Whatever Happened Too Harbour Air Electric Plane

[Cap'n Jack]

There are some little-known inconvenient truths about batteries. Just to supply current demand, terrific environmental devastation and human death is being perpetrated in China and Africa, among others. And that supposedly terrible CO2 we used to generate here with our industries is now being generated elsewhere, as if it doesn't count anymore. It's absurd.
https://notalotofpeopleknowthat.wordpress.com/2021/01/25/toxic-secrets-behind-clean-energy/

This is Truth, not politics, no matter how one might try to spin it.

Lead acid batteries are still being produced. Mostly from old batteries. The same will happen with whatever battery chemistries we settle on.

 

[Cap'n Jack]

Yes, rare earth and carbon inputs to manufacturing are both issues — that's not exactly a big reveal, despite what some over-dramatic, self-described #TRUTH!!! bloggers might think (I mentioned the first earlier in this thread).

The only harmless way to reduce carbon is to travel less — the electric car isn't a magic panacaea that will let us keep doing the same thing as before with all upside and no downside. It's just a matter of weighing costs vs benefits of different means of propulsion for different applications, and increasingly, electric is coming out ahead of fossil fuels or biofuels for many (not all) uses.

About 15 (?) years ago, The Economist reported on research in this area. IIRC, factoring in the extra carbon inputs during manufacturing, it took 3 years of typical use for an electric car to break even with an ICE car for total carbon cost; after that, it turned into a net positive. And, of course, there are other issues like smog in cities like Delhi and Beijing that are killing hundreds of thousands every year, so reducing that is an additional benefit if electric vehicles independent of carbon reduction.

In our case, we don't drive much (we live in a walkable urban neighbourhood with good pyblic transit) and Ottawa doesn't suffer from smog, so we figure it makes more sense to keep our 2013 Mazda 3 running for now, since the carbon costs from its production are long-ago amortised. But when it wears out, we'll reassess and see if electric will be a better choice for a new car (not perfect, just better).

I've been to Beijing within the past two years. They've done a lot to clear the air, literally. The first time I went to Shanghai, it was like living downwind of the volcano on Hawaii. In Nov 2019, it was much better, much, much cleaner air. If we clear this virus, I may get to go this year.
New Delhi still has a long way to go.

 

[David Megginson]

I've been to Beijing within the past two years. They've done a lot to clear the air, literally. The first time I went to Shanghai, it was like living downwind of the volcano on Hawaii. In Nov 2019, it was much better, much, much cleaner air. If we clear this virus, I may get to go this year.
New Delhi still has a long way to go.

Exactly. We had to do the same kinds of cleanups in the rich world a little earlier. For example, we used to have smog warnings in the summer in Ottawa and Toronto, but those vanished once Ontario stopped burning coal to generate electricity. I mentioned the Great Smog of 1953 in London earlier in this thread; that may have killed over 10,000 people in just a few days, and led directly to the decline of coal use in the UK:

https://en.wikipedia.org/wiki/Great_Smog_of_London

 

[GRG55]

Electric vehicles will prevail. There's too many advantages. But I think battery tech is ultimately a dead end path. The electric vehicles that will actually displace hydrocarbon ICE in large numbers will be hydrogen fueled, not limited energy capacity batteries made from exotic metals that require digging and processing tons of dirt.

Hydrogen is going to be the way we efficiently store excess "green" electricity when it's not needed for immediate consumption on the grid.

My partnership businesses in the USA and Canada are heavily involved in industrial gas transport and services. Although the majority of our equipment currently involves CNG and LNG, we've been seeing a steady increase in our hydrogen activity even during this COVID period. We expect it's going to ramp up even faster in the USA under the new Administration.

 

[Cap'n Jack]

Electric vehicles will prevail. There's too many advantages. But I think battery tech is ultimately a dead end path. The electric vehicles that will actually displace hydrocarbon ICE in large numbers will be hydrogen fueled, not limited energy capacity batteries made from exotic metals that require digging and processing tons of dirt.

Hydrogen is going to be the way we efficiently store excess "green" electricity when it's not needed for immediate consumption on the grid.

My partnership businesses in the USA and Canada are heavily involved in industrial gas transport and services. Although the majority of our equipment currently involves CNG and LNG, we've been seeing a steady increase in our hydrogen activity even during this COVID period. We expect it's going to ramp up even faster in the USA under the new Administration.

Maybe it will. Hydrogen doesn't have great energy density, even under high pressure. There's some people working on that by adsorption or other means. Hydrogen tanks can be filled quickly, but some of the newer batteries in the pipeline can also be charged quickly. Current fuel cells still require exotic metals-maybe that will change.

 

[David Megginson]

Electric vehicles will prevail. There's too many advantages. But I think battery tech is ultimately a dead end path. The electric vehicles that will actually displace hydrocarbon ICE in large numbers will be hydrogen fueled, not limited energy capacity batteries made from exotic metals that require digging and processing tons of dirt.

Hydrogen is going to be the way we efficiently store excess "green" electricity when it's not needed for immediate consumption on the grid.

My partnership businesses in the USA and Canada are heavily involved in industrial gas transport and services. Although the majority of our equipment currently involves CNG and LNG, we've been seeing a steady increase in our hydrogen activity even during this COVID period. We expect it's going to ramp up even faster in the USA under the new Administration.

A hybrid ICE/battery solution for a light aircraft is a non-starter because of the weight, but I wonder if there's some other energy source we could use that wouldn't add as much weight, but allow in-flight recharging of batteries for longer flights. How heavy would a hydrogen- or LNG-powered generator need to be, for example?

 

[Cap'n Jack]

A hybrid ICE/battery solution for a light aircraft is a non-starter because of the weight, but I wonder if there's some other energy source we could use that wouldn't add as much weight, but allow in-flight recharging of batteries for longer flights. How heavy would a hydrogen- or LNG-powered generator need to be, for example?

Internal combustion or fuel cell?
You don't get a much range out of hydrogen, even liquid hydrogen. LNG is better. Gasoline or Jet-A is better still. It's better to look at it as how much oxygen is used, as you'll get about 400 kJ/mol oxygen, as molecules [1]. More oxygen used means a more energetic fuel. For every molecule of oxygen, you'll need 2 of hydrogen. For LNG, assuming it is mainly methane, each molecule uses 2 oxygen molecules. Methane gives much more energy for the same volume (roughly) than hydrogen, but it isn't as good as the liquid hydrocarbons, even while operating at a low efficiency.

[1] https://pubs.acs.org/doi/10.1021/acs.jchemed.5b00333

 

[GRG55]

A hybrid ICE/battery solution for a light aircraft is a non-starter because of the weight, but I wonder if there's some other energy source we could use that wouldn't add as much weight, but allow in-flight recharging of batteries for longer flights. How heavy would a hydrogen- or LNG-powered generator need to be, for example?

The issue with airplanes is fuel energy density per unit of fuel weight.
Very difficult to compete with avgas and even more so with a middle distillate like jet fuel. Packs a lot of punch in a small, comparatively light package.

Part of the problem is that aircraft engines run continuously at high power output. For anyone with experience owning a Prius, they will know using it at highway speeds for extended periods doesn't work as well as an in-town runabout.

 

[GRG55]

Maybe it will. Hydrogen doesn't have great energy density, even under high pressure. There's some people working on that by adsorption or other means. Hydrogen tanks can be filled quickly, but some of the newer batteries in the pipeline can also be charged quickly. Current fuel cells still require exotic metals-maybe that will change.

There isn't ANY "perfect" solution, or alternative. Every one of them has advantages and disadvantages. The primary disadvantage of gasoline or diesel is, apparently, that it comes from oil and produces a carbon emission.

So to eliminate one problem usually means some compromises in other respects.

The reason I think batteries are a dead end is threefold:

• They are all chemical reactions of some sort, which means both charge and discharge rates have limits (time function);
• They require the mining of all sorts of commodities, most of which need diesel to dig and move tonnes of dirt, so not really "carbon free";
• They will penetrate part of the market that isn't range limited (return-to-base) and then probably plateau, giving way to some other technology to fuel the electric power train - hydrogen is my expectation, as I said before, because it uses electricity to manufacture.

 

[Palmpilot]

In Canada? The person I replied to lives there.

U.S.

It was reportedly a goal. I'm skeptical of the idea that it could happen that soon.

 

[Dan Thomas]

Internal combustion or fuel cell?
You don't get a much range out of hydrogen, even liquid hydrogen. LNG is better. Gasoline or Jet-A is better still. It's better to look at it as how much oxygen is used, as you'll get about 400 kJ/mol oxygen, as molecules [1]. More oxygen used means a more energetic fuel. For every molecule of oxygen, you'll need 2 of hydrogen. For LNG, assuming it is mainly methane, each molecule uses 2 oxygen molecules. Methane gives much more energy for the same volume (roughly) than hydrogen, but it isn't as good as the liquid hydrocarbons, even while operating at a low efficiency.

[1] https://pubs.acs.org/doi/10.1021/acs.jchemed.5b00333

If the goal is to cut CO2 emissions, why would we bother with natural gas at all?

 

[Cap'n Jack]

There isn't ANY "perfect" solution, or alternative. Every one of them has advantages and disadvantages. The primary disadvantage of gasoline or diesel is, apparently, that it comes from oil and produces a carbon emission.

So to eliminate one problem usually means some compromises in other respects.

The reason I think batteries are a dead end is threefold:

• They are all chemical reactions of some sort, which means both charge and discharge rates have limits (time function);
• They require the mining of all sorts of commodities, most of which need diesel to dig and move tonnes of dirt, so not really "carbon free";
• They will penetrate part of the market that isn't range limited (return-to-base) and then probably plateau, giving way to some other technology to fuel the electric power train - hydrogen is my expectation, as I said before, because it uses electricity to manufacture.

• Burning hydrocarbons is a chemical reaction, too. Your conclusion doesn't follow.
• It depends on the battery chemistry we use. If calcium pans out, that is very readily available. Like I pointed out earlier, new lead-acid batteries are mainly made from old ones, now. Whatever we choose to use will almost certainly be recycled, too.
• Maybe. I won't rule it out. But hydrogen isn't very "energy dense", either.

 

[Cap'n Jack]

If the goal is to cut CO2 emissions, why would we bother with natural gas at all?

That wasn't my idea. Read the thread to get the context.

 

[Cap'n Jack]

U.S.

It was reportedly a goal. I'm skeptical of the idea that it could happen that soon.

As am I.

 

[GRG55]

• Burning hydrocarbons is a chemical reaction, too. Your conclusion doesn't follow.
• It depends on the battery chemistry we use. If calcium pans out, that is very readily available. Like I pointed out earlier, new lead-acid batteries are mainly made from old ones, now. Whatever we choose to use will almost certainly be recycled, too.
• Maybe. I won't rule it out. But hydrogen isn't very "energy dense", either.

• What conclusion doesn't follow?
• As for battery chemistry, it's all incremental. The much desired big breakthrough, leap forward in battery technology has been something I've been hearing about for about as long as I can remember - not years, decades. Might happen. But I doubt it.
• I never said hydrogen was energy dense; where did you conclude that? What I said is there is no perfect solution.

 

[GRG55]

If the goal is to cut CO2 emissions, why would we bother with natural gas at all?

You think you can make the leap from where we are today to a true carbon free economy without using natural gas as a transition fuel?
Ain't ever going to happen.

Right now the big, big push is electrification of our North American economy.
A couple of the largest shifts underway right now are 1) aggressively moving away from things like diesel power in stationary/quasi-stationary applications, and 2) exponential increases in computing power installations for things like 5G networks.

There's no practical way to produce that much new power without using natural gas. Period.

 

[David Megginson]

You think you can make the leap from where we are today to a true carbon free economy without using natural gas as a transition fuel?
Ain't ever going to happen.

Right now the big, big push is electrification of our North American economy.
A couple of the largest shifts underway right now are 1) aggressively moving away from things like diesel power in stationary/quasi-stationary applications, and 2) exponential increases in computing power installations for things like 5G networks.

There's no practical way to produce that much new power without using natural gas. Period.

Well, nuclear, but that has its own issues. And places with lots of lakes and rivers, like Quebec and Labrador, can manage it all with hydroelectric power (with lots to spare), and Iceland can pull it off with geothermal, but most jurisdictions don't have those kinds of natural resources.

 

[GRG55]

Well, nuclear, but that has its own issues. And places with lots of lakes and rivers, like Quebec and Labrador, can manage it all with hydroelectric power (with lots to spare), and Iceland can pull it off with geothermal, but most jurisdictions don't have those kinds of natural resources.

Most of the viable hydroelectric sites worldwide have already been exploited. It's not like one can build new ones anywhere we want. You need elevation change.

Nuclear? Seriously. After Tepco Fukushima Daiichi? You probably have a better chance of getting an oil pipeline built in North America than a nuclear plant in our remaining lifetime. I don't even see the chance of another CANDU being built, and it has the safety advantages of a deuterium oxide moderator and fuel that isn't enriched. The public consultation and political hurdles seem almost insurmountable now.

As I said, there's absolutely no way to meet the demand curve for new power generation in this decade alone without using a LOT of natural gas. Those jurisdictions with natural gas, such as the USA and Canada, will have an economic advantage. Those that don't will be importing a lot of LNG by ocean tanker.

 

[Cap'n Jack]

• What conclusion doesn't follow?
• As for battery chemistry, it's all incremental. The much desired big breakthrough, leap forward in battery technology has been something I've been hearing about for about as long as I can remember - not years, decades. Might happen. But I doubt it.
• I never said hydrogen was energy dense; where did you conclude that? What I said is there is no perfect solution.

The conclusion in this statement doesn't support any disadvantages of batteries:

They are all chemical reactions of some sort, which means both charge and discharge rates have limits (time function);

Burning hydrocarbons is a chemical reaction, too. It happens fast enough.

Batteries have made great strides. A Tesla gets about 200 miles of range in about 15 minutes. That's about 25% of the time required when they started selling those cars. They intend to reduce that time further still so you need less time to get 200 miles, or get more range in 15 minutes. You don't see the improvement in your cell phones, tablets, or computers because they shrink the batteries down and add features that need more power.

No, you didn't say hydrogen was energy dense. But that's it's major drawback. You can refill quickly into a pressurized tank, but you need to do it more often than with other energy storage systems. There are ideas floating around to improve the energy density of hydrogen, such as hydrides, but they haven't come to fruition yet. You are right, there is no perfect solution. Hydrogen may become the storage medium of choice. Or maybe not.

 

[YKA]

And again, that's your situation. That's not most people even in Canada, much less the USA. Most people don't drive far nor carry much load. No one is telling you you need to give up whatever you are driving.

Yet a few people on this very forum are all about getting rid of gas and diesel engine vehicles. So they do want to tell me what I can drive...

 

[Cap'n Jack]

Yet a few people on this very forum are all about getting rid of gas and diesel engine vehicles. So they do want to tell me what I can drive...

I haven't seen that sentiment, although it is likely that I've missed it. I'd appreciate a link.

There's some Teslarati here, at least one, but I remember he raves about how good the car is, and less that it should be as a pickup truck. I'm glad it fits his situation, but it isn't for everyone, anymore than a PC-12 meets my flying needs. It's a nice plane, but not for my flying needs.

 

[Cervieres]

^speaking of, the ICE need not be dead. I was talking to a guy this past weekend at the airport with a DA62.. he'll get 170 KTAS cruise at 13-14 gph (combined).. Those are fantastic figures for a big 7 passenger 5,100 lb twin engine plane. How did they do it? They used a modern engine with FADEC not a 70 year old WW2 era relic for a powerplant

Heretic.

 

[jsstevens]

^speaking of, the ICE need not be dead. I was talking to a guy this past weekend at the airport with a DA62.. he'll get 170 KTAS cruise at 13-14 gph (combined).. Those are fantastic figures for a big 7 passenger 5,100 lb twin engine plane. How did they do it? They used a modern engine with FADEC not a 70 year old WW2 era relic for a powerplant

They are modern engines, yes. But they are also diesels. Jet fuel (and diesel fuel) have more energy in a given volume than gas and that accounts for much of the efficiency improvement.

Shamelessly reused from Wikipedia:
Jet A-1
34.7 MJ/L

100LL
31.59 MJ/L

(I used to have a DA-42 panel shot as my desktop background. I really wanted one of those for a while.) But by all accounts I've read, those modern diesels in the Diamonds have lots of maintenance expenses. Diesel engines should be a good match for aircraft-high torque at (relatively) low RPM, and thrive on constant speed operation. But they tend to be heavy.

Still an impressive plane!

John

 

[jsstevens]

I've been to Beijing within the past two years. They've done a lot to clear the air, literally. The first time I went to Shanghai, it was like living downwind of the volcano on Hawaii. In Nov 2019, it was much better, much, much cleaner air. If we clear this virus, I may get to go this year.
New Delhi still has a long way to go.

I've been watching some Dragnet 1967 shows on You Tube. They almost always start with panoramic views of Los Angeles and Jack Webb's "This is the city..." narration. It is a stark reminder of how bad the smog was in LA in those days.

 

[Cap'n Jack]

They are modern engines, yes. But they are also diesels. Jet fuel (and diesel fuel) have more energy in a given volume than gas and that accounts for much of the efficiency improvement.

Shamelessly reused from Wikipedia:
Jet A-1
34.7 MJ/L

100LL
31.59 MJ/L

(I used to have a DA-42 panel shot as my desktop background. I really wanted one of those for a while.) But by all accounts I've read, those modern diesels in the Diamonds have lots of maintenance expenses. Diesel engines should be a good match for aircraft-high torque at (relatively) low RPM, and thrive on constant speed operation. But they tend to be heavy.

Still an impressive plane!

John

Are you using the correct term here? Without going into details, I was under the impression that the higher efficiency of those engines was related to the higher compression ratios in these engines. Perhaps we are looking at efficiency in different terms, in that a smaller volume of Jet-A or diesel is needed for a given charge of air. This is then similar to my comments about hydrogen.

 

[jsstevens]

Are you using the correct term here? Without going into details, I was under the impression that the higher efficiency of those engines was related to the higher compression ratios in these engines. Perhaps we are looking at efficiency in different terms, in that a smaller volume of Jet-A or diesel is needed for a given charge of air. This is then similar to my comments about hydrogen.

Some of both. Jet A has higher energy per liter (Mega Joules/Liter specified in the quote) as well as needing less volume per given charge of air (probably two sides of the same coin). I'd have to look up some math to convert MJ to horsepower, but a given volume of Jet A has more horsepower (potential) in it than the same volume of 100LL.

And to address the higher compression, that just gets more oxygen molecules into the cylinder that con potentially react with the hydrogen and carbon in the fuel. Simply put, the limit to power in an internal combustion engine is how much oxygen you can pump through it and match with fuel. That's why turbo and super charging work as do intercoolers, higher RPM (more pumps of air/oxygen), high compression, etc. It's all ways to get more oxygen through the engine. Also, nitrous oxide adds an oxygenation agent (hence more oxygen).

 

[Tantalum]

(I used to have a DA-42 panel shot as my desktop background. I really wanted one of those for a while.) But by all accounts I've read, those modern diesels in the Diamonds have lots of maintenance expenses. Diesel engines should be a good match for aircraft-high torque at (relatively) low RPM, and thrive on constant speed operation. But they tend to be heavy.

That or the DA62 is my dream plane for what would currently fit my mission and be, potentially, at some point, maybe achievable (emphasis on the maybe)

I had a chance to talk to the owner of this plane over the weekend, he's owned it since 2018 and was clearly in love with it. He let me sit in it, sick ride. I asked about the diesel engines as I've read similar about the maintenance on them, low TBO, etc. He contended that the newer Austro engines solved many of the issues the older ones, especially the Thielert had. Seems that in 2+ years of ownership there weren't any notable powerplant issues



Mind you.. before he pulled on I was oggling over this beautifully maintained 310 (it's a Cessna but at least the wings are in the right place!)

 

[David Megginson]

We still use horses to pull things. We still have water wheels and windmills. We still have boats powered by sail. We still have steam engines.

ICE engines will be around in 100 years, too; they'll just be used a lot less than they are now. So ignore the scare stories — no one's kicking down your door to arrest you and take your diesel away.

 

[jsstevens]

That or the DA62 is my dream plane for what would currently fit my mission and be, potentially, at some point, maybe achievable (emphasis on the maybe)

I had a chance to talk to the owner of this plane over the weekend, he's owned it since 2018 and was clearly in love with it. He let me sit in it, sick ride. I asked about the diesel engines as I've read similar about the maintenance on them, low TBO, etc. He contended that the newer Austro engines solved many of the issues the older ones, especially the Thielert had. Seems that in 2+ years of ownership there weren't any notable powerplant issues

View attachment 93578

Mind you.. before he pulled on I was oggling over this beautifully maintained 310 (it's a Cessna but at least the wings are in the right place!)
View attachment 93579

Yeah. I'm drooling over twins myself. I love the looks of the 310, but I'm leaning more to Aztec because by all accounts its more forgiving. IR first, then multi, then plane shopping maybe, I keep hoping the bubble will burst on pricing.

 

[David Megginson]

Also, as a ref point, here's the current state of the art for personal electric planes: 90 min endurance (60 excluding the 30 min VFR reserve), 87 kt, two seats. Apparently, they're flying off the shelf, but that's not attaractive to me yet.

https://www.aopa.org/news-and-media...urce=News&utm_medium=Content&utm_campaign=RSS

We can reasonably expect two more doublings of battery capacity from what's in the Pipistrel, though, before we get too close to the chemical limit for what a battery can do. 6 hours at 87 kt, or maybe 4 hours at 110 kt, would start to get my attention as a possible fun retirement plane, and would more than meet most flight school's needs

 

[Tantalum]

but I'm leaning more to Aztec

Same here.. plane camping was discussed in another thread. You just can't beat how freaking *BIG* the Aztec is inside and how much it can carry, plus it's rugged nature, feels like s schoolbus. The DA62 actually felt a touch smaller upfront than the SR22 but the back seemed slightly bigger

But +1 on the Aztec for sure. Over 2,000 lbs useful and rugged as hell. You really can't beat it as far as versatile GA plane. Not super fast.. but I've been told if you don't care about the fuel burn you can inch them up towards 180 KTAS.. whatever. My personal cutoff is 150 KTAS, and it beats that

I've been flying a Duchess to build twin time and am set to officially get my Aztec checkout at the end of February.. just in time for a Death Valley camping trip!

 

[jsstevens]

Also, as a ref point, here's the current state of the art for personal electric planes: 90 min endurance (60 excluding the 30 min VFR reserve), 87 kt, two seats. Apparently, they're flying off the shelf, but that's not attaractive to me yet.

https://www.aopa.org/news-and-media...urce=News&utm_medium=Content&utm_campaign=RSS

We can reasonably expect two more doublings of battery capacity from what's in the Pipistrel, though, before we get too close to the chemical limit for what a battery can do. 6 hours at 87 kt, or maybe 4 hours at 110 kt, would start to get my attention as a possible fun retirement plane, and would more than meet most flight school's needs

That would meet the flight school's needs for one flight, but what about back to back to back students (which seems to be how flight schools make money)? What's the charging time between flights? As a retirement plane that could be nice.

 

[jsstevens]

Same here.. plane camping was discussed in another thread. You just can't beat how freaking *BIG* the Aztec is inside and how much it can carry, plus it's rugged nature, feels like s schoolbus. The DA62 actually felt a touch smaller upfront than the SR22 but the back seemed slightly bigger

But +1 on the Aztec for sure. Over 2,000 lbs useful and rugged as hell. You really can't beat it as far as versatile GA plane. Not super fast.. but I've been told if you don't care about the fuel burn you can inch them up towards 180 KTAS.. whatever. My personal cutoff is 150 KTAS, and it beats that

I've been flying a Duchess to build twin time and am set to officially get my Aztec checkout at the end of February.. just in time for a Death Valley camping trip!

Give us a writeup of that! (Please!)

 

[Tantalum]

Also, as a ref point, here's the current state of the art for personal electric planes: 90 min endurance (60 excluding the 30 min VFR reserve), 87 kt, two seats

So basically you can do a ONE way 50 nm cross country. What on earth could this plane's use case possibly be?? Flying to me is a way to beat traveling by car and avoid the airlines. A plane like this would relegate me to staying with a 40 nm radius.. which arguably would save a total of zero minutes over driving. Plus it's ugly as sin, I need to wash my eyes after looking at it

but that's not attaractive to me yet

Me either! I have no political allegiance towards electric or gas, but at this point I stand remarkably unimpressed with what electric offers, both in cars and planes. Maybe in 50 years as I'm approaching death the incremental gains we're all being promised will give something remotely viable.

 

[David Megginson]

That would meet the flight school's needs for one flight, but what about back to back to back students (which seems to be how flight schools make money)? What's the charging time between flights? As a retirement plane that could be nice.

6 hours air time (I'm talking a hypothetical future plane, not the Pipistrel) would be good for about three students in a row.

But we don't have that now. I'm not sure how the European flight schools with the current Pipistrel Alpha (90 min air time) are managing things, but the Pipistrel's batteries charge fully in 45 min (and pilots should be landing with 1/3 of the charge still there for legal reserve), so I guess they could do a lesson every 2 hours in a pinch (60 min flying time, 30 min recharging, and 30 min for preflight, taxiing, etc). I can see making a go of that, especially with the massively-reduced maintenance and fuel overhead, but you'd have to be well-organised on the ground.

 

[David Megginson]

So basically you can do a ONE way 50 nm cross country. What on earth could this plane's use case possibly be?? Flying to me is a way to beat traveling by car and avoid the airlines. A plane like this would relegate me to staying with a 40 nm radius.. which arguably would save a total of zero minutes over driving. Plus it's ugly as sin, I need to wash my eyes after looking at it
View attachment 93581


Me either! I have no political allegiance towards electric or gas, but at this point I stand remarkably unimpressed with what electric offers, both in cars and planes. Maybe in 50 years as I'm approaching death the incremental gains we're all being promised will give something remotely viable.

Fair enough. We can never have an all-electric plane with the performance, load, and range of, say, a Cirrus SR22 or Beech Bonanza, because there's just no way chemistry and physics will cooperate, but we can reasonably hope to have an all-electric plane with the performance and range of a Piper PA-28-140 before we hit the hard limits. I don't know how long it will take for two more doublings of battery tech, and whether I'll still be alive and able to pass a medical when it happens, but anyone who's OK with that level of performance (suitable for up to, say 300 nm trips) would be able to go to electric.

 

[Cap'n Jack]

Some of both. Jet A has higher energy per liter (Mega Joules/Liter specified in the quote) as well as needing less volume per given charge of air (probably two sides of the same coin). I'd have to look up some math to convert MJ to horsepower, but a given volume of Jet A has more horsepower (potential) in it than the same volume of 100LL.

And to address the higher compression, that just gets more oxygen molecules into the cylinder that con potentially react with the hydrogen and carbon in the fuel. Simply put, the limit to power in an internal combustion engine is how much oxygen you can pump through it and match with fuel. That's why turbo and super charging work as do intercoolers, higher RPM (more pumps of air/oxygen), high compression, etc. It's all ways to get more oxygen through the engine. Also, nitrous oxide adds an oxygenation agent (hence more oxygen).

I respectfully disagree. You get better energy efficiency with higher compression ratios. The efficiency is proportional to 1/(r ^(y-1)), where r= compression ratio, and y = the heat capacity ratio of the gas. This is further defined as the ratio of a gases' heat capacity at a constant pressure to that at a constant volume. Go look it up in a thermodynamics book if you really want to get lost down a rabbit hole.

Otherwise, we agree on the rest of your posting.

 

[Cap'n Jack]

That would meet the flight school's needs for one flight, but what about back to back to back students (which seems to be how flight schools make money)? What's the charging time between flights? As a retirement plane that could be nice.

Right now, not fast enough. A reduction in charging time are some of the battery improvements I hope will occur with the improved capacities. I've read reports of very fast charging times, and I agree these may not work in the real world. I'm cautiously optimistic.

 

[Dan Thomas]

They are modern engines, yes. But they are also diesels. Jet fuel (and diesel fuel) have more energy in a given volume than gas and that accounts for much of the efficiency improvement.

Shamelessly reused from Wikipedia:
Jet A-1
34.7 MJ/L

100LL
31.59 MJ/L

(I used to have a DA-42 panel shot as my desktop background. I really wanted one of those for a while.) But by all accounts I've read, those modern diesels in the Diamonds have lots of maintenance expenses. Diesel engines should be a good match for aircraft-high torque at (relatively) low RPM, and thrive on constant speed operation. But they tend to be heavy.

Still an impressive plane!

John

Jet have more energy per volume, but per pound diesel and Jet are nearly identical to Avgas. And it's pounds that are important for an airplane.

 

[Dan Thomas]

You think you can make the leap from where we are today to a true carbon free economy without using natural gas as a transition fuel?
Ain't ever going to happen.

Right now the big, big push is electrification of our North American economy.
A couple of the largest shifts underway right now are 1) aggressively moving away from things like diesel power in stationary/quasi-stationary applications, and 2) exponential increases in computing power installations for things like 5G networks.

There's no practical way to produce that much new power without using natural gas. Period.

I was responding to this, from Captain Jack:

Internal combustion or fuel cell?
You don't get a much range out of hydrogen, even liquid hydrogen. LNG is better. Gasoline or Jet-A is better still. It's better to look at it as how much oxygen is used, as you'll get about 400 kJ/mol oxygen, as molecules [1]. More oxygen used means a more energetic fuel. For every molecule of oxygen, you'll need 2 of hydrogen. For LNG, assuming it is mainly methane, each molecule uses 2 oxygen molecules. Methane gives much more energy for the same volume (roughly) than hydrogen, but it isn't as good as the liquid hydrocarbons, even while operating at a low efficiency.