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Australia's first electric aircraft has begun test flights

abc.net.au

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Re: Australia's first electric aircraft has begun test flights

#61

Post by dogma1138 »

kevincox wrote: post #27
TillE wrote: post #25

Are there denser ways to store electrical energy? Hydrogen fuel cells maybe? Seems like you need something much lighter than lithium-ion batteries to even begin to fill the role of passenger planes.

Hydrogen fuel cells would also make refuelling much faster. In the video they claimed an hour recharge time for the small plane. While you can get more parallelism as you add more batteries it still seems like making it much faster would be beneficial.

Hydrogen fuel cells would solve another problem and that is when you expand the hydrogen you reduce the weight of the aircraft.

The problem with batteries is that a full battery and a discharged one weigh the same.

Re: Australia's first electric aircraft has begun test flights

#63

Post by seanmcdirmid »

alextheparrot wrote: post #56
seanmcdirmid wrote: post #47

Earlier quoted context omitted.

How is the useful heat used? I know some places have central heating, so the hot water is just piped throughout the city, but if not that, what would they do with it?

The term that the original poster didn’t include is “Cogeneration” [0]. Another use case would be desalination in areas without an adequate supply of freshwater. [0] https://en.m.wikipedia.org/wiki/Cogeneration

Ya, I get that, it just doesn’t seem to be always the case that you’d find something to do with the heat, especially given proximity of the coal plant to places that could use it. It wouldn’t seem to work well for Australia, at first glance (no serious heating needs, no desalination plants).

Re: Australia's first electric aircraft has begun test flights

#64

Post by bobsil1 »

dogma1138 wrote: post #60
bobsil1 wrote: post #8

Earlier quoted context omitted.

Tesla is driving (heh) battery energy density up.

Not really, also while Tesla does work on batteries it’s more Panasonic which makes he batteries for Tesla, LG chem and the likes that actually work on that.

Tesla drives down cost via scale, it is driving energy density for downstream segments: EVs, drones, e-planes, et al.

Re: Australia's first electric aircraft has begun test flights

#65

Post by dogma1138 »

bobsil1 wrote: post #64
dogma1138 wrote: post #60

Earlier quoted context omitted.

Not really, also while Tesla does work on batteries it’s more Panasonic which makes he batteries for Tesla, LG chem and the likes that actually work on that.

Tesla drives down cost via scale, it is driving energy density for downstream segments: EVs, drones, e-planes, et al.

It doesn’t work like that there are more “denser” batteries than what Tesla uses, their density isn’t that impressive while they benefit from it its not something they are driving.

P.S. Drones use LiPo batteries.

Re: Australia's first electric aircraft has begun test flights

#66

Post by mveety »

Shivetya wrote: post #54

An interesting idea, my question is how high can you fly before temperatures lower the efficiency of the batteries? Let us assume a pressurized battery compartment to eliminate the air pressure issues, anyone familiar with the energy costs to keep cargo areas relatively stable? That might be equivalent for a battery compartment.

Well on pressurized aircraft the cargo areas are generally inside the pressure vessel so temperatures will be similar to the passenger areas. Also the batteries will be producing heat when in use, so I would imagine cooling would be a bigger issue, especially when the plane is baking in the sun at the airport for the whole day in the summer.

Re: Australia's first electric aircraft has begun test flights

#67

Post by mveety »

dreamcompiler wrote: post #36
daurnimator wrote: post #13

Earlier quoted context omitted.

Touring motor gliders are often sold to couples that want to travel together. I've known people who own/fly: Dimona H36 and Taifun 17E. I have a family member who recently purchased a TL Sting S4 (a microlight) for similar purposes.

Not this one. Pipistrel brings their planes to EAA Oshkosh every year and their internal combustion planes are marketed as touring motor gliders. But the electric Alpha Electro is just touted as a training plane because its range is so short.

I don't see how practical it is as a trainer though. At least when I was learning, those planes wouldn't get much if any downtime. You will still need more time to charge than it does to just throw some avgas in the plane. Also it would be impossible to do some parts of your flight training in this plane because of its tiny endurance.

Re: Australia's first electric aircraft has begun test flights

#68

Post by bobsil1 »

dogma1138 wrote: post #65
bobsil1 wrote: post #64

Earlier quoted context omitted.

Tesla drives down cost via scale, it is driving energy density for downstream segments: EVs, drones, e-planes, et al.

It doesn’t work like that there are more “denser” batteries than what Tesla uses, their density isn’t that impressive while they benefit from it its not something they are driving. P.S. Drones use LiPo batteries.

They're driving down mass-market LiIon specific energy cost ($ per Wh/kg) via Gigafactory. No?

Re: Australia's first electric aircraft has begun test flights

#69

Post by chrismorgan »

goodcanadian wrote: post #45
chrismorgan wrote: post #38

Earlier quoted context omitted.

Where’s the €65,000 number coming from? I found http://www.flypipistrel.com/price-lists/PIPISTREL-ALPHA-ELEC... which suggests €159,000. That datasheet also says 700 cycles to 75% battery capacity, rather than the “about 1,000” of this article. The $3/hour figure doesn’t seem to me to match the other numbers, either: 60kW for takeoff and 20kW for cruising; let’s ignore takeoff (it’s rounding error) and just call it 2…

Price of electricity varies greatly depending on where you are. My residential rate is about $0.13/kWh, so completely consistent with the article.

Interesting. I was going off my experience in Victoria, combined with quick searching for Perth which showed about the same rates, then subtracting the appropriate N% for paying on time (a pricing model that I wish was illegal—expressing it as penalties for overdue payments would make life much easier) which generally gets it down to 20–25¢/kWh. 13¢/kWh is much lower than I’ve ever seen in Australia, not that I’ve looked all over the country.

Re: Australia's first electric aircraft has begun test flights

#70

Post by chrismorgan »

totalZero wrote: post #55

I look forward to the day when solar panels are efficient enough that an aircraft can appreciably recharge its batteries while gliding.

I looked for a figure and found this suggestion for sunny days: 800W/m².

If the plane uses 20kW while flying, this would mean you’d need 25m² of 100% efficiency solar panels to fly without draining the battery.

10.5m wing span, depth uncertain but looks to be under a metre, and we’re not even halfway there. The fuselage isn’t suitable for a solar array. The tail, maybe a bit.

Verdict: ignoring solar panel mass and fragility, you could probably already design something that would get you another five minutes during your hour of powered flight time, but I think you’d have to change things up a lot to increase it much beyond that.

I think if you were trying to do such a thing seriously, you’d try to increase wing and body top surface area.

Note that the plane can regenerate 2–5kW while gliding, making the propeller act as a windmill. (Source: https://www.avweb.com/videos/Video-Pipistrel-Alpha-Electro-A..., https://www.avweb.com/videos/Video-Flying-Pipistrels-Electri.... Other interesting details in those too.)

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