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June 2023

Arthur_Foyt

Thank goodness all the “outright” lies about battery powered planes seems to be over; thought the euphemism of “thermal engine” instead of ICE is a bit funny.

June 2023

Brian_Smith

Why are so many AVWeb readers so obviously against electric airplanes? Obviously we’re not all going to be flying them in the next five years, but what if that’s what everybody is flying in 20 years? Wouldn’t that be cool?

6 replies
June 2023 ▶ Brian_Smith

avi8tor.tom

“AVWeb readers against electric airplanes?”
Hi Brian,
Speaking only for myself: Against premature and optimistic claims of the virtues of electric aircraft. Electric -motor- technology is good and is here now. Electrical energy storage capacity: not so much. I’m eternally hopeful but, unless some miracle happens, lack of useful electrical storage capacity will keep pure elec-tech on the ground. Battery tech: Many years away.
I can make a three hour flight in my Piper Cub and arrive on short final with an hour of reserve energy in the tanks. Many/most fossil fuel aircraft have far better endurance than that.

1 reply
June 2023

Mikko_Hamunen

How much is “so many”? A few out of a large group is nothing and I don’t see that “AVWeb readers are against electric airplanes”. Many aviators, on the other hand, master basic arithmetic skills and the basics of physics and therefore wonder how the dreams of green fanatics can be realized in the real world based on current knowledge. Even more enlightened people know that climate change is the main reason for the variation in carbon dioxide levels and not the other way around. No one knows for sure what the future will bring - whether the Earth will be hot or cool. That is cool.

1 reply
June 2023

roganderson60

Looked like it was covered with ice, or the paint was peeling.

June 2023 ▶ Brian_Smith

Arthur_Foyt

Brian, there is only so much product teasing that reasonable people can tolerate from vendors. There is also the issue of prioritizing public money to support business solutions for a non-crisis. THEN there are the truly ugly “demonstrators” here that add weight, drag, complexity, and cost (to an otherwise beautiful aircraft) and tell us that it’s worth it for a few lower dB and a questionably lower emissions profile.

Like 100LL announcements, just because I’m tired of the 4 decades of announcements does NOT mean I’m against a change.

June 2023

jimhanson

Electric airplanes are a laudable goal, but always “just around the corner”–much like the “search for perpetual motion” of the LAST century.

The physics just aren’t there o produce a useful manned long-range and high-speed electric device. Pure electric power dreams have morphed into “hybrids”–a liquid fueled aircraft with auxiliary electric motors, like this example. One must ask “WHY?” Aircraft have moved from multi-motors to the amazingly efficient single-engine high-speed pressurized aircraft–only to have that concept reversed with the addition of multiple electric motors.

The reality is that NOBODY has produced the “electric dream machine” of high-speed AND long range required for a practical aircraft. AvWeb has done its job of presenting these failed programs–but the tide has turned from optimism on these programs to a collective yawn at the latest offerings.

Let us know when a practical electric airplane is certified.

1 reply
June 2023 ▶ Mikko_Hamunen

johnphi

Mikko, please enlighten me to the evidence showing that “climate change is the main reason for the variation in carbon dioxide levels and not the other way around.” It seems that the ice core, sediment core, tree ring, peat bog and just about any other paleoclimate data set would disagree with your statement. I could be wrong, or maybe I just misunderstand what enlightened means, but if you’re using the classical definition, then I need to be enlightened as to how the past century of research is wrong.

I’m also curious about the basic arithmetic and physics skills you speak of, I’m guessing you mean current engineering challenges. If not, please enlighten me of these as well. Thanks.

2 replies
June 2023 ▶ Brian_Smith

Larry_S

Wishful thinking (of Mikko’s 'green fanatics [below]) does NOT turn fantasy into reality, Brian. As Art says, “we” are tired of vaporware and boastful claims that are nothing more than bravo sierra.

Furthermore, there’s no doubt that an electric motor is far more reliable than a reciprocating gas engine BUT … to get the same thrust, the ‘system’ (in toto) will likely be far heavier. Beyond that, there’s no long-term proof that the support electronics – controlling large amounts of power – are up to the task any more than the lack of energy density of current battery technologies.

1 reply
June 2023 ▶ Larry_S

b757pilot

“Bravo Sierrra” aka “Brown-25”

1 reply
June 2023 ▶ b757pilot

rpstrong

We’re at Uranus.

June 2023 ▶ johnphi

Arthur_Foyt

It’s basic Chemistry 101. Look up the Ksp of CO2 in water. As temperatures increase, CO2 is released. If you’re not a chemist and don’t have a CRC manual handy, then open 2 soda cans (one hot and one cold) and see the difference in CO2 solubility/release from water.

As it gets warmer, CO2 is less soluble in water and thus is released.
By the way, research is not “wrong” but it’s useless when the dataset is wrong. Ice core, sediment core, tree ring, peat bog, etc, are not thermometers. Using them is “a guess” at best and a source of manipulation at worst.

June 2023 ▶ Brian_Smith

Skypark

The reason many AV Web followers are critical of electric aircraft announcements is likely related to the fact pilots as a class are more likely than the average citizen to take a “systems” view of such things. Through training and experience they are aware that successful air travel depends on attention to every link of a complex chain.

Example: A fellow pilot is enthusiastically discussing his preparations for a family vacation revolving around investing in a new plane and flying in it to a beautiful isolated tropical island, only four hours away and well within the five-hour range of the aircraft. He explains all the reasons this will be the best vacation ever. When pressed, he acknowledges there is no airport on the island and published engineering surveys all show there is no suitable terrain for one. Would you not feel motivated to suggest it might be prudent to resolve the missing link before totally committing to the plan?

June 2023 ▶ johnphi

johnphi

Mr. Foyt, I’m sorry your memory is short these days. I’ll paste my previous reply to your nonsense about the Ksp and soda can below, but the quick summary is that your example of soda cans, Ksp and CO2 is great for liquids. Thankfully though, we live in an atmosphere that is a gas where the chemistry/physics is different, longer explanation below (from the previous rebuttal against your misunderstandings of the chemistry/physics).

More importantly, ice cores, sediment cores, tree rings and the other data sources are actually very, very good guesses. We can correlate them precisely using known temperatures during the past 100 or so years. They are still guesses (like virtually all of science), but guesses backed by exabytes of data (like virtually all of science). Just like it’s a guess that next week the temperature in Tampa will be higher than the temperature in Ushuaia, also backed by lots of data.

I hope you’re just trolling us scientists with your Chemistry 101 examples, but just in case, here’s the Ksp lesson from last month:

Mr. Foyt, thank you for finally showing that the emperor has no clothes. I was really hoping for some research showing that global warming is the cause of rising CO2. Instead you seem to be confused by the difference between CO2’s properties as a gas, liquid and solid, while interacting with a gas (atmosphere), liquid (ocean/lakes) and solid (I’ll leave other planetary bodies out of this discussion). The Ksp of CO2 in water plays no real role in the atmospheric interaction of CO2 and the photons from the earth and sun, I’ll explain below.

But first, I do like that you included the can of coke though, it’s always a great way of explaining some fundamental physics and chemistry. Unfortunately according to both Henry’s Law which you allude to, and the ideal gas law which plays a greater role when a can is opened, don’t bolster your argument regarding atmospheric CO2.

First off, both a cold can of coke and a warm can of coke release CO2 when opened. I’m assuming by cold we mean refrigerated (not super cooled to near 0K). And by hot I’m assuming warmed in the sun or left by a heater (not superheated to a plasma or something). When you open either can, and release the pressure, via the ideal gas law and Henry’s Law we know that some of the CO2 that dissolved in the liquid immediately boils out due to the reduced pressure (same way blood boils in space despite the very low temperatures). So I’m not sure where you have done experiments showing a cold can of coke will absorb CO2 in normal conditions. In fact to get the liquid coke to absorb CO2, the canning facility has to inject it under rather high pressure which causes the temperature to rise significantly. Anyhow, enough of the coke can, it really has nothing to do with your statement about global warming causing an increase in CO2 (even if we include the oceans, the analogy is so misconstrued as to be dysfunctional).

So, in the atmosphere, CO2 is in it’s gaseous form and with photons, not liquids where Ksp plays a role. So we have to abandon that red herring and instead focus on radiative transfer. Here we just look at CO2 as a molecule, and the earth and sun as sources of radiation (not the bad kind at the really short end of the spectrum to the right, but the longer ones more towards the middle part of the spectrum we call infrared).

It turns out that by looking at the blackbody curves of the sun (roughly 5780K) and the earth (roughly 255K), and using Wien’s Displacement Law, Stefan Boltzman Law along with Planck Function (I include these for the geeks and the curious who want to look them up), we can figure out how those CO2 molecules are effectively transparent at 5780K, but act like a barrier at 255K. So that radiation (aka heat) from the sun makes it through to the surface, but the radiation from earth, is absorbed by the CO2 molecules in the atmosphere (and yes, even more so by other molecules including H2O, the most effective). Because of the physics behind electrons getting excited, the CO2 molecule increases it’s vibration/energy. As explained in other comments, increasing the energy of a molecule is the definition of increased temperature. This radiative transfer process where CO2 is transparent to incoming radiation, but absorbs outgoing radiation is the same process that allows a small glass building in the back yard to be transparent to the incoming radiation from the sun, but opaque to the outgoing radiation from the ground, and we call it a greenhouse.

So as you can see, it is not the Ksp of CO2 in water, or the can of coke, but how the CO2 in the atmosphere and black body radiative transfer physics that demonstrates irrefutably that an increase in CO2 raises the temperature of an gas. Now we can debate if that raised temperature is good or bad, but you cannot debate the physics, and nobody does, at least on this planet with our current knowledge of Newtonian physics.

Now in reality this is a good thing, it is this physics that makes life as we know it possible on the surface of the earth. This radiative transfer has made the planet warm enough to live on. And thankfully because CO2 is a trace gas and doesn’t absorb too much of that earthly radiation, we’re not in a Venus situation where CO2 is the primary gas in the atmosphere and spacecraft melt/die in minutes because it’s really hot, like damn hot.

So, in the end, blackbody physics and CO2 is not the same as aqueous physics and CO2. So Ksp not so relevant, Mie and Rayleigh Scattering very relevant.

4 replies
June 2023 ▶ johnphi

Arthur_Foyt

  1. We live on a water planet. That’s why the Ksp is the answer to warmer equals more co2.
  2. The atmosphere is not a closed system.
  3. Do your own research on historic data and beware of using tree rings with any order of scientific precision.
    4)Surface warming without atmospheric warming negates the theory that warming occurs first in the atmosphere.
June 2023 ▶ avi8tor.tom

Mike_S

…and it doesn’t take hours to top off the fuel and launch again, if you’re travelling beyond one fill up’s range. Recharging time is another limitting factor.

June 2023 ▶ johnphi

rpstrong

Thanks for the repost; I was thinking of it when I saw your reply - and I enjoyed the new intro.

June 2023 ▶ johnphi

Arthur_Foyt

“The Ksp of CO2 in water plays no real role in the atmospheric interaction of CO2 and the photons from the earth and sun”

That is of course a true, but think it through. It’s when there is a warming that the oceanic CO2 is released and THEN it will interact at some level with radiation from outside of Earth. Warming releases CO2; cooling sequesters it. Basic chemistry.

June 2023 ▶ johnphi

johnphi

Good, once again we see that we can agree on things.

  1. It’s nice to see that you agree that the planet is warming due to more CO2 in the atmosphere. In your case you believe that this is because the oceans are releasing it like a soda can. Again, some pretty basic physics here disputes this, and in fact the oceans are a massive carbon sink where a very large chunk of atmospheric CO2 ends up being stored these days. Of course this likely won’t last forever, so eventually your example may come to be, then things will get even worse (search for: the oceanic sink for anthropogenic CO2 from 1994 to 2007, if you’re curious to learn more).

  2. Agreed, though not sure why you included it. My example pointed this out.

  3. Agreed, I did my own research on historic data, for many, many years whether on ice sheets, forests or lakes. Not sure if you mean all historic data or just tree rings. I personally have only worked on projects involving ice cores, lacustrine cores (mostly pollen stuff), and tree rings, so definitely not an expert on all of them. But if only I had a nickel for every ice core I’ve had to slice, or dendrochronologist I’ve had to help core trees, well I could at least buy a really nice dinner. The ice cores and tree rings in particular are impressive with their correlation as we can look at recent weather observations and see how they match so very well (mostly dealing with O16/018 ratios since you seem to enjoy chemistry) going back over a century. With the sediment cores, again we use chemistry and back it up with pollen record, and low and behold, as it gets warmer or colder according to the chemistry, we wee the pollen of plants that grow in warmer or colder environments. It’s almost as if the data has been tested and tested and tested and just keeps on agreeing.

Again, these sources of historic data have been debated and debated for many decades and are accepted as extremely reliable by the science community.

  1. Okay, maybe we don’t agree on this one. Though I’m not entirely sure what you actually are trying to imply. Every morning when the sun shines the surface of the earth warms before the atmosphere above it, not sure if that’s what you mean, but if so, then I agree. That gets back to my radiative heating stuff above. Though, it seems you have a hypothesis about something, I’m not sure what, without any data to support it. So I’ll stick with my theory that is based on a hypothesis that is backed up by more than a century of research by thousands of researchers producing yottabytes of data demonstrating that we need to encourage people to read more so they can have a better appreciation of science and the world around us.
2 replies
June 2023 ▶ jimhanson

Raf

News Flash: In the land of Aviatopia, electric airplanes are experiencing short flight times due to the mischievous actions of Electric Pixies and Current Gnomes. These magical creatures are known for tampering with the electrical systems, draining the batteries, and causing chaos during flights. Manufacturers, consisting of approximately 100 entities worldwide, are facing frustration but persist in their efforts to improve flight durations. The teams dedicated to combating the Electric Pixies and Current Gnomes are not giving up, and more developments are expected in the future. Stay tuned for further updates.

June 2023 ▶ johnphi

Arthur_Foyt

Just because warmer means more CO2, it does not mean that CO2 is driving the warming (quite the reverse).
A “better appreciation of science” can only happen when there is unbiased research and reporting. When 100% of climate funding is to go out an prove a theory , it’s already against the scientific method. The only wonder becomes why only 97% taking the money agree to a theory; LOL.

June 2023 ▶ johnphi

johnphi

As always, I enjoy the debate with you. Since I can’t debate the conspiracy ideas of funding, I’ll just leave it to the data.

I have pulled ice cores out of an ice sheet, cut it into tiny pieces, put it through a mass spec, analyzed the results and seen the results both published and made publicly available. So if you’re curious for an unbiased look, I encourage you to simply google the many, many sources of publicly available data, analyze them yourself and see if it agrees with the 99.999% of paleoclimatologists (including those funded by the many oil companies) who see that indeed atmospheric CO2 is the driver of the temperature change on the planet. Again, this is not new, it did not start when you starting paying attention to it relatively recently, the research has been showing this for more than a century and is well established.

I understand that many don’t like it because it goes against their sociopolitical beliefs, but thankfully physics is belief agnostic. So instead of debating whether or not physics is real, we should debate what to do about it. It’s just like flying, we don’t debate that an airplane will eventually return to the earth, we just debate the best way to grease the landing.

I look forward to the next time you bring up Ksp and the soda can…

June 2023

simkot

If you guys are done showing off your scientific chops to each other…, I think we can all probably agree that, power system aside, having the entire wing “blown” by the distributed thrust could offer some interesting aero advantages, at least this thing has WINGS!

1 reply
June 2023 ▶ Brian_Smith

bserra

Cool, if that happened in 5 years. Unfortunately, with the present technology, that relies mainly in the use of batteries as a provider of electric power or the use of hydrogen, not even in 25 years that cool thing will happen, Mr. Brian Smith.

June 2023

newtexan

I’m not against electric airplanes, cars, or anything. I’m just wondering what the options are when the battery explodes and engulfs the airframe in fire.
You know, like we see cars on the news?

2 replies
June 2023 ▶ simkot

jimhanson1

“Blown thrust” has been a factor for decades as well–almost every prop-driven aircraft has “blown thrust.” That may or may not be an asset–consider flight in icing conditions (I live in the northern tiers of states). How do you de-ice those multiple engines and multiple blades? It takes a LOT of TKS to keep that many blades clean–in ADDITION to the wing and windshield. If you use electrothermal deice–consider just how much power 6 or 8 multi-blade props will consume.

A lot of aircraft have used the “blown thrust” idea over the past 70 years–how many have been successful? The concept is hardly new–one would THINK that the concept would have been proposed before–and it WAS–(the YC-14 and 15).The Custer Channel Wing was perhaps the most infamous proponent of the concept–it didn’t make it, either–though some STOL airplanes blow the flaps for added lift–not the leading edge. The Navy funded a number of blown-wing concept aircraft–they didn’t make it, either. Some concepts have an unlimited life–kind of like “perpetual motion”–a new version is proposed every few years.

1 reply
June 2023 ▶ Brian_Smith

Roger_Mullins

If every airplane were electric it would slow down the rate of CO2 “growth” by about .2%. So don’t let them tell you that if we don’t start flying electric planes in 8 years we will all be dead, NOT GONNA HAPPEN.

June 2023

Roger_Mullins

Help me to understand this. An electric motor is 75% efficient, A generator is 99% efficient, a gasoline engine is 28% efficient. If a 28% efficient engine turns a 99% efficient generator to run a 75% efficient electric motor would that not make an increase in overall range for a given fuel consumption?

2 replies
June 2023 ▶ newtexan

tordseriksson

I have seen big American cars with V8s catch fire, a friend’s new BMW (petrol-driven) caught fire in an instant, and I’ve seen buses (spent 30 years around buses) on fire powered by diesel, biogas, and batteries. Batteries need to be cooled and monitored, fighter jet aircraft need to use inert-gas systems to avoid explosions in their tanks, and I’ve been aboard a huge ferry that caught fire in the middle of nowhere (just a couple died, thankfully).

So the choice of propulsion doesn’t say anything about if your aircraft catches fire (as yet I have not heard of it happening to electric aircraft).

With cars hybrid powered vehicles catch fire more often than either petrol, diesel, or gas.

The problem with batteries is their weight, and you can’t dump the battery if you need to make an emergency landing!

June 2023 ▶ jimhanson1

Larry_S

I was AT Edwards in the late 70’s when the YC-14 and YC-15 were in flight test. ONLY the Boein YC-14 had blown lift flaps. The other was a conventional design … which LATER morphed into the C-17. That’s how much the USAF thought of the idea. To be fair … there were other reasons they went for the -17 … starting with 4 engines.

June 2023 ▶ newtexan

Larry_S

When it catches fire … you get to meet the five guys that just got squished on the Titanic tourist sub.

1 reply
June 2023 ▶ Larry_S

Raf

I value you candor, Larry.

June 2023 ▶ Roger_Mullins

jethro442

Yes.

June 2023 ▶ Roger_Mullins

Arthur_Foyt

No, you start with a 28% engine and then take away percentages for the generator, voltage conversion, electrical resistance, and then percentages to run the less-than-perfect electric motor. You don’t gain efficiency, you lose efficiency over just having the engine running the prop in the first place,

2 replies
June 2023

jethro442

The question was “would that not make an increase in overall range for a given fuel consumption?”

My answer was yes. Yes it would not make an increase in overall range for a given fuel consumption.

There would be a loss of efficiency.

1 reply
June 2023 ▶ jethro442

Arthur_Foyt

If you want range, ditch the dead weight of the battery completely and replace it with lighter weight, higher energy density fuel. You gain efficiency and range. It’s that simple.

Honestly, the whole switch to hybrids underscores that people now know that batteries are not a solution. Putting a sharp pencil to the problem also means that inefficient hybrids will also be hard sell if you want to fly, and actually carry stuff, and actually go places. Heck, all you have to do is look at hybrid cars and see that economy on long high speed driving (akin to flying) gets less performance and fuel mileage. To be fair some now disconnect most of the generator drag and a “break even” with non-hybrid cars.

1 reply
June 2023 ▶ Arthur_Foyt

Raf

Right you are, Arthur J Foyt.

June 2023

Raf

From the 'hood: Engaging in an argument with someone who thinks they’re the big shot in their area of expertise is like challenging a chingón in the Mexican gang banger world. You’ll find yourself scratching your cabeza in confusion while they effortlessly climb to the top of the hierarchía and stash away their mad skills. Pero hey, after checking their loco claims, you might still learn a few truquitos, just make sure you’re not barking up the wrong pinche tree! ¡Órale!

June 2023 ▶ Arthur_Foyt

thomas.boyle

You lose efficiency in the powertrain right up to the propeller. Having more propellers (larger total area) is more efficient. A bigger factor is that by “blowing” the wing you can use a smaller wing, which reduces cruise drag - hopefully by enough to more than offset the loss in powertrain efficiency. Theory says it can work; practice is trying to catch up but hasn’t yet. Electric motors make it practical to try. Battery capacity can be quite small, so battery tech isn’t a big issue.

June 2023 ▶ Arthur_Foyt

thomas.boyle

Engineers working on electric flight have known this for years; it’s not a new insight, and it’s not controversial, among the people actually working on electrified aircraft. Electrification started with small, lightweight, battery-only platforms because it cost less and simplified the problem. The reason we’re seeing a “switch” to hybrids now is that there’s been enough progress on the early integration tasks to move on to the next phase - not because the engineers have suddenly woken up to the limitations of batteries.

As for the comparison to hybrid cars, again, the fact that aircraft don’t get the same benefits from stop-start driving as hybrid cars do, has been obvious to engineers working on electrification since forever. Also not a new insight, and stop-start driving is not the theory around which these aircraft concepts are being developed.