially.
3. Everything else, and there's a lot of it, sits here. And there are some pretty big engineering problems as well, but yeah, those aren't show-stoppers. How do you get the energy out? How do you turn a flood of 14 MeV neutrons into electricity?
in some cases theoretically 0)
It's not theoretically 0, it's really actually 0. It's a macroscopic manifestation of a quantum-level effect. In high-temperature superconductors, there is a finite resistance, but in 'classical' superconductors, it's really zero: current flows with no applied voltage.
The problem with superconductors as a transmission line isn't so much the temperature (although that is a problem). It's not even the materials properties (high-temperature superconductors are basically ceramics. They're brittle and not very strong, which means they aren't very useful as wires). It's the fact that, in addition to a critical temperature Tc above which they don't superconduct, superconductors also have a critical magnetic field and a critical current density. Exceed any of those, and they stop being superconductors, which can lead to some quite catastrophic failures. High-temperature superconductors have much higher critical field strengths than low-temperature ones, and higher critical current densities, but you can't just run all the current you want through them and expect them to not blow up/melt/spontaneously disassemble.
I think you could take care of inductive and capacitive losses by going to DC.
This is, in fact, what is done for long-haul lines. The disadvantage if that you need to convert at either end, but as the transmission line length increases, there comes a point where it's more cost-effective to do that than it is to run AC and lose efficiency charging and discharging a big capacitor 60 times a second. And thyristors have gotten a lot cheaper. You also avoid corona discharge, dielectric losses, and so forth. But you've still got to have at least a couple of hundred miles of transmission line to make it worth it, so you only see it in the longer runs (or underwater, where the capacitive losses are much higher.)
Fission also produces neutrons.
Fusion produces orders of magnitude more neutrons.
In a fission plant, excess neutrons are bad. You want the pile to be barely critical, a stable, but not runaway, chain reaction. So you actually don't have a lot of neutrons flying out of the pile. You moderate the ones you do produce, and use them to fission additional fuel atoms.
But in a D-T fusion scheme, the bulk of the liberated energy is produced in the form of a very energetic 14 megaelectron-volt neutron. And this neutron doesn't participate in additional reactions, DT fusion isn't a chain-reaction process like fission is. The neutron will leave the plasma. Heck, ideally, that's how you get energy out of the reactor, by trapping that neutron in a surrounding blanket, causing that blanket to heat up so you can use that heat to boil water. Every single D-T fusion generates one of these neutrons, so the neutron flux will be many many times that of a fission plant.
But that's not an issue because of "radioactive waste." The wastes we're concerned about from fission aren't neutrons, they're from fission fragments and decay daughters. Some of those might emit neutrons themselves, but really, that's not the primary concern; neutron-induced radioactivity is actually pretty short-lived.
The reasons neutrons are a concern in a fusion plant is that continuous high-energy neutron bombardment does very bad things to all known materials that you might want to build a reactor vessel out of. When a neutron strikes an atom, it displaces it within the crystal lattice. If that happens once, no big deal, but in a commercial fusion reactor, the reactor vessel will experience 300 to 500 displacements per atom over the lifetime of the device. That means that, right now, we don't even know what to build one of these things out of. Austinitic steels start to swell, crack, and degrade after only about 30dpa, and the very best candidate materials we know of can only handle about 150; those might be acceptable, if the cost of changing the inner wall out isn't too high, but we just don't know.
And ITER won't even begin to explore those issues. ITER's flux will only generate 3 displacements per atom.
Fusion is very very hard. My money says that we'll never use commercial fusion power.
After you get over the initial "thrill" of a force-feedback experience
And it's not like it's any kind of credible feedback, anyway. There's an unbalanced weight that spins around, and it's either on, or it's off. That's not feedback anymore than a light going on would be feedback.
I mean, I've done the following:
Driven a car; driven a truck; flown in a CH-47 helicopter; gone skiing; gone mountain biking; gone sailing; ridden a jet-ski; ridden a dirt bike; driven a 3-wheeler; fired guns; set off high explosives.
In none of those things have I ever experienced anything that's even vaguely similar to the sensation of a rumble pack rumbling. It seriously might as well be beeping at me for all the 'feedback' it's providing.
Foie gras is amazing. It's like warm, meat-flavored butter.
Wow, does their motion-sensing controller seem like a horrible idea.
First, they dismissed the Revolution controller as a gimmick. That's fine, their prerogative to do so and all that. But then shutting up about it for a while and announcing "Hey guys, our controller does that gimmick also!" makes it sound like a last-minute hack rather that the product of a conscious and reasoned set of design priorities.
Second, the Wii controller was designed from the ground up to "sense movement, allowing the player to move an onscreen avatar 'naturally'." The shape, the button placement, the flying dongle, all are part of that design. Sony seems to have just taken their standard two-handed controller and added motion sensors to it. I can't even imagine how you'd grab that controller and move it to swing a sword or aim and gun and have it seem 'natural.'
The 2-second delay is normally a little thing called "autofocus".
Nope. That shutter delay with point-and-shoot digital cameras is due to the fact that the CCD is forced to do double-duty to get the live preview on the LCD viewfinder. When you hit the shutter release, it needs to switch modes, and get ready to capture shutter-speed's worth of incoming light.
DSLRs have autofocus as well, and when you press the shutter release, there's no lag. It just takes the picture, because you weren't already using the CCD to feed an LCD so you can compose the shot.
P&S cameras are getting better in this regard, however. But the lag that's there, isn't there because of autofocus.
It would be, but unfortunately the 300cc of thermal paste the kit comes with is insufficient for a MacBook Pro, so you'll have to buy extra.
As the motor speed up it generates back-emf which reduces the current thru the motor.
You are entirely correct. My bad.
Gasoline engines are restricted by the tolerances of their mechanical parts
Well, so's an electric drivetrain. The big difference is the torque curve. An internal combustion engine at 0 rpm stalls out, providing absolutely 0 torque, so you need some way to couple non-rotating parts (red light!) to an engine that has to idle at some minimum rpms. And then the engine delivers more torque as you spin it up.
Electric motors deliver their maximum torque at 0 rpm, and then it drops off as mechanical friction starts acting as a parasite. And since you don't need to worry about mating non-rotating to rotating parts, your drivetrain can be more efficient overall, since you can get out some of the lossy linkages.
You're right. This is nothing new. I saw a video online of an all-electric car beating a Ferrari off the line years and years ago (And not just beating, dominating). But at the end of the quarter-mile it needed a recharge. There are a lot more obstacles to electric cars replacing IC cars than just performance.
Since a turboshaft is just a turbojet with these extra components
No, that's a gross oversimplification. The bypass ratio of a high-thrust jet engine and that of a high-torque helicopter engine are entirely different, and you don't change that significantly with the described modifications. He's still got an engine designed to produce a lot of shaft horsepower, and you don't get a lot of thrust out of that just because you remove the shaft.
I mean, come on. He doesn't have the engine actually hooked up to any gears to turn the wheels. He just has it mounted on the back of the car, and he's relying on the engine thrust to push the car along.
... yet -
Trouble is that that kind of engine isn't designed to do that. It's a T-58 engine, a turboshaft engine off of a helicopter. While the engine on a jet is designed to shoot lots of hot air out the back, producing thrust to drive the jet forward, turboshafts are designed to, well, turn a shaft, to turn a rotor blade. In other words, they're torquey, not thrusty, and helicopters don't go fast because of the engine exhaust, they go fast because of the rotor.
I was looking to buy a (ex-Soviet) MiG 15 or MiG 17 jet engine.
He'd have been far better off doing that. The engine off a MiG-17 develops 6,000 ft-lbs of thrust.
I mean, look what kind of performance he gets with his 1500-horsepower jet engine:
He said that a jet-boosted run will "pin the speedometer and that's at 140." He thinks that when it hits 160 mph -- he hasn't seen that
140? My 300-horsepower Mustang GT is perfectly capable of hitting 140, and would probably do 160 if a governor doesn't kick in. 1500-horsepower is the power of the gas turbine in an M-1 tank; if he had this thing hooked into the drive wheels, he'd go like a bat out of hell. But as it is, all he's doing is making a lot of noise.
Which I mean is fun and all, but fundamentally, he doesn't have a jet-powered car. He's got a car with a jet engine in the trunk.
According to our latest poll, at time of writing 74% of Whitedust readers believe that Wal-Mart have manipulated Wiki.
A purported *security* company thinks this is valid evidentiary support? "The lurkers support me in email" is even lamer in the real world than it is on Usenet.
Sorry, but all your saying is you might (if you are lucky) survive the first ball bearing.
... if avoids creating debris
Nope. What I am saying is that there are ways to deal with ball bearings in LEO. Your assertion that it's not possible to armor against the energy levels involved is nonsense. In fact, for the energies involved actual penetration levels are very low; the impactor vaporizes in very short order, creating a wide, shallow crater, so several inches of steel over the vulnerable bits on the frontal side of a satellite would actually serve to protect against a number of impacts. And I think you seriously underestimate how many ball bearings you'd need to put up there to reliably score repeated hits against anything in LEO.
And again, yes, I'm aware that having to launch that much additional mass would drastically increase launch costs. If we could get the same intel at a lower cost or greater reliability with things-other-than-satellites, fine, we'd do that.
They fact is they are a limited number of useful orbits for any particular target area on the earth.
"Useful" is not a binary condition. There are orbits that are more useful than others, but for a given location on the surface there are a large number of orbits that can put a satellite over the horizon above it at regular intervals.
There is a reason they want lasers to take out 'enemy' satellites
Um...no. That's not at all certain. Maybe you can just cook off the solar arrays or antennas, but by and large lasers damage targets via plain old delivery of mechanical force in the form of shear stress. Hit a propellant tank, and you're definitely going to create debris.
The advantage to a laser lies chiefly in the fact that if the satellite's over the horizon, you can hit it, and keep hitting it until it's destroyed.
And it'd probably be good against ball bearings, too.
You've got to get out of here. If they find out you've seen this, your life will be worth less than a truckload of dead rats in a tampon factory!
Wrong. The test "failed" in that the military didn't get all the data they were looking for. The test succeeeded in that it *actually disabled the satellite*. I mean, since you're so quick with the Wikipedia links, I'd have thought you'd have clicked through to MIRACL from the page you linked to:
http://en.wikipedia.org/wiki/MIRACL
It didn't destroy the satellite, but they also weren't firing at full-power.
Seriously, are you actually claiming that you can't propagate EM waves through a medium once the strength of the E field becomes greater than the dielectric strength of the medium? Are you *high*? Who taught you EM theory? Seawater has a dielectric strength of essentially zero, what with all those dissolved ions, and high-power lasers propagate through it just fine.
Blooming is a problem. But what causes it is *energy density*. When you get more than about a megajoule/cm2, that's when you start losing energy to blooming. But you don't have to build "lots of little lasers" to prevent that. What's far easier, and what is actually done by people who, you know, build these things, is to use shorter laser pulses or wider beams/lasing cavities/mirrors. Keep the pulse short enough, and blooming doesn't have time to start. Widen the beam enough, and you keep things below that critical density.
Saying "You can't do this because of blooming" is like saying "You can't fly faster than the speed of sound because of friction!" It's a problem, a loss of efficiency, you need to take it into account when you build. But it's not a show-stopper like you're claiming. THEL, which isn't an ASAT platform but is instead a point-defense against short-range threats, has had considerable success shooting down things like missiles and artillery shells without being stopped by blooming.
You can't armour against anything travelling at those velocities except in science fiction.
.6875" diameter, that's a mass of 22 grams, that's an impact energy of 2.815 megajoules.
Utter nonsense. LEO requires an orbital velocity of about 8km/s. So double that for your opposite-direction impact. Call density of steel about 8g/cc, call the ball bearings
Yes, we can in fact armor against those energies. That's about 600 grams of TNT. But not quite, because it won't penetrate anywhere near as well as 600 grams of high explosive formed into a shaped charge. Even several inches of steel plate would serve well; like I said, it's certainly not as good as not having to deal with the problem (higher costs to orbit, lower lifetime, higher chance of occasional total failure, etc), but to claim there's no solution possible is asinine.
'Cheap' satellites that survive for a fraction of a second is just a silly idea
I said fraction of an orbit, not fraction of a second. I'm pretty sure if anyone tries launching enough ball-bearings to so saturate LEO that nothing could survive for longer than a fraction of a second, we'd notice.
And once you get beyond LEO, space is big. Really, really big. Having to put satellites into higher orbits would, again, not be as desirable as not having to, but it's certainly not insurmountably difficult, either.
You cannot generate a laser beam powerfull enough to destroy a satellite from the ground. IF you tried you would just make a lot of plasma in the air above your laser.
You. Are. Fucking. High. Learn2physics, kthx.
Here in the real world, the one in which people actually understand electromagnetic propagation through a medium, MIRACL, a megawatt-class deuterium-fluoride chemical laser, successfully disabled a satellite in orbit almost 10 years ago.