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Electric Powered Aircraft
Norway aviation firm orders 60 electric planes tipped to be “Tesla” of flight
https://thedriven.io/wp-content/uplo...32-800x450.jpg The Bye Aerospace eFlyer. Source: OSM Aviation A Norwegian aviation group has ordered 60 all-electric eFlyer2 planes, built by Colorado-based Bye Aerospace, with the intention of training a future generation of pilots in electric flight. The order was announced on Thursday (overnight, Australian time) by OSM Aviation, which specialises in the training and supply of aircrew and which says the electric aircraft will be used at its flight training centres to qualify pilots. With aviation accounting for around 12% of all global transport emissions, the order is a step towards a sustainable future for OSM Aviation and Norway’s goal to shift all short-haul routes to electric flight by 2040. “We’re proud to take the lead in the future of green aviation.” said OSM Aviation Group CEO Espen Høiby in a statement. “This is the largest order for commercial electric planes to date. “It’s important that the airline industry steps up to the challenge of developing more environment-friendly transport. At OSM Aviation, we’re committed to pursuing a socially responsible and sustainable business,” Høiby said. “We’re training the next generation of pilots, and are determined to attract the best candidates. “We offer a forward-looking education which they can be proud to take part in. This order for 60 all-electric aircraft is a key step in that respect,” said Bjørn Granviken, managing director of the OSM Aviation Academy. The eFlyer, formerly the Sun Flyer, is a 2-seater electric fixed wing plane that has been described by Bye Aerospace’s Norwegian partner Elfly AS as a game changer for the aviation industry. “I think [Bye Aerospace] will be the first to mass produce a certified FAR 23 and EASA 23 all-electric airplane,” said Eric Lithun, CEO of Elfly AS in a statement. “This is the game changer of aviation for small airplanes. The Bye Aerospace eFlyer will be the Tesla of the general aviation industry.” So far, Bye Aerospace say it has received almost 300 orders for the eFlyer2, which completed its first successful test at Centennial Airport, south of Denver, Colorado in February this year and is kitted with electric propulsion from Siemens. With electric flight offering not only reduced carbon emissions but also noise pollution, as well as superior speed and altitude performance according to Høiby, he says that the electrification of the aviation industry is inevitable. This opinion is echoed by Ketil Solvik Olsen, former Norwegian minister for transport and communications and now responsible for establishing the OSM Aviation Academy. “The state-owned Avinor company, which operates most of Norway’s civilian airports, made headlines last year when it piloted test flights with an electric plane,” Solvik Olsen noted in a statement. “This made more people aware of the potential for green aviation. Now OSM shows that the business community is ready to take charge and move the industry further along this positive trend.” OSM Aviation joins other short-haul airlines beginning to switch to electric flight , such as Hawaiian Mokulele Airlines which plans to offer converted electric Cessnas for flight by 2021. Link to article: https://thedriven.io/2019/04/12/norw...sla-of-flight/ |
Is it powered by a lithium ion battery? I suspect the weight would prevent any decent payload for a serious commercial operation. |
I would be a lot more impressed if there was mention of Horsepower, Battery capacity etc. At the moment this just comes across as a ‘puff piece’. |
There was a live broadcast from Malmi airfield on a Finnish channel, maybe last summer but perhaps the one before, of a chap who flew a circuit in an electric airplane. I was quite impressed. Can't remember much more. |
These guys are currently just round the corner from me at Staverton - https://electro-flight.com/
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Originally Posted by KiloB
(Post 10446177)
I would be a lot more impressed if there was mention of Horsepower, Battery capacity etc. At the moment this just comes across as a ‘puff piece’.
Bye were quoting 65 orders 3 years ago, but AFAIK only one example has flown to date. |
If they are interested in utilising an electric aircraft and considering the number of lakes in Norway. I believe a better fit would be this Norwegian amphibian.
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So using their own figures, it has an endurance of about 26 min at 75% cruise, not counting taxi and takeoff! |
Originally Posted by KiloB
(Post 10446177)
I would be a lot more impressed if there was mention of Horsepower, Battery capacity etc. At the moment this just comes across as a ‘puff piece’. - 440 lb payload (subtracting projected EW of 1460 lbs including batteries, from projected GTOW of 1900 lbs) - 3.5 hours endurance - 92 kWh total battery capacity, in 6 packs. - Siemens SP70D motor - max. output 90kW, continuous output 70kW, obviously "throttled" to less than that to obtain projected endurance - 135 kts max speed - engine weight 57 lbs - $3 per hour operating costs Note the engine and battery suppliers have changed since Dave's 2016 specs. It flies - remains to be seen how fast, for how long, and how far. |
Brilliant Idea
OSM are indeed ahead of the pack.
3,5 hrs endurance , now that is good. Considering the total world pollution from Aviation IS 2% and OSM CLAIMS it is 12% I for one would like dobbelcheck any and all numbers that comes out of that outfit. Tok litt vell mye Møllers Tran der du. ( "Overdosed slightly on the Codliver Oil " as the add goes in Norway!) Aviation Pollution is NOT a problem in the world, at 2 %! If it was 12% I would agree it needs fixing. It aint broke Why fix it. Mind you there will eventually be some elec planes around, and training is for sure the place to start. Need a bit more then 26 min endurance me thinks Regards Cpt B |
Horizon Flyer
Now that was cool!
Not sure I would fly that thing especially on water! The wings are to low and close on landing so any roll/bank and I suspect it is game over, but that is the pessimist and the old floatpilot in me. If put into production it definitely has potential. Lots of plastic fantastic stuff out there and combined with elec and amfib is indeed cool |
Car battery (varta e44 77Ah) Weight 18 kg. Usable energy stored 2.21MJ. 18 kg Jet A1 or gasoline: 803MJ of usable energy.
Going any fancy battery (lithium ion) will do x2 energy x10 price for the same weight. Best commercial battery in the world x3 energy, x100 price. I know you don't believe me, but these are the facts. You need roughly 100 times the weight in fuel (because electric engines extract energy from batteries roughly 2x better than piston engines from fuel). So if you load 120kg of gas in your cessna 172 to do a trip, you would need 12000kgs (yes, 12 tons) of batteries to do the same trip. Only now of course you need an A318 to lift the batteries. To sum it up, if you retrofit an airbus 318 with half a million $ worth of batteries (12000kg) and you find someone to donate two electric engines with enough thrust, you end up with a theoretical range of 57km. As of today, we produce electricity basically burning stuff. In cars, regen braking and all, you produce the same CO2 with an electric car than with a petrol one. They make a little sense because you take pollution away from city center. But in planes, where wheels do not happily cancel the weight penalty at constant speed, the idea is crazy beyond belief. Completely derailed. |
I was hired to conduct a design review toward approval of an electric refit for a 172. The plans had merit, but where it lost traction was that for a half to an hour of flying, there would be a many hour recharge period. Either the aircraft would be out of service for most of the rest of the day charging, or it would be necessary to change out heavy battery packs multiple times; meaning owning several, and then inevitable damage to the airframe handling such a heavy weight in and out or around regularly. The time will come, but right now the investment in a costly aircraft which must sit idle and change hours per minutes of flying is difficult to justify for a working plane.
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Originally Posted by Pilot DAR
(Post 10446417)
The time will come, but right now the investment in a costly aircraft which must sit idle and change hours per minutes of flying is difficult to justify for a working plane.
e.g. for fastest charging in the case of a Tesla you use a DC supply that bypasses the internal Charger(s) in the vehicle. 400 V DC as I recall. https://en.wikipedia.org/wiki/Pipistrel_Alpha_Trainer "It has energy for one flight hour plus reserves, and can recharge in 45 minutes or have its batteries replaced in 5 minutes" https://electrek.co/2018/11/08/porsc...harging-250kw/ "Porsche claims that the 800V chargers can charge the battery pack to 80% in about 15 minutes" I suspect that you need to slow down for the last bit as the batteries approach full charge. The deal is done. Another deal - Tesla recently bought Maxwell Technologies - "Maxwell claims this could boost battery capacity to 300 Wh/kg, a 20% jump over the best available electric-car batteries." They say it just needs productionised. This is interesting - Blown wing to reduce stall speed and allow much higher wing loading for cruise efficiency. https://en.wikipedia.org/wiki/Airbus_E-Fan Also the Pipistrel above "has 277 pounds (126 kg) of LiPo cells, however the water cooled electric motor weighs 11 kg". This allows much more power to be available for a short time for a small weight penalty. e.g. At present a twin engine helicopter carries around a spare gas turbine all the time for the case where one engine fails. A spare engine in the Pipistrel would only weigh 11 kg! (Of course perhaps an 80hp gas turbine only weighs 11kg - I am not sure?). There seems the possibility of hybrid aircraft where say gas turbines are used for cruise and electric propulsion added for take-off and landing. A lot of development going on for sure. |
With so many getting into it now an advancements it’s only a matter of time. Perfdct for its Mission - https://www.magnix.aero/ |
Yeah, dream all you want. BTDT. When you have 400 times less energy per kg, all things considered, no amount of politics will make it a viable alternative for airborne trasport. Period.
You can reduce it to a 40 times worse by using the best batteries, and the best engines and the best engine drivers and then bending the numbers up to their ultimate tensile strength, but there you hit a wall. That 300wh/kg of that fantanstic battery from maxwell (which I totally not believe) means a total 1.08Mj/kg. Gas has 46.4Mj/kg. Except that the former is ideal conditions and the latter is always. Usual problems nobody tells you until it's too late: - You cannot extract all the energy from a battery, no matter at which rate you do it. - You cannot extract any energy from a battery if it is freezing. - The energy you get from a battery is inversely proportional to how fast you discharge it and how cold it is. - You may trade energy density at the cost of power density, so never pay attention to a number without the other. - After each cycle, battery stores less and less energy. A typical bad case scenario (typical bad load profile, typical bad temperature, typical bad wear...) is several times worse that the ideal. Only you need to guarantee the range in any sort of vehicle in typical bad scenarios. Gas is not affected by any of that, LI-ON is. Many politicians have been fooled already and many more will, but this is a dead end until somebody invents a 40x better battery. |
Originally Posted by horizon flyer
(Post 10446259)
If they are interested in utilising an electric aircraft and considering the number of lakes in Norway. I believe a better fit would be this Norwegian amphibian.
Home |
Originally Posted by ecto1
(Post 10446571)
Yeah, dream all you want. BTDT. When you have 400 times less energy per kg, all things considered, no amount of politics will make it a viable alternative for airborne trasport. Period.
You can reduce it to a 40 times worse by using the best batteries, and the best engines and the best engine drivers and then bending the numbers up to their ultimate tensile strength, but there you hit a wall. That 300wh/kg of that fantanstic battery from maxwell (which I totally not believe) means a total 1.08Mj/kg. Gas has 46.4Mj/kg. Except that the former is ideal conditions and the latter is always. Usual problems nobody tells you until it's too late: - You cannot extract all the energy from a battery, no matter at which rate you do it. - You cannot extract any energy from a battery if it is freezing. - The energy you get from a battery is inversely proportional to how fast you discharge it and how cold it is. - You may trade energy density at the cost of power density, so never pay attention to a number without the other. - After each cycle, battery stores less and less energy. A typical bad case scenario (typical bad load profile, typical bad temperature, typical bad wear...) is several times worse that the ideal. Only you need to guarantee the range in any sort of vehicle in typical bad scenarios. Gas is not affected by any of that, LI-ON is. Many politicians have been fooled already and many more will, but this is a dead end until somebody invents a 40x better battery. But in certain applications, electric doesn't just make sense, it's highly preferable- such as training which this aircraft is aimed at. Another is self launching/ sustainer engines for gliders, there are already several commercially available. |
Something doesn't add up
Originally Posted by ecto1
(Post 10446571)
Yeah, dream all you want. BTDT. When you have 400 times less energy per kg, all things considered, no amount of politics will make it a viable alternative for airborne trasport. Period.
You can reduce it to a 40 times worse by using the best batteries, and the best engines and the best engine drivers and then bending the numbers up to their ultimate tensile strength, but there you hit a wall. That 300wh/kg of that fantanstic battery from maxwell (which I totally not believe) means a total 1.08Mj/kg. Gas has 46.4Mj/kg. Except that the former is ideal conditions and the latter is always. Usual problems nobody tells you until it's too late: - You cannot extract all the energy from a battery, no matter at which rate you do it. - You cannot extract any energy from a battery if it is freezing. - The energy you get from a battery is inversely proportional to how fast you discharge it and how cold it is. - You may trade energy density at the cost of power density, so never pay attention to a number without the other. - After each cycle, battery stores less and less energy. A typical bad case scenario (typical bad load profile, typical bad temperature, typical bad wear...) is several times worse that the ideal. Only you need to guarantee the range in any sort of vehicle in typical bad scenarios. Gas is not affected by any of that, LI-ON is. Many politicians have been fooled already and many more will, but this is a dead end until somebody invents a 40x better battery. |
I believe that electric flight could be privately explored for research purposes. And probably we need test pilots, and we need to train them and this may be a good plane to do it. So far so good, as long as I don't pay.
But I don't swallow the "almost there" mantra, nor that this aircraft is the TESLA of general aviation. I don't agree if you say training for gas flight is better done in an electric trainer (I'm not sure you said that, I'm sorry if you didn't). And specially not that electric flight offers "superior speed and altitude performance". It makes me sad to see that people manipulates the truth with such impunity. If cessnas necessitated superior speed and altitude performance, regardless of the rest of factors such as price or measuring endurance in hours or minutes, they would simply use a couple cylinders more and 10 times less fuel. |
Originally Posted by msjh
(Post 10446595)
If you get 400 times less energy per kg, how do Teslas manage to work?
As of today, we produce electricity basically burning stuff. In cars, regen braking and all, you produce the same CO2 with an electric car than with a petrol one. They make a little sense because you take pollution away from city center. But in planes, where wheels do not happily cancel the weight penalty at constant speed, the idea is crazy beyond belief. Completely derailed. And it absolutely does not "work" from an economic perspective, judging by Tesla's financials. But it's a nice way to signal ones green virtue, if you have a hundred grand lying around. Just don't speak too loudly of the environmental horror that li-ion batts on that scale represent. |
Originally Posted by msjh
(Post 10446595)
If you get 400 times less energy per kg, how do Teslas manage to work?
Drag (the main reason you need energy to commute) is proportional to frontal area, which is not affected by how many kgs of "energy storage" you move about (in cars). Weight is cancelled "for free" by the wheels. But in planes, weight is balanced with lift, and lift needs wings, and wings produce drag (proportionally). So every new kg of weight need either more wings or more AOA, both producing drag proportionally. In addition, more wings are also more kgs, in a non-linear way (think of the base of the eiffel tower), which contributes to the problem. *Model S has 540 kgs of batteries, more or less equivalent to 1.35 kgs of fuel, 1.83L of diesel and a range of 400km. You can have a x3 because batteries are very good expensive Li-IO, x2 of electric vs thermal motor at ideal conditions and then an additional x2 due to generative braking (plus you get a bonus of almost ridiculous acceleration if you install the motors and electronics you need for powerful regenerative braking). So, in ideal conditions, it carries the equivalent of 22L of diesel fuel. My car (same size and weight) uses 6.0 l of diesel each 100 km, pure thermal, so there you have it: 400km. In ideal conditions. But there are reports of much much shorter trips depleting the batteries, as it is no surprise for me. |
The idea is to get cheaper rates for flight training. Nobody is talking about long range electric flight (yet). Although someone is talking about electric VTOL supersonic flight already: Just wait until he get's some time off from SpaceX, Tesla, The Boring Company and whatever else he is doing at the moment... |
Originally Posted by ecto1
(Post 10446626)
Because in cars, the penalty for overweight is zero at constant speed, and very little at variable speed if you compare with a solution without generative braking*.
Drag (the main reason you need energy to commute) is proportional to frontal area, which is not affected by how many kgs of "energy storage" you move about (in cars). Weight is cancelled "for free" by the wheels. But in planes, weight is balanced with lift, and lift needs wings, and wings produce drag (proportionally). So every new kg of weight need either more wings or more AOA, both producing drag proportionally. In addition, more wings are also more kgs, in a non-linear way (think of the base of the eiffel tower), which contributes to the problem. *Model S has 540 kgs of batteries, more or less equivalent to 1.35 kgs of fuel, 1.83L of diesel and a range of 400km. You can have a x3 because batteries are very good expensive Li-IO, x2 of electric vs thermal motor at ideal conditions and then an additional x2 due to generative braking (plus you get a bonus of almost ridiculous acceleration if you install the motors and electronics you need for powerful regenerative braking). So, in ideal conditions, it carries the equivalent of 22L of diesel fuel. My car (same size and weight) uses 6.0 l of diesel each 100 km, pure thermal, so there you have it: 400km. In ideal conditions. But there are reports of much much shorter trips depleting the batteries, as it is no surprise for me. I think for the compassion to work you need to compare
Three years ago, Forbes reported a study by scientists that Teslas (and EVs in general) produce substantially less pollution than ICE cars when all factors are taken into account. (Incidentally, I photographed a small electric plane at Farnborough Air Show a few years back. |
Originally Posted by msjh
(Post 10446645)
I'm afraid neither of these arguments convinces me (yet). But I am willing to learn!
I think for the compassion to work you need to compare
Three years ago, Forbes reported a study by scientists that Teslas (and EVs in general) produce substantially less pollution than ICE cars when all factors are taken into account. (Incidentally, I photographed a small electric plane at Farnborough Air Show a few years back. There are many more figures that go into the comparison, none of them changing the result. For example, the weight of a foam filled fuel tank is usually 10% of the capacity, so for a cessna it would be about 12kg. Which equals the battery management system (BMS), roughly, for that power. If i take into account the average weight of the system during a trip, a x1.5 is instantly granted to the thermal fuel, which you don't need to carry when you are almost empty. In the advanced electric propulsion world, the figure you shoud use is x100 (x400 is fuel vs standard car battery, x2 / x3 electric motor efficiency vs thermal motor, x2 LI-IOn vs standar car battery). But do remember that if you use x100 you pay over 25000$ to have a equivalent energy storage capacity of 50L of fuel (vs the fuel tank itself at about 500$) And remember the only reason that topping a battery is cheaper than topping a fuel tank is politics. It doesn't make any sense that the elaborated product (electricity) is cheaper than the base product (gas). In 2014, 66% of world electricity was generated burning stuff. Even if it were any difference in price, it would never ever be greater than x1.5 or something. I wish electricity was actually cheaper, don't get me wrong, I wish a solar plant or aero generator wasn't so weak in terms of power / $. I hope this changes in the future. It may change. But electric flight? short of battery technology breakthrough, no way. |
By the way, that report previously posted:
https://www.ucsusa.org/sites/default...ull-report.pdf Is flagrantly ignoring HUGE factors: - The kwh/mi of the whole study are 0.333. TESLA model S and any other EV with some resemblance of range is is 0.38 (it is even recognized in the study). the 80mi range family of cars is another monster. apples vs apples please. - The charging and discharging efficiency of the batteries is not even there anywhere! We are talking about 90% in both processes combined! But the ovbious trick is to compare an average fuel powered car with an average EV. If you are concerned about CO2, you don't buy a supercharged V8. The typical thermal car (full size gasoline) from the study emits about 350g CO2/km (+500/mi) during operation (see for yourself, figure 7, page21). Well, my 200+hp full size sedan (no hybrid) claims 121. I wonder were the rest comes from (they don't say) |
Originally Posted by ecto1
(Post 10446571)
- You cannot extract any energy from a battery if it is freezing.
Originally Posted by ecto1
(Post 10446571)
- After each cycle, battery stores less and less energy.
Model X 90D “Deuxy” Achieves 300,000 Miles In Less Than Two Years The rest of your contribution to this thread is on par with the two items above - your belief is based on incorrect information. Maybe you should do a bit more research about electric cars in general and electric planes in particular. For short range applications, it is already reality today even if you do not want to accept it. |
It is true that when a person states even one fact that is incredibly false - batteries produce no power when it is freezing - they lose all credibility in anything they say. I live where we have had many days with temps below -40 this winter, C or F, whichever you want to use. My vehicles outside will turn over by battery but will not fire off. Need electrical glow plugs, electrical coolant heaters, and fuel additives in order to go. Granted a battery loses power at the cold temps but at least it provides power while my petroleum engines need boosting. Sure it will take time for aviation to move to electric power but think of an electric motor turning the fan instead of the gas turbine that sporadically spews parts in all directions. Anyone buying hand power tools will realize that corded tools today are rare having been replaced with lithium ion battery powered tools, Recent offerings are chain saws and lawn mowers where one would assume battery weight would be an issue, but instead the reduced size electric motor and continually improved batteries have resulted in lightweight products without the reliability problems of the petroleum powered ones they replace. So maybe you won't be flying a electric powered A319, but I would never say never.
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There was an article this week on the BBC website regarding a German company that believe they have developed a battery that no longer relies on the heavy metals that are hard to source and that will give approx. 600 miles on a single charge. Estimate was for a production model within 5 years. Technology is always getting better and I think an electric car in the mid 20s will outrun a Diesel engine with ease so an electric plane within 10-15 years should be feasible. Haven’t EasyJet set themselves a target to fly an electric plane by 2028? |
Electric Airplane on Salt Water
Top seaplane airline Harbour Air switching to battery-powered aircraft
[img]https://www.theglobeandmail.com/resizer/fpjf8UpExITztLDz8X4maUDcTEw=/620x0/filters:quality(80)/arc-anglerfish-tgam-prod-tgam.s3.amazonaws.com/public/BJ3ZJTYKQVBQ5G7FIBXSZIFD54.JPGGreg McDougall, CEO of Harbour Air Seaplanes, at the Vancouver Harbour Flight Centre in Vancouver, on March 25, 2019. Seaplane operator Harbour Air, which regularly shuttles B.C.'s political class to and from Victoria, is looking to become the first all-electric fleet of commercial planes in Canada – but the company head says passengers have nothing to fear. Greg McDougall, founder of the company that bills itself as North America’s largest seaplane airline, said Monday that “I’ll be the first guy to fly one. I’ll be the test pilot of it.” He was referring to an electric-powered prototype the company will test within months as a prelude to electrifying the fleet within about two years. By November, the company is planning to be testing a de Havilland Canada DHC 2 Beaver, a six-passenger aircraft equipped with an all-electric motor developed by magniX, a company based in Redmond, Wash. MagniX has been crafting the technology on the ground, but has yet to operate it in an aircraft. “I wouldn’t put myself in there if I thought there was a problem. I certainly wouldn’t put my loved ones in there if I thought there was a problem – or my passengers," Mr. McDougall said. “We have to prove a standard of safety that’s equal to or better than what we currently have.” Mr. McDougall, who founded Harbour Air in 1982 with a pair of small seaplanes, says he is making the shift to keep ahead of the electrification of transportation, and also to reduce the company’s environmental impact. He said his company is in a unique position to advance the concept of electric flight because its flights are relatively short, with average lengths of about 30 minutes in single-engine aircraft that don’t require as much power or battery capacity as other aircraft. The company also has flights to and from destinations such as Nanaimo, B.C., and Tofino, B.C., on Vancouver Island as well as Whistler, B.C., , Sechelt, B.C., and Salt Spring Island, B.C., among other locations. They carry about 500,000 passengers a year. Steve Holding, chief instructor for aviation technical programs at the British Columbia Institute of Technology, said electric flight is being developed but without breakthroughs on the scale Harbour Air is proposing. “Powering a larger aircraft with batteries is still really a huge technical challenge just because of the weight of batteries required to put out the power to allow a larger aircraft to take off and climb – one I wish we could overcome as quickly as possible,” he said.Roei Ganzarski, chief executive of magniX, agreed on the battery issue. “Battery density is not where we want it to be for long-range flying, similar to where automobiles were seven years ago,” he said in an interview. However, he said the company has been working on the technology, and electric makes sense for Harbour Air, which would not have to significantly change their operations for electric flight. Asked about whether he had ever heard of an airline anywhere executing the idea, Mr. Holding referred to a media report from late 2018 about an airline using small aircraft in the Orkney Islands, an archipelago off Scotland’s northeastern coast, looking at the idea. Like Alberta and Quebec, British Columbia’s legislature is not in the province’s largest city. While Vancouver is B.C’s urban centre, the legislature, and key offices of the civil service, are in Victoria more than 100 kilometres south across the Georgia Strait. That creates a need for movement between the two cities that is met by the ferries, commercial helicopter flights, and by Harbour Air. The airline, which has a fleet of about 40 aircraft, will eventually face a path of approval from Transport Canada and the U.S. Federal Aviation Agency – flights to and from Seattle are among the dozen routes it offers. Mr. McDougall said the company has already been in touch with regulators in both countries. He said this shift is not a whim, but a mandate he handed to his executive team. It took off when he made a connection with magniX. https://www.magnix.aero/products/ |
Originally Posted by ecto1
(Post 10446571)
Gas has 46.4Mj/kg.
Except that the former is ideal conditions and the latter is always. Usual problems nobody tells you until it's too late: The latter isn't "always"; it's not even "ideal conditions". You *might* get about half that, more likely 25% to 40%. |
Originally Posted by Wizofoz
(Post 10446578)
….Except the e-flyer exists and has flown- the amphibian is just one more "paper aeroplane",
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Originally Posted by ecto1
(Post 10446571)
Yeah, dream all you want. BTDT. When you have 400 times less energy per kg, all things considered, no amount of politics will make it a viable alternative for airborne trasport. Period.
Tesla claims an efficiency over 90%, while a gas turbine may perhaps reach the 30's? Toyota made a big deal of it when making a gasoline engine reach 38% efficiency... |
There seems to be an enormous amount of ignorance about thermodynamics and chemistry displayed on this thread. Ecto 1 may not be the most diplomatic of contributors but he has a good grasp of the science and engineering, as does Elon Musk but he is also a great salesman from whom I would not buy a used car.
If you are so concerned about global warming and CO2 levels, don't travel. |
I'm not sure why ecto1 bothers. There is more wishful ideology than science being expressed. That becomes obvious when you see attempts to equate battery-powered cars and power tools to airplanes.
Fossil fuels have a net calorific value roughly 100 times of a manganese type lithium-ion battery. Thus an internal combustion engine at 38%, even at a low efficiency of 25%, vastly outperforms the best battery in terms of energy-to-weight ratio. The capacity of a battery would need to increase twenty-fold before it could compete head-to-head with fossil fuel. (A kerosene-powered turbine is even more efficient than an ICE, power-to-weight). Tesla's claimed efficiency is for the power produced, not the power stored, which seems to confuse people. Fossil fuelled engines ARE less efficient than electric motors, but when the fuel source is still many multiples higher in NCV than the batteries necessary to store electricity they're going to be the only economically viable choice for weight-critical applications unless the battery tech improves exponentially. |
Originally Posted by nolimitholdem
(Post 10446868)
The capacity of a battery would need to increase twenty-fold before it could compete head-to-head with fossil fuel. (A kerosene-powered turbine is even more efficient than an ICE, power-to-weight).
In the mean time everybody should be happy somebody bothers to research alternatives and try new applications for our current level of technology. |
As can be seen from all the comments the problems is the storage of electrons and the energy to weight factor.
Avgas has about 11 kw per kilo but IC engines at 25% efficient so can only extract about 3 kw/kilo. Electric motors are up at 90+% so only need a battery of 2.5 to 3.5 kw/kilo to match Avgas. Lithium has a theoretical energy density of about 10kilowatts/kilo. At the moment the best lithium batteries are around 500 watts/kilo so 5 five times the weight for the same amount of Avgas. Billions of dollars are being spent on battery research so higher densities are coming. The holy grail is lithium air batteries, these should meet or exceed the 2.5kw/kilo target to make liquid fuels obsolete. A US university has an experimental Lithium air that is looking good, time will tell. In the last ten years the cost of EV batteries have dropped by a factor of ten to about 175 dollars per Kilowatt and heading towards $100 per Kw which makes the manufacture of EVs the same as an IC vehicles, plus the density has doubled and will keep increasing. So for aircraft at the moment batteries are not a total replacement solution but a 2 hour endurance is just feasible, which would be good for training. A hybrid is the best solution at the moment it has so many good points a high speed high power density IC engine gas or diesel with no gear box or harmonic problems. Props can be located almost any place on the airframe. So electric drive is compelling and I think will be more reliable and cost less to operate in the future. |
United Technologies is working on a hybrid electric aircraft.
https://www.utc.com/en/news/2019/03/28/project-804 Their demonstrator is a Bombardier Dash 8, not a part 23 Cessna. |
Originally Posted by horizon flyer
(Post 10447316)
Avgas has about 11 kw per kilo...
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