Meanwhile, in another anecdote, a history professor I know was on a review committee for a junior high-level history textbook used in Texas (among other states, I believe); they did fully review the textbook, only to have a significant portion of their suggested corrections ignored. Also, I don't believe he was lavished much in the way of free dinners, vacations, etc. (maybe they save that for the physicists).
This was the first developmental test flight of their New Shepard, but they've been launching rockets since 2006. From https://en.wikipedia.org/wiki/...:
Second test flight: 13 November 2006, 06:30 (Goddard)
Third test flight: 22 March 2007 (Goddard)
Fourth test flight: 19 April 2007 (Goddard)
Fifth test flight: 6 May 2011 (New Shepard propulsion module (PM2))
Sixth test flight: 24 August 2011 (PM2, failure, loss of vehicle)
Pad escape test flight: 19 October 2012
(Their first test flight was a jet-powered controls testbed, so their first rocket flight was on the second test flight.)
To be spending $0.70/mile on a vehicle putting down 50k+ miles a year, means spending over $35,000 a year on vehicle maintenance.
Much of this cost will be energy cost. Electric powertrains are about three times as efficient as conventional combustion engine powertrains, and on top of that, electricity is cheaper per kilowatt-hour than gas or diesel. Regenerative braking, and not having to idle the engine, would improve the mileage as well.
And yes, it's technically possible to add technology to single-rotor design systems to automate the corrective actions to keep them stable. But by using an octocopter, you can do it a lot more cheaply and more easily.
That's not true; multicopters are computer-stabilized by necessity - they are much harder to manually control than a conventional helicopter configuration. I don't believe it would be significantly more expensive or difficult to add computer stabilization to a conventional R/C helicopter. The main difference is that multicopters are much simpler mechanically, and multicopters with many rotors are more failure-tolerant (e.g., if you have 8 motors and one fails, you can still fly with control and stability on the remaining 7).
gasoline doesn't lose any significant energy on its way from the gas station pump to the car's gas tank to the engine
(Actually, there is energy required for the car's gas pump, but that's still pretty insignificant compared to the charging and discharging losses from a battery.)
When you punch an electric motor, it stay 98% efficient. When you punch an internal combustion engine, its already miserable efficiency drops into the single digits.
I'm not sure where you're getting your data for this, but I don't think this is typically true. If you look at specific fuel consumption curves (which are inversely proportional to efficiency), most internal combustion engines seem to lose maybe 20% of their efficiency (e.g., from 28% efficient* to 22% efficient) from their peak to "punching" - certainly not dropping into the single digits.
Also, if you're going to make a fair comparison to an electric motor in this context, you need to account for the battery efficiency, which is maybe 85% - gasoline doesn't lose any significant energy on its way from the gas station pump to the car's gas tank to the engine, but an electric car will experience some energy loss from the plug to the battery to the motor (e.g., the batteries heat up under charge and discharge, which is an energy loss, and more energy may be required to cool them back down to keep them comfortable).
*I'm estimating the efficiency of the uninstalled engine, not including drivetrain losses, accessory losses, etc.
I assume you're talking about the right image in the Encyclopedia Astronautica link - that is an educated (and ultimately incorrect) guess by Encyclopedia Astronautica of what the vehicle would look like, from years before actual images were released (see http://www.blueorigin.com/upda...).
Incorrect. The F-22 and F-35 have both active and passive seekers, and they're able to determine range, altitude, and bearing with just their passive seeker.
What passive seeker are you referring to on the F-22? It doesn't have much, relatively, and certainly nothing like the F-35's infrared search and track/electro-optical targeting system. The F-22 normally relies on either datalinked targeting information from another aircraft or its own LPI (low-probability-of-intercept) radar.
the only passive seeker that will always remain effective is IR band, because they kinda need the engines to fly. but its also rather short range, wont give real accurate RAB (RAB being only really relevent for BVR) and if you're that close and can pickup his tailpipes, you already know where he's at, and which way hes going.
Actually, modern infrared search and track systems (http://en.wikipedia.org/wiki/IRST) are quite capable - the range is less than radar, but can be dozens of miles, which is plenty of distance to acquire and track a target and launch a missile, which could also employ a passive seeker.
Exactly: they are using 747 engines to save money. The engines (along with other components) will actually be salvaged from old 747s. Even brand new, the 747 engines cost about half as much as 777 engines.
The fact that they don't even produce a 4th generation fighter of their own design (most of their fighters are copied/adapted from Russian designs) and suddenly they unveil this supposed 5th generation fighter supposedly without any foreign technology.
This statement would have held weight 15 years ago, but China's been modernizing their military quickly. They have recently designed (and put into service) the capable J-10 themselves, including a modern updated version (J-10B), as well as the JF-17 with Pakistan.
Technology stolen would probably include anti-radar coatings and perhaps engine and avionics.
The J20 is simply too big to be very stealthy.
Size has little to do with stealth. The B-2 is about seven times as big as the F-117, but still manages a radar cross-section of 0.1 square meters.
Not to mention that we don't actually know the J-20's dimensions or weight. It may not be any bigger than an F-22.
Anti-radar coatings is a reasonable guess, but China has access to much more modern engine and avionics technology via Russian fighter jets.
You mean like... china, paper, woodblock printing, gunpowder, compass, the fork, fireworks, go, maglev wind power generators, negative numbers, menus, tea, toilet paper or the toothbrush?
I mean, granted, not all of these are new things - in fact most of them are all fairly old (the maglev being the exception), but I really doubt any of us would want to go without them.
1. They are not talking about autonomous UAVs. These UAVs are essentially remote-controlled aircraft piloted by real pilots. I think some people assume these things think for themselves but that's not the case. Now that doesn't automatically discount concerns of safety, but "skynet" is not the case here.
Well they're not really remote-controlled aircraft; instead of responding to, say, pitch, roll, and throttle commands, you tell them where to go and what to do and they figure out how to get there themselves. This has worked out very well for the military, but the FAA hasn't trusted UAVs enough to allow them to prove themselves in large-scale civil usage. For example, the military wanted to use their UAVs to help out with Katrina efforts, but since it was in civil airspace, they weren't allowed to.
2. This is not specifically for military only. Many uses for UAVs exist outside of military applications such as basic transport. Of course they'll use them for surveillance, but they already do that with aircraft. UAVs can simply linger longer because one pilot can take over during flight. Similar to how large aircraft do it now with redundant crew members.
I think initially these are going to be used to supplement/replace things like news, traffic and police aircraft/helicopters. NASA's already been using some for years to help with monitoring California wildfires.
747-400 still has slightly longer range than 777. The longest flights are still on 747s - Newark NJ -> Singapore (nonstop).
Actually I believe all the 777 models currently in production (777-200ER, 777-200LR, 777-300ER) have longer range than the 747-400 (although the older models, the 777-200 and the 777-300, did not). Also, the last passenger 747-400s produced have a similar interior to the 777.
Now I'm completely lost. How would YOU not know what song YOU are playing? If there is song tag info, wouldn't your player display that for you? Why on Earth would anyone need to connect to some service for this info?
Well, Last.fm has to know the correct artist and song name for their algorithms to work best (so they can group all songs played by that artist together, for example). Sometimes people misspell a name ("Stained" instead of "Staind", or something), and it would be detrimental to Last.fm's data mining if it treated some Staind songs as being by "Stained" instead.
That being said, the prime function of Last.fm is not to correct mistagged songs, but doing so aids its algorithms and makes the website more useful, since it more accurately reflects its users' listening habits.
True, the Kuiper Airborne Observatory (KAO) was retired in 1995 to free up funding for SOFIA. Work on SOFIA started in the 90s and it made its first flight with the telescope installed last year. SOFIA is a similar idea to KAO, but on a much larger scale (the telescope is 2.5 m in diameter, compared to 91.5 cm for the KAO) and representing a significantly larger engineering challenge.
But yeah, I don't know why this is news now. Science flights aren't supposed to start taking place until next year.
Interestingly, it won't really be ready for science flights next year, but every ten years the US National Research Council does its decadal surveys of all the science programs it's supporting and decides which ones to continue funding on. SOFIA's been so delayed that if it doesn't have any science results by mid-2009 (when the 2010 decadal survey will be taking its data), it runs a real risk of having its US government funding cut. If this happens, DLR (German Aerospace Center), another one of the big funders, will be likely to cut funding as well, resulting in a bleak future for the SOFIA program.
(I worked on SOFIA as an intern at NASA last year.)
"It is perhaps worth noting that those launch companies that succeeded also took their lumps along the way. A friend of mine wrote to remind me that only 5 of the first 9 Pegasus launches succeeded; 3 of 5 for Ariane; 9 of 20 for Atlas; 9 of 21 for Soyuz; and 9 of 18 for Proton." - Elon Musk, 26 March 2006
Sorry, my point is that the F-117 can carry the JDAMs and the laser bombs where the B-2 can only carry the JDAMS (as I understand it, because the aircraft requires a laser emitter for the bomb to follow). I don't know about what the B-2 can carry, but the laser designator does not have to be on the same aircraft as the one with the bombs. Lots of times one aircraft will designate targets for others with bombs, or even someone on the ground will designate the target for the aircraft. I think this was a common practice in Vietnam.
My point is, JDAM gave the B-2 tactical strike capability. The F-117 has laser guided bombs, which, as far as I know, can hit a moving vehicle where the JDAMs would be less effective. Does the F-117 not carry JDAMs too? I was under the impression it did, and the Wikipedia article confirms this, but I don't have a better source offhand.
It seems to me that the B-2 fills many of the rolls the F-117 did. The F-117 may be smaller and slightly more maneuverable but since the development of GPS guided bombs the F-117 seemed to be outdated. The B-2 also has the advantage of a longer range and larger payload. That's true; I think the F-117 must have significantly dropped in importance when the B-2 became operational. However, since we still kept the F-117s around even with the B-2, I assume they must have filled a certain niche well. Maybe it's an economics reason? I think I remember hearing the unit cost of the F-117 was only around $47 million or something (possibly that's in 1980s dollars), and I'm sure upkeep/support is much simpler and cheaper for the Nighthawk than the B-2.
Also, there are surely times when a tactical strike aircraft is more what you need than a strategic bomber.
The stealth fighter was really more of a proof of concept of what stealth technology could do. The plane sacrificed quite a bit in aerodynamics to be stealth capable. It was a subsonic vehicle and, despite what it's name suggests, it had no air-to-air combat abilities.
Although it was revolutionary at the time it first came out, keeping this aircraft in the skies would be a disservice to the taxpaying public. I think that's a little harsh... it was a very valuable aircraft for over a decade, and until the F-22 entered service recently it was the only aircraft that could perform that particular mission. But now that the F-22 is in service, I agree that there's no reason to keep the F-117 around.
Either the F-22 has better stealth than we realize, or there's something newer, more stealthier and more secretive coming around. Yeah, I believe the F-22 does have very effective stealth. The F-117 was first-generation stealth (unless you count the SR-71), and there's been so much development since then that I wouldn't be surprised if the F-22 were more stealthy than the F-117, and I believe its stealth-related maintenance is much lower than the F-117's as well. There were a lot of compromises in the F-117's design that we don't have to make anymore.
It did make a maiden flight - and an F104 crashed into it and the program was killed. It sucks to think that this beauty was killed off due to no fault of its own. Actually the F-104 crashed into one XB-70 on that aircraft's 46th flight, and the second XB-70 made a total of of 83 flights, 33 of them after the crash. The cancellation of the program was a result of the increasing performance of Soviet anti-aircraft missiles - the bomber program was actually canceled before the aircraft were built, and all the flights were research flights.
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Meanwhile, in another anecdote, a history professor I know was on a review committee for a junior high-level history textbook used in Texas (among other states, I believe); they did fully review the textbook, only to have a significant portion of their suggested corrections ignored. Also, I don't believe he was lavished much in the way of free dinners, vacations, etc. (maybe they save that for the physicists).
This was the first developmental test flight of their New Shepard, but they've been launching rockets since 2006. From https://en.wikipedia.org/wiki/...:
Second test flight: 13 November 2006, 06:30 (Goddard)
Third test flight: 22 March 2007 (Goddard)
Fourth test flight: 19 April 2007 (Goddard)
Fifth test flight: 6 May 2011 (New Shepard propulsion module (PM2))
Sixth test flight: 24 August 2011 (PM2, failure, loss of vehicle)
Pad escape test flight: 19 October 2012
(Their first test flight was a jet-powered controls testbed, so their first rocket flight was on the second test flight.)
To be spending $0.70/mile on a vehicle putting down 50k+ miles a year, means spending over $35,000 a year on vehicle maintenance.
Much of this cost will be energy cost. Electric powertrains are about three times as efficient as conventional combustion engine powertrains, and on top of that, electricity is cheaper per kilowatt-hour than gas or diesel. Regenerative braking, and not having to idle the engine, would improve the mileage as well.
And yes, it's technically possible to add technology to single-rotor design systems to automate the corrective actions to keep them stable. But by using an octocopter, you can do it a lot more cheaply and more easily.
That's not true; multicopters are computer-stabilized by necessity - they are much harder to manually control than a conventional helicopter configuration. I don't believe it would be significantly more expensive or difficult to add computer stabilization to a conventional R/C helicopter. The main difference is that multicopters are much simpler mechanically, and multicopters with many rotors are more failure-tolerant (e.g., if you have 8 motors and one fails, you can still fly with control and stability on the remaining 7).
gasoline doesn't lose any significant energy on its way from the gas station pump to the car's gas tank to the engine
(Actually, there is energy required for the car's gas pump, but that's still pretty insignificant compared to the charging and discharging losses from a battery.)
When you punch an electric motor, it stay 98% efficient. When you punch an internal combustion engine, its already miserable efficiency drops into the single digits.
I'm not sure where you're getting your data for this, but I don't think this is typically true. If you look at specific fuel consumption curves (which are inversely proportional to efficiency), most internal combustion engines seem to lose maybe 20% of their efficiency (e.g., from 28% efficient* to 22% efficient) from their peak to "punching" - certainly not dropping into the single digits.
Also, if you're going to make a fair comparison to an electric motor in this context, you need to account for the battery efficiency, which is maybe 85% - gasoline doesn't lose any significant energy on its way from the gas station pump to the car's gas tank to the engine, but an electric car will experience some energy loss from the plug to the battery to the motor (e.g., the batteries heat up under charge and discharge, which is an energy loss, and more energy may be required to cool them back down to keep them comfortable).
*I'm estimating the efficiency of the uninstalled engine, not including drivetrain losses, accessory losses, etc.
Looking at Bezos's New Shepherd Vertical Takeoff Vertical Landing vehicle you might think that somewhere along the line Jeff caught a glimpse of Boeing's old design.
I assume you're talking about the right image in the Encyclopedia Astronautica link - that is an educated (and ultimately incorrect) guess by Encyclopedia Astronautica of what the vehicle would look like, from years before actual images were released (see http://www.blueorigin.com/upda...).
Incorrect. The F-22 and F-35 have both active and passive seekers, and they're able to determine range, altitude, and bearing with just their passive seeker.
What passive seeker are you referring to on the F-22? It doesn't have much, relatively, and certainly nothing like the F-35's infrared search and track/electro-optical targeting system. The F-22 normally relies on either datalinked targeting information from another aircraft or its own LPI (low-probability-of-intercept) radar.
the only passive seeker that will always remain effective is IR band, because they kinda need the engines to fly. but its also rather short range, wont give real accurate RAB (RAB being only really relevent for BVR) and if you're that close and can pickup his tailpipes, you already know where he's at, and which way hes going.
Actually, modern infrared search and track systems (http://en.wikipedia.org/wiki/IRST) are quite capable - the range is less than radar, but can be dozens of miles, which is plenty of distance to acquire and track a target and launch a missile, which could also employ a passive seeker.
Exactly: they are using 747 engines to save money. The engines (along with other components) will actually be salvaged from old 747s. Even brand new, the 747 engines cost about half as much as 777 engines.
The fact that they don't even produce a 4th generation fighter of their own design (most of their fighters are copied/adapted from Russian designs) and suddenly they unveil this supposed 5th generation fighter supposedly without any foreign technology.
This statement would have held weight 15 years ago, but China's been modernizing their military quickly. They have recently designed (and put into service) the capable J-10 themselves, including a modern updated version (J-10B), as well as the JF-17 with Pakistan.
Technology stolen would probably include anti-radar coatings and perhaps engine and avionics.
The J20 is simply too big to be very stealthy.
Size has little to do with stealth. The B-2 is about seven times as big as the F-117, but still manages a radar cross-section of 0.1 square meters.
Not to mention that we don't actually know the J-20's dimensions or weight. It may not be any bigger than an F-22.
Anti-radar coatings is a reasonable guess, but China has access to much more modern engine and avionics technology via Russian fighter jets.
You mean like ... china, paper, woodblock printing, gunpowder, compass, the fork, fireworks, go, maglev wind power generators, negative numbers, menus, tea, toilet paper or the toothbrush?
I mean, granted, not all of these are new things - in fact most of them are all fairly old (the maglev being the exception), but I really doubt any of us would want to go without them.
You mean the maglev that was designed and built by Germans?
1. They are not talking about autonomous UAVs. These UAVs are essentially remote-controlled aircraft piloted by real pilots. I think some people assume these things think for themselves but that's not the case. Now that doesn't automatically discount concerns of safety, but "skynet" is not the case here.
Well they're not really remote-controlled aircraft; instead of responding to, say, pitch, roll, and throttle commands, you tell them where to go and what to do and they figure out how to get there themselves. This has worked out very well for the military, but the FAA hasn't trusted UAVs enough to allow them to prove themselves in large-scale civil usage. For example, the military wanted to use their UAVs to help out with Katrina efforts, but since it was in civil airspace, they weren't allowed to.
2. This is not specifically for military only. Many uses for UAVs exist outside of military applications such as basic transport. Of course they'll use them for surveillance, but they already do that with aircraft. UAVs can simply linger longer because one pilot can take over during flight. Similar to how large aircraft do it now with redundant crew members.
I think initially these are going to be used to supplement/replace things like news, traffic and police aircraft/helicopters. NASA's already been using some for years to help with monitoring California wildfires.
747-400 still has slightly longer range than 777. The longest flights are still on 747s - Newark NJ -> Singapore (nonstop).
Actually I believe all the 777 models currently in production (777-200ER, 777-200LR, 777-300ER) have longer range than the 747-400 (although the older models, the 777-200 and the 777-300, did not). Also, the last passenger 747-400s produced have a similar interior to the 777.
I believe Newark-Singapore nonstop is only flown by the A340-500.
777-200: 5235 nm
777-300: 6015 nm
747-400: 7259 nm
747-400ER: 7670 nm
777-200ER: 7700 nm
777-300ER: 7930 nm
777-200LR: 9450 nm (!!)
Now I'm completely lost. How would YOU not know what song YOU are playing? If there is song tag info, wouldn't your player display that for you? Why on Earth would anyone need to connect to some service for this info?
Well, Last.fm has to know the correct artist and song name for their algorithms to work best (so they can group all songs played by that artist together, for example). Sometimes people misspell a name ("Stained" instead of "Staind", or something), and it would be detrimental to Last.fm's data mining if it treated some Staind songs as being by "Stained" instead.
That being said, the prime function of Last.fm is not to correct mistagged songs, but doing so aids its algorithms and makes the website more useful, since it more accurately reflects its users' listening habits.
True, the Kuiper Airborne Observatory (KAO) was retired in 1995 to free up funding for SOFIA. Work on SOFIA started in the 90s and it made its first flight with the telescope installed last year. SOFIA is a similar idea to KAO, but on a much larger scale (the telescope is 2.5 m in diameter, compared to 91.5 cm for the KAO) and representing a significantly larger engineering challenge.
But yeah, I don't know why this is news now. Science flights aren't supposed to start taking place until next year.
Interestingly, it won't really be ready for science flights next year, but every ten years the US National Research Council does its decadal surveys of all the science programs it's supporting and decides which ones to continue funding on. SOFIA's been so delayed that if it doesn't have any science results by mid-2009 (when the 2010 decadal survey will be taking its data), it runs a real risk of having its US government funding cut. If this happens, DLR (German Aerospace Center), another one of the big funders, will be likely to cut funding as well, resulting in a bleak future for the SOFIA program.
(I worked on SOFIA as an intern at NASA last year.)
"It is perhaps worth noting that those launch companies that succeeded also took their lumps along the way. A friend of mine wrote to remind me that only 5 of the first 9 Pegasus launches succeeded; 3 of 5 for Ariane; 9 of 20 for Atlas; 9 of 21 for Soyuz; and 9 of 18 for Proton." - Elon Musk, 26 March 2006