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PiperCruisin

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Against my better judgement, I'll jump into the fray.

Green or not, I'm a big fan of improving efficiency, anyway it makes sense. I like the idea of electric aircraft for the potential improved reliability and distributed propulsion and reduced cost. Certainly the reliability, cost and energy density are not there yet. But I'm somewhat optimistic. For now, the only place it might be useful is a self-launch glider and/or a hybrid/backup/boost system. If we get a 2.5-3X improvement in energy density, now you have something interesting, but then energy production becomes a limiting factor. Why we don't spend more resources investigating Thorium molten salt nuclear power, I don't know.

As far as subsidies are concerned, maybe they should not exist at all. However, they do and it would be nice to get a pittance to promote and advance general aviation versus all the energy and dollars to send up more space junk (love the GPS, but it made us stupid...this will turn into a "What did Romans ever do for us" moment). More NAsA than NaSA is my vote.
 

Dan Thomas

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c. For now, the only place it might be useful is a self-launch glider and/or a hybrid/backup/boost system.
We've discussed the hybrid idea many times. Nobody, I think, has any idea how to implement it without ending up with a heavier airplane. You still need the IC engine, plus batteries, plus electric motor, plus a sizeable generator.....it gets ridiculous. Light airplanes are extremely weight-sensitive; every ounce matters.
 

tspear

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I like electric/hybrid airplanes for a few possible reasons.
1. The potentially for radically reduced maintenance induced failure. With so many less moving parts, there is less risk in almost every aspect of maintenance.
2. The potentially for longer term cost reductions. Batteries keep dropping in power. The hourly cost in MX on every plane I have owned has gone up every year. At some point electric will be cheaper.
3. A series hybrid, or range extender, is a short term fix for energy density issues. The advantage is primary power and battery power of 30 minutes can basically get you to land safely if the generator dies. This means the genset does not need to be maintained to the same crazy level in theory as the current ICE.

Tim
 

Vigilant1

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I like electric/hybrid airplanes for a few possible reasons.
I agree that electric power may someday be a practical power source for many aviation use cases. But today? No, it isn't. You've named some advantages electric power will bring, but the energy densitty limitation of present batteries just overwhelms every other consideration.

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3. A series hybrid, or range extender, is a short term fix for energy density issues.
In practice, it is not a practical fix. Find a use case, get real weights for the needed IC engine, associated generator, needed battery, electric motor(s), and cabling. Be realistic with the power requirements (e.g need the ability to execute a pattern and a go-around even immediately after takeoff, etc) and you'll see that the weight of a series hybrid is not comparable to an IC engine alone. To address reliability issues, a second IC engine still weighs less than the series hybrid, and provides much more mission flexibility.
 
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Hephaestus

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and you'll see that the weight of a series hybrid is not comparable to an IC engine alone.
And that's where the super lightweight microturbines come in.

But due to the turbine in the name the costs are pretty extreme. But... Jaguar has some for next year's supercar hybrid - so we should see some options coming up.
 

Dan Thomas

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I like electric/hybrid airplanes for a few possible reasons.
1. The potentially for radically reduced maintenance induced failure. With so many less moving parts, there is less risk in almost every aspect of maintenance.
It's a more complex system, introducing more possibilities for maintenance mistakes. And there are MORE moving parts, not fewer. As a mechanic, I (and every other mechanic) found the simplest airplanes presented the least hassles and maintenance errors, and the more complex had to be watched carefully during maintenance so that some error didn't get overlooked. And more complexity meant more time and more cost.
 

Hot Wings

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In practice, it is not a practical fix. Find a use case, get real weights for the needed IC engine, associated generator, needed battery, electric motor(s), and cabling. Be realistic with the power requirements
Plenty of other threads here about this. Old rabbit hole. :D;)

I agree when it comes to conventional aircraft and even training flights. We just aren't there yet. But.............
There are corner cases where pure electric and even hybrid make sense today - even from an engineering perspective.
Part 103s, gliders and planes with missions like my future AV-361 can benefit from a hybrid system. The weight of the system is competitive with a pure ICE in the power class and there are some advantages. Neither simplicity or ease of design are one of them.
 

RonL

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There's no way I can explain the connection between this and an electric airplane, but there are possibilities.


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pictsidhe

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Plenty of other threads here about this. Old rabbit hole. :D;)

I agree when it comes to conventional aircraft and even training flights. We just aren't there yet. But.............
There are corner cases where pure electric and even hybrid make sense today - even from an engineering perspective.
Part 103s, gliders and planes with missions like my future AV-361 can benefit from a hybrid system. The weight of the system is competitive with a pure ICE in the power class and there are some advantages. Neither simplicity or ease of design are one of them.
I looked at a hybrid for my 103 to give good takeoff power with a cruise size (and weight) engine. Had some advantages, but would be a PITA to engineer. Simpler it is not. I'm going for a bigger ICE instead. If I was bothered about range, I may consider it worth the effort.
 

Bigshu

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It does buy its way in on technical merit, for limited use cases. ~1 hour training flights happens to be one of the use cases that it works for, similar to the Harbour Air short hop flights. The batteries can be recharged in 45 minutes or replaced in 5 minutes, so 2 battery packs can keep a training plane running 1 hour flights all day. You'd still need another plane for cross countries, but it would work for about 75% of training flights, and has the advantage of being able to train prop-stopped engine out scenarios with instant power available when the inevitable mistakes are made by the student.

It doesn't meet your use case, nor mine, nor nearly everyone on this message board, but it does work in limited roles, which is what they are promoting here. We're decades from electric long haul airliners, and it will probably be at least 10 years (by my estimation) from small planes getting even close to practical ranges, but they do fit this particular niche now.
I'm not so sure it doesn't meet a lot of builder's needs to have an alternative power plant available. One of the arguments against electric is that the battery pack weighs the same charged or discharged, so there's no gain in performance as a petro fueled aircraft sees as it gets lighter. But on the other hand, you don't see the W/B issues with the battery packs, there's no change as you fly along to trim out. Also, the simplicity and reliability of electric motors has the potential to substantially reduce the maintenance cost of the aircraft. I see that as a win, even if it takes decades to make recharging totally from renewable sources. Zero % of fossil fuels are renewable in reasonable time frames, so what's the beef? There are lots of practical things to electric power that people don't even consider, like never having to sump a fuel tank again. Or never having to clean the oil off the belly of the aircraft.
 

Bigshu

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My perception is that most normal people just think of little airplanes as little airplanes, not "clean" or "dirty."
When someone comes along hawking a new (expensive) airplane as "clean," then increasingly my little airplane may be seen as "dirty." I don't think that helps me. And I don't think it helps GA, since the pressure builds to make all GA planes "clean" despite 1) they are no dirtier than they have always been and contribute a trifling amount of polution in comparison to other things and 2) these "clean" airplanes can't do 98% of the things people want to do with GA airplanes.
I'm not against this petition, but the way they are selling it is not honest and won't get my support. They label this is as "sustainable", so what does that make my plane? Nope, thanks.
Not everyone who sees renewable energy as the future is too dense to get that legacy vehicles will be around for a while, and aren't evil. Electric cars are making bigger in roads every day, but no one is saying IC powered cars must be outlawed immediately.
The reality is that electric vehicles don't compete well economically due to battery technology, so they need a marketing boost to keep them viable until the energy storage problem is worked out. If calling them "clean" to get people to jump on the bandwagon to allow them to pass regulatory muster is the best path forward, so be it. As someone said in the $10 dollar avgas thread said, we'll see electric airplanes long before we see unleaded 100 octane fuel.
 

Bigshu

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It was luck. You can do everything right, and still run into it. Had it happen with an instructor on board and he turned it into a very good learning opportunity.

I love the idea of electric aircraft, for the simplicity, the easy operation, the potential to park the airplane with a solar panel all week long and have free flying every weekend. All good stuff. Like some others, I roll my eyes when the "green" language is trotted out - light planes fly so few total hours that even electrifying the entire fleet would have exactly zero effect on "the environment." The only "green" issue in aviation is the airliner fleet, not GA. A single airliner flight across the US burns more fuel than a light sportplane will burn in its entire life, several times over. And there are tens of thousands of airliner flights every day around the world.

I think training seems, at first, to be an ideal niche for these early-stage electric airplanes. The duty cycle is certainly about right. But as Dan and some others have pointed out, the little habits and muscle-memory you learn in the first part of your training carry through your entire life flying airplanes, and take a lot of re-training to overcome. To paraphrase the military, "train like you fly and fly like you train," applies especially to new pilots. A useful example comes from self-launching sailplanes and motorgliders. Pilots who have primarily or solely been (unpowered) sailplane pilots throughout their entire flying time have a very hard time grasping the idea, at the "gut" level, that engines are sometimes hard to start on the first attempt, sometimes don't start on the first attempt. These pilots tend to get too low trying to "scratch" out on a thermal or ridge lift and, when it doesn't pan out, turn to the engine as if it will always immediately start perfectly. They don't have the experience of sitting on an apron, grinding away on the flight-school trainer that doesn't want to go fly on a cold weekend morning. That'll give you a different attitude about starting engines, if you began your flight training that way. Teaching students to fly in an electric airplane is going to give them the fundamental "gut" belief that the engine will always start immediately when they throw the switch, something that isn't necessarily true of any IC engine they end up flying.

Once the electric airplane is common in the GA fleet, then electric trainers are going to have all the advantages that 12 notes has pointed out. But until then, IMHO, training in one is going to be training very differently than how you're going to end up flying "for real," and that's potentially very dangerous.
Well, using the example of a hard starting, or hot restarting IC engine just makes the point that antiquated engine technology needs to be dragged into the 21st century. When's the last time your car was hard starting? If it's built since the 90's, you probably never have starting or drivability issues with a fuel injected, electronic ignition car. So it should be with light aircraft. Regardless of whether we should be promoting electric aircraft, (we should) we can't say that training pilots is degraded if they don't have to train on balky, old, crappy engine technology. The kids we're trying to entice into an expensive pursuit, that requires some tenacity and focus to master, won't be persuaded, if we continue to train as if you can never count on the engine, the avionics, etc. It's one thing to train for contingencies, but it's another to reduce the students faith in the vehicle. Why on Earth would anyone want to stake their life on technology that they have been trained from the beginning not to trust. I trust my car, but I still pay attention to safe driving techniques like maintaining following distance, always leaving myself an "out" if I need to get to a shoulder, etc. I haven't had my car quit on me on the road in ages. That's what aviation needs to strive for.
 

12notes

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I'm not so sure it doesn't meet a lot of builder's needs to have an alternative power plant available. One of the arguments against electric is that the battery pack weighs the same charged or discharged, so there's no gain in performance as a petro fueled aircraft sees as it gets lighter. But on the other hand, you don't see the W/B issues with the battery packs, there's no change as you fly along to trim out. Also, the simplicity and reliability of electric motors has the potential to substantially reduce the maintenance cost of the aircraft. I see that as a win, even if it takes decades to make recharging totally from renewable sources. Zero % of fossil fuels are renewable in reasonable time frames, so what's the beef? There are lots of practical things to electric power that people don't even consider, like never having to sump a fuel tank again. Or never having to clean the oil off the belly of the aircraft.
You don't have balance issues, but you have a huge weight issue. The battery packs are simply too dense for any more than about an hour's use. This is the critical limitation, every other problem is minor in comparison. The benefits are well known, and have been considered multiple times here, but none of the benefits matter if the weight of the battery makes it impractical for most GA aircraft.

There is unlikely to be a huge jump in battery density, simply because it's an industrial technology and advances are slow and steady, and have been consistently since the 60's. It's going to be about 10 years for a 200-mile range electric GA plane, and 20-30 years before they'll be a reasonable replacement for most gasoline powered GA planes in utility.
 
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Dan Thomas

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Well, using the example of a hard starting, or hot restarting IC engine just makes the point that antiquated engine technology needs to be dragged into the 21st century. When's the last time your car was hard starting? If it's built since the 90's, you probably never have starting or drivability issues with a fuel injected, electronic ignition car. So it should be with light aircraft. Regardless of whether we should be promoting electric aircraft, (we should) we can't say that training pilots is degraded if they don't have to train on balky, old, crappy engine technology. The kids we're trying to entice into an expensive pursuit, that requires some tenacity and focus to master, won't be persuaded, if we continue to train as if you can never count on the engine, the avionics, etc. It's one thing to train for contingencies, but it's another to reduce the students faith in the vehicle. Why on Earth would anyone want to stake their life on technology that they have been trained from the beginning not to trust. I trust my car, but I still pay attention to safe driving techniques like maintaining following distance, always leaving myself an "out" if I need to get to a shoulder, etc. I haven't had my car quit on me on the road in ages. That's what aviation needs to strive for.
Lycoming built the ie2 engine. EFI and EI, the works. It's way too expensive, since certification costs are expensive. Testing takes time and costs money. And without that testing, no one can be sure that the new engine will be any more reliable than the old. Ease of starting is a minor issue compared to reliability.
Carmakers spread their R&D costs out over many millions of vehicles. Airframe and aircraft engine manufacturers spread their R&D out over a few dozen airplanes. The math is really inconvenient. When cars quit they coast to the side of the road. When an airplane quits someone gets hurt or dead. Insurance companies are nervous about new stuff, and that's not convenient either.
The solutions are not simple. Or cheap. If they were we wouldn't be having this discussion.
 

Dan Thomas

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The reality is that electric vehicles don't compete well economically due to battery technology, so they need a marketing boost to keep them viable until the energy storage problem is worked out. If calling them "clean" to get people to jump on the bandwagon to allow them to pass regulatory muster is the best path forward, so be it.
https://media4.manhattan-institute.org/sites/default/files/mines-minerals-green-energy-reality-checkMM.pdf
A quote from that:

A lithium EV battery weighs about 1,000 pounds. While there are dozens of variations, such a battery typically contains about 25 pounds of lithium, 30 pounds of cobalt, 60 pounds of nickel, 110 pounds of graphite, 90 pounds of copper, about 400 pounds of steel, aluminum, and various plastic components. Looking upstream at the ore grades, one can estimate the typical quantity of rock that must be extracted from the earth and processed to yield the pure minerals needed to fabricate that single battery:
•Lithium brines typically contain less than 0.1% lithium, so that entails some 25,000 pounds of brines to get the 25 pounds of pure lithium.
•Cobalt ore grades average about 0.1%, thus nearly 30,000 pounds of ore.
•Nickel ore grades average about 1%, thus about 6,000 pounds of ore.
•Graphite ore is typically 10%, thus about 1,000 pounds per battery.
•Copper at about 0.6% in the ore, thus about 25,000 pounds of ore per battery.
In total then, acquiring just these five elements to produce the 1,000-pound EV battery requires mining about 90,000 pounds of ore. To properly account for all of the earth moved though—which is relevant to the overall environmental footprint, and mining machinery energy use—one needs to estimate the overburden, or the materials first dug up to get to the ore. Depending on ore type and location, overburden ranges from about 3 to 20 tons of earth removed to access each ton of ore. This means that accessing about 90,000 pounds of ore requires digging and moving between 200,000 and over 1,500,000 pounds of earth—a rough average of more than 500,000 pounds per battery.
 

Vigilant1

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I'm eager to see the total taxpayer costs in subsidies for each hour of flight instruction, as well as the average number of flight hours taken by these students to get their license.
A giant boondoggle of feel-good-ism.
 

bmcj

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I'm eager to see the total taxpayer costs in subsidies for each hour of flight instruction, as well as the average number of flight hours taken by these students to get their license.
A giant boondoggle of feel-good-ism.
You hit one of the major concerns about this program, but it’s just the staff pilots flying the Alpha Electros (no lessons) because AFAIK, they still don’t have FAA approval for giving instruction in them. To get around that restriction, they recently bought some taxpayer funded Rotax-powered Alphas for giving instruction. (Does anyone see the irony of this?)

The less obvious, but more serious implication of this program is not that the government is paying for this (that’s just the Modus Operand of many government agencies). The real issue is that this government funded program was set up in nice big hangars at the municipal airport (where others have long been on a waiting list for a hangar), and the flight hours will be subsidized in direct competition with the (rent and tax paying) flight schools at the airport. The end results is that the brick and mortar flight schools can’t match the rental rate that the subsidized program is offering.
 
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Bigshu

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https://media4.manhattan-institute.org/sites/default/files/mines-minerals-green-energy-reality-checkMM.pdf
A quote from that:

A lithium EV battery weighs about 1,000 pounds. While there are dozens of variations, such a battery typically contains about 25 pounds of lithium, 30 pounds of cobalt, 60 pounds of nickel, 110 pounds of graphite, 90 pounds of copper, about 400 pounds of steel, aluminum, and various plastic components. Looking upstream at the ore grades, one can estimate the typical quantity of rock that must be extracted from the earth and processed to yield the pure minerals needed to fabricate that single battery:
•Lithium brines typically contain less than 0.1% lithium, so that entails some 25,000 pounds of brines to get the 25 pounds of pure lithium.
•Cobalt ore grades average about 0.1%, thus nearly 30,000 pounds of ore.
•Nickel ore grades average about 1%, thus about 6,000 pounds of ore.
•Graphite ore is typically 10%, thus about 1,000 pounds per battery.
•Copper at about 0.6% in the ore, thus about 25,000 pounds of ore per battery.
In total then, acquiring just these five elements to produce the 1,000-pound EV battery requires mining about 90,000 pounds of ore. To properly account for all of the earth moved though—which is relevant to the overall environmental footprint, and mining machinery energy use—one needs to estimate the overburden, or the materials first dug up to get to the ore. Depending on ore type and location, overburden ranges from about 3 to 20 tons of earth removed to access each ton of ore. This means that accessing about 90,000 pounds of ore requires digging and moving between 200,000 and over 1,500,000 pounds of earth—a rough average of more than 500,000 pounds per battery.
Interesting info, but unless the argument is that fossil fueled IC engines don't contain most of the listed items, and they are all built from recycled, existing materials (no acquisition impact from building engines), then what I'm getting from your info is that we shouldn't be making the batteries we already make, much less look to make better ones. I don't see how anyone can support the production of any extracted resource, given these facts. <Hyperbole insertion off>
Unless I totally misunderstood what you're saying. There is a much greater than zero chance that's true!
 
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