[RahulNagaraj]

The world's first all-electric passenger plane has completed its maiden test flight.

The all-electric plane called Alice, developed by Israeli-based Eviation took to the skies on Tuesday morning from Grant County International Airport in Washington state. The short test flight lasted eight minutes, with the all-electric plane reaching an altitude of 3,500 feet.



Alice, the all-electric passenger plane, is said to come with battery technology similar to that of electric cars. Eviation is targeting one or two hours of flying after 30 minutes of charge and with a total of nine passengers on board, plus 2 pilots. The aviation company is also said to be aiming at a total range of 250 nautical miles. It is expected to have a max cruising speed of 250 knots (287 mph / 463 kmph).

The company will now review all the data received from its maiden test flight to move ahead with the next steps. Eviation will then start developing FAA-certified aircraft through 2025, followed by a year or two of testing, before entering Alice into commercial service in 2027.

Eviation is planning three different versions of Alice: Commuter, Executive and Cargo. The commuter version will hold nine passengers and 2 pilots, with 386 kg of cargo. The Executive version will hold 6 passengers, while the Cargo version will have a total of 450 cubic feet of volume.

Source: CNN

Link to Team-BHP news

[GTO]

There is a time & a place for everything. The time isn't yet correct for battery-powered planes as current battery tech / life is limited. And imagine the sheer weight in a commercial airliner. Unfeasible, I reckon.

For the big machines (trucks, buses, ships and may be planes), hydrogen fuel cells are perhaps more suitable.

[saket77]

Originally Posted by GTO

There is a time & a place for everything. The time isn't yet correct for battery-powered planes as current battery tech / life is limited. And imagine the sheer weight in a commercial airliner. Unfeasible, I reckon.

For the big machines (trucks, buses, ships and may be planes), hydrogen fuel cells are perhaps more suitable.

May be adding a jet engine in the tail section which can take up duty if the plane goes out of charge mid-flight will make it more viable.

[GForceEnjoyer]

Electric power may not be the replacement for fossil fuels in aviation due to the reasons mentioned above: weight, cost and battery life with current technology. Additionally, unless batteries that don't use lithium become mainstream, there simply won't be enough lithium to sustain such usage.

Hybrid electric aircraft may be a more feasible alternative. They are mostly made to take off and land on electric power, but can cruise conventional distances using fossil fuel. For example, the Airbus E-Fan X, a hybrid electric prototype that was derived from the BAe 146. The project was unfortunately canceled due to Covid-19.

Originally Posted by saket77

May be adding a jet engine in the tail section which can take up duty if the plane goes out of charge mid-flight will make it more viable.

I'm not sure how feasible that would be, cost and complexity wise. Planes like the DC-10 had an additional engine at the base of the vertical stabiliser due to the need of additional thrust which engine technology at the time wasn't capable of providing. Now, twin-engine jets are more than capable of traversing the seas and travelling extremely long distances. Having another source of power using completely different technology, only for emergency purposes would be a huge expense, since it still has to be robust enough to withstand the extreme conditions thrown at it from flying. Just my two cents.

Somewhat off topic: The issue of noise which is faced with current fossil fuel engine technology will also be faced to an extent with electric aircraft, as long as they use propellors or rotor blades. A ton of the noise is merely due to the air passing through, especially with turboprops (think of how you can hear your car's engine pretty well while engine braking, even with no combustion taking place). So while this problem will be reduced to an extent, it will not be completely eliminated. This will hold true for any technology that makes use of propellors or rotors.

[sagarpadaki]

Battery powered aircrafts will not replace the long haul flying since it would be impossible with LiIon battery weight to fly across continents. Rather, the scope of these electric aircrafts would be for regional connectivity moving cargo and people between cities 500 to 700 kms apart with smaller payload.

I think it is just not possible to think of a B737/A320 sized all-electric aircraft flying between say, BLR-DEL or BLR-BOM. Atleast not as of today.

[aim120]

This may make sense for short travel distance. It will also have lower operating cost and lower noise.

Low cost airlines use turbo prop planes, which offer you complimentary free hearing loss.

But then again these are twice as slow as jet powered aircraft or even a turbo prop.

[Gansan]

Originally Posted by GTO

The time isn't yet correct for battery-powered planes as current battery tech / life is limited. And imagine the sheer weight in a commercial airliner. Unfeasible, I reckon.

An airship powered by electric motors may be more feasible. I read they are making a come baCK.

[turbospooler]

I think the biggest challenge for electric powered aircraft is taking off.
I say it is a challenge due to 2 primary reasons:
i) as many of you pointed out the weight of battery adding to the thrust requirement for take-off
ii) range gets limited as you consume higher energy due to take-off.

Can we think of a slingshot contraption which can sling the aircraft forward (like we see on aircraft carriers)?
If so, the bulk of the energy saved in taking off can translate into range and the range anxiety can be minimised (if not eliminated).

[V.Narayan]

Originally Posted by RahulNagaraj

The world's first all-electric passenger plane has completed its maiden test flight.

The all-electric plane called Alice, developed by Israeli-based Eviation took to the skies on Tuesday morning from Grant County International Airport in Washington state. The short test flight lasted eight minutes, with the all-electric plane reaching an altitude of 3,500 feet.

Dear Rahul,
Thank you for sharing this. You beat me to this post. I am always happy to read about aircraft and the Israeli's have been working on this aircraft {Alice} most systematically and with the backing of their Govt. This will no doubt become the first all-electric to enter scheduled service.

All,

Forgive me for my fastidiousness. Just a small correction to the media misrepresentation. Alice is not the first all-electric aircraft flight of a passenger aircraft. That credit most probably goes to a DHC-2 Beaver converted from ICE engines to an all-electric configuration which did its maiden flight in December 2019 in Canada. The project was led by the owners Harbour Seaplanes of Vancouver. - post #1 in the link below. Infact even before that there were about half a dozen all-electrics that flew carrying one or two including the pilots but those were technology demonstrators at best.

The heaviest flight of an all-electric so far {I don't know what weight Alice took off at} goes to a converted Cessna Caravan 208B that can carry 8 passengers, has an all up weight of 3600 kgs and flew a 30-minute circuit at 100 knots {185 kmph} on its maiden flight in May 2020. {post #15 in the link below}

What Alice is, to give credit where it is due, is that it is the first all-electric grounds up design that has taken full advantage that modern technology gives for using the lightest materials and the most streamlined fuselage and wings. The pusher props too are marginally more efficient than the traditional puller props we see. As a technology demonstrator it is remarkable. From a first look they have done everything, it seems, to cut weight - a V-tail that reduces the tail empennages from 3 to 2. A tail wheel tricycle which compared to a nose wheel tricycle also saves a few precious kilogrammes. This is what one can see. I'm sure many other nifty details lurk inside.

Problem with all-electric aircraft is that the energy density of a lithium ion battery is 48 times lower than that of aviation fuel. That is simply too vast a gap to bridge with better aerodynamics or lighter weight materials. To that extent for the time being the options here are limited. But never say never.

https://www.team-bhp.com/forum/comme...ircraft-2.html

[SmartCat]

Worst nightmare for somebody who has both EV range anxiety and fear of flying.

From physics point of view, how can an electric motor generate as much thrust as a turboprop?

[V.Narayan]

https://www.youtube.com/watch?v=qjPO4_oe5h8

https://edition.cnn.com/videos/busin...t.cnn-business

Some interesting videos of Alice. Note the clean wing with no obstructions like engine nacelles. Engines when mounted on a wing reduce the wings aerodynamic effectiveness.

Originally Posted by SmartCat

From physics point of view, how can an electric motor generate as much thrust as a turboprop?

Unsure of what is the question. An electric motor can be made as large or small as needed from a fraction of a kw to 20,000 kw and much more. The Alice has two magniX 700 kw motors similar to the larger versions of the P&W PT-6A turboprops. Only point is that kw for kw of output an electric motor with its accessories would weigh more than a turbine engine.

One application of electric aircraft would be as autonomous cargo delivery machines to smaller airports. Given the slender dynamics of weight - drag and battery capacity saving the weight of one or two pilots {90 to 180 kgs} means a lot to an aircraft with a design payload of 1100 kgs. USA and to a lesser degree Europe has a massive volume of small packet cargo deliveries to its ~14,400 airports. And that is where this sort of machine will count in reducing costs of air delivery.

Errata: In post#9 I wrote it has pusher props. Correction it has aft mounted puller props.

[SR-71]

We dont have the battery technology that is compact enough to fit in cars and has enough capacity to drive beyond 250 miles and charge in resonable time at pitstops and we are already talking planes ? I believe the answer lies in alternative and or hybrid technology for larger machines let alone planes.

[SatheeshBHP]

Originally Posted by V.Narayan

Problem with all-electric aircraft is that the energy density of a lithium ion battery is 48 times lower than that of aviation fuel. That is simply too vast a gap to bridge with better aerodynamics or lighter weight materials. To that extent for the time being the options here are limited. But never say never.

One more important parameter is once aircraft starts flying and burns off fuel, aircraft becomes lighter but fully charged and empty batteries still weigh same! This is critical in long haul flights since Fuel weight is almost 30% of Maximum Gross Takeoff weight [MGTOW] and reduced weight results in increased range.

[v1p3r]

Originally Posted by SmartCat

From physics point of view, how can an electric motor generate as much thrust as a turboprop?

Thrust is just a reaction force, which is directly proportionate to the amount of exhaust / air being accelerated by the engine. The engine can be an axial turbine (what a turboprop is), a piston engine connected to a propeller (like old WW2 planes) or an electric motor connected to a propeller.

Electric motors actually have a much better torque spread than any combustion engines, which would work better. The issue is with the energy density of the fuel.

[alpha1]

Energy density of kerosene (ATF = tighter spec Kero):

Mass-wise: 46.2 MJ/kg
Volumetric: 38.3 MJ/L
https://neutrium.net/properties/spec...more%20rows%20


Energy density of best possible rechargeable battery:

Mass-wise: 450 Wh/kg = 1.62 MJ/kg
Volumetric: 1150 Wh/L = 4.14 MJ/L
https://insights.globalspec.com/arti...eries-unveiled

Even assuming 10% efficiency for Brayton cycle* and 100% efficiency for electric motors , the batteries still have a long way to go.

*(turbine engines used in aircrafts would usually deliver at least 30%, and electric motor based engine typically 90%)