I can't wait for electric/hybrid aircraft.
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Adam - o you really think that 'they' cannot control electricity? Essentially electricity cannot be stored - at least not in serious quantities - unless yuou have your own hydroelectric dam, or a set of cells which could power a samll village.
As for your nonsense about transporting fuel? Why do you suppose it happens? Because petrol/diesel has an energy density whcih makes the whole thing possible. Petrol has a massive amountof energy - making the comparative low efficiency 0f 30% work.
Electricity? Well amazingly if is largely generated from fossils fuels - and the best efficiency is just over 40% - unless you use nuclear. So your 'clean' energy generates the same level of pollution and then you need a hugely expensive transmission system.
The Scottish government have just completed a public enquiry to look at the costs of upgrading the power transimission system to take power from the northa dn bring it into the grid. Costs are estimated to be in excess of £300M. Really cost effective? Only if it lasts for in excess of 50 years......
I suggest you don't old your breathe waitng for electrical aircraft. After 100 years we cannot make a practical electrical car - the easiest of modern devices................
As for your nonsense about transporting fuel? Why do you suppose it happens? Because petrol/diesel has an energy density whcih makes the whole thing possible. Petrol has a massive amountof energy - making the comparative low efficiency 0f 30% work.
Electricity? Well amazingly if is largely generated from fossils fuels - and the best efficiency is just over 40% - unless you use nuclear. So your 'clean' energy generates the same level of pollution and then you need a hugely expensive transmission system.
The Scottish government have just completed a public enquiry to look at the costs of upgrading the power transimission system to take power from the northa dn bring it into the grid. Costs are estimated to be in excess of £300M. Really cost effective? Only if it lasts for in excess of 50 years......
I suggest you don't old your breathe waitng for electrical aircraft. After 100 years we cannot make a practical electrical car - the easiest of modern devices................
I'm a bit more optimistic regarding power station capacity. Whether it saves energy is another matter - the biggest argument for electric cars isn't that they're more efficient but that they're cleaner. This is a much bigger issue at ground level in cities than in the middle of the sky over the countryside. Also, electric power gets a boost in relative efficiency for city driving, because it's much better than petrol when you're stopped at the lights. Not so relevant for aircraft.
My understanding is that the biggest problem for the grid at the moment, is peaks of power consumption - people putting the kettle on at half time of the world cup final etc. So there's actually excess capacity during times of relatively low demand. I don't see why it would inevitably break the grid to charge cars and aircraft overnight or when the wind's blowing and the turbines are whirring.
Some existing, commercially available batteries can be charged at rates of 5c or above (i.e in 12 minutes) so although it may be slower than filling a tank with petrol, charge times can still be perfectly practical.
As for taxing home wind turbines or solar panels on aircraft hangars... I don't think they'll be able to tax it (how much for my solar powered calculator?) but I'd be surprised if it were cost-effective any time soon.
The real cost benefit of electric power, in my view, would lie in the lack of maintenance required. One moving part. No need for a TBO. Battery packs with monitors that tell you how healthy your batteries are and when they need attention...
My understanding is that the biggest problem for the grid at the moment, is peaks of power consumption - people putting the kettle on at half time of the world cup final etc. So there's actually excess capacity during times of relatively low demand. I don't see why it would inevitably break the grid to charge cars and aircraft overnight or when the wind's blowing and the turbines are whirring.
Some existing, commercially available batteries can be charged at rates of 5c or above (i.e in 12 minutes) so although it may be slower than filling a tank with petrol, charge times can still be perfectly practical.
As for taxing home wind turbines or solar panels on aircraft hangars... I don't think they'll be able to tax it (how much for my solar powered calculator?) but I'd be surprised if it were cost-effective any time soon.
The real cost benefit of electric power, in my view, would lie in the lack of maintenance required. One moving part. No need for a TBO. Battery packs with monitors that tell you how healthy your batteries are and when they need attention...
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There is no battery technology which can be charged at 5C or anywhere near that and which will give you 1k cycles.
That argument is not so clear.
All "steam cycle" power plants (coal, oil, nuclear fission and even fusion when they get it working) are limited to ~ 40% efficiency.
Gas turbine plants are higher; not sure how, but there is not so much gas around.
Of course with nuclear, if you can deal with the waste, the efficiency is irrelevant. If you could fuse seawater, with the product being inert, 10% efficiency would be just fine
A diesel engine has at best 30-40% efficiency. Electric has 90%. Even if all your electricity comes from coal fired power plants, it's still environmentally better than extracting oil, refining it, trucking it, burning it in an inefficient gas engine.
All "steam cycle" power plants (coal, oil, nuclear fission and even fusion when they get it working) are limited to ~ 40% efficiency.
Gas turbine plants are higher; not sure how, but there is not so much gas around.
Of course with nuclear, if you can deal with the waste, the efficiency is irrelevant. If you could fuse seawater, with the product being inert, 10% efficiency would be just fine
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The real cost benefit of electric power, in my view, would lie in the lack of maintenance required
Inherently I think that electric aircraft are more expensive than Avgas aircraft. Its just taxation of Avgas that makes it more expensive.
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I am deeply suspicious of battery life claims.
I have never had any consumer product, with any battery technology, where the battery has made more than 100-200 cycles.
Just now, I have a Thinkpad laptop, original cost over £1000, whose "6hr" battery now makes about 1.5hrs. To be fair I probably knackered it by frequently topping it off before a trip, but that will happen with a car/plane too.
Only this one I can replace with an Ebay fake one for maybe £100 which will do "6hrs" (really maybe 4hrs, for maybe 100 cycles, before that goes in the bin too).
The £5k battery in your car or the £20k battery in your plane won't have an Ebay option
Presently the whole business, and most of the photovoltaics business, hangs together only due to huge subsidies, and a lot of people being more "green" than having brains, not to mention a lot of bent salesmen.
When I started in electronics business in 1978, my first product was a differential temperature controller for solar water heating Some of the salesmen who sold the systems ended up in jail; in some cases for assaulting customers. Their prey was mostly the retired rich homeowners in the more remote parts of the UK, west of Bournemouth especially. Apart from this "sharp" end of things, little has changed. Almost none of the systems will pay back before they fall to bits. Only swimming pool solar heating makes sense, due to using low grade heat and cheap and dirty materials.
I'd love to see electric cars and planes because it is such a super way to produce motion, but it is many years away before mainstream.
I have never had any consumer product, with any battery technology, where the battery has made more than 100-200 cycles.
Just now, I have a Thinkpad laptop, original cost over £1000, whose "6hr" battery now makes about 1.5hrs. To be fair I probably knackered it by frequently topping it off before a trip, but that will happen with a car/plane too.
Only this one I can replace with an Ebay fake one for maybe £100 which will do "6hrs" (really maybe 4hrs, for maybe 100 cycles, before that goes in the bin too).
The £5k battery in your car or the £20k battery in your plane won't have an Ebay option
Presently the whole business, and most of the photovoltaics business, hangs together only due to huge subsidies, and a lot of people being more "green" than having brains, not to mention a lot of bent salesmen.
When I started in electronics business in 1978, my first product was a differential temperature controller for solar water heating
Some of the salesmen who sold the systems ended up in jail; in some cases for assaulting customers. Their prey was mostly the retired rich homeowners in the more remote parts of the UK, west of Bournemouth especially. Apart from this "sharp" end of things, little has changed. Almost none of the systems will pay back before they fall to bits. Only swimming pool solar heating makes sense, due to using low grade heat and cheap and dirty materials.I'd love to see electric cars and planes because it is such a super way to produce motion, but it is many years away before mainstream.
My experience of rechargeable batteries is that they are not that reliable or long lifed. Capacity drops as they get old and they are very costly.
I have some experience with A123 batteries. They're a completely different kettle of fish from anything else I've used. Mine still hold 90% of their charge after 5 years and 100s of cycles. Other people have gotten 1000s of charges out of them. But at present, the specific energy density just isn't there.
The other question is how much the scrap value of a battery is... If you buy a battery for £5000 and scrap it for £4000 after 200 cycles, the economics change again (plucked those numbers out of thin air...). Whatever the figure, it compares well with the scrap value of avgas.
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IO, your TBO = battery life. There's no maintenance on the motors except bearing wear, so it's reasonable to accept this. Everything else will be simpler than it is now - everything. Isn't this a reasonable initial tradeoff to make? I say this as my aircraft is stuck in Chicago 1800 miles away from home with 2 trashed cylinders and one bad mag. If it had been electric, that airplane would have been home weeks ago for a fraction of the cost. Down time of exactly how long it would take to FedEx a new battery to me... Time is money.
Last edited by AdamFrisch; 26th Sep 2011 at 22:19.
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I am far from an expert, but owning one of the few electric powered aircraft (my self-sustaining glider) in the UK, having worked in the car industry mostly at the R&D end and in financial control of same, and general reading plus input from abgd and others, my opinion FWIW is this:
Electrics for gliders (get you home, or even self launch) – fine. Limited range is needed, payload is only one or at most two people, and it’s in a very efficient airframe (L/D say 50 for a modern glider in which these systems are becoming available, compared with 7 for a Cessna 162 say, and somewhat better but nothing like a glider for modern composite spamcan equivalents). For my glider, a one-off battery set specially shipped from Korea would cost about £5000 when it gets here. Some reduction in cost if greater volumes are sold. I guess the write-off/replacement cost is at most £10 per hour of use or per flight, and my use for gliding (to save an outlanding and a road retrieve, or to extend flight for various reasons) would only be as much as an hour (my system’s maximum – though there are others with greater duration) on a few flights per year out of the 50-100 I would expect to do. That is adequate capability for me. The capital cost of the modification is about the same as for an internal combustion engine self-sustaining set up which has greater range/duration (on at least some gliders) but is otherwise disadvantageous in several ways by comparison.
I think electrics for at least some power flying schools could also be viable, where mostly short details are required, and several battery packs per aircraft could be on charge. There is up front cash flow for multiple packs, but the amortised cost per flight is the same as for only one dedicated pack . With only one pack, and recharging taking however long it would, there would be consequent downtime and low utilisation. Even so, I doubt it would be profitable compared with conventional flying school aircraft.
For touring, I think only specialised aircraft, glider-like in performance etc., would be viable until there is a big advance in battery technology. I don’t know where that would come from.
From what I have seen of cars, electrics are hopelessly expensive in total cost of ownership and use, compared with petrol or diesel, and will be for decades. Hybrids are a bit better and may be worth what they really cost to some users. More, if governments skew the cost/benefit ratio by incentives such as traffic charging, tax etc. Otherwise, there too, a breakthrough in battery technology and cost is needed.
As to the general question of electric power generation, IMHO the world in general and the UK in particular are pursuing idiotic policies. Wind farms are generally a rubbish idea, grossly expensive, stupidly subsidised. We should be going nuclear and spend what it takes to ensure safety and long-term disposition of spent fuel. But that is a whole different ball game, and the government will not come to its senses for a decade or several.
Chris N
Electrics for gliders (get you home, or even self launch) – fine. Limited range is needed, payload is only one or at most two people, and it’s in a very efficient airframe (L/D say 50 for a modern glider in which these systems are becoming available, compared with 7 for a Cessna 162 say, and somewhat better but nothing like a glider for modern composite spamcan equivalents). For my glider, a one-off battery set specially shipped from Korea would cost about £5000 when it gets here. Some reduction in cost if greater volumes are sold. I guess the write-off/replacement cost is at most £10 per hour of use or per flight, and my use for gliding (to save an outlanding and a road retrieve, or to extend flight for various reasons) would only be as much as an hour (my system’s maximum – though there are others with greater duration) on a few flights per year out of the 50-100 I would expect to do. That is adequate capability for me. The capital cost of the modification is about the same as for an internal combustion engine self-sustaining set up which has greater range/duration (on at least some gliders) but is otherwise disadvantageous in several ways by comparison.
I think electrics for at least some power flying schools could also be viable, where mostly short details are required, and several battery packs per aircraft could be on charge. There is up front cash flow for multiple packs, but the amortised cost per flight is the same as for only one dedicated pack . With only one pack, and recharging taking however long it would, there would be consequent downtime and low utilisation. Even so, I doubt it would be profitable compared with conventional flying school aircraft.
For touring, I think only specialised aircraft, glider-like in performance etc., would be viable until there is a big advance in battery technology. I don’t know where that would come from.
From what I have seen of cars, electrics are hopelessly expensive in total cost of ownership and use, compared with petrol or diesel, and will be for decades. Hybrids are a bit better and may be worth what they really cost to some users. More, if governments skew the cost/benefit ratio by incentives such as traffic charging, tax etc. Otherwise, there too, a breakthrough in battery technology and cost is needed.
As to the general question of electric power generation, IMHO the world in general and the UK in particular are pursuing idiotic policies. Wind farms are generally a rubbish idea, grossly expensive, stupidly subsidised. We should be going nuclear and spend what it takes to ensure safety and long-term disposition of spent fuel. But that is a whole different ball game, and the government will not come to its senses for a decade or several.
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The only way self-generation would work would be if efficiency of solar panels at least doubles. It's on the cards, but not while the Government is encouraging bulk uptake of the low-efficiency panels by subsidising them.
The only reason that people are rushing to install at present is because of the crazy feed in tariff established by the government. This means you get paid about 45p/unit of electricity generated by solar power. Currently you can buy this same unit of electricity for about 11p/unit.
This means that it almost pays you to rig up a huge bank of lights running from the mains to illuminate your solar cells at night to continue getting the subsidy.
Of course, who pays for this....you guessed it the electricity consumer. Every one of us pays about £18 on our electricity bill to electricity companies. They then have to earmark this "tax" and spend it by subsidising daft things like solar cells.
If only they would spend the money getting insulation standards up to Nordic levels and getting heatpumps installed there would be real saving.
So, running your aircraft from electricity generated by solar cells is a non starter. The cost of the cells and the batteries would far exceed any savings on Avgas.
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What is needed is a quantum leap in "energy development" which will only come from someones back shed. & I don't think Dilithium Crystals will be involved.
Many years ago on "Tomorrows World" a self leveling device was demonstrated on a model a/c. This used the "atmopheric electromagnetic potential". This "energy" force was measured by sensors on each wing tip & the appropriate control inputs made by battery power.
Apparently this force changes with height but not by temperature/pressure/terain.
So how much energy is floating around that we with current technology know nothing about?
Another Tomorrows World thing was a water splitting system, used by some guy in Africa using a solar panel & river water to run a gas cooker.
Another used about 3 volts to split water & burn a hole in a piece of steel plate. Were these devices all a hoax? & if not where did they go? These things were described in the days when you could, I think, trust BBC2 to tell the truth.
Yes this is probably pie in the sky drivel, but I firmly believe that if some government/big business really put their mind to it the energy generating/battery development could be improved massively. In the same way that things happen when there is a war.
Many years ago on "Tomorrows World" a self leveling device was demonstrated on a model a/c. This used the "atmopheric electromagnetic potential". This "energy" force was measured by sensors on each wing tip & the appropriate control inputs made by battery power.
Apparently this force changes with height but not by temperature/pressure/terain.
So how much energy is floating around that we with current technology know nothing about?
Another Tomorrows World thing was a water splitting system, used by some guy in Africa using a solar panel & river water to run a gas cooker.
Another used about 3 volts to split water & burn a hole in a piece of steel plate. Were these devices all a hoax? & if not where did they go? These things were described in the days when you could, I think, trust BBC2 to tell the truth.
Yes this is probably pie in the sky drivel, but I firmly believe that if some government/big business really put their mind to it the energy generating/battery development could be improved massively. In the same way that things happen when there is a war.
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Apparently the earth gets hit daily by sun energy equal to the energy we use in a year globally.
But the goal with this thread was to claim the superiority of brushless electrical propulsion as the prime mover and how excellently well suited they are for aviation. It wasn't really my intention that it should become an alternative fuel/greenhouse discussion and certainly not a perpetuum mobile quasi-science thread, even though perhaps the two can't be entirely separated. I don't really care how or where the energy to power these electric motors come from, as long as it makes sense. Hybrids, batteries etc - whatever turns out to be cheaper and better for us.
But the goal with this thread was to claim the superiority of brushless electrical propulsion as the prime mover and how excellently well suited they are for aviation. It wasn't really my intention that it should become an alternative fuel/greenhouse discussion and certainly not a perpetuum mobile quasi-science thread, even though perhaps the two can't be entirely separated. I don't really care how or where the energy to power these electric motors come from, as long as it makes sense. Hybrids, batteries etc - whatever turns out to be cheaper and better for us.
Last edited by AdamFrisch; 28th Sep 2011 at 23:17.
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Adam.
In that respect I entirely agree with you. Electric motors would be the solution (full stop). The facts are that they are improving, but, In my opinion, not quickly enough. The advances made in batteries recently, power tools for example, point to the possibilities, which look encouraging. But there is not enough enthusiasm in them at the top to make it cheap enough & it is that fact that is disapointing.
In that respect I entirely agree with you. Electric motors would be the solution (full stop). The facts are that they are improving, but, In my opinion, not quickly enough. The advances made in batteries recently, power tools for example, point to the possibilities, which look encouraging. But there is not enough enthusiasm in them at the top to make it cheap enough & it is that fact that is disapointing.
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I'm sure I read that Audi were experimenting with wind power to create and store hydrogen for use in their cars. This seems like a solution to the problem of storing 'electricity' during the peaks and troughs of the weather. I could just imagine a little wind turbine on people's garages and a pipe leading to their car. And of course this would overcome the distribution problem. Or would it?
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Around the edges, there is a lot you can do.
I know a bloke who lives in the north and he has loads of photovoltaic panels and a 6kW wind turbine. Being where he is, the turbine obviously runs at 100% output 24/7 He could easily run his (specially built) house and an electric car off that lot. Or an electric plane.
But most people don't have that option. Wind turbines make a lot of noise; it needs to be a few hundred m away from the nearest neighbour.
And he spent several hundred k on the technology.
I know a bloke who lives in the north and he has loads of photovoltaic panels and a 6kW wind turbine. Being where he is, the turbine obviously runs at 100% output 24/7
He could easily run his (specially built) house and an electric car off that lot. Or an electric plane.But most people don't have that option. Wind turbines make a lot of noise; it needs to be a few hundred m away from the nearest neighbour.
And he spent several hundred k on the technology.
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IO540, If your friend lives in the North, he could simply dig a hole in his garden 200' or so deep and burn the coal that he excavates in a boiler running a steam generating set (he will have no shortage of water for the boiler). When he has to go to church or something, his children could help with 'winning' the coal.
The whole setup could generate 10's of KW reliably 24/7 and cost a fraction of what he (or the taxpayer) has spent on salesmen's bonuses. In addition, his energy plant will last 100yrs, won't reach an output half life in 2/3 years like the photvoltaics or blow down in a gale like the windmill either.
Come to think of it, I'm sure some Northerners have thought of this already...
The whole setup could generate 10's of KW reliably 24/7 and cost a fraction of what he (or the taxpayer) has spent on salesmen's bonuses. In addition, his energy plant will last 100yrs, won't reach an output half life in 2/3 years like the photvoltaics or blow down in a gale like the windmill either.
Come to think of it, I'm sure some Northerners have thought of this already...
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Could you burn the coal in situ, by igniting it and pumping air down there?
I think I will call my coal based invention "green, renewable energy". Compared with the vast resources needed to make photovoltaics, batteries, rare earth motors and windmills with their pitiful service life, it hits the spot.
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Meanwhile at Sonoma!
Monday morning, September 26, many of us had our first view of an electric airplane in flight.
After the weighing team rolled Jim Lee and Jeff Shingleton’s Phoenix motorglider from the hangar onto its impound location and completed initial weigh-ins for the remaining three aircraft, the airplanes were staged for the first flying event of the Green Flight Challenge sponsored by Google.
With technical inspections and weighing completed, the four airplanes lined up to check their noise levels and their ability to clear an imaginary 50-foot barrier atop a cherry picker 2,000 feet from the top of the number “9″ on runway 19 at Santa Rosa, California’s Charles M. Schulz Sonoma County Airport. As each aircraft rolled out to their takeoff point, the cluster of photographers under the cherry picker focused and waited for a green flag to fall at the takeoff point.
Top of flag marks 50-foot level
All the aircraft passed cleared the 50-foot flag, and e-Genius was judged to be quietest of the entrants after it took a second run. Its first had been marred by the noise of a Cessna allowed to take off on an adjoining runway. Although sound level results have not been announced, it was noted that e-Genius, even with the intruding sound, was a whisper-quiet 4 decibels quieter than the nearest competitor, the Pipistrel G4.
Even the Rotax-powered machines acquitted themselves admirably, being notably quieter than the more traditional light aircraft on the field.
As Monday’s efforts came to a close, all competitors could be happy with their quiet, but high-performance machines.
More at.
Green Flight Challenge – Day Two
EAA News - e-Genius, Pipistrel Contend for GFC Prize
Charlie
Monday morning, September 26, many of us had our first view of an electric airplane in flight.
After the weighing team rolled Jim Lee and Jeff Shingleton’s Phoenix motorglider from the hangar onto its impound location and completed initial weigh-ins for the remaining three aircraft, the airplanes were staged for the first flying event of the Green Flight Challenge sponsored by Google.
With technical inspections and weighing completed, the four airplanes lined up to check their noise levels and their ability to clear an imaginary 50-foot barrier atop a cherry picker 2,000 feet from the top of the number “9″ on runway 19 at Santa Rosa, California’s Charles M. Schulz Sonoma County Airport. As each aircraft rolled out to their takeoff point, the cluster of photographers under the cherry picker focused and waited for a green flag to fall at the takeoff point.
Top of flag marks 50-foot levelAll the aircraft passed cleared the 50-foot flag, and e-Genius was judged to be quietest of the entrants after it took a second run. Its first had been marred by the noise of a Cessna allowed to take off on an adjoining runway. Although sound level results have not been announced, it was noted that e-Genius, even with the intruding sound, was a whisper-quiet 4 decibels quieter than the nearest competitor, the Pipistrel G4.
Even the Rotax-powered machines acquitted themselves admirably, being notably quieter than the more traditional light aircraft on the field.
As Monday’s efforts came to a close, all competitors could be happy with their quiet, but high-performance machines.
More at.
Green Flight Challenge – Day Two
EAA News - e-Genius, Pipistrel Contend for GFC Prize
Charlie