Aircraft get in the air by simple thrust power from a jet engine or drag power by a propeller driven aircraft, once aloft the aerofoil section wing creates lift and keeps the aircraft in the sky. The world has mainly gone to jet engines for passenger aircraft, with turbo props used for only small regional hoppers, and props for private hobby use, and remote islands.
Let's take the latest two examples given.
"get aircraft with take-off weights of up to 1,800 kg (2 ton) off the ground. We're convinced that the use of hybrid-electric drives in regional airliners with 50 to 100 passengers is a real medium-term possibility."
Back to propeller driven aircraft then. But they haven't said where the electric power will come from (batteries?) to power these new electric motors. Have they factored that into their take off weight calculations? The smallest A318 aircraft with 110 seats has a take off weight of about 66 tons. The Gulfstream G280 business jet carries 10 passengers, take of weight 18 tons.
Also so the definition of term wasn't stated. Short term 5 years? medium term 20 years, long term 50 years?. Ok so they have invented a better electric motor driven propeller, and clearly want to bang the drum about it and sell some. PR blurb.
Next example
All electric ships with powerful propulsion are now possible for example.
Northrop Grumman Corporation have successfully load tested the most powerful electric motor ever tested by the U.S. Navy and the world’s first 36.5 megawatt (49,000 horsepower) high temperature superconductor (HTS) ship propulsion motor, double the Navy’s power rating test record.
Electric motors provide rotating shaft horsepower, they do not in themselves generate thrust. To achieve that they have to be connected to a driving device, either a ship or aircraft propeller. And the electric motor still needs to be driven by electricity generated separately. Usually on board ship that is by diesel engine generating sets, or gas turbines. Obviously impractical on an aircraft.
"In the the new UK aircraft carrier power is supplied by two Marine Trent MT30 36 MW (48,000 hp) gas turbine coupled to AC generator units, and four Wärtsilä diesel generator sets (two 12,000 hp and two 15,000 hp). The Trents and diesels together feed the low-voltage electrical systems as well as four GE Power Conversion's 20 MW Advanced Induction electric propulsion motors (arranged in tandem) that drive the twin fixed-pitch propellers." 104 Auxiliary Transformers for all of the ships mission system and domestic supplies.
So the latest ships are not all electric, by any means, and never will be. Even hunter killer subs need nuclear reactors to provide basic power.
Waiting for Godot & salvation :-)
Why do doctors have to practice?
You'd think they'd have got it right by now
Something can never be all electric as the electricity comes from somewhere, always. Be that a solar panel, some kind of reactor or whatever.
My point is that there is progress being made in creating increasingly more powerful electric propulsion at the same or lower weight.
On the other side solar panels are getting better, batteries getting a higher weight to energy ratio, alternative in flight recharging options being researched, mobile generators created etc. There are plenty of smart people trying to make a change and they are making significant progress. Continue making progress for a long enough time and you will eventually achieve your goals.
As I see it your trying to make a point that it's all wasted effort, we as mankind will will never succeed.
The drive to go electric comes from multiple reasons, it more silent, thus will increase comfort. But more importantly it allows to reduce and eventually stop fossil fuel usage and doing so save the environment and make us independent of the oil producing countries. Even a nuclear reactor does not produce CO2.
What may be of interest, or not depending, is the following two key curves :
The upper diagram indicates what the Sun delivers to us at this planet. If you want more then shift the orbit closer in, make gigantic space mirrors etc. For each choice of light wavelength you can gauge how much optical power ( energy per time ) is delivered that lands on a given area ( to be exact : the en-face equivalent perpendicular to the direction of the Sun ). To the left side are shorter wavelength and higher frequency photons ( more energy per photon ) and to the right side are longer wavelength but lower frequency photons ( less energy per photon ).
{ Photon energy is proportional to frequency and inversely proportional to wavelength. Thus, for example, a 400 nm photon has three times the energy of a 1200 nm one. }
The lower diagram indicates a measure, per wavelength, of the efficiency a solar cell to deliver usable energy to some electrical circuit eg. wheels, propellers, TVs, batteries, Nintendo etc. The horizontal scale is in micrometers ie. multiply by 1000 to equate the upper diagram. The red line is the theoretical/engineering expectation, the blue is what is measured ( so is 400 to 1200 nm approx ). The red isn't some limit of physics, just the limit of the silicon lattices as used etc.
One obvious point is that the most energetic photons ( lower wavelength ) are also those which have the least efficiency to generate current at the solar cell. Roughly speaking it will harvest the energy of higher energy photons at half the rate of lower energy ones. Also note the altitude comment : the higher above ground you go the more radiation there is ie. the atmosphere stops us frying. Obviously the more area you have, or the longer you wait, then the more energy one might accumulate in storage or expend on some load.
Don't take this description as too exact, but it describes the situation very well overall. For instance if you wanted to estimate the power production ( per square meter of exposed silicon ) then the area under the top curve adjusted for the yield as per the lower curve is the answer ( ie. integrate the combined function b/w ordinate limits ). Better answers require one to get right down in the weeds of more precise actual device specification ......
What would be tremendous is some other new device type/technology that exceeds silicon substrate's ability in converting incident light to electron energies in a useful way. For example your swimming pool cover already partly does that as we speak, however no current can be directly derived from that ! You'd have to insert some other process to do that. Oh, I don't know ..... heat water to steam and run a turbine that spins a generator ..... whatever. Which is what all that entropy crap, alluded to earlier, was all about. :-)))
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
Ah now, Mikes top chart certainly shows how it is doesn't it. This fictitious electric aircraft lands on the runway at sea level or thereabouts, below cloud cover and, oooops it stays there. Has to be towed off to the stand as no power. Solar power will never produce the levels of energy to provide meaningful public transport, particularly aircraft.
Modern aircraft use the engines when running to generate internal power. When at the stand the ground crew attach cables to power it.
Electric vehicles are not new, anyone over 60 in the UK will remember the ubiquitous Express Dairy Milk Float, rattling down the street with glass bottles in metal crates. All gone now, but they needed an all night charge to operate the next day. And did you see the size of the batteries in those? We still have electric forklift trucks in factories but they have to be permanently connected to a charger when not used.
Electric motive power has been around in commerce and industry for many decades, but is only recently that it has been applied to passenger vehicles. I can see it catching on for taxi firms, maybe public transport up to a point, but not for mass ownership of private vehicles across the board.
Ok we know solar, wind, nor wave power will generate the electrical power we need. So we have to generate it in another ways. At present for the public it is by Power stations fired by coal, gas, oil, hydro electric, or nuclear. the first 3 are fossil fuels which will run out, the 4th ruins the environment, the last has waste disposal problems.
Aircraft run on aviation spirit which is based on oil, which will run out one day. Diesel electricity generators run on Diesel fuel, based on oil, which will run out one day. Bio-diesel fuels maybe a possibility. It is unlikely that we can invent miniature nuclear power plants to go in aircraft or vehicles. Yes in submarines but that is military. So let people invent better electrical equipment, motors, generators, whatever. The day will come in time when we won't need them. But hey let them make a buck while they can
Possibly massive underground nuclear power plants coupled with super battery technology for charging and storage might pave the way for ground living and transport. But with no oil left we won't need tankers with massive electric motors to drive them. Will we need long distance air travel by any means? Possibly not. Warships? Who knows.
The latest UK carrier was not nuclear powered because of cost. When there is no other option than nuclear that is the way it will go.Unless some sort of anti gravity drive or star trek transporter gets invented :-))
Waiting for Godot & salvation :-)
Why do doctors have to practice?
You'd think they'd have got it right by now
Indeed. The figure of great practical merit is that single digit Watts per square meter per nanometre order of magnitude via photocells achievable at present.
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
Spot on Mike. Solar power is limited in what it can do at present. Anywhere near the tropics will benefit from all day sunlight, us poor souls that live in the northern latitudes will miss out big time. But it has to be said that solar panels are being developed that can charge on a cloudy or overcast day, but are as yet expensive. They will get more efficient with time, but only up to a point.
Going back to this notion of solar power satellites for a minute, there would have to be many thousands of them and in Geo-stationary orbit, to cover the whole earth, so that half of them would always be on the dark side of the earth every night as the planet rotates. Not very good for long haul overnight aircraft flights. The concept is totally flawed!
Aircraft run on aviation spirit which is based on oil, which will run out one day. Diesel electricity generators run on Diesel fuel, based on oil, which will run out one day. Bio-diesel fuels maybe a possibility. It is unlikely that we can invent miniature nuclear power plants to go in aircraft or vehicles. Yes in submarines but that is military. So let people invent better electrical equipment, motors, generators, whatever. The day will come in time when we won't need them. But hey let them make a buck while they can.
ACTUALLY the US and Russia have been there done that and got the t-shirt to prove it by putting a nuclear reactor on an airplane and flying it back in the 1950's!
A nuclear-powered aircraft is a concept for an aircraft intended to be powered by nuclear energy. During the Cold War, the USA and Russia researched nuclear-powered bomber aircraft, the greater endurance of which could enhance nuclear deterrence, but neither country created any such operational aircraft, and the reactor never powered the engines.
One inadequately solved design problem was the need for heavy shielding to protect the crew and those on the ground from radiation.
However, the advent of ICBM's and Nuclear subs in the 1960s greatly diminished the tactical advantage of such aircraft, and respective projects were cancelled; the inherent danger of the technology has prevented its civilian use.
On Earth, thorium is 8.1 ppm in the Earth's crust, mainly in monazite, euxenite and thorianite. It is one of the most abundant of the heavy elements. But worldwide production of thorium is low, at a few tens of tons per year. Non-radioactivity-related uses have been on decline since the 1950s. Many applications of thorium are becoming obsolete due to environmental concerns largely stemming from the radioactivity of thorium and its decay products. Thorium is thus being phased out of many of its uses.
Thorium has been suggested as a potent nuclear power source and a possible replacement to the currently used uranium and plutonium. But the used fuel is difficult and dangerous to reprocess because many of the daughters of 232Th and 233U are strong gamma emitters.
I do not see any likelihood of all electric aircraft or nuclear powered aircraft in the foreseeable future, no matter how many people want to imagine that it might just be possible. Renewable Biodiesel fuels are available now which can power existing aircraft Jet engines, stationary diesel generating sets, and other renewable bio-fuels are being developed for land transport. That is the real practical future for the time being.
Waiting for Godot & salvation :-)
Why do doctors have to practice?
You'd think they'd have got it right by now
Aircraft get in the air by
Aircraft get in the air by simple thrust power from a jet engine or drag power by a propeller driven aircraft, once aloft the aerofoil section wing creates lift and keeps the aircraft in the sky. The world has mainly gone to jet engines for passenger aircraft, with turbo props used for only small regional hoppers, and props for private hobby use, and remote islands.
Let's take the latest two examples given.
Back to propeller driven aircraft then. But they haven't said where the electric power will come from (batteries?) to power these new electric motors. Have they factored that into their take off weight calculations? The smallest A318 aircraft with 110 seats has a take off weight of about 66 tons. The Gulfstream G280 business jet carries 10 passengers, take of weight 18 tons.
Also so the definition of term wasn't stated. Short term 5 years? medium term 20 years, long term 50 years?. Ok so they have invented a better electric motor driven propeller, and clearly want to bang the drum about it and sell some. PR blurb.
Next example
Electric motors provide rotating shaft horsepower, they do not in themselves generate thrust. To achieve that they have to be connected to a driving device, either a ship or aircraft propeller. And the electric motor still needs to be driven by electricity generated separately. Usually on board ship that is by diesel engine generating sets, or gas turbines. Obviously impractical on an aircraft.
So the latest ships are not all electric, by any means, and never will be. Even hunter killer subs need nuclear reactors to provide basic power.
Waiting for Godot & salvation :-)
Why do doctors have to practice?
You'd think they'd have got it right by now
I don't really get your
I don't really get your point.
Something can never be all electric as the electricity comes from somewhere, always. Be that a solar panel, some kind of reactor or whatever.
My point is that there is progress being made in creating increasingly more powerful electric propulsion at the same or lower weight.
On the other side solar panels are getting better, batteries getting a higher weight to energy ratio, alternative in flight recharging options being researched, mobile generators created etc. There are plenty of smart people trying to make a change and they are making significant progress. Continue making progress for a long enough time and you will eventually achieve your goals.
As I see it your trying to make a point that it's all wasted effort, we as mankind will will never succeed.
The drive to go electric comes from multiple reasons, it more silent, thus will increase comfort. But more importantly it allows to reduce and eventually stop fossil fuel usage and doing so save the environment and make us independent of the oil producing countries. Even a nuclear reactor does not produce CO2.
What may be of interest, or
What may be of interest, or not depending, is the following two key curves :
The upper diagram indicates what the Sun delivers to us at this planet. If you want more then shift the orbit closer in, make gigantic space mirrors etc. For each choice of light wavelength you can gauge how much optical power ( energy per time ) is delivered that lands on a given area ( to be exact : the en-face equivalent perpendicular to the direction of the Sun ). To the left side are shorter wavelength and higher frequency photons ( more energy per photon ) and to the right side are longer wavelength but lower frequency photons ( less energy per photon ).
{ Photon energy is proportional to frequency and inversely proportional to wavelength. Thus, for example, a 400 nm photon has three times the energy of a 1200 nm one. }
The lower diagram indicates a measure, per wavelength, of the efficiency a solar cell to deliver usable energy to some electrical circuit eg. wheels, propellers, TVs, batteries, Nintendo etc. The horizontal scale is in micrometers ie. multiply by 1000 to equate the upper diagram. The red line is the theoretical/engineering expectation, the blue is what is measured ( so is 400 to 1200 nm approx ). The red isn't some limit of physics, just the limit of the silicon lattices as used etc.
One obvious point is that the most energetic photons ( lower wavelength ) are also those which have the least efficiency to generate current at the solar cell. Roughly speaking it will harvest the energy of higher energy photons at half the rate of lower energy ones. Also note the altitude comment : the higher above ground you go the more radiation there is ie. the atmosphere stops us frying. Obviously the more area you have, or the longer you wait, then the more energy one might accumulate in storage or expend on some load.
Don't take this description as too exact, but it describes the situation very well overall. For instance if you wanted to estimate the power production ( per square meter of exposed silicon ) then the area under the top curve adjusted for the yield as per the lower curve is the answer ( ie. integrate the combined function b/w ordinate limits ). Better answers require one to get right down in the weeds of more precise actual device specification ......
What would be tremendous is some other new device type/technology that exceeds silicon substrate's ability in converting incident light to electron energies in a useful way. For example your swimming pool cover already partly does that as we speak, however no current can be directly derived from that ! You'd have to insert some other process to do that. Oh, I don't know ..... heat water to steam and run a turbine that spins a generator ..... whatever. Which is what all that entropy crap, alluded to earlier, was all about. :-)))
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
Ah now, Mikes top chart
Ah now, Mikes top chart certainly shows how it is doesn't it. This fictitious electric aircraft lands on the runway at sea level or thereabouts, below cloud cover and, oooops it stays there. Has to be towed off to the stand as no power. Solar power will never produce the levels of energy to provide meaningful public transport, particularly aircraft.
Modern aircraft use the engines when running to generate internal power. When at the stand the ground crew attach cables to power it.
Electric vehicles are not new, anyone over 60 in the UK will remember the ubiquitous Express Dairy Milk Float, rattling down the street with glass bottles in metal crates. All gone now, but they needed an all night charge to operate the next day. And did you see the size of the batteries in those? We still have electric forklift trucks in factories but they have to be permanently connected to a charger when not used.
Electric motive power has been around in commerce and industry for many decades, but is only recently that it has been applied to passenger vehicles. I can see it catching on for taxi firms, maybe public transport up to a point, but not for mass ownership of private vehicles across the board.
Ok we know solar, wind, nor wave power will generate the electrical power we need. So we have to generate it in another ways. At present for the public it is by Power stations fired by coal, gas, oil, hydro electric, or nuclear. the first 3 are fossil fuels which will run out, the 4th ruins the environment, the last has waste disposal problems.
Aircraft run on aviation spirit which is based on oil, which will run out one day. Diesel electricity generators run on Diesel fuel, based on oil, which will run out one day. Bio-diesel fuels maybe a possibility. It is unlikely that we can invent miniature nuclear power plants to go in aircraft or vehicles. Yes in submarines but that is military. So let people invent better electrical equipment, motors, generators, whatever. The day will come in time when we won't need them. But hey let them make a buck while they can
Possibly massive underground nuclear power plants coupled with super battery technology for charging and storage might pave the way for ground living and transport. But with no oil left we won't need tankers with massive electric motors to drive them. Will we need long distance air travel by any means? Possibly not. Warships? Who knows.
The latest UK carrier was not nuclear powered because of cost. When there is no other option than nuclear that is the way it will go.Unless some sort of anti gravity drive or star trek transporter gets invented :-))
Waiting for Godot & salvation :-)
Why do doctors have to practice?
You'd think they'd have got it right by now
Indeed. The figure of great
Indeed. The figure of great practical merit is that single digit Watts per square meter per nanometre order of magnitude via photocells achievable at present.
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
Spot on Mike. Solar power is
Spot on Mike. Solar power is limited in what it can do at present. Anywhere near the tropics will benefit from all day sunlight, us poor souls that live in the northern latitudes will miss out big time. But it has to be said that solar panels are being developed that can charge on a cloudy or overcast day, but are as yet expensive. They will get more efficient with time, but only up to a point.
Going back to this notion of solar power satellites for a minute, there would have to be many thousands of them and in Geo-stationary orbit, to cover the whole earth, so that half of them would always be on the dark side of the earth every night as the planet rotates. Not very good for long haul overnight aircraft flights. The concept is totally flawed!
UK power grid tinkering
Waiting for Godot & salvation :-)
Why do doctors have to practice?
You'd think they'd have got it right by now
Chris S_2 wrote: Aircraft
ACTUALLY the US and Russia have been there done that and got the t-shirt to prove it by putting a nuclear reactor on an airplane and flying it back in the 1950's!
http://mentalfloss.com/article/53184/brief-history-nuclear-airplanes
A nuclear-powered aircraft is
A nuclear-powered aircraft is a concept for an aircraft intended to be powered by nuclear energy. During the Cold War, the USA and Russia researched nuclear-powered bomber aircraft, the greater endurance of which could enhance nuclear deterrence, but neither country created any such operational aircraft, and the reactor never powered the engines.
One inadequately solved design problem was the need for heavy shielding to protect the crew and those on the ground from radiation.
However, the advent of ICBM's and Nuclear subs in the 1960s greatly diminished the tactical advantage of such aircraft, and respective projects were cancelled; the inherent danger of the technology has prevented its civilian use.
info link
Waiting for Godot & salvation :-)
Why do doctors have to practice?
You'd think they'd have got it right by now
Perhaps Thorium will be our
Perhaps Thorium will be our new main energy source.
Who knows if we could make such things portable enough for usage in aircraft.
On Earth, thorium is 8.1 ppm
I do not see any likelihood of all electric aircraft or nuclear powered aircraft in the foreseeable future, no matter how many people want to imagine that it might just be possible. Renewable Biodiesel fuels are available now which can power existing aircraft Jet engines, stationary diesel generating sets, and other renewable bio-fuels are being developed for land transport. That is the real practical future for the time being.
Waiting for Godot & salvation :-)
Why do doctors have to practice?
You'd think they'd have got it right by now