You still aren't getting it. First, one-ninth of a 12-gauge slug would be 48 grains -- that's a.22 bullet, not a.308. Second, you're assuming the projectiles all follow the same trajectory, and that's impossible. Blowing up a meteorite would be analogous to firing those nine.22 bullets from a shotgun. So...load up a shotgun with #00 buckshot (that's about the same pellet weight), fire it at a human-size silhouette target at 100 yards, and count the holes. If you find any.
The explosion alters the trajectory of every particle. That's the point of the exercise.
Nearly everybody is missing the point. Blow the object into smithereens, and every smithereen acquires its own vector increment of velocity. The farther away it is at the time of the detonation, the farther those increments take the pieces away from the original trajectory. So it was headed for Chicago? OK, some of the pieces will hit there. Some will hit Lake Michigan. Some will hit Caracas. And quite a few will miss the planet altogether.
The answer to your pellets-vs-slug question? At ten feet, it doesn't matter. At a hundred yards, you damn well bet I'd take the pellets.
We had something like that here in the Denver area in the Seventies, in the form of a program called High Street that ran weekly on a small FM rock station. The performers were four students at the U of Denver (located on High Street, and yes, the double entendre was apt). It ran in the same time slot as the late-evening movie on a non-network TV station, and the idea was to turn the TV sound down and let the High Street guys provide the audio.
They typically floundered for a few minutes until they'd settled on a plot premise (always extemporaneously, they claimed) and then they would get on a roll. They were incredibly creative, kept everybody in stitches -- and when Sammy Davis Jr. did a commercial for I-forget-what schlocky consumer product, they outdid themselves.
The squat switch tells the pressurization controller to limit the cabin differential to a small positive value to provide the fuselage stiffening effect.
If you landed with substantial pressure in the airplane and the squat switch just triggered the valve open, you'd bust eardrums. The pressure has to be bled smoothly all the way down to ambient, and the controller accomplishes that...if you have an electrical failure, you have to open a manual valve.
You can't get a "pop" by opening the door, because with pressure in the airplane you'd never get it open.
RTFP. Before takeoff. Takeoffs are made with a small positive pressure in the airplane, which puts the cabin altitude below ground level. As the airplane climbs, the cabin altitude climbs with it, up to a maximum of 8000 feet. It is always below the altitude of the airplane.
As another poster says, it's sea level pressure minus 4.4 psi...the pressurization is actually engaged before takeoff to put a slight positive pressure in the airplane. That makes the fuselage a bit more rigid, reducing the amount of structural fatigue it gets in the takeoff roll. If you're wearing one of those digital watches with an altimeter feature, you'll see the reading go somewhat below the ground elevation.
You apply the heat to a black object exposed to space, and it radiates heat away -- unlike the "radiator" in your car, which actually dumps most of its heat by conduction to the surrounding air.
A space radiator is very effective: it can get things extremely cold just by circulating the fluid without any active refrigeration (i.e, no compressor, no phase changes). The only hitch is that you have to keep sunlight off it, by a combination of sunshades and spacecraft attitude control.
We tend to lose sight of how effective radiation is here on Earth where we have air redistributing heat, but the moon is a good example: its surface temp is about 110C on the dayside and -180C on the nightside.
Correct: each bird is flying in the upward-moving side of the tip vortex from the guy ahead, and it reduces their induced drag by something on the order of 10%. The strongest flyers trade off the lead position.
The power a bird (or other animal) can put out is roughly proportional to its weight...but because of the scaling relation I mentioned above, that's relatively plentiful for a hummingbird and scarce for, say, a condor. All birds eat heavily.
A bird's wing is an aerodynamic lifting body, and model ornithopters were flying before the Wright Brothers. They don't "fight against the lift" of the wing, but use it in a pretty sophisticated way.
We don't have human-carrying ornithopters because scaling effects get in the way. The ability of a wing to produce lift (and the muscle power available to it, in the case of a bird) goes up as the square of the size, but the weight goes up as the cube.
This is what limits the size of birds. A hummingbird can fly all day, even hovering motionless. A robin needs to rest once in a while. An eagle can only fly under muscle power in bursts; most of the time he has to soar on rising thermal currents like a sailplane. An ornithopter big enough to carry a human is going to need a LOT of power.
Precisely. We already have flapping-wing aircraft, and they fly much more efficiently than birds because we know how to make a rotating joint and nature doesn't. Consequently we flap with economical rotary motion instead of energy-wasting reciprocating motion.
Actually, glow fuel is mostly methanol with some nitromethane added to improve ignition and horsepower, plus the lubricant you mention. The nitromethane content is typically 5-20%, though it was practically zero for about a year after a 1991 explosion that took out one of only two plants that make it in the US.
There are jet models using ducted fans powered by glow-plug engines, but it's a pretty kludgey solution, because it takes very high rpm and power levels for piston engines. The engines have aft-mounted exhaust ports so they can run a tuned pipe down the middle of the "jet" exhaust, and the pipe is tuned for an rpm just a little bit south of disintegration. They perform very impressively, but the noise is extremely obnoxious and excludes them from a lot of flying sites.
True turbojets began to appear in the Seventies and are common now. The big hurdle in making turbojets (or any gas turbine engine) is that you have to make the turbine wheel out of some exotic, hard-to-fabricate materials; the designers got over that one by adapting automotive turbocharger parts. They sound remarkably quiet, partially because a lot of the sound is above human hearing...your dog's mileage may vary.
Precisely. If you attach the line to the bow, the only direction you'll be able to go is downwind. Attach it near the center of the hull, like the mast of a sailboat, yaw the hull with the rudder, and you can go a reasonable angle off the wind.
You'll never be able to go to windward (i.e., more than 90 degrees away from downwind), because even with a steerable kite the force on the line will always have a positive component downwind...but you could very likely go 45 degrees off downwind.
You might have better luck at CompUSA now. They were nailed with an FTC order because of just such abuses, and had to implement a streamlined rebate procedure. You just go to their website, type in a number from your purchase receipt, and it's automatic from there; no forms to fill out, no clipping of UPCs, nothing to mail. Of course, "Allow 6-8 weeks for processing" still means you get your check in 7 weeks and 6 days, but you get it.
I believe one or two of the other big-box retailers got the same order.
Slashdot Mirror
In numerous jurisdictions, yes.
rj
Ummm...because people steal other people's identities, rip them off, the whole banking community suffers losses, and YOU have a bank account?
Or because some of those unprotected systems get turned into bots and throw spam at ME?
rj
The Russians sell stick time in a dual-control MiG-29 too...they manage to handle the training requirements for that.
rj
If all your gas is of the same octane rating, and Ferraris work in the UK, you're being screwed.
rj
The explosion alters the trajectory of every particle. That's the point of the exercise.
rj
Nearly everybody is missing the point. Blow the object into smithereens, and every smithereen acquires its own vector increment of velocity. The farther away it is at the time of the detonation, the farther those increments take the pieces away from the original trajectory. So it was headed for Chicago? OK, some of the pieces will hit there. Some will hit Lake Michigan. Some will hit Caracas. And quite a few will miss the planet altogether.
The answer to your pellets-vs-slug question? At ten feet, it doesn't matter. At a hundred yards, you damn well bet I'd take the pellets.
rj
They typically floundered for a few minutes until they'd settled on a plot premise (always extemporaneously, they claimed) and then they would get on a roll. They were incredibly creative, kept everybody in stitches -- and when Sammy Davis Jr. did a commercial for I-forget-what schlocky consumer product, they outdid themselves.
rj
The squat switch tells the pressurization controller to limit the cabin differential to a small positive value to provide the fuselage stiffening effect.
If you landed with substantial pressure in the airplane and the squat switch just triggered the valve open, you'd bust eardrums. The pressure has to be bled smoothly all the way down to ambient, and the controller accomplishes that...if you have an electrical failure, you have to open a manual valve.
You can't get a "pop" by opening the door, because with pressure in the airplane you'd never get it open.
rj
rj
Which can be estimated pretty well by counting the "aftermarket user manual" titles at Barnes & Noble...
rj
No. The cabin altitude in passenger service can be as high as 8,000 feet.
rj
As another poster says, it's sea level pressure minus 4.4 psi...the pressurization is actually engaged before takeoff to put a slight positive pressure in the airplane. That makes the fuselage a bit more rigid, reducing the amount of structural fatigue it gets in the takeoff roll. If you're wearing one of those digital watches with an altimeter feature, you'll see the reading go somewhat below the ground elevation.
rj
You apply the heat to a black object exposed to space, and it radiates heat away -- unlike the "radiator" in your car, which actually dumps most of its heat by conduction to the surrounding air.
A space radiator is very effective: it can get things extremely cold just by circulating the fluid without any active refrigeration (i.e, no compressor, no phase changes). The only hitch is that you have to keep sunlight off it, by a combination of sunshades and spacecraft attitude control.
We tend to lose sight of how effective radiation is here on Earth where we have air redistributing heat, but the moon is a good example: its surface temp is about 110C on the dayside and -180C on the nightside.
rj
They have tons of white meat
White meat is the atrophied pectoral muscle of a flightless bird, with very little blood supply. Ducks and geese are all dark meat.
rj
Correct: each bird is flying in the upward-moving side of the tip vortex from the guy ahead, and it reduces their induced drag by something on the order of 10%. The strongest flyers trade off the lead position.
rj
The power a bird (or other animal) can put out is roughly proportional to its weight...but because of the scaling relation I mentioned above, that's relatively plentiful for a hummingbird and scarce for, say, a condor. All birds eat heavily.
rj
This is what you'd call mathematics, but if you have a different take on the relative power-to-weight ratios of birds and helicopters I'm listening.
rj
No, it's not a rotating joint. It's a bending joint, and you can't rotate your arm 360 degrees in any axis without also rotating it in another axis.
Hold an umbrella over your head, keep a firm grip on the handle, and see how far you can rotate it on its axis.
rj
Very lush, swampy environment with lots of food...they didn't have to fly very far and expend much energy to find it.
rj
A bird's wing is an aerodynamic lifting body, and model ornithopters were flying before the Wright Brothers. They don't "fight against the lift" of the wing, but use it in a pretty sophisticated way.
We don't have human-carrying ornithopters because scaling effects get in the way. The ability of a wing to produce lift (and the muscle power available to it, in the case of a bird) goes up as the square of the size, but the weight goes up as the cube.
This is what limits the size of birds. A hummingbird can fly all day, even hovering motionless. A robin needs to rest once in a while. An eagle can only fly under muscle power in bursts; most of the time he has to soar on rising thermal currents like a sailplane. An ornithopter big enough to carry a human is going to need a LOT of power.
rj
Sure works for flying cars.
rj
rj
Actually, glow fuel is mostly methanol with some nitromethane added to improve ignition and horsepower, plus the lubricant you mention. The nitromethane content is typically 5-20%, though it was practically zero for about a year after a 1991 explosion that took out one of only two plants that make it in the US.
There are jet models using ducted fans powered by glow-plug engines, but it's a pretty kludgey solution, because it takes very high rpm and power levels for piston engines. The engines have aft-mounted exhaust ports so they can run a tuned pipe down the middle of the "jet" exhaust, and the pipe is tuned for an rpm just a little bit south of disintegration. They perform very impressively, but the noise is extremely obnoxious and excludes them from a lot of flying sites.
True turbojets began to appear in the Seventies and are common now. The big hurdle in making turbojets (or any gas turbine engine) is that you have to make the turbine wheel out of some exotic, hard-to-fabricate materials; the designers got over that one by adapting automotive turbocharger parts. They sound remarkably quiet, partially because a lot of the sound is above human hearing...your dog's mileage may vary.
rj
Precisely. If you attach the line to the bow, the only direction you'll be able to go is downwind. Attach it near the center of the hull, like the mast of a sailboat, yaw the hull with the rudder, and you can go a reasonable angle off the wind.
You'll never be able to go to windward (i.e., more than 90 degrees away from downwind), because even with a steerable kite the force on the line will always have a positive component downwind...but you could very likely go 45 degrees off downwind.
rj
You might have better luck at CompUSA now. They were nailed with an FTC order because of just such abuses, and had to implement a streamlined rebate procedure. You just go to their website, type in a number from your purchase receipt, and it's automatic from there; no forms to fill out, no clipping of UPCs, nothing to mail. Of course, "Allow 6-8 weeks for processing" still means you get your check in 7 weeks and 6 days, but you get it.
I believe one or two of the other big-box retailers got the same order.
rj