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On Sat, 7 Sep 2019 18:52:38 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:
On Saturday, September 7, 2019 at 1:40:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 3:25 pm, Rick C wrote:
On Saturday, September 7, 2019 at 1:03:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 1:12 pm, Bill Sloman wrote:
On Saturday, September 7, 2019 at 12:22:32 PM UTC+10, Clifford Heath wrote:
On 7/9/19 11:51 am, Bill Sloman wrote:
On Saturday, September 7, 2019 at 3:19:27 AM UTC+10, John Larkin wrote:
On Fri, 6 Sep 2019 09:37:06 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 12:13:48 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 6 Sep 2019 08:57:43 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 1:27:17 AM UTC-4, Rick C wrote:
This is interesting
https://arstechnica.com/science/2019/09/crops-under-solar-panels-can-be-a-win-win/
They report that not only do crops grow better using less water for the amount of food produced the solar panels stay cooler improving their electrical production. True win-win.
--
Rick C.
- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
Study was conducted in arid area of southwest where literally anything is an improvement. It is not a general recommendation.
The solar cells can power water sprayers.
The water is a more valuable commodity than the electricity it takes to run irrigation pumps, and they really want to be using drip irrigation in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff doesn't do well in shade. Notice they didn't mention any of the economics, but the crummy vegetable crop isn't going to make up for the loss of revenue due to greatly reduced panel density.
Modern agriculture is heading for catastrophic collapse in so many ways. They have HUGE problems. Here is a story about their plastics problem:
https://www.greenbiz.com/article/how-can-agriculture-solve-its-1-billion-plastic-problem
These plastic products are absolutely essential, but it's getting unsustainable.
There's gloom and destruction everywhere you look. Enjoy.
Some fathead Dem candidate said that driving cars will "destroy the
planet" as he boarded his private plane.
Driving electric cars would be fine. Aircraft are more of a problem. There really aren't enough private planes to create a problem, but international tourism probably has to go.
https://www.monbiot.com/books/heat/
George Monbiot pointed this out back in 2006, and it still seems to be true.
A new generation of more bulbous aircraft with enough room for liquid hydrogen fuel - rather lower energy density than liquid hydrocarbons - might save the tourist industry, but it would take a while and a great deal of expensive development.
It's not just the lower energy density. There's probably no way to
encase useful amounts of hydrogen in a viable aircraft.
What makes you think that? Liquid hydrogen has been used as a rocket fuel.
Also, all those rockets were single-use.
That was just an expedient as Musk is showing us.
Rubbish. His rockets are liquid-fuelled. Show me a similar re-usable
hydrogen-fuelled rocket and we have something to talk about.
Why is that relevant? The limitation to reusing rockets is the control to allow them to land and be recovered.
How many were reusing rockets of any type until Musk did it?
Someone said it's not practical to use Hydrogen fuel, then someone else pointed out those examples were single use, but there is nothing inherent in hydrogen fuel that makes a reusable rocket impractical.
Those reusable stages have mainly been the first stage, i.e. running
in a high atmospheric pressure, in which the trust drops compared to
vacuum. In such environments it makes sense to use exhaust gases with
higher molecular weight.
In addition, the LH2 would require huge tanks. Think about how huge
the first stage of Saturn V have been, if the fuel had been LH2
instead of kerosine. On the Shuttle, LH2 takes out the main part of
the ET and still you need those SRBs as the first stage.
On Sunday, September 8, 2019 at 6:17:35 AM UTC-4, upsid...@downunder.com wrote:
On Sat, 7 Sep 2019 18:52:38 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:
On Saturday, September 7, 2019 at 1:40:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 3:25 pm, Rick C wrote:
On Saturday, September 7, 2019 at 1:03:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 1:12 pm, Bill Sloman wrote:
On Saturday, September 7, 2019 at 12:22:32 PM UTC+10, Clifford Heath wrote:
On 7/9/19 11:51 am, Bill Sloman wrote:
On Saturday, September 7, 2019 at 3:19:27 AM UTC+10, John Larkin wrote:
On Fri, 6 Sep 2019 09:37:06 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 12:13:48 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 6 Sep 2019 08:57:43 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 1:27:17 AM UTC-4, Rick C wrote:
Someone said it's not practical to use Hydrogen fuel, then someone else pointed out those examples were single use, but there is nothing inherent in hydrogen fuel that makes a reusable rocket impractical.
Those reusable stages have mainly been the first stage, i.e. running
in a high atmospheric pressure, in which the trust drops compared to
vacuum. In such environments it makes sense to use exhaust gases with
higher molecular weight.
In addition, the LH2 would require huge tanks. Think about how huge
the first stage of Saturn V have been, if the fuel had been LH2
instead of kerosine. On the Shuttle, LH2 takes out the main part of
the ET and still you need those SRBs as the first stage.
ET?
I don't know why people find typing to be so difficult.
On Saturday, September 7, 2019 at 8:28:14 AM UTC-7, jla...@highlandsniptechnology.com wrote:
Boiloff limits hydrogen fuel-cell flights to something like 2 hours
max. A rocket uses up all its 1st stage fuel supply in minutes.
And rockets are expensive.
How much do you pay for a paper match and a wrap of aluminum foil?
Someone has been overcharging you very badly.
For aircraft, there's AIR available, the 'first stage fuel' in an expensive space rocket
is burned so quckly because that's how you avoid lifting (among other things)
a lot of liquid oxygen. The economics of space rockets don't apply to aircraft.
On Sunday, September 8, 2019 at 11:17:53 PM UTC+10, Rick C wrote:
On Sunday, September 8, 2019 at 6:17:35 AM UTC-4, upsid...@downunder.com wrote:
In addition, the LH2 would require huge tanks. Think about how huge
the first stage of Saturn V have been, if the fuel had been LH2
instead of kerosine. On the Shuttle, LH2 takes out the main part of
the ET and still you need those SRBs as the first stage.
ET?
I don't know why people find typing to be so difficult.
I think it's more that they want to create the impression that they are so familiar with the material that the acronyms pop up automatically.
Anybody who want to make sure that they are informing their readers - as opposed to impressing them - spells out that kind of acronym. For one thing short acronyms are ambiguous - ET tends to mean "extraterrestrial" more often than "external tank".
On Sunday, September 8, 2019 at 6:17:35 AM UTC-4, upsid...@downunder.com wrote:
On Sat, 7 Sep 2019 18:52:38 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:
On Saturday, September 7, 2019 at 1:40:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 3:25 pm, Rick C wrote:
On Saturday, September 7, 2019 at 1:03:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 1:12 pm, Bill Sloman wrote:
On Saturday, September 7, 2019 at 12:22:32 PM UTC+10, Clifford Heath wrote:
On 7/9/19 11:51 am, Bill Sloman wrote:
On Saturday, September 7, 2019 at 3:19:27 AM UTC+10, John Larkin wrote:
On Fri, 6 Sep 2019 09:37:06 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 12:13:48 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 6 Sep 2019 08:57:43 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 1:27:17 AM UTC-4, Rick C wrote:
This is interesting
https://arstechnica.com/science/2019/09/crops-under-solar-panels-can-be-a-win-win/
They report that not only do crops grow better using less water for the amount of food produced the solar panels stay cooler improving their electrical production. True win-win.
--
Rick C.
- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
Study was conducted in arid area of southwest where literally anything is an improvement. It is not a general recommendation.
The solar cells can power water sprayers.
The water is a more valuable commodity than the electricity it takes to run irrigation pumps, and they really want to be using drip irrigation in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff doesn't do well in shade. Notice they didn't mention any of the economics, but the crummy vegetable crop isn't going to make up for the loss of revenue due to greatly reduced panel density.
Modern agriculture is heading for catastrophic collapse in so many ways. They have HUGE problems. Here is a story about their plastics problem:
https://www.greenbiz.com/article/how-can-agriculture-solve-its-1-billion-plastic-problem
These plastic products are absolutely essential, but it's getting unsustainable.
There's gloom and destruction everywhere you look. Enjoy.
Some fathead Dem candidate said that driving cars will "destroy the
planet" as he boarded his private plane.
Driving electric cars would be fine. Aircraft are more of a problem. There really aren't enough private planes to create a problem, but international tourism probably has to go.
https://www.monbiot.com/books/heat/
George Monbiot pointed this out back in 2006, and it still seems to be true.
A new generation of more bulbous aircraft with enough room for liquid hydrogen fuel - rather lower energy density than liquid hydrocarbons - might save the tourist industry, but it would take a while and a great deal of expensive development.
It's not just the lower energy density. There's probably no way to
encase useful amounts of hydrogen in a viable aircraft.
What makes you think that? Liquid hydrogen has been used as a rocket fuel.
Also, all those rockets were single-use.
That was just an expedient as Musk is showing us.
Rubbish. His rockets are liquid-fuelled. Show me a similar re-usable
hydrogen-fuelled rocket and we have something to talk about.
Why is that relevant? The limitation to reusing rockets is the control to allow them to land and be recovered.
How many were reusing rockets of any type until Musk did it?
Someone said it's not practical to use Hydrogen fuel, then someone else pointed out those examples were single use, but there is nothing inherent in hydrogen fuel that makes a reusable rocket impractical.
Those reusable stages have mainly been the first stage, i.e. running
in a high atmospheric pressure, in which the trust drops compared to
vacuum. In such environments it makes sense to use exhaust gases with
higher molecular weight.
In addition, the LH2 would require huge tanks. Think about how huge
the first stage of Saturn V have been, if the fuel had been LH2
instead of kerosine. On the Shuttle, LH2 takes out the main part of
the ET and still you need those SRBs as the first stage.
ET?
I don't know why people find typing to be so difficult.
On Sunday, September 8, 2019 at 10:21:44 AM UTC-4, Bill Sloman wrote:
On Sunday, September 8, 2019 at 11:17:53 PM UTC+10, Rick C wrote:
On Sunday, September 8, 2019 at 6:17:35 AM UTC-4, upsid...@downunder.com wrote:
In addition, the LH2 would require huge tanks. Think about how huge
the first stage of Saturn V have been, if the fuel had been LH2
instead of kerosine. On the Shuttle, LH2 takes out the main part of
the ET and still you need those SRBs as the first stage.
ET?
I don't know why people find typing to be so difficult.
I think it's more that they want to create the impression that they are so familiar with the material that the acronyms pop up automatically.
Anybody who want to make sure that they are informing their readers - as opposed to impressing them - spells out that kind of acronym. For one thing short acronyms are ambiguous - ET tends to mean "extraterrestrial" more often than "external tank".
His usage still isn't clear to me. "On the Shuttle, LH2 takes out the main part of the ET and still you need those SRBs as the first stage." Is he trying to say it makes the Shuttle smaller? I don't know what he means by "takes out".
On Sun, 8 Sep 2019 06:17:48 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:
On Sunday, September 8, 2019 at 6:17:35 AM UTC-4, upsid...@downunder.com wrote:
On Sat, 7 Sep 2019 18:52:38 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:
On Saturday, September 7, 2019 at 1:40:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 3:25 pm, Rick C wrote:
On Saturday, September 7, 2019 at 1:03:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 1:12 pm, Bill Sloman wrote:
On Saturday, September 7, 2019 at 12:22:32 PM UTC+10, Clifford Heath wrote:
On 7/9/19 11:51 am, Bill Sloman wrote:
On Saturday, September 7, 2019 at 3:19:27 AM UTC+10, John Larkin wrote:
On Fri, 6 Sep 2019 09:37:06 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 12:13:48 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 6 Sep 2019 08:57:43 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 1:27:17 AM UTC-4, Rick C wrote:
This is interesting
https://arstechnica.com/science/2019/09/crops-under-solar-panels-can-be-a-win-win/
They report that not only do crops grow better using less water for the amount of food produced the solar panels stay cooler improving their electrical production. True win-win.
--
Rick C.
- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
Study was conducted in arid area of southwest where literally anything is an improvement. It is not a general recommendation.
The solar cells can power water sprayers.
The water is a more valuable commodity than the electricity it takes to run irrigation pumps, and they really want to be using drip irrigation in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff doesn't do well in shade. Notice they didn't mention any of the economics, but the crummy vegetable crop isn't going to make up for the loss of revenue due to greatly reduced panel density.
Modern agriculture is heading for catastrophic collapse in so many ways. They have HUGE problems. Here is a story about their plastics problem:
https://www.greenbiz.com/article/how-can-agriculture-solve-its-1-billion-plastic-problem
These plastic products are absolutely essential, but it's getting unsustainable.
There's gloom and destruction everywhere you look. Enjoy.
Some fathead Dem candidate said that driving cars will "destroy the
planet" as he boarded his private plane.
Driving electric cars would be fine. Aircraft are more of a problem. There really aren't enough private planes to create a problem, but international tourism probably has to go.
https://www.monbiot.com/books/heat/
George Monbiot pointed this out back in 2006, and it still seems to be true.
A new generation of more bulbous aircraft with enough room for liquid hydrogen fuel - rather lower energy density than liquid hydrocarbons - might save the tourist industry, but it would take a while and a great deal of expensive development.
It's not just the lower energy density. There's probably no way to
encase useful amounts of hydrogen in a viable aircraft.
What makes you think that? Liquid hydrogen has been used as a rocket fuel.
Also, all those rockets were single-use.
That was just an expedient as Musk is showing us.
Rubbish. His rockets are liquid-fuelled. Show me a similar re-usable
hydrogen-fuelled rocket and we have something to talk about.
Why is that relevant? The limitation to reusing rockets is the control to allow them to land and be recovered.
How many were reusing rockets of any type until Musk did it?
Someone said it's not practical to use Hydrogen fuel, then someone else pointed out those examples were single use, but there is nothing inherent in hydrogen fuel that makes a reusable rocket impractical.
Those reusable stages have mainly been the first stage, i.e. running
in a high atmospheric pressure, in which the trust drops compared to
vacuum. In such environments it makes sense to use exhaust gases with
higher molecular weight.
In addition, the LH2 would require huge tanks. Think about how huge
the first stage of Saturn V have been, if the fuel had been LH2
instead of kerosine. On the Shuttle, LH2 takes out the main part of
the ET and still you need those SRBs as the first stage.
ET?
I don't know why people find typing to be so difficult.
Sorry for the confusion, apparently I spent too many decades in
sci.spce.shuttle and sci.space (now defunct) newsgroups.
Liquid hydrogen has a much lower density than liquid oxygen or
kerosine. When burning substances the critical thing is the _mass_
ratio between fuel and oxidizer. Thus, to get the sufficient number of
kilograms of liquid hydrogen, a very large tank volume is needing,
which also requires heavier tank structures.
Most parts of the external tank (ET) are thus required for hydrogen, a
much smaller part is occupied by oxygen. If the Shuttle would take off
solely with hydrogen, the tank size would have to be many times
larger. To avoid this, the solid rocket booster (SRB) will create the
most trust during liftoff.
On Sunday, September 8, 2019 at 1:16:06 PM UTC-4, upsid...@downunder.com wrote:
On Sun, 8 Sep 2019 06:17:48 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:
On Sunday, September 8, 2019 at 6:17:35 AM UTC-4, upsid...@downunder.com wrote:
On Sat, 7 Sep 2019 18:52:38 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:
On Saturday, September 7, 2019 at 1:40:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 3:25 pm, Rick C wrote:
On Saturday, September 7, 2019 at 1:03:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 1:12 pm, Bill Sloman wrote:
On Saturday, September 7, 2019 at 12:22:32 PM UTC+10, Clifford Heath wrote:
On 7/9/19 11:51 am, Bill Sloman wrote:
On Saturday, September 7, 2019 at 3:19:27 AM UTC+10, John Larkin wrote:
On Fri, 6 Sep 2019 09:37:06 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 12:13:48 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 6 Sep 2019 08:57:43 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 1:27:17 AM UTC-4, Rick C wrote:
This is interesting
https://arstechnica.com/science/2019/09/crops-under-solar-panels-can-be-a-win-win/
They report that not only do crops grow better using less water for the amount of food produced the solar panels stay cooler improving their electrical production. True win-win.
--
Rick C.
- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
Study was conducted in arid area of southwest where literally anything is an improvement. It is not a general recommendation.
The solar cells can power water sprayers.
The water is a more valuable commodity than the electricity it takes to run irrigation pumps, and they really want to be using drip irrigation in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff doesn't do well in shade. Notice they didn't mention any of the economics, but the crummy vegetable crop isn't going to make up for the loss of revenue due to greatly reduced panel density.
Modern agriculture is heading for catastrophic collapse in so many ways. They have HUGE problems. Here is a story about their plastics problem:
https://www.greenbiz.com/article/how-can-agriculture-solve-its-1-billion-plastic-problem
These plastic products are absolutely essential, but it's getting unsustainable.
There's gloom and destruction everywhere you look. Enjoy.
Some fathead Dem candidate said that driving cars will "destroy the
planet" as he boarded his private plane.
Driving electric cars would be fine. Aircraft are more of a problem. There really aren't enough private planes to create a problem, but international tourism probably has to go.
https://www.monbiot.com/books/heat/
George Monbiot pointed this out back in 2006, and it still seems to be true.
A new generation of more bulbous aircraft with enough room for liquid hydrogen fuel - rather lower energy density than liquid hydrocarbons - might save the tourist industry, but it would take a while and a great deal of expensive development.
It's not just the lower energy density. There's probably no way to
encase useful amounts of hydrogen in a viable aircraft.
What makes you think that? Liquid hydrogen has been used as a rocket fuel.
Also, all those rockets were single-use.
That was just an expedient as Musk is showing us.
Rubbish. His rockets are liquid-fuelled. Show me a similar re-usable
hydrogen-fuelled rocket and we have something to talk about.
Why is that relevant? The limitation to reusing rockets is the control to allow them to land and be recovered.
How many were reusing rockets of any type until Musk did it?
Someone said it's not practical to use Hydrogen fuel, then someone else pointed out those examples were single use, but there is nothing inherent in hydrogen fuel that makes a reusable rocket impractical.
Those reusable stages have mainly been the first stage, i.e. running
in a high atmospheric pressure, in which the trust drops compared to
vacuum. In such environments it makes sense to use exhaust gases with
higher molecular weight.
In addition, the LH2 would require huge tanks. Think about how huge
the first stage of Saturn V have been, if the fuel had been LH2
instead of kerosine. On the Shuttle, LH2 takes out the main part of
the ET and still you need those SRBs as the first stage.
ET?
I don't know why people find typing to be so difficult.
Sorry for the confusion, apparently I spent too many decades in
sci.spce.shuttle and sci.space (now defunct) newsgroups.
Liquid hydrogen has a much lower density than liquid oxygen or
kerosine. When burning substances the critical thing is the _mass_
ratio between fuel and oxidizer. Thus, to get the sufficient number of
kilograms of liquid hydrogen, a very large tank volume is needing,
which also requires heavier tank structures.
Most parts of the external tank (ET) are thus required for hydrogen, a
much smaller part is occupied by oxygen. If the Shuttle would take off
solely with hydrogen, the tank size would have to be many times
larger. To avoid this, the solid rocket booster (SRB) will create the
most trust during liftoff.
So why use hydrogen fuel? Was it the enviromental issues? They don't stop people from using other, not so environmentally friendly fuels in other rockets. Didn't someone post here that Musk is using kerosene? Is that why his rockets landing look like movie props from the 50's? Anyone else notice that?
Or maybe it's just because they are landing rather than taking off?
ET?
I don't know why people find typing to be so difficult.
On Sunday, September 8, 2019 at 1:16:06 PM UTC-4, upsid...@downunder.com wrote:
On Sun, 8 Sep 2019 06:17:48 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:
On Sunday, September 8, 2019 at 6:17:35 AM UTC-4, upsid...@downunder.com wrote:
On Sat, 7 Sep 2019 18:52:38 -0700 (PDT), Rick C
gnuarm.deletethisbit@gmail.com> wrote:
On Saturday, September 7, 2019 at 1:40:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 3:25 pm, Rick C wrote:
On Saturday, September 7, 2019 at 1:03:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 1:12 pm, Bill Sloman wrote:
On Saturday, September 7, 2019 at 12:22:32 PM UTC+10, Clifford Heath wrote:
On 7/9/19 11:51 am, Bill Sloman wrote:
On Saturday, September 7, 2019 at 3:19:27 AM UTC+10, John Larkin wrote:
On Fri, 6 Sep 2019 09:37:06 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 12:13:48 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 6 Sep 2019 08:57:43 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 1:27:17 AM UTC-4, Rick C wrote:
This is interesting
https://arstechnica.com/science/2019/09/crops-under-solar-panels-can-be-a-win-win/
They report that not only do crops grow better using less water for the amount of food produced the solar panels stay cooler improving their electrical production. True win-win.
--
Rick C.
- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
Study was conducted in arid area of southwest where literally anything is an improvement. It is not a general recommendation.
The solar cells can power water sprayers.
The water is a more valuable commodity than the electricity it takes to run irrigation pumps, and they really want to be using drip irrigation in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff doesn't do well in shade. Notice they didn't mention any of the economics, but the crummy vegetable crop isn't going to make up for the loss of revenue due to greatly reduced panel density.
Modern agriculture is heading for catastrophic collapse in so many ways. They have HUGE problems. Here is a story about their plastics problem:
https://www.greenbiz.com/article/how-can-agriculture-solve-its-1-billion-plastic-problem
These plastic products are absolutely essential, but it's getting unsustainable.
There's gloom and destruction everywhere you look. Enjoy.
Some fathead Dem candidate said that driving cars will "destroy the
planet" as he boarded his private plane.
Driving electric cars would be fine. Aircraft are more of a problem. There really aren't enough private planes to create a problem, but international tourism probably has to go.
https://www.monbiot.com/books/heat/
George Monbiot pointed this out back in 2006, and it still seems to be true.
A new generation of more bulbous aircraft with enough room for liquid hydrogen fuel - rather lower energy density than liquid hydrocarbons - might save the tourist industry, but it would take a while and a great deal of expensive development.
It's not just the lower energy density. There's probably no way to
encase useful amounts of hydrogen in a viable aircraft.
What makes you think that? Liquid hydrogen has been used as a rocket fuel.
Also, all those rockets were single-use.
That was just an expedient as Musk is showing us.
Rubbish. His rockets are liquid-fuelled. Show me a similar re-usable
hydrogen-fuelled rocket and we have something to talk about.
Why is that relevant? The limitation to reusing rockets is the control to allow them to land and be recovered.
How many were reusing rockets of any type until Musk did it?
Someone said it's not practical to use Hydrogen fuel, then someone else pointed out those examples were single use, but there is nothing inherent in hydrogen fuel that makes a reusable rocket impractical.
Those reusable stages have mainly been the first stage, i.e. running
in a high atmospheric pressure, in which the trust drops compared to
vacuum. In such environments it makes sense to use exhaust gases with
higher molecular weight.
In addition, the LH2 would require huge tanks. Think about how huge
the first stage of Saturn V have been, if the fuel had been LH2
instead of kerosine. On the Shuttle, LH2 takes out the main part of
the ET and still you need those SRBs as the first stage.
ET?
I don't know why people find typing to be so difficult.
Sorry for the confusion, apparently I spent too many decades in
sci.spce.shuttle and sci.space (now defunct) newsgroups.
Liquid hydrogen has a much lower density than liquid oxygen or
kerosine. When burning substances the critical thing is the _mass_
ratio between fuel and oxidizer. Thus, to get the sufficient number of
kilograms of liquid hydrogen, a very large tank volume is needing,
which also requires heavier tank structures.
Most parts of the external tank (ET) are thus required for hydrogen, a
much smaller part is occupied by oxygen. If the Shuttle would take off
solely with hydrogen, the tank size would have to be many times
larger. To avoid this, the solid rocket booster (SRB) will create the
most trust during liftoff.
So why use hydrogen fuel? Was it the enviromental issues? They don't stop people from using other, not so environmentally friendly fuels in other rockets. Didn't someone post here that Musk is using kerosene? Is that why his rockets landing look like movie props from the 50's? Anyone else notice that?
Or maybe it's just because they are landing rather than taking off?
On Saturday, September 7, 2019 at 1:40:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 3:25 pm, Rick C wrote:
On Saturday, September 7, 2019 at 1:03:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 1:12 pm, Bill Sloman wrote:
On Saturday, September 7, 2019 at 12:22:32 PM UTC+10, Clifford Heath wrote:
On 7/9/19 11:51 am, Bill Sloman wrote:
On Saturday, September 7, 2019 at 3:19:27 AM UTC+10, John Larkin wrote:
On Fri, 6 Sep 2019 09:37:06 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 12:13:48 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 6 Sep 2019 08:57:43 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 1:27:17 AM UTC-4, Rick C wrote:
This is interesting
https://arstechnica.com/science/2019/09/crops-under-solar-panels-can-be-a-win-win/
They report that not only do crops grow better using less water for the amount of food produced the solar panels stay cooler improving their electrical production. True win-win.
--
Rick C.
- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
Study was conducted in arid area of southwest where literally anything is an improvement. It is not a general recommendation.
The solar cells can power water sprayers.
The water is a more valuable commodity than the electricity it takes to run irrigation pumps, and they really want to be using drip irrigation in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff doesn't do well in shade. Notice they didn't mention any of the economics, but the crummy vegetable crop isn't going to make up for the loss of revenue due to greatly reduced panel density.
Modern agriculture is heading for catastrophic collapse in so many ways. They have HUGE problems. Here is a story about their plastics problem:
https://www.greenbiz.com/article/how-can-agriculture-solve-its-1-billion-plastic-problem
These plastic products are absolutely essential, but it's getting unsustainable.
There's gloom and destruction everywhere you look. Enjoy.
Some fathead Dem candidate said that driving cars will "destroy the
planet" as he boarded his private plane.
Driving electric cars would be fine. Aircraft are more of a problem. There really aren't enough private planes to create a problem, but international tourism probably has to go.
https://www.monbiot.com/books/heat/
George Monbiot pointed this out back in 2006, and it still seems to be true.
A new generation of more bulbous aircraft with enough room for liquid hydrogen fuel - rather lower energy density than liquid hydrocarbons - might save the tourist industry, but it would take a while and a great deal of expensive development.
It's not just the lower energy density. There's probably no way to
encase useful amounts of hydrogen in a viable aircraft.
What makes you think that? Liquid hydrogen has been used as a rocket fuel.
Also, all those rockets were single-use.
That was just an expedient as Musk is showing us.
Rubbish. His rockets are liquid-fuelled. Show me a similar re-usable
hydrogen-fuelled rocket and we have something to talk about.
Why is that relevant? The limitation to reusing rockets is the control to allow them to land and be recovered.
On 8/9/19 11:52 am, Rick C wrote:
On Saturday, September 7, 2019 at 1:40:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 3:25 pm, Rick C wrote:
On Saturday, September 7, 2019 at 1:03:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 1:12 pm, Bill Sloman wrote:
On Saturday, September 7, 2019 at 12:22:32 PM UTC+10, Clifford Heath wrote:
On 7/9/19 11:51 am, Bill Sloman wrote:
On Saturday, September 7, 2019 at 3:19:27 AM UTC+10, John Larkin wrote:
On Fri, 6 Sep 2019 09:37:06 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 12:13:48 PM UTC-4, jla...@highlandsniptechnology.com wrote:
On Fri, 6 Sep 2019 08:57:43 -0700 (PDT),
bloggs.fredbloggs.fred@gmail.com wrote:
On Friday, September 6, 2019 at 1:27:17 AM UTC-4, Rick C wrote:
This is interesting
https://arstechnica.com/science/2019/09/crops-under-solar-panels-can-be-a-win-win/
They report that not only do crops grow better using less water for the amount of food produced the solar panels stay cooler improving their electrical production. True win-win.
--
Rick C.
- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
Study was conducted in arid area of southwest where literally anything is an improvement. It is not a general recommendation.
The solar cells can power water sprayers.
The water is a more valuable commodity than the electricity it takes to run irrigation pumps, and they really want to be using drip irrigation in places like this, and drip is low power.It probably drove the idea of using the panels for shading in the first place, although a lot stuff doesn't do well in shade. Notice they didn't mention any of the economics, but the crummy vegetable crop isn't going to make up for the loss of revenue due to greatly reduced panel density.
Modern agriculture is heading for catastrophic collapse in so many ways. They have HUGE problems. Here is a story about their plastics problem:
https://www.greenbiz.com/article/how-can-agriculture-solve-its-1-billion-plastic-problem
These plastic products are absolutely essential, but it's getting unsustainable.
There's gloom and destruction everywhere you look. Enjoy.
Some fathead Dem candidate said that driving cars will "destroy the
planet" as he boarded his private plane.
Driving electric cars would be fine. Aircraft are more of a problem. There really aren't enough private planes to create a problem, but international tourism probably has to go.
https://www.monbiot.com/books/heat/
George Monbiot pointed this out back in 2006, and it still seems to be true.
A new generation of more bulbous aircraft with enough room for liquid hydrogen fuel - rather lower energy density than liquid hydrocarbons - might save the tourist industry, but it would take a while and a great deal of expensive development.
It's not just the lower energy density. There's probably no way to
encase useful amounts of hydrogen in a viable aircraft.
What makes you think that? Liquid hydrogen has been used as a rocket fuel.
Also, all those rockets were single-use.
That was just an expedient as Musk is showing us.
Rubbish. His rockets are liquid-fuelled. Show me a similar re-usable
hydrogen-fuelled rocket and we have something to talk about.
Why is that relevant? The limitation to reusing rockets is the control to allow them to land and be recovered.
Because the single-use rockets are *fragile*. They are simply not
engineered to work at the duty cycle that commercial aviation needs, and
would be four times heavier if they were.
How many were reusing rockets of any type until Musk did it?
Even those are not likely to last a dozen launches, and that's good
engineering, since the failure rate from other causes is still higher
than that. They certainly couldn't approach the safety and duty cycle
needed for commercial aviation.
Rick C <gnuarm.deletethisbit@gmail.com> wrote in news:d5c46a04-9f9e-
49b8-91ea-6970a12a6fd3@googlegroups.com:
ET?
I don't know why people find typing to be so difficult.
external tank. That's my guess.
Are you not the twerp that does the "lol" thing so often?
It has been a long established norm for mil and space gear to have a
lot of acronyms (and acronymic like abbreviations). Hell the US
governement et al.
On 9/9/19 3:52 am, Rick C wrote:
On Sunday, September 8, 2019 at 1:16:06 PM UTC-4, upsid...@downunder.com wrote:
Liquid hydrogen has a much lower density than liquid oxygen or
kerosine. When burning substances the critical thing is the _mass_
ratio between fuel and oxidizer. Thus, to get the sufficient number of
kilograms of liquid hydrogen, a very large tank volume is needing,
which also requires heavier tank structures.
Most parts of the external tank (ET) are thus required for hydrogen, a
much smaller part is occupied by oxygen. If the Shuttle would take off
solely with hydrogen, the tank size would have to be many times
larger. To avoid this, the solid rocket booster (SRB) will create the
most trust during liftoff.
So why use hydrogen fuel? Was it the enviromental issues? They don't stop people from using other, not so environmentally friendly fuels in other rockets. Didn't someone post here that Musk is using kerosene? Is that why his rockets landing look like movie props from the 50's? Anyone else notice that?
Or maybe it's just because they are landing rather than taking off?
Hydrogen/Oxygen has a low molecular mass exhaust (very high
energy/momentum ratio), and the shuttle main engine is basically just
idling while the SRBs are firing . SRBs use rubber to produce a very
high molecular mass exhaust - high momentum/energy ratio suitable for
lower-speed (atmospheric) flight. When the SRBs are gone, the main
engine ramps up. I've tried to explain this before, but it matters
because at high speed, you're throwing out exhaust from a fuel you
previously had to spend energy accelerating. It's not an adequate
analysis to just look at the frame of reference of the rocket in flight,
you must consider how it reached that point. Low velocity high molecular
mass (= momentum) works better at slower speeds.
Clifford Heath.
On 8/9/19 11:52 am, Rick C wrote:
On Saturday, September 7, 2019 at 1:40:24 AM UTC-4, Clifford Heath wrote:
On 7/9/19 3:25 pm, Rick C wrote:
On Saturday, September 7, 2019 at 1:03:24 AM UTC-4, Clifford Heath wrote:
Also, all those rockets were single-use.
That was just an expedient as Musk is showing us.
Rubbish. His rockets are liquid-fuelled. Show me a similar re-usable
hydrogen-fuelled rocket and we have something to talk about.
Why is that relevant? The limitation to reusing rockets is the control to allow them to land and be recovered.
Because the single-use rockets are *fragile*. They are simply not
engineered to work at the duty cycle that commercial aviation needs, and
would be four times heavier if they were.
How many were reusing rockets of any type until Musk did it?
Even those are not likely to last a dozen launches, and that's good
engineering, since the failure rate from other causes is still higher
than that. They certainly couldn't approach the safety and duty cycle
needed for commercial aviation.
On Sunday, September 8, 2019 at 7:41:49 PM UTC-4, Clifford Heath wrote:
On 9/9/19 3:52 am, Rick C wrote:
On Sunday, September 8, 2019 at 1:16:06 PM UTC-4, upsid...@downunder.com wrote:
Liquid hydrogen has a much lower density than liquid oxygen or
kerosine. When burning substances the critical thing is the _mass_
ratio between fuel and oxidizer. Thus, to get the sufficient number of
kilograms of liquid hydrogen, a very large tank volume is needing,
which also requires heavier tank structures.
Most parts of the external tank (ET) are thus required for hydrogen, a
much smaller part is occupied by oxygen. If the Shuttle would take off
solely with hydrogen, the tank size would have to be many times
larger. To avoid this, the solid rocket booster (SRB) will create the
most trust during liftoff.
So why use hydrogen fuel? Was it the enviromental issues? They don't stop people from using other, not so environmentally friendly fuels in other rockets. Didn't someone post here that Musk is using kerosene? Is that why his rockets landing look like movie props from the 50's? Anyone else notice that?
Or maybe it's just because they are landing rather than taking off?
Hydrogen/Oxygen has a low molecular mass exhaust (very high
energy/momentum ratio), and the shuttle main engine is basically just
idling while the SRBs are firing . SRBs use rubber to produce a very
high molecular mass exhaust - high momentum/energy ratio suitable for
lower-speed (atmospheric) flight. When the SRBs are gone, the main
engine ramps up. I've tried to explain this before, but it matters
because at high speed, you're throwing out exhaust from a fuel you
previously had to spend energy accelerating. It's not an adequate
analysis to just look at the frame of reference of the rocket in flight,
you must consider how it reached that point. Low velocity high molecular
mass (= momentum) works better at slower speeds.
Clifford Heath.
You have me confused. Momentum is the name of the game, no? Isn't that the product of velocity and mass?
I thought the issue was a bit like nuke power plants vs. gas turbines. Solid rocket boosters can't be controlled once ignited. Liquid fuel can be controlled. So you can't do the whole job with solid rockets unless you don't care about the end game as is the case in missiles as weapons.
Doing a bit of searching...
"Compared to liquid engines, solid motors have a lower specific impulse â the measure rocket fuel efficiency that describes thrust per amount of fuel burned. However, the propellant is dense and burns quite quickly, generating a whole lot of thrust in a short time. And once theyâve burned their propellant and helped propel SLS into space, the boosters are discarded, lightening the load for the rest of the spaceflight."
So the real difference is that solid rockets have more thrust because the burn more rapidly. While they actually have lower specific impulse which means at the end of their burn they impart less energy to the space craft than a liquid fueled rocket would have, they do it more quickly getting the space craft up to speed faster.
So it doesn't seem to do with there being any advantage to "high molecular mass exhaust", rather simply the faster burn rate. In other words, solid fuels don't actually require a rocket engine as such, so their thrust is not limited by the same factors as liquid fueled rockets.
In case you didn't know, this isn't an aerospace group, so when
discussing aerospace topics it makes no sense to think everyone
will understand your abbreviations.
On 9/9/19 2:13 pm, Rick C wrote:
On Sunday, September 8, 2019 at 7:41:49 PM UTC-4, Clifford Heath wrote:
On 9/9/19 3:52 am, Rick C wrote:
On Sunday, September 8, 2019 at 1:16:06 PM UTC-4, upsid...@downunder.com wrote:
Liquid hydrogen has a much lower density than liquid oxygen or
kerosine. When burning substances the critical thing is the _mass_
ratio between fuel and oxidizer. Thus, to get the sufficient number of
kilograms of liquid hydrogen, a very large tank volume is needing,
which also requires heavier tank structures.
Most parts of the external tank (ET) are thus required for hydrogen, a
much smaller part is occupied by oxygen. If the Shuttle would take off
solely with hydrogen, the tank size would have to be many times
larger. To avoid this, the solid rocket booster (SRB) will create the
most trust during liftoff.
So why use hydrogen fuel? Was it the enviromental issues? They don't stop people from using other, not so environmentally friendly fuels in other rockets. Didn't someone post here that Musk is using kerosene? Is that why his rockets landing look like movie props from the 50's? Anyone else notice that?
Or maybe it's just because they are landing rather than taking off?
Hydrogen/Oxygen has a low molecular mass exhaust (very high
energy/momentum ratio), and the shuttle main engine is basically just
idling while the SRBs are firing . SRBs use rubber to produce a very
high molecular mass exhaust - high momentum/energy ratio suitable for
lower-speed (atmospheric) flight. When the SRBs are gone, the main
engine ramps up. I've tried to explain this before, but it matters
because at high speed, you're throwing out exhaust from a fuel you
previously had to spend energy accelerating. It's not an adequate
analysis to just look at the frame of reference of the rocket in flight,
you must consider how it reached that point. Low velocity high molecular
mass (= momentum) works better at slower speeds.
Clifford Heath.
You have me confused. Momentum is the name of the game, no? Isn't that the product of velocity and mass?
I thought the issue was a bit like nuke power plants vs. gas turbines. Solid rocket boosters can't be controlled once ignited. Liquid fuel can be controlled. So you can't do the whole job with solid rockets unless you don't care about the end game as is the case in missiles as weapons.
Doing a bit of searching...
"Compared to liquid engines, solid motors have a lower specific impulse â the measure rocket fuel efficiency that describes thrust per amount of fuel burned. However, the propellant is dense and burns quite quickly, generating a whole lot of thrust in a short time. And once theyâve burned their propellant and helped propel SLS into space, the boosters are discarded, lightening the load for the rest of the spaceflight."
So the real difference is that solid rockets have more thrust because the burn more rapidly. While they actually have lower specific impulse which means at the end of their burn they impart less energy to the space craft than a liquid fueled rocket would have, they do it more quickly getting the space craft up to speed faster.
So it doesn't seem to do with there being any advantage to "high molecular mass exhaust", rather simply the faster burn rate. In other words, solid fuels don't actually require a rocket engine as such, so their thrust is not limited by the same factors as liquid fueled rockets.
Ok, I'll try again, because you still haven't got it.
Consider a Hydrogen/LOX motor at subsonic/transsonic speeds. The fuel is
light, but bulky, and the exhaust velocity is very high, much higher
than the speed of the rocket. The exhaust has residual kinetic energy in
proportion to the (speed delta) squared, and returns momentum
proportionate to speed times mass flow rate as with any rocket.
Now introduce a high molecular mass gas into the exhaust stream, for
example by burning something that doesn't burn very well. It doesn't use
much LOX, but it produces a greatly increased exhaust density, which
means for the same peak nozzle temperature, you get a much slower
exhaust stream. Now you need less heat to produce the same momentum
change, so you can replace some of the H2/O2 fuel with the solid that
you're burning. You have to expend energy lifting (accelerating) that
extra reaction mass as you go.
If you run the numbers on this, it turns out that optimum performance is
achieved when the exhaust is at a slower velocity than H2/O2 alone; as
long as the rocket itself is still in small Mach numbers.
When you get to higher Mach numbers, the amount of energy you have to
expend in accelerating the extra reaction mass (in order to have brought
it with you) increases to the point it's not worth doing it. There's
little or nothing to be gained by using a high molecular mass exhaust gas..
This is how the space shuttle works. The SRBs lift the shuttle through
the atmosphere to around Mach 2 or so, then the main engine ramps up to
full power for higher speeds.
I suspect that NASAs scientists understand this a lot better than your
high-school physics allows you to. Please don't respond again unless
you're actually prepared to write a program that crunches the numbers on
it, as I have done (for a related problem also in rocketry). I won't
respond to further displays of ignorance.
Clifford Heath.