Eviation Alice (Electric Regional Airliner)

The fact that the company remains tight lipped about what the range will be with a full payload with IFR reserves is worrying.
maybe because leehamnews is not so far from the truth:


The Alice, with its large 3720kg 820kWh battery, can fly a still air 200nm route in Europe and land with a 30 minutes regulatory VFR reserve. For the 45 minutes US reserve, there is not enough energy.

If an IFR alternate of 100nm is required with 30 minutes circling (EU rules), the range falls below 100nm.
 

A quick summary of what we know so far about the first flight of the aircraft and the long road this project has to travel to get certified. A lot of articles still quote the 440nm range without realizing that it's just the ferry range in ideal conditions with light winds. The fact that the company remains tight lipped about what the range will be with a full payload with IFR reserves is worrying.
The fact that the CEO Omer Bar-Yohay and executive chairman Roei Ganzarski both left the company in surprise departures earlier this year, well after the company starting claiming that the first flight was only a handful of good weather testing days away back in January, is also worrying...!

I didn't realise that the 440nm range was so conditional. Do you have a source?


If you scroll down to the very bottom, there is a small disclaimer that says " *Target range, zero wind, no payload, IFR reserves"
 

"“Eviation is validating the changes we made to the aircraft after our initial ground testing as we prepare for flight,” a company spokesperson told AIN sister publication FutureFlight. Eviation did not elaborate on exactly what changes have been made to the aircraft since ground testing was completed."

First flight expected by October. I wonder what issues were discovered that needed to be rectified that delayed the test program for so long. This article for some reason has an outdated image of the first version of the aircraft that was shown way back in 2015. It is interesting to see how the design evolved during the last 7 years.
 
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There might have not been any meaningful changes to the aircraft since the last testing, because they just choosed a longer runway. Of course, for a plane with low range, it will not be very usefull to depend on large runways...
 

I never noticed this before. Are these openings at the underside of the fuselage designed to help vent the batteries in case of a thermal runaway event ?
 

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Some interesting nuggets of information quoted from the articles above :

“It’s the first Part 23 aircraft that’s all fly-by-wire,” Bar-Yohay says. “It was a very, very painful aspect of the development of this system. It makes the system much more complex and it takes a long time and a lot of money to do this right.”

"The fractional weight of the battery system is roughly 50 percent of the MTOW of the aircraft. The battery is very big. In fact, Bar-Yohay says the “battery itself functions as a structural part of the aircraft. Meaning the plane cannot fly without the battery there, from a load bearing perspective.”

"Over the past seven years, Eviation considered several design options before it settled on this one. “We looked at canards. We looked at box tail designs,” Bar-Yohay says. “We looked at the wingtip propellers and we landed with something that is very avant-garde, while still being a plane.”


“The biggest technical challenge that Eviation has to overcome is the development of batteries,” he said. “We really do need the industry to boost the energy density.” Because of that, Davis said he doesn’t expect that Alice will win regulatory approval until 2025, and won’t be carrying paying passengers until 2027"

"The plane that flew this morning was Eviation’s “proof of concept” aircraft, Davis said. With a five-year gap before the expected entry into service, and with technologies developing rapidly, “we absolutely will make evolutions to the aircraft,” he said."
 
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I never noticed this before. Are these openings at the underside of the fuselage designed to help vent the batteries in case of a thermal runaway event ?
Yes, there are markings on the side of the fuselage that says 'burst disc keep clear' so I presume they are vents for battery thermal runaway - presumably to try to minimise the gas ingress in to the cabin.
If that true, they should not have build them tangent to the fuselage. Any positive attitude could prevent to reach vacuum conditions at the outlet. Vents have to be designed with that in mind.
 



Some interesting nuggets of information quoted from the articles above :

“It’s the first Part 23 aircraft that’s all fly-by-wire,” Bar-Yohay says. “It was a very, very painful aspect of the development of this system. It makes the system much more complex and it takes a long time and a lot of money to do this right.”

"The fractional weight of the battery system is roughly 50 percent of the MTOW of the aircraft. The battery is very big. In fact, Bar-Yohay says the “battery itself functions as a structural part of the aircraft. Meaning the plane cannot fly without the battery there, from a load bearing perspective.”

"Over the past seven years, Eviation considered several design options before it settled on this one. “We looked at canards. We looked at box tail designs,” Bar-Yohay says. “We looked at the wingtip propellers and we landed with something that is very avant-garde, while still being a plane.”


“The biggest technical challenge that Eviation has to overcome is the development of batteries,” he said. “We really do need the industry to boost the energy density.” Because of that, Davis said he doesn’t expect that Alice will win regulatory approval until 2025, and won’t be carrying paying passengers until 2027"

"The plane that flew this morning was Eviation’s “proof of concept” aircraft, Davis said. With a five-year gap before the expected entry into service, and with technologies developing rapidly, “we absolutely will make evolutions to the aircraft,” he said."
It seems, they committed that they do have range problem and they depend on others (battery suppliers) to solve it.

No doubt, it is a nice looking plane and certainly aerodynamic efficient, but building a quite conventional electric plane is not that demanding, every aircraft builder could do that. The quest is enabling a sufficient range other than by hoping of future batteries which might or might not become a realistic. With incredible battery performance, even the Lilium jet will work, but I don’t see it.
 
Interesting find!

As I speculated in #227, Mr. Russo also believes in a CG problem. In combination with the increased weight, I guess my idea of additional batteries to increase the range which might have caused a weight/CG problem could be (one) of the explanations.
 
Uuhh... "zero wind, no payload" was changed into MTOW range. That only means they have refined their range prediction with some test results and with their latest design iteration.

Nothing fancy here.
 

I never noticed this before. Are these openings at the underside of the fuselage designed to help vent the batteries in case of a thermal runaway event ?
Yes, there are markings on the side of the fuselage that says 'burst disc keep clear' so I presume they are vents for battery thermal runaway - presumably to try to minimise the gas ingress in to the cabin.
If that true, they should not have build them tangent to the fuselage. Any positive attitude could prevent to reach vacuum conditions at the outlet. Vents have to be designed with that in mind.
Who knows, a burst disc could be made to burst open with a vent that gets around the tangency issue. The escaping gas pressure could be high enough to exit in to the airflow anyway. They might have figured out they'll only have a problem on the ground. And so on...

As a comparison, burst discs on airbus wings I am familiar with are flush to the wing lower surface and do not incorporate any features to help extract internal air or liquids.
The misconception comes from the fact that fuel fumes are not lethal and the burst disk on Airbus planes won't act to prevent fuel odor to be detected in the fuselage.

Batteries outgasing byproducts, on the contrary, do kill. When you've a fire, it's already too late.

See the diagram of the system as installed on A320:
1664477758972.png
The overpressure breaches the disc and the tangent airflow only helps in the evacuation.
 
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I never noticed this before. Are these openings at the underside of the fuselage designed to help vent the batteries in case of a thermal runaway event ?
Yes, there are markings on the side of the fuselage that says 'burst disc keep clear' so I presume they are vents for battery thermal runaway - presumably to try to minimise the gas ingress in to the cabin.
If that true, they should not have build them tangent to the fuselage. Any positive attitude could prevent to reach vacuum conditions at the outlet. Vents have to be designed with that in mind.
Who knows, a burst disc could be made to burst open with a vent that gets around the tangency issue. The escaping gas pressure could be high enough to exit in to the airflow anyway. They might have figured out they'll only have a problem on the ground. And so on...

As a comparison, burst discs on airbus wings I am familiar with are flush to the wing lower surface and do not incorporate any features to help extract internal air or liquids.
The misconception comes from the fact that fuel fumes are not lethal and the burst disk on Airbus planes won't act to prevent fuel odor to be detected in the fuselage.

Batteries outgasing byproducts, on the contrary, do kill. When you've a fire, it's already too late.

See the diagram of the system as installed on A320:
View attachment 684735
The overpressure breaches the disc and the tangent airflow only helps in the evacuation.
That doesn't change anything I said. Prob best to let this go Tomcat - I know what those burst disks do on the A320, and I know why.
This is not an A320. Those are not fuel tanks. This is what we are discussing.
 
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I'm wondering. Did this concept predate the original prototype, or does it mark an interim step?

And was the airframe shown at Paris the intended-to-fly prototype that was subsequently lost in a fire, or a mock up?


eviation-alice.jpeg
 
Yes - This was the original sketch (art work). It always struck me this was drawn by someone who was desperate for something different and was totally unaware of any of the basics of laying out an inherently safe architecture. After this sketch, the nonsense just kept on coming;- whoops, not enough power so lets a third motor driving an aft pusher propeller, but now it obviously won’t balance, so make it a tail dragger, only there’s no propeller tip clearance, so just put a tiny one on…..Oh sod it, let’s just build it. ….Oh dear, it caught fire. Please Mr finance, can we have another go?

Following this pantomime, the answer being yes is just beyond belief.
 
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When they get better batteries, they will gain reasonable range, as say a 10% improvement is 44 miles, but that goes on the 250 VFR range, so now 294, almost a 20% improvement.

Also they could offer early buyers, a battery upgrade, and ship the old batteries for ground energy storage uses, i.e. airport charging stations.
 
Every aircraft company could built electric airplanes, if they don't do it, it is simply because there is no battery available which could fulfil their needs. The business model of all those electric aircraft start-ups, is claiming, that they found an innovative approach to enable feasable electric airplanes within the near future. They promise, they could do what the traditional aircraft builders can’t. If there will be fantastic batteries available in the near future, all the well-established aircraft companies would come out with electric planes within short time. So waiting for better batteries is no real option to save the business model for those start ups.
 

Very informative article on this project. Shocking that this aircraft could cost as much as 8 million dollars if it ever goes into production. That's a lot of money for a small 11 seat aircraft, I don't know how small commuter airlines like Cape Air could ever afford it. Also, the projected 250 mile range is not that impressive and needs to be improved. I wonder if Estol projects like the Electra would more practical than the Alice.

 
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The one interesting bit of new information is that Eviation is closely studying Cape Air's operations to design the plane to their needs, and one aspect that is being emphasized is that this aircraft must have a very short turnaround time in order to pack in as many flights as possible. Developing a rapid charging system will be crucial.
 

"Aircraft developer Eviation is using masses of data from the first flight of its all-electric Alice commuter aircraft last year to inform the design of the production version, but says it has no plans to fly the prototype again soon."

"Post-flight analysis verified that overall aircraft and energy system performance compared well with predictions, boosting Eviation’s confidence in the design tools and models used to develop Alice."

“The findings were excellent,” says Davis, who adds: “We will fly the airplane again when the time calls for it. We don’t have an immediate need to go and find out anything more about the airplane.”

"The nine-passenger aircraft is designed to fly 250 nm on an 8,300-lb. battery pack housed beneath the fuselage in two large compartments"

This seems odd. If the prototype performed well on its maiden flight and you have confidence in your design, then why not fly it again to continue exploring the flight envelope ? This aircraft only flew a grand total of 8 minutes. There's much data that you can continue gathering until the definitive version flies. According to the article the production conforming version will be a simpler, easier to build design that will incorporate fewer parts with more advanced batteries. It will have a single-piece rudder and ailerons, as well as larger trailing edge flaps in order to improve short field performance. ( which could explain why the prototype was disassembled and transported to an airport with a longer runway for its maiden flight) They are predicting that at the current rate of battery tech improvement, by 2027 the aircraft should have 20% more available energy than what they have now. That still seems to fall a bit short if you factor in things like the mandatory IFR reserves needed for commercial ops. They expect to finalize the production conforming design by 2025, then built a fleet of 3 test aircraft in order to achieve certification by 2027.

I'm sorry but there's just no way they can do all the flight testing and certification work in just 2 years. The much simpler Tecnam P2012 flew in the summer of 2016 and did not enter revenue service with Cape Air until the spring of 2020. This is an extremely advanced aircraft that has fly by wire controls, pressurization, cutting edge electric engines ( which have their own complex software), as well as a whopping 8,300 pounds of batteries that have to be carefully managed and protected to prevent any thermal runaways.
 
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To me it seems, like they are designing again a completely new aircraft, this time probably without pressurization, retractable landing gear and fly by wire therefore with improved lift devices and I guess also with larger wings and tail surfaces. They might also come to the conclusion, that the variable load should be closer to the center of lift... Instead on focusing on maximum aerodynamic efficiency, they might prioritize lighter weight and more maximum lift to carry as much batteries as possible. I doubt, that they will built a better plane than the Tecnam Traveller which is a simple design for the same purpose and even the same main customer.
 
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According to the article the production conforming version will be a simpler, easier to build design that will incorporate fewer parts with more advanced batteries. It will have a single-piece rudder and ailerons, as well as larger trailing edge flaps in order to improve short field performance. ( which could explain why the prototype was disassembled and transported to an airport with a longer runway for its maiden flight)

There’s only so much you can squeeze out of larger flaps before the secondary impacts (larger HTP) becomes grievously penalising to say cruise performance. That’s why things such as leading edge droops become attractive…. But these are more complicated/components ….whoops best not tell the investors.

They are predicting that at the current rate of battery tech improvement, by 2027 the aircraft should have 20% more available energy than what they have now. That still seems to fall a bit short if you factor in things like the mandatory IFR reserves needed for commercial ops.

Not according to my crystal ball….I even bought the deluxe V2.0 model.
 
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"Alice is to carry nine passengers (the regulatory limit for single-piloted aircraft), fly at speeds up to 260kt (482km/h) and have about 250nm (463km) of range in visual flight conditions, plus an additional 30min of reserve flight time."

"Roughly 30min of charging should provide enough power for about 1h of flight, and operators can expect to replace Alice’s batteries after 3,000h of operation"

"Completing the first flight suggested Eviation has recovered from a setback in January 2020, when another prototype was destroyed by fire while on the ground in Prescott, Arizona. That prototype’s lithium-ion batteries ignited due to a “thermal runaway event”, Davis says."

"Alice now has a battery management system that can control and “isolate” the battery’s individual “sub-packs”, which each contribute about 1% of total power."

"Eviation’s earlier round of funding enabled it to develop the technology behind Alice and to bring the aircraft through first flight. “We are now in the middle of our next funding round,” Davis says."

A lot of people don't realize that the first prototype that we saw at the Paris Air Show in 2019 burned down in Arizona in early 2020 while preparing for it's maiden flight. It was after that that they abandoned the radical 3 engine concept that they designed and went for something more practical. In retrospect, it may have been a blessing in disguise that their first thermal runaway event happened early in the program on the ground where no one was injured. That allowed them to make the necessary design modifications to prevent any further incidents. Also losing the first aircraft forced them to build another one, where they made major design changes based on what customers were telling them. Interesting that they are admitting that they are currently seeking additional investment to continue the program. I wonder if that could explain the lack of flight testing since October.


This article from 2019 shows what the first prototype looked like. Very interesting to note that they were originally projecting a whopping 650nm range with this aircraft, now down to 250nm. As recently as late 2021, they were still projecting a range of 440 nm.
 
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Interesting that they are admitting that they are currently seeking additional investment to continue the program. I wonder if that could explain the lack of flight testing since October.
Completing a single 8 minute test flight in September (a full 8 months after teasing "we are about 5 to 6 days away from starting the flight campaign" back in January.....) and now they are another 6 months down the line and NO further flight time logged...

Does anyone else with experience in aerospace flight testing find that strange - and that only now do they put it down to funding?
This article from 2019 shows what the first prototype looked like. Very interesting to note that they were originally projecting a whopping 650nm range with this aircraft, now down to 250nm. As recently as late 2021, they were still projecting a range of 440 nm.
Yes It's remarkable, though in retrospect perhaps not a massive surprise that range is significantly below initial projections/deluded marketing claims. Did they really expect that battery density would improve that quickly?!

I really want to believe in the concept and the company and will continue following developments with interest, and see if progress is made on other fully electric projects like the Bye eFlyer 800 and the Heart ES-30...
 
View: https://www.youtube.com/watch?v=mIU5VOfgzSc&ab_channel=SkyshipsEng


A good detailed overview of the program. It should be noted that the prototype still has not made any further test flights since it's first one in September 2022. So this airframe has a grand total of 8 minutes flying time. I wonder if they have serious financial or technical issues that have brought the flight test program to a halt that they're being quiet about. For example, in December 2021 the aircraft began taxi tests that took a whopping 9 months to complete before its maiden flight. They still have not given a satisfactory explanation for the massive delay.
 
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Maybe it takes that long to charge the batteries? Or can they afford to charge the batteries?
 
Not a fan myself, certainly doubtful of the viability of the program, however, is it also possible that they are also being hampered by the FAA? I really think the FAA would really prefer not to have any of this new aviation stuff mucking about that makes the ultimate bureaucrats have to do something and take risk. I mean look at how long Leonardo has been trying to get the 609 approved.
 
It might well be, that the FAA became super cautious after the 737 max disaster, but I don’t believe that there is any intention of stopping electric planes. The prototype is a super complex design with pressurisation, fly by wire, retractable landing gear and a completely new propulsion system, not an easy job for the FAA.

As said before, I bet, that Ellice is working on a much simplified version without all the fancy stuff. They seem to have lost any interest in their prototype design.
 
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…The prototype is a super complex design with pressurisation, fly by wire, retractable landing gear and a completely new propulsion system, not an easy job for the FAA.

Although that what’s been claimed, the few published interior photo’s tell a different story;- it’s a bare shell, with tug by wire cables.
 

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