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mike734
10th Jul 2019, 01:59
Does this all Electirc plane have a chance at ever being certified? I will be surprised.
https://youtu.be/aXR_jiKBaoY

Old Dogs
10th Jul 2019, 02:13
Does this all Electirc plane have a chance at ever being certified? I will be surprised.
https://youtu.be/aXR_jiKBaoY

Israeli product.

Pilot DAR
10th Jul 2019, 02:29
Certification of electric planes will happen. This one....? I remain to be convinced. I still worry about the wing low slipped crosswind landing. $200 per hour direct operating cost - maybe, but amortizing the cost of the plane while it sits not producing any revenue while it recharges is a cost too. And, that looks like kind of high wing loading, it still will be required to be able to glide to a safe landing. But I bet they'll have some kind of automated system using instant differential power to prevent a pilot groundlooping it, taildragger experience not required!

For my work with electric plane certification planning, I know that there will be a breadth of thinking, and innovative system design opportunities which seem hardly imaginable to us now. The certification standards will need updating, as there are some standards which simply never envisioned an electric plane. The authorities are eager to work to create new standards, and there are industry working groups doing work in the background. What we lack at this point, is the massive investment in thinking and standard creation which came from military specification experience to support the civil initiative. Many of the present and recent design standards were based upon military experience, which the civil manufacturers probably could not afford back then. That military experience is probably not there this time, so it's up to the civil industry, but the inertia is there. It's going to happen, it's just a matter of time.

DaveReidUK
10th Jul 2019, 06:34
eviation alice test flight

Test flight ?

That's the one thing there's absolutely no reference to in the video ...

ATC Watcher
10th Jul 2019, 15:44
I have tried to get more technical info in Le Bourget a few weeks ago where it was presented, and then the lady in charge of PR, stopped me and said there were other people waiting and shove me off teh CEO, . maybe it was true but I have a gut feeling all the problems have not been resolved yet. A very nice model aircraft , full of good ideas, but which has not flown yet I believe.

The correct questions were what is the real actual endurance at MTOW with 100% charge ( they claim 600 NM but it is hard to believe ) and how long it takes to recharge to recharge to 100%? Changing the batteries after each flight is an option of course, but are those easily accessible/removable as they are supposed to be 65% of the weight of the aircraft.
But that said, I admire the innovation and the guts to produce this aircraft.

Machdiamond
10th Jul 2019, 18:29
This article has some data https://www.ainonline.com/aviation-news/air-transport/2019-06-19/eviations-alice-fly-year

Let's see, 14000 lb maximum takeoff weight minus 8200 lb of batteries minus 2000 lb of useful load (9 passengers and bags plus one pilot at 200 lb each) that leaves 3800 lb for the structure, systems, cabin interior, landing gear, propulsion system. That's an empty weight of 27% takeoff weight while the norm for this size aircraft is consistently around 62% with very few outliers, even with advanced composites structure.

On the battery side, they apparently mistook energy density at the pack level with the cell level. Industry best numbers currently stand around 170 Wh/kg and 260 Wh/kg respectively, so the claimed 960 kWh will require nearly 12000 lb of batteries instead of 8200 lb (which turns out to match the 260 Wh/kg so it really does look like they made that basic mistake).

If they ever get this thing to fly, at best it will have 5000 lb of batteries with a capacity of 380 kWh, optimistically giving a no-reserves range of about 70 nm according to quick napkin calculations.

It's also going to be a noisy aircraft like the Avanti, always a given with pusher propellers.

a_q
11th Jul 2019, 10:11
Passenger aircraft already have standard "form factor" baggage containers (Unit Load Devices).
Why not install some of the batteries the same way? With a big connector to slot into.
Can be recharged independently of the aircraft. Probably installed quicker than refuelling too.

Also means you can swap hold capacity for range.

Just an idea - put out in the public domain so no going off patenting it.....

bill fly
12th Jul 2019, 11:40
Ladies and Gentlemen, We area bit low on charge, so would all passengers with iPhones and laptops and power packs please plug into the usb ports now? Thank you for the cooperation.

ShyTorque
12th Jul 2019, 11:53
It will probably go like the clappers but as with electric road vehicles, for commercial aircraft the problems not yet solved are battery capacity/weight and recharge to full capacity time.

meleagertoo
12th Jul 2019, 11:58
If they ever get this thing to fly, at best it will have 5000 lb of batteries with a capacity of 380 kWh, optimistically giving a no-reserves range of about 70 nm according to quick napkin calculations.


This is a graphic illustraton of how far we are from electric aircraft being a practical reality.
5000lb of batteries give just 70 miles no reserves.
How far would this thing go with 5000lb of Jet A1?

The gap in energy density is still around 40:1 in favour of hydrocarbon fuel.
Over 70 years we have pushed the jet engine to perhaps a three-four fold improvement in fuel efficiency - 40 fold is simply an unachieveable increment.
I for one doubt that batteries are capable of beig pushed anywhere near that far - electric aircraft will probably need something else - and that something hasn't been invented yet.

bill fly
12th Jul 2019, 12:34
This is a graphic illustraton of how far we are from electric aircraft being a practical reality.
5000lb of batteries give just 70 miles no reserves.
How far would this thing go with 5000lb of Jet A1?

The gap in energy density is still around 40:1 in favour of hydrocarbon fuel.
Over 70 years we have pushed the jet engine to perhaps a three-four fold improvement in fuel efficiency - 40 fold is simply an unachieveable increment.
I for one doubt that batteries are capable of beig pushed anywhere near that far - electric aircraft will probably need something else - and that something hasn't been invented yet.

Well it has really - Solar Impulse for instance had in flight charging - obviously a marginal aircraft but an impressive demo.
As for how far this ship would go with 5,000 kgs Avtur - not very far unless they change the engine. ^_^

Machdiamond
12th Jul 2019, 12:58
How far would this thing go with 5000lb of Jet A1?

Unpressurized at 10000 ft, approximately 1500 nm.

The gap in energy density is still around 40:1 in favour of hydrocarbon fuel.

You have to correct for efficiencies. An electric motor and inverter is about 90% while a turboprop is about 40-45% (actually a lot less if you include taxi and descent segments), so you are looking at a factor of less than 20:1 on jet fuel vs batteries today.

Long range applications will be out of reach for a very long time or will need a technology breakthrough, but short range stuff (less than 100 nm) is already technically and commercially viable today. Like small trainer aircraft (Pipistrel Alpha Electro), or very short range commuter aircraft in specific markets (eg. Harbour Air in Vancouver or Loganair's Orkney Inter Island service to name just two).

DieselOx
12th Jul 2019, 13:37
I'm a mechanical designer working on battery thermal management right now.

Couple comments:

Battery energy density is being actively pushed by large infusions of govt grants to get to 500wh/kg in 10 years, Tesla claims they have 350wh/kg in development, release is eminent.
In the lab, densities equivalent to diesel fuel have been achieved, but need a benevolent billionaire to go all in, or something similar, to get to market.

Battery swap technology is ready for release in the wild, it's just a matter of resolving turf wars over the business model. Everyone wants to be in charge, no one has set up a good overall standard that deals with pack aging, ownership, repeated abusers of the system (you get a fresh pack every swap, so people would be naturally disincentivized to take take care of the packs.

An Israeli company actually has/had a good system ready to go, and Tesla was on board for a while, but the drudgery of execution has taken over.

I can post supporting sources for all the above later.

Pilot DAR
12th Jul 2019, 13:50
Battery swap technology.............. Everyone wants to be in charge,

Good one! :D

bill fly
12th Jul 2019, 15:57
Good one! :D

Watts wrong with that?

bill fly
12th Jul 2019, 17:34
Watts wrong with that?

Currently no- one has the Capacity to answer - Iím off Ohm

Espada III
12th Jul 2019, 20:12
The Israeli company Better Place offered Renault based electric cars with swappable batteries in Israel and Australia but the business collapsed. It was probably about two or three years ahead of its time.

it had battery swap stations, easy home charging and a standard car but it wasn't good enough for the market. It's a pity because it could have set a standard for battery size and shape for the whole market.

the same may apply to Eviation...

DaveReidUK
12th Jul 2019, 20:58
it had battery swap stations, easy home charging and a standard car but it wasn't good enough for the market. It's a pity because it could have set a standard for battery size and shape for the whole market.

the same may apply to Eviation...

Or not, as the case may be.

My understanding is that the Alice doesn't have a single, consolidated battery pack but rather that the storage capacity is distributed over a large proportion of the airframe.

So a "battery swap" isn't an option with the current architecture.

In fact you could argue that, contrary to the suggestions in previous posts, the batteries should be considered part of the OEW. After all, there is negligible weight difference between flat and charged batteries. :O

n5296s
12th Jul 2019, 21:55
I just don't buy the whole battery swap thing. The battery is such a huge component of an electric vehicle that it is heavily constrained by the shape of the vehicle - or else the vehicle shape must be constrained by the battery. Can you really imagine the world's car manufacturers agreeing on a standard size, layout, architecture etc, removing all freedom to make a car longer, shorter, narrower, wider, ...

And that's just for cars, which don't have to worry over-much about aerodynamics. Now apply this thought to aircraft design. One, or maybe a handful, of standard batteries that will work for everything from 2-person helicopters to LSA trainers to commuter aircraft? And every FBO is going to have these on hand, so that when you fly your electric R22 or electric Caravan into Ailerona Muni, you can be sure they will have a suitable battery on hand and charged - just like you can be sure they will have Avgas or Jet A1 today?

Not to mention, battery technology is moving very fast (though nowhere near fast enough for the dream of electric aircraft to succeed any time soon). Standards don't work well when the technology is constantly changing. What happens when you arrive with a size X battery on board, but yours is a 500Ah Mk 3, and all they have is a 800 Ah Mk 5?

Electric cars may have a future (though personally I doubt it, once the hydrogen infrastructure is in place). I'm pretty sure that electric aircraft are a very long way off, if ever.

cappt
12th Jul 2019, 23:26
The way this aircraft is being marketed is borderline fraud. It will never achieve those numbers being thrown out. Most likely just looking to bilk a few more millions before they quietly fade away.

capngrog
13th Jul 2019, 01:11
I have noticed the title of this thread, "Eviation Alice Test Flight", but I've not yet seen any post that indicates that this thing has actually flown. Has the "Alice" (not the one in Wonderland) actually flown yet?

Cheers,
Grog

futurama
13th Jul 2019, 01:31
I have noticed the title of this thread, "Eviation Alice Test Flight", but I've not yet seen any post that indicates that this thing has actually flown. Has the "Alice" (not the one in Wonderland) actually flown yet?

Not yet. First flight "later this year".

DaveReidUK
13th Jul 2019, 06:38
I have noticed the title of this thread, "Eviation Alice Test Flight", but I've not yet seen any post that indicates that this thing has actually flown. Has the "Alice" (not the one in Wonderland) actually flown yet?

Eviation have been backpedalling somewhat on the timescale, capability and economics.

In November, it announced that the prototype would fly at Le Bourget in June (it didn't, and hasn't yet), that it would cruise at 240 kts (now apparently 220 kts) and that DOCs would be around 20% of a comparable sized turboprop (now 30%).

Bloomberg: Pioneering Electric Plane Needs $200 Million for Final Push. (https://www.bloomberg.com/news/articles/2018-11-12/pioneering-electric-plane-needs-200-million-for-final-push)

I wish them well, but they have a bumpy road ahead.

Ascend Charlie
13th Jul 2019, 06:58
They need $200mill? Those CGI geeks must be an expensive lot.