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The largest electric aircraft just flew [video]

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Re: The largest electric aircraft just flew [video]

#151

Post by MobiusHorizons »

infotainment wrote: post #81
QuantumNoodle wrote: post #32

These kind of startup excite me. More so than the "next killer app" or "look what we shoved AI into." Cheap electric transportation can finally offset USA's lacking rail commutes and attack Europe's short flight market (which is already cheap). Now we need bigger planes or more frequent planes and the next startup to solve the energy needs.

> Cheap electric transportation can finally offset USA's lacking rail commutes I'm not sure how building an electric aircraft would help with this. Are people going to suddenly switch to commuting by plane? Fixing America's commute problem is primarily an urban planning one (ie, putting all the homes nowhere near anything) and not an insufficient-electric-aircraft one.

I think you could make a case for that, especially when landing in water. Quite a few dense urban areas people might need to get to have water nearby suitable for landing seaplanes. I think you would end up creating communities further from the urban areas dedicated to this mode of transport. It’s definitely not a simple or guaranteed idea, but it is actually feasible politically and technically.

Re: The largest electric aircraft just flew [video]

#152

Post by _heimdall »

dyauspitr wrote: post #145
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…

It uses aviation fuel only after the electric battery is empty. And uses the fuel to run generators, the motors are all electric.

Its hard to call that the largest electric aircraft IMO. It's electric until it can't, then its not.

Re: The largest electric aircraft just flew [video]

#153

Post by Barbing »

brucehoult wrote: post #132
Barbing wrote: post #119

Earlier quoted context omitted.

Wow wow! Might see planes just a smidge differently now :)

In sailplanes we add up to around 200 litres of water to wing tanks in single-seat gliders (empty weight typically around 280kg) to improve the high speed performance (typically up to 270 km/h these days) and ability to fly comfortably in turbulence. It's surprising what you can fly formation with, even without an engine [1] :-) https://www.youtube.com/watch?v=G0icOICQLTc Dumping (most of the) water before landing: h…

What a rabbithole this is now :D

That glider next to the world's fastest aircraft (in 1953) dressed up for a fight, how about that.

And they can water the grass...

-

So several thousand $ to get trained and certified and finally be ready to get towed and soar...

but just a few hundred (California) to try for half an hour behind a pro in the cockpit--oh yeah!

...omg they let you fly the thing for another couple bucks!!!

Re: The largest electric aircraft just flew [video]

#154

Post by jmward01 »

werdnapk wrote: post #134
luma wrote: post #87

Earlier quoted context omitted.

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.

So what do regular aircraft do when they run out of fuel? They require a forced landing. Aircraft fly with a buffer of fuel though to avoid such situations, so why can't an electric aircraft fly with a similar buffer on it's range? ie. Always fly less than the current charged range of the aircraft.

Lots of down votes on this but it is a legitimate question. The goal is likely to have the majority of flight off of batteries. That being said, the total weight of the emergency fuel plus generators is likely far less than the weight of the extra batteries they would haul around for the safety margin they need. So they end up lighter and more capable AND don't need to burn fuel. That being said, I wouldn't be surprised if they didn't start the generators during critical phases so they may end up using some fuel for a flight, but not much. Total guess on that though.

Re: The largest electric aircraft just flew [video]

#155

Post by class3shock »

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 contains 2,916 kwh of energy. Jet engines are not very efficient, so lets say only 30% of this energy actually ends up being used. So 875 kwh.

Lets say we are using batteries that are 300 wh/kg (0.3 kwh/kg), which seems on the high side of what electric cars are using now (and that there are no efficiency loses in the electric motors or elsewhere).

Now maybe I messed up my unit conversions but I think that means to carry the same energy onboard you would need 6,428 lbs of batteries. And you are still going to carry atleast 1,600 lbs of fuel on top of that. And you have the weight of both electric and conventional engines.

I could see this reducing costs like they say but when many big costs are fixed (pilot, hangar, etc.) will this actually make sense? Will airlines fly something that has thousands of pounds less payload than a competitor but lower running costs? I don't know but it will be interesting to see.

(1) https://airinsight.com/seat-miles-gallon-fuel-burn-update/ (2) https://en.wikipedia.org/wiki/Jet_fuel

Re: The largest electric aircraft just flew [video]

#156

Post by jmward01 »

'The first clean sheet airliner to be flown in any category. electric or not, in the US in the last 18 years'

This is the statement that matters and why I think electric is a huge deal. We can't get new designs into the air. It costs too much and takes too long. Electric has the potential to bring the design cycle back to something reasonable. Electric engines, and the supporting systems around them, are just so much simpler so there is so much less to certify. Once we really start designing for electric, and iterating on those designs, I think we will start seeing massive gains very rapidly.

Re: The largest electric aircraft just flew [video]

#157

Post by ticulatedspline »

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…

This graphic always reminds me why it's so hard to beat gasoline and that batteries kinda suck.

https://en.wikipedia.org/wiki/Energy_density#/media/File:Ene...

Re: The largest electric aircraft just flew [video]

#158

Post by jcims »

jmward01 wrote: post #156

'The first clean sheet airliner to be flown in any category. electric or not, in the US in the last 18 years' This is the statement that matters and why I think electric is a huge deal. We can't get new designs into the air. It costs too much and takes too long. Electric has the potential to bring the design cycle back to something reasonable. Electric engines, and the supporting systems around them, are just so much…

First time I saw an electric plane with the cowling off was something like this:

https://www.wired.com/story/magnix-electric-plane-motor/

So much simpler.

Re: The largest electric aircraft just flew [video]

#159

Post by walrus01 »

The interesting part to me is that a lot of current electric aircraft development seems to be waiting for battery technology to catch up. They're far ahead in terms of the motors, propeller, electric propulsion control system. The limitation is the battery capacity.

Companies like Joby, Archer and others also seem to be taking the huge gamble that battery density in Watt-hours per kilogram will SIGNIFICANTLY increase in the next 5-10 years (before they run out of money/investors) making the range of their aircraft much greater, and more viable for commercial operation.

Re: The largest electric aircraft just flew [video]

#160

Post by walrus01 »

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 turbine engines are not cheap.

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