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Electric aircraft set to take flight by 2026 under new agreements

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Re: Electric aircraft set to take flight by 2026 under new agreements

#111

Post by Robotbeat »

saddlerustle wrote: post #39
itsrajju wrote: post #12

Wendover Productions (who else?!) recently released a video[1] on the future of electric planes. Quite a lot of information in there! [1]: https://www.youtube.com/watch?v=aH4b3sAs-l8

LNA, an aviation industry newsletter, recently came to a very different conclusion [1]. The biggest difference to Wendover Productions's numbers is a hugely higher estimate in the cost of replacing the battery every 5-10 years due to battery degradation. [1] https://leehamnews.com/2021/07/01/the-true-cost-of-electric-...

The cost of replacing a battery is about the same cost as a turboprop engine overhaul, and depending on the battery type and other details, it may occur less often.

Turboprop engines like the PT6 have a Time Between Overhauls of about 3000 hours, maybe longer. At 240 knots, that's 720,000 nautical miles between overhauls. If your electric aircraft has a range of 500 nautical miles and a 1500 cycle life, that's the same time. For an electric aircraft with a 900kWh battery like the Eviation Alice, and a cost per kWh of $170-$300/kWh, that's $150,000-300,000, the same as a turboprop engine overhaul.

Cycle lifes well beyond that are feasible, though, and battery costs are reducing over time.

Re: Electric aircraft set to take flight by 2026 under new agreements

#112

Post by [deleted] »

IshKebab wrote: post #72
thunderrabbit wrote: post #51

Earlier quoted context omitted.

Thank you for bringing up this other conclusion. I still side with Wendover overall. Even if batteries have to be replaced that often now, the technology will continue to improve, becoming both cheaper and more reliable. Computers used to be the size of rooms and break due to literal insects in them.

I don't think you can cite the technology that has advanced most dramatically out of all the technologies to support some kind of rule that all technology inevitably advances rapidly. Yes they'll get better, but they might get 10% better over the next 20 years or something like that.

[deleted]

Re: Electric aircraft set to take flight by 2026 under new agreements

#113

Post by cogman10 »

audunw wrote: post #83
saddlerustle wrote: post #39

Earlier quoted context omitted.

LNA, an aviation industry newsletter, recently came to a very different conclusion [1]. The biggest difference to Wendover Productions's numbers is a hugely higher estimate in the cost of replacing the battery every 5-10 years due to battery degradation. [1] https://leehamnews.com/2021/07/01/the-true-cost-of-electric-...

That sounds like a ridiculous assumption. Airplanes are basically guaranteed to not discharge the batteries lower than 20% for safety reasons. I’m guessing they’ll also not charge to fully 100%, like some BEVs. On fixed routes they could charge only what they need to get to where they’re supposed to go plus the required buffer for emergencies. The batteries will probably also be cooled. So it could be an ideal scenar…

> they’ll use a different chemistry than the standard Li-ion chemistries we have today.

I somewhat doubt it. The characteristics that make a good battery for a plane make a good battery for a car. I think the only place there's a difference is airlines are likely willing to spend more on batteries.

Re: Electric aircraft set to take flight by 2026 under new agreements

#114

Post by deregulateMed »

itsrajju wrote: post #12

Wendover Productions (who else?!) recently released a video[1] on the future of electric planes. Quite a lot of information in there! [1]: https://www.youtube.com/watch?v=aH4b3sAs-l8

Anyone get a weird feeling about Wendover? I used to think he was a decent authority until I watched his channel Half As Interesting.

Maybe he hires a writer, but his sarcastic joking nature comes off as extremely sincere and authoritative. This makes me question how solid his Wendover points are. He has a commanding voice and we believe him.

Re: Electric aircraft set to take flight by 2026 under new agreements

#115

Post by topspin »

gregmac wrote: post #108
gamegoblin wrote: post #99

I recently had a pie-in-the-sky business idea and I would love for someone who knows more about the industry why it will definitely fail. I assume it's unworkable for a lot of reasons, but it is just plausible enough to be a fun idea for a sci-fi novel. Get a fleet of 2-4 seater unpowered glider planes [1] Get a bunch of rural properties spaced ~100km apart. Put little glider landing and launch strips on each propert…

> Develop software that can fly the planes autonomously from strip to strip (I assume this is the really hard part, but I am under the impression that autonomous flying is a much easier problem than autonomous driving?). As a software developer, this part is what I don't like. We're still quite a ways from fully autonomous driving cars (as in: don't rely on a human taking over for backup). A bad bug in an autonomous…

Point of information; certified autoland systems appeared on airliners in 1968. Yes, we're a ways off from the level of automation for a fully pilotless system as proposed here, but I think it a matter of a few years, perhaps a decade.

Re: Electric aircraft set to take flight by 2026 under new agreements

#116

Post by _0w8t »

Robotbeat wrote: post #100
FabHK wrote: post #94

Earlier quoted context omitted.

A good rule of thumb (in general aviation at least) is that anything aviation grade is about 10x the "normal" price, or more.

Fuel isn’t. Jet fuel is basically no more expensive than diesel and sometimes cheaper (no road tax). You can consider batteries basically like jet fuel.

In Norway jet fuel costs like 3 times less than gasoline due to absence of taxes. For these reason some amateur flight school use small planes with jet engines, like DA40NG, to get much lower operational costs. It can be even cheaper to fly such plane than drive a car.

Re: Electric aircraft set to take flight by 2026 under new agreements

#117

Post by amirhirsch »

gamegoblin wrote: post #99

I recently had a pie-in-the-sky business idea and I would love for someone who knows more about the industry why it will definitely fail. I assume it's unworkable for a lot of reasons, but it is just plausible enough to be a fun idea for a sci-fi novel. Get a fleet of 2-4 seater unpowered glider planes [1] Get a bunch of rural properties spaced ~100km apart. Put little glider landing and launch strips on each propert…

Electric aircraft (not necessarily gliders) could use a tethered assisted take-off and ascent as a way to save on the initial power draw. You probably would want to use another assistant plane (not a ground station) to pull the passenger plane to altitude and speed and then return to a runway while the other continues on it's longer flight.

Re: Electric aircraft set to take flight by 2026 under new agreements

#118

Post by Leherenn »

gamegoblin wrote: post #99

I recently had a pie-in-the-sky business idea and I would love for someone who knows more about the industry why it will definitely fail. I assume it's unworkable for a lot of reasons, but it is just plausible enough to be a fun idea for a sci-fi novel. Get a fleet of 2-4 seater unpowered glider planes [1] Get a bunch of rural properties spaced ~100km apart. Put little glider landing and launch strips on each propert…

A winch gets you maybe about 1/3 of the cable length (and thus strip length) at best. A typical cable length is between 1 to 2km long. Let's say you can gain 500 m height. A glide ratio around 50 is probably on the higher end of what's achievable, so you're looking at 25 km of range. That's before you account for wind, that the world is not flat or the fact that you don't start your landing at 0 m, but more like 200/300 m from the ground.

Honestly, for short ranges, you're much better served by electric planes, or gliders with a self-launch motor. Small strips and winches don't go together.

Re: Electric aircraft set to take flight by 2026 under new agreements

#119

Post by nradov »

Robotbeat wrote: post #65
thunderrabbit wrote: post #51

Earlier quoted context omitted.

Thank you for bringing up this other conclusion. I still side with Wendover overall. Even if batteries have to be replaced that often now, the technology will continue to improve, becoming both cheaper and more reliable. Computers used to be the size of rooms and break due to literal insects in them.

And it really depends on the chemistry. Some chemistries can last 10,000-100,000 cycles and so the battery may never need to be replaced in the life of the airframe. One thing short haul electric aircraft have going for them is the regulatory requirement to have a 45 minute reserve. That essentially means that the battery will never be cycled to anywhere close to 0% but probably maintain at least 20% almost all the t…

The FAA regulations don't require just a 45 minute reserve. They need to be able to fly a missed approach at the destination airport, then fly to the alternate airport and land, plus still have a reserve.

Re: Electric aircraft set to take flight by 2026 under new agreements

#120

Post by Robotbeat »

nradov wrote: post #119
Robotbeat wrote: post #65

Earlier quoted context omitted.

And it really depends on the chemistry. Some chemistries can last 10,000-100,000 cycles and so the battery may never need to be replaced in the life of the airframe. One thing short haul electric aircraft have going for them is the regulatory requirement to have a 45 minute reserve. That essentially means that the battery will never be cycled to anywhere close to 0% but probably maintain at least 20% almost all the t…

The FAA regulations don't require just a 45 minute reserve. They need to be able to fly a missed approach at the destination airport, then fly to the alternate airport and land, plus still have a reserve.

Sure, which increases the cycle life even more.
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