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The largest electric aircraft just flew [video]

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Re: The largest electric aircraft just flew [video]

#311

Post by Toutouxc »

bluGill wrote: post #284
Toutouxc wrote: post #240

Earlier quoted context omitted.

I am, but it doesn’t take a genius to know that 125 miles as the crow flies is “less than 2 hours of driving” between like 6 specific pairs of destinations in the whole world.

125 miles as the crow flies is less than three hours (two hours is a little tight) of driving for most trips of that distance people make! People tend to have friends and family they want to visit regularly. So they try plan their life around not moving too far from where they grew up. That means people won't even look at a move of 125 miles away if there is not good transportation back. In turn if the high speed rou…

I live in Czechia, in Europe, a first-world country with dense population and a very normal road network. I am now on vacation, and I’m exactly 205 km as the crow flies from where my parents live. If I wanted to drive to them right now, it would be a 309 km trip estimated to take 3.5 hours or, avoiding highways, a 252 km trip, over 4 hours.

I don’t care about the rest of your post, I just want you to understand that a completely straight highway through some corn fields isn’t how the rest of the planet drives.

Re: The largest electric aircraft just flew [video]

#312

Post by ddlsmurf »

notahacker wrote: post #277
ddlsmurf wrote: post #265

Earlier quoted context omitted.

It's trivial to compete if you don't have R&D costs, and don't care about stuff like your employees, regulations or safety, or even sales since you can just use government money (this is not without consequence either). And it's not only about free market stuff, why do you think they're so excited for all countries to use their 5g products for example ? Don't think this is benign.

There are plenty of legitimate criticisms of Chinese policy, but you should probably reread your arguments and check for coherence. Chinese EV trucks make no economic sense even though they're 30% of China's fleet but also they're only investing all that as a trojan horse even though they use them almost exclusively domestically, plus the old "Asians don't innovate they just copy" canard even though there wasn't much…

I really don't see the contradiction, if that 30% was true, which, really... but ok, it still would normal for the CCP to do stupid stuff because they think it makes them look modern or ecological or similar. That's why there's no need for economic sense to explain that development at all. There are also excellent non financial reasons to want to dominate that market. So to circle back, their use of trucks, which if you buy the 30% "omg lol" as they say, is in no way an argument to them making sense, neither economically nor ecologically.

Re: The largest electric aircraft just flew [video]

#313

Post by tonyarkles »

dmitrygr wrote: post #269
tonyarkles wrote: post #216

Earlier quoted context omitted.

Typical reserve requirement is 30 min for a turbine aircraft (45 for piston). Given the 125 mile battery-only range and the probability that it flies at at least 200 kts (230 mph), it’s pretty unlikely to hit even a 30 min reserve on only batteries. I like the design, I think they get the problem and have a decent solution for it

> and have a decent solution for it Unless we ignore the additional maintenance cost of having to completely different proportion systems to maintain (and it is worse than a twin engine plane, because the propulsion systems are different, so you have to stock up on more different kinds of parts and possibly have different kinds of mechanics on staff to understand them)

Something that wasn’t super clear to me was whether the turbines are actually used for propulsion or if they’re used solely as generators to recharge the batteries/power the electric motors. I could honestly see it going either way.

Having the turbine, electric motor, gearbox, and potentially clutches to isolate the turbine or electric motor from the transmission seems pretty viable though. This would waste a little bit of power keeping the turbine spinning (unless there are clutches) but would also ensure that the turbine’s been spun recently, the oil pumps are primed and the bearings are lubed and ready to go.

Not that I’m saying a turboprop turbine like a PT6A is a simple device, but compared to a high-bypass turbofan like you’d see on a 737 or A320, they are considerably simpler.

Edit: looking quick, the time-before-overhaul (TBO) on modern PT6As can be up to 6000 hours, with a ~2000hr Hot Section Inspection. I’m not sure how “spinning but not burning fuel” counts on TBO, but it should at least mean the HSI is simple.

Re: The largest electric aircraft just flew [video]

#314

Post by kccqzy »

phire wrote: post #163
MobiusHorizons wrote: post #138

Earlier quoted context omitted.

Regular aircraft are required to have enough fuel to be able to divert to the alternate airfield in their flight plan plus all the margins for taxiing and waiting for a landing clearance. If a plane is low on fuel they can declare an emergency and get priority over other traffic, but that obviously is disruptive and should not happen on well planned flights unless something pretty significant happens after takeoff.

> and should not happen on well planned flights You make it sound like it is acceptable for a badly planned flight to have a fuel emergency. It is not. If there is a fuel emergency (or the plane lands with less than 30min of fuel) there will be an incident investigation that treats the situation as serious as if the plane had crashed. If the investigation discovers it was nothing more than bad planning, (at minimum)…

> there will be an incident investigation that treats the situation as serious as if the plane had crashed

No the investigation isn’t as serious as if the plane had crashed. In July 2026 nine planes simultaneously had a fuel emergency in London. You bet it’s different from nine planes simultaneously crashing in London.

It helps to understand different kinds of fuel emergency. Declaring a fuel emergency to get to a diversion airport is very very different from having 30 minutes of fuel left.

Re: The largest electric aircraft just flew [video]

#315

Post by IceHegel »

It's very interesting. On the one hand, it seems obviously silly, given that the energy density of a battery is still much higher than hydrocarbons.

But the drone explosion, the economies of scale around electric power, are very attractive.

Of course the biggest unlock in the whole equation is a fully autonomous flight computer.

Re: The largest electric aircraft just flew [video]

#316

Post by ZiiS »

IrishTechie wrote: post #195
giancarlostoro wrote: post #182

Earlier quoted context omitted.

Honestly, I'd feel better knowing it has a reserve system in case there's any issues, even if the batteries have more than enough power, beats having it and never using it, than needing it and suffering as a result.

Do current aircraft have a backup in-case their fuel tanks run dry?

Yes the are strict regulations requiring them to carry extra fuel; despite its weight having a real cost. Carrying extra battery would be too heavy even compared to having a whole extra engine.

Re: The largest electric aircraft just flew [video]

#317

Post by bluGill »

Toutouxc wrote: post #311
bluGill wrote: post #284

Earlier quoted context omitted.

125 miles as the crow flies is less than three hours (two hours is a little tight) of driving for most trips of that distance people make! People tend to have friends and family they want to visit regularly. So they try plan their life around not moving too far from where they grew up. That means people won't even look at a move of 125 miles away if there is not good transportation back. In turn if the high speed rou…

I live in Czechia, in Europe, a first-world country with dense population and a very normal road network. I am now on vacation, and I’m exactly 205 km as the crow flies from where my parents live. If I wanted to drive to them right now, it would be a 309 km trip estimated to take 3.5 hours or, avoiding highways, a 252 km trip, over 4 hours. I don’t care about the rest of your post, I just want you to understand that…

> I am now on vacation

That is the key here. People go all over the world for vacation. However vacations are not normal life (at least not for the vast majority of people), and can be ignored.

In normal life people have a place they live, and they have people they visit. When looking for a place to live they consider the real trips they take (not cutting through corn fields), and that guides where they move to. People do refuse jobs because they have to move too far from friends/family. People who choose to move away from friends (which does often, it isn't the majority but still common) are choosing to leave behind those friends.

Re: The largest electric aircraft just flew [video]

#318

Post by class3shock »

walrus01 wrote: post #160
class3shock wrote: post #155

Doing some math. Regional jets get somewhere around 45.9 seat miles per gallon (1). So 30 seats, going 125 miles would take around 80 gallons of jet fuel. This is likely low because all the jets listed are bigger and likely flying longer flights that are more efficient but just go with it. Jet fuel has a specific energy of 12 kwh/kg and a density of 6.7 lb/gal (2). So 80 gallons of jet fuel is 536 lb, or 243 kg, and…

If they can get the range to within what, for example, an Alaska Airlines/Horizon Q400 flies from Seattle for regional flights (with reserve for diversion airport), that may be sufficient for some purposes. In terms of operating cost, not just cost of fuel, but if the electric engines can be much less costly in terms of periodic maintenance and overhaul. Maintenance and overhaul costs on turboprop and small jet turbi…

So if they are doing the hybrid approach and just using the conventional engines during cruise they will have way reduced maintenance costs on them. The need for max thrust during takeoff drives a ton off wear and tear, so removing that would be big. If they are able to do electric only that is even better.

Re: The largest electric aircraft just flew [video]

#319

Post by seanmcdirmid »

luma wrote: post #87
alberth wrote: post #83

Is this EV or Hybrid? The founder seems to sneak in the word "hybrid", around 1m30 mark in the video below. https://youtu.be/nM86DBOqgPM?si=5unXLmPxk6M_kmuN&t=86 Note: not being negative, I just want to ensure I understand correctly since the title might imply something else. Update: confirmed, it does use aviation fuel. > "The airplane will also include a reserve-hybrid configuration, consisting of two turbo generat…

Hybrid after the first 125 miles, total range 500 miles. Their problem is diversions - an incident at the destination airport may mean an passenger aircraft may need to land at an airport which could be a couple hundred miles away. The hybrid powerplant throws the fuel efficiency numbers off so goal is not to run it unless needed, but they could not get certification without it.

I remember reading about making ground effects electric planes for this reason. You need a reserve, but if your plane could double as a boat and was flying over water, that would satisfy the requirement.

Re: The largest electric aircraft just flew [video]

#320

Post by class3shock »

llukas wrote: post #223
tonyarkles wrote: post #220

Earlier quoted context omitted.

I’d guess comparable for a 30-seat regional, you’d probably want to compare with a PT6, especially since this aircraft is prop driven. That’s only about 250lb dry.

It seems you're right. Would nice to see breakdown for this plane how it actually maps to real world prototype.

The thing I quoted is more for bigger jets with much larger engines (it was the first reasonable looking source I found). In any case their hybrid has four engines, two electric, two conventional, so you are really should think of it as needing to haul two extra engines on top of what a conventional only jet would have.
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