Please tell me where my maths is wrong. Volume of a cylinder is area of the base times the height. Area of the base is piD, 3.14 x 5.87m = 18.0864m2 times the height, 73.9 is 1336m3. There are 1000l per cubic metre so 1,336,000 litres.
Where did I go wrong?
Even leaving that out. Increasing the length of the aircraft by 16% is a massive deal breaker for no additional carrying capacity! The expense would be astronomical and the entire thing would have to be designed from scratch. It would have crappier flight characteristics, higher drag, require significantly more structural support due to the additional length and weight.
They are both equally important. Especially in things like aircraft. To carry the amount of energy required the size of the hydrogen tanks would be stupidly large. So large that it you wouldn't have any room for anything else. The 777s cary 181,300 L of fuel, this is 6,708,100 MJ of energy. If you assume the same efficiency for a hydrogen burning engine you will need 1,197,875L of liquid hydrogen fuel.
When you then consider that the 777 is 73.9m long and has a cabin diameter of 5.87m which, if treated as a cylinder is 1,362,000 L you start to see the problem. Even if you assume that all 181k of jet fuel is carried in the wings, you have cut your cabin space down to just 345m3 from the original 1362m3 just to hold the extra fuel volume. And this would be an over estimate as it is based on the plane being a tube.
Different strokes for different folks. Fallout 3 left me bored, I never could get into it. I just didn't care. NV was worth playing. Fallout 4 kinda falls between the two. I enjoy it while I am playing it but I don't seem to ever feel an incentive to start it up.
Energy density for liquid hydrogen needs to be measure in MJ/L for you to really see why it sucks to use. LH2 is 5.6MJ/L and a LiPo is 2.28 MJ/L.
While batteries are probably a long way from being capable of driving aircraft liquid hydrogen is a non starter because it takes up too much space. Standard Kerosene jet fuel has an energy density of 37MJ/L and has none of the painful storage or explosive risks of hydrogen.
No question that liquid fuel is more energy dense then batteries. But what is the conversion ratio of that stored energy to thrust. From here, http://www.ipcc.ch/ipccreports..., I get average efficiency of 30-37%.
If it is 37% though you are down to an effective energy store of 14 MJ/KG. Electric engines can be in the 98%+ efficiency level. So while it is still a huge distance to span it's not as big as the pure fuel density implies.
Also when you compare energy density per litre vs per kg batteries do better. Kero is 37 MJ/L and Lipoly is up to 2.25MJ/L. Given that you are now down to a difference of 13.69 vs 2.2ish. Potentially you are in the vicinity of batteries allowing different air frame designs that the higher weight can be, to some degree, compensated.
There is a long way to go before we are replacing jets but I don't think it is quite as insurmountable as you put it.
Is it though? Do you really need a display where you are unable to determine the pixels? I can read a 720 display easily well inside the 0.3 arc minute distance that is meant to be the human eye resolution. Also those displays were from back in 2012 so I would assume an improvement in tech since then. Sony also have a 680 x 400 screen which is.23" in diagonal. That comes in at "retina" level at under an inch. I don't actually know where they measure the retina level from though, is it from the exterior of the eye or from the retina?
So orders of magnitude? No.
As for the power, cooling etc I absolutely agree with you. I was talking about the display resolution.
This would be so useful if they could make it work, though I have no idea how they would power it.
Immediately off the top of my head, navigation would be a huge selling point, a HUD compass would be really useful, especially when travelling in foreign countries. Then there is an instant clipboard. If I could look at something, blink and then had it as a screenshot in the top left it would be brilliant. How many times have you scrawled something on a scrap of paper or had to cycle through to that buried notepad instance or webpage?
Then there would be the ability to see places you cant. Slide a thin camera into a space and you can see the bolt you are trying to get your fingers on to.
Sure all of this can be done already with various devices. But the ease of the integration would make it fantastic. That was why google glass sucked. Sure people in the US freaked about the privacy aspect but the reason no one used them was they were horrible to use and almost useless.
Why? I know that eating chocolate and drinking loads of soft drink makes me fat an unhealthy. Doesn't stop me doing it.
Knowing that CO2 is a GHG isn't going to stop me driving my car. I don't believe that the solution to the problem is to go back to pre industrial populations and lifestyles.
In the early 1900s there was a generally accepted belief that cities couldn't exceed a certain size because of the huge problem of horse shit. The car solved that problem. I believe that we will solve the GHG emission problem as well, whether that is nuclear power, electric cars, solar, or some as yet unknown process I believe we will solve it.
But just like the horse shit was a huge impactor on health and quality of life I think we will see major impacts from climate change before it is solved.
Same. It is the two monitors which is the biggest reason for the docking station. You can get away with a wireless KB&M with a little logitech dongle. But how many laptops support dual digital video easily?
I can't comment on iOS as I've never really used it. But Android is still well short of being able to be used for productivity with any ease. No multi windows, and a clunky clipboard will make even college papers a painful experience. Given how cheap laptops with windows are Android at least still needs more development. Of course if they go down that path it will stop being mobile focussed and that can have its own challenges.
If the tablet ran a useful OS then yes but Android and iOS are still not there when it comes to things like running word.
That said most people I know buy laptops and then mess around with a million cables when they want to do any real work. That would drive me nuts.
At the moment I'm using a dell latop plugged into a docking station which has dual DVI monitors kb, mouse, speakers, external drive port, and a mobile phone cradle plugged into it. I just couldn't be bothered bulk plugging and unplugging that that would require without the station. Not to mention the laptop itself doesn't have dual video out on it by default.
I dont think $100 is that expensive for the dell ones. They are really well made and stand up to the test of time. I've been using mine for the last 8 years with multiple laptops. We have heaps of them in the office and I can't recall ever seeing one fail.
I've never understood why docking stations aren't absolutely everywhere. They are one of the biggest reasons I keep buying Dell latitude laptops. Docking stations is permanently plugged in with all my peripherals and a power supply and I just sit down to start work.
How long has it been since you used a linux distro? I've been able to do all of what you describe for at least the last 5 years perfectly seamlessly. Certainly more seamlessly than windows manages it.
As for breaking your wireless card? WTF? You talk about buying decent hardware but you must have bought the most random chipset to have had that problem in the last decade. Recognising your monitor and using lynx? I don't think I could even drive lynx if I needed to..... and I've been running linux as my primary OS since 2008.
This suggests that energy prices and the perceived abundance of energy sources are the most relevant factors in attitudes toward nuclear power, rather than safety concerns prompted by nuclear incidents.
I haven't had any stability issues on any of my machines running nVidia cards and I am running a variety of hardware from an optimus laptop to an SLI rig and haven't had a single crash in years.
No question Starfish Prime was space. But there were 10 high altitude detonations. However some of those are under the 70 or 100km altitude that people count as space, so of the 10 high altitudes how many you would count as space depends on your definition. Altitudes are 26, 76, 43, 200, 240, 540, 50, 400, 147, 97km.
You would easily count 5 of them as space, the other 5 maybe not.
More like the US has set off 10 high altitude nuclear bombs. It just depends on which ones you want to count as space. Starfish Prime was not the furthest out either, one of the earlier ones was at 570km as opposed to the 400km of starfish. That said starfish was a 1.4Mt bomb so it made the biggest impact.
One of the soviet ones managed to push out an EMP measuring in the thousands of amps. It melted hundreds of kms of telephone and power lines and caused a power station to burn to the ground. It went off at about 290km.
Where as I am the opposite. I simply don't care if the source is closed or not. I care if it works. And currently I would never buy an AMD card to run on Linux until their drivers improve dramatically. Linux is why I don't use AMD.
I've read a bit about how it behaves in the past and looked at some amazing videos. Everything I saw had almost no visible flame. I really wonder what the heat signature would be like as it doesn't look concentrated at all.
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Please tell me where my maths is wrong. Volume of a cylinder is area of the base times the height. Area of the base is piD, 3.14 x 5.87m = 18.0864m2 times the height, 73.9 is 1336m3. There are 1000l per cubic metre so 1,336,000 litres.
Where did I go wrong?
Even leaving that out. Increasing the length of the aircraft by 16% is a massive deal breaker for no additional carrying capacity! The expense would be astronomical and the entire thing would have to be designed from scratch. It would have crappier flight characteristics, higher drag, require significantly more structural support due to the additional length and weight.
Ummmmmm. Liquid hydrogen is heavier than air.... So for the purposes of an aircraft it actually makes you fall....
They are both equally important. Especially in things like aircraft. To carry the amount of energy required the size of the hydrogen tanks would be stupidly large. So large that it you wouldn't have any room for anything else. The 777s cary 181,300 L of fuel, this is 6,708,100 MJ of energy. If you assume the same efficiency for a hydrogen burning engine you will need 1,197,875L of liquid hydrogen fuel.
When you then consider that the 777 is 73.9m long and has a cabin diameter of 5.87m which, if treated as a cylinder is 1,362,000 L you start to see the problem. Even if you assume that all 181k of jet fuel is carried in the wings, you have cut your cabin space down to just 345m3 from the original 1362m3 just to hold the extra fuel volume. And this would be an over estimate as it is based on the plane being a tube.
Different strokes for different folks. Fallout 3 left me bored, I never could get into it. I just didn't care. NV was worth playing. Fallout 4 kinda falls between the two. I enjoy it while I am playing it but I don't seem to ever feel an incentive to start it up.
Energy density for liquid hydrogen needs to be measure in MJ/L for you to really see why it sucks to use. LH2 is 5.6MJ/L and a LiPo is 2.28 MJ/L.
While batteries are probably a long way from being capable of driving aircraft liquid hydrogen is a non starter because it takes up too much space. Standard Kerosene jet fuel has an energy density of 37MJ/L and has none of the painful storage or explosive risks of hydrogen.
I thought the whole point of the efficiency measure was the conversion of stored energy to thrust. If thats not what it's measure what is it?
No question that liquid fuel is more energy dense then batteries. But what is the conversion ratio of that stored energy to thrust. From here, http://www.ipcc.ch/ipccreports..., I get average efficiency of 30-37%.
If it is 37% though you are down to an effective energy store of 14 MJ/KG. Electric engines can be in the 98%+ efficiency level. So while it is still a huge distance to span it's not as big as the pure fuel density implies.
Also when you compare energy density per litre vs per kg batteries do better. Kero is 37 MJ/L and Lipoly is up to 2.25MJ/L. Given that you are now down to a difference of 13.69 vs 2.2ish. Potentially you are in the vicinity of batteries allowing different air frame designs that the higher weight can be, to some degree, compensated.
There is a long way to go before we are replacing jets but I don't think it is quite as insurmountable as you put it.
Is it though? Do you really need a display where you are unable to determine the pixels? I can read a 720 display easily well inside the 0.3 arc minute distance that is meant to be the human eye resolution. Also those displays were from back in 2012 so I would assume an improvement in tech since then. Sony also have a 680 x 400 screen which is .23" in diagonal. That comes in at "retina" level at under an inch. I don't actually know where they measure the retina level from though, is it from the exterior of the eye or from the retina?
So orders of magnitude? No.
As for the power, cooling etc I absolutely agree with you. I was talking about the display resolution.
No not quite. It has 2 years before the glass came out, early 2012, and it was a guy that had a prosthetic eye piece that was attacked in Maccas.
Sony already makes surgical huds with OLEDs that as 1280x720 with an 18mm diagonal. So thats about 2000ppi
http://www.sony.net/SonyInfo/N...
This would be so useful if they could make it work, though I have no idea how they would power it.
Immediately off the top of my head, navigation would be a huge selling point, a HUD compass would be really useful, especially when travelling in foreign countries. Then there is an instant clipboard. If I could look at something, blink and then had it as a screenshot in the top left it would be brilliant. How many times have you scrawled something on a scrap of paper or had to cycle through to that buried notepad instance or webpage?
Then there would be the ability to see places you cant. Slide a thin camera into a space and you can see the bolt you are trying to get your fingers on to.
Sure all of this can be done already with various devices. But the ease of the integration would make it fantastic. That was why google glass sucked. Sure people in the US freaked about the privacy aspect but the reason no one used them was they were horrible to use and almost useless.
Why? I know that eating chocolate and drinking loads of soft drink makes me fat an unhealthy. Doesn't stop me doing it.
Knowing that CO2 is a GHG isn't going to stop me driving my car. I don't believe that the solution to the problem is to go back to pre industrial populations and lifestyles.
In the early 1900s there was a generally accepted belief that cities couldn't exceed a certain size because of the huge problem of horse shit. The car solved that problem. I believe that we will solve the GHG emission problem as well, whether that is nuclear power, electric cars, solar, or some as yet unknown process I believe we will solve it.
But just like the horse shit was a huge impactor on health and quality of life I think we will see major impacts from climate change before it is solved.
Same. It is the two monitors which is the biggest reason for the docking station. You can get away with a wireless KB&M with a little logitech dongle. But how many laptops support dual digital video easily?
I can't comment on iOS as I've never really used it. But Android is still well short of being able to be used for productivity with any ease. No multi windows, and a clunky clipboard will make even college papers a painful experience. Given how cheap laptops with windows are Android at least still needs more development. Of course if they go down that path it will stop being mobile focussed and that can have its own challenges.
If the tablet ran a useful OS then yes but Android and iOS are still not there when it comes to things like running word.
That said most people I know buy laptops and then mess around with a million cables when they want to do any real work. That would drive me nuts.
At the moment I'm using a dell latop plugged into a docking station which has dual DVI monitors kb, mouse, speakers, external drive port, and a mobile phone cradle plugged into it. I just couldn't be bothered bulk plugging and unplugging that that would require without the station. Not to mention the laptop itself doesn't have dual video out on it by default.
I dont think $100 is that expensive for the dell ones. They are really well made and stand up to the test of time. I've been using mine for the last 8 years with multiple laptops. We have heaps of them in the office and I can't recall ever seeing one fail.
I've never understood why docking stations aren't absolutely everywhere. They are one of the biggest reasons I keep buying Dell latitude laptops. Docking stations is permanently plugged in with all my peripherals and a power supply and I just sit down to start work.
How long has it been since you used a linux distro? I've been able to do all of what you describe for at least the last 5 years perfectly seamlessly. Certainly more seamlessly than windows manages it.
As for breaking your wireless card? WTF? You talk about buying decent hardware but you must have bought the most random chipset to have had that problem in the last decade. Recognising your monitor and using lynx? I don't think I could even drive lynx if I needed to..... and I've been running linux as my primary OS since 2008.
Latest android does this
From your own link.
This suggests that energy prices and the perceived abundance of energy sources are the most relevant factors in attitudes toward nuclear power, rather than safety concerns prompted by nuclear incidents.
I haven't had any stability issues on any of my machines running nVidia cards and I am running a variety of hardware from an optimus laptop to an SLI rig and haven't had a single crash in years.
No question Starfish Prime was space. But there were 10 high altitude detonations. However some of those are under the 70 or 100km altitude that people count as space, so of the 10 high altitudes how many you would count as space depends on your definition. Altitudes are 26, 76, 43, 200, 240, 540, 50, 400, 147, 97km.
You would easily count 5 of them as space, the other 5 maybe not.
More like the US has set off 10 high altitude nuclear bombs. It just depends on which ones you want to count as space. Starfish Prime was not the furthest out either, one of the earlier ones was at 570km as opposed to the 400km of starfish. That said starfish was a 1.4Mt bomb so it made the biggest impact.
One of the soviet ones managed to push out an EMP measuring in the thousands of amps. It melted hundreds of kms of telephone and power lines and caused a power station to burn to the ground. It went off at about 290km.
Where as I am the opposite. I simply don't care if the source is closed or not. I care if it works. And currently I would never buy an AMD card to run on Linux until their drivers improve dramatically. Linux is why I don't use AMD.
Now that's a claim not many people can make!
I've read a bit about how it behaves in the past and looked at some amazing videos. Everything I saw had almost no visible flame. I really wonder what the heat signature would be like as it doesn't look concentrated at all.