Eviation Alice (Electric Regional Airliner)

[alberchico]

How Do You Make an Airplane Climate Friendly? Start by Shaping It Like a Whale

Air travel is one of the worst polluters of the atmosphere, but carbon-free, battery-powered flight is finally ready to take off

www.rollingstone.com

Very interesting that the plan is to build a total of 3 prototypes for certification tests.

"Its battery packs weigh more than 8,000 pounds and are hidden in chubby, curved sections on either side of the fuselage. The packs are strong enough to contribute to the integrity of the aircraft, saving weight. And the wide bottom of the plane acts like a wing. “The body itself takes part in lifting the weight of the battery,” Bar-Yohay says."

 

[Nicknick]

The Battery pact is fixed like a drawer (see No 205) with very few attachments point, this surly doesn’t help a lot with aircraft integrity (but enables a fast exchange). Retractable landing gears are nothing new and pressurisation doesn’t make a lot of sense if you fly short and low. The lifting body fuselage is quite similar to the Piaggio P.180, it might help a bit, but not by a magnitude. I also doubt that fly by wire will save a lot of weight.

More or less, the Alice is a nice looking, efficient but fairly conventional plane from the layout. There is nothing revolutionary which will cause sensational good L/D ratios.

 

[Nicknick]

"This arrangement splits up the airplane's lifting force, and gives it a rather high (67.07 lb/sq ft.) wing loading. The forward wing produces about 25 percent of the airplane's lift. The main wing makes 45 percent of the lift, the horizontal stabilizer makes 10 percent of the lift (while producing zero down force), and the other 20 percent is produced by the fuselage's unique shape."

Turbine Pilot

The Piaggio P180 Avanti — a turboprop twin with jet performance Remember the Avanti? The Italian design that debuted in the U.S. market in 1990, only to slide into oblivion by 1994? Well, it's attempting a comeback, under new management and with a more aggressive approach to service centers.

www.aopa.org

 

[alberchico]

That "no payload" fine print in the specifications is interesting, and new. It certainly wasn't there a few weeks ago. They also added the word "target" before "specifications".

It's good that Eviation finally comes clean with it. One does not need to be a rocket scientist to find out that with a takeoff weight of 16500 lb, minus 8200 lb of batteries, and 200 lb for single crew, you end up with roughly 8000 lb empty weight which, at 50% fraction, would represent an amazing achievement. And it leaves nothing at all for any payload whatsoever.

Thus you trade battery modules for payload and with a payload of 2500 lb you get down to 5700 lb of batteries, at most. More realistically 5000 lb like I pointed out in this thread last February (post #164).

So that translates to a range of 200 nm without any reserves, and a negative range number with IFR divert and reserves legally required for scheduled commercial flights.

I wonder if that was the reason two prominent executives left the organization just after the prototype was rolled out. I guess we'll know soon enough once the prototype starts flight tests. Having the useful range cut by more than half would scare away so many potential customers that this project could be doomed to failure. I think this design is simply too ambitious for the battery tech currently available and they should have opted for a simple layout like the one being developed at Airflow with their Estol concept. Considering that electric aviation is still in it's infancy, the Eviation Alice is at least 10-15 years ahead of its time.

Airflow is now part of Electra

www.airflow.aero

Embraer is also exploring the feasibility of developing a family of electric and hybrid aircraft and one concept that is fully electric with 9 seats and a range of 200nm would not be ready to enter service until 2035. So either the people at Eviation are geniuses who have developed a ground breaking design that can accomplish something that no other aircraft can, or they screwed up and over promised and are now going to under deliver. This feels like the Eclipse 500 saga all over again, which is a shame because I really want this project to be a roaring success.

Embraer Outlines Electric Propulsion Vision with New Energia Aircraft Concepts - Avionics International

Embraer unveiled its new Energia family of four electric and hydrogen powered aircraft of varying sizes that could see first entry into service by 2030.

www.aviationtoday.com

 

[Nicknick]

"This arrangement splits up the airplane's lifting force, and gives it a rather high (67.07 lb/sq ft.) wing loading. The forward wing produces about 25 percent of the airplane's lift. The main wing makes 45 percent of the lift, the horizontal stabilizer makes 10 percent of the lift (while producing zero down force), and the other 20 percent is produced by the fuselage's unique shape."

Turbine Pilot

The Piaggio P180 Avanti — a turboprop twin with jet performance Remember the Avanti? The Italian design that debuted in the U.S. market in 1990, only to slide into oblivion by 1994? Well, it's attempting a comeback, under new management and with a more aggressive approach to service centers.

www.aopa.org

It is a widely held misconception, but false nonetheless.

Just think about it for a minute, a wing is really efficient when it has a high aspect ratio. Look at the aspect ratio of the fuselage, it is well below 1, actually closer to 0.1. Awfully inefficient. Then look at the geometric constraint of the fuselage profile such as tail clearance on rotation, or windshield field of view, or cabin floor angle during cruise flight, and you quickly realize that you have to move away from an efficient airfoil profile as well.

Those two negative factors combined together means that any lift produced by the fuselage would severely hurt the overall aircraft lift to drag ratio. So what you want to have is a fuselage that produces no lift at all, in order to minimize drag (that's what the wing incidence angle is all about). And let the wing and tail do their thing.

Generally speaking, people who think the fuselage produces lift are those who are looking at the spanwise lift distribution curve and misunderstand the meaning of it not dropping off inside the fuselage area, and taking that percentage as fuselage contribution. It's just not factual since when you remove the fuselage in wind tunnel or CFD, you end up with a superior lift curve regardless of any fuselage shape.

Things which are more curved on the upper part than on the bottom tend to produce lift. The Volkswagen Beetle e.g., produced a lot of unwanted lift as do most other cars (mainly to a smaller amount). Probably even bananas can produce lift without being designed for that . The fuselage of the P.180 will surly produce lift, it may be less than 20 % but definitely not zero.

 

[TomcatViP]

I see that the misunderstanding comes with which aspect of the mission lift from the fuselage is suitable for. Fuselage lift is generally associated with the phases of flight with a greater AoA. During these sequences the contribution from the fuselage decrease the associated requirements on the wing: your wing can then be made thinner, slender with less complex and heavy lift augmentation devices.
If you expect lift from the fuselage to be beneficial during the high efficiency regime, effectively, the fuselage has to be built like a wing with a larger frontal section to the point that it becomes some form of flying wing (but that's not always true and others aspect of the mission blend-in to complicate the narrative).
There (fuselage lift), the expected benefits are generally in freeing the other part of the mission to seek after more efficient cruise while keeping good takeoffs and landings as higher climb rate parameters.

 

[Nicknick]

Maybe we should start a new thread about that. Lift is something which just happens, if you have a stronger curvature on the top than on the bottom. The first generation Audi TT wasn’t optimized at all for producing lift but severe accident (luckily for Audi not in the US) proved it did. They had to add a spoiler to the rear to interrupt the airflow around the roundish ass.

It is another question wether lift by the fuselage is efficient or not and when it peaks, but will be certainly there if the fuselage has such a curveture

 

[VTOLicious]

To compare aircraft with things that accidentally produce lift is like apples and oranges... or bananas

 

[Nicknick]

That's physics, not the intention matters, but the boundary conditions.

 

[Zoo Tycoon]

Maybe we should start a new thread about that. Lift is something which just happens, if you have a stronger curvature on the top than on the bottom.

It is another question wether lift by the fuselage is efficient or not and when it peaks, but will be certainly there if the fuselage has such a curveture

Lift only happens with an appropriate differential airspeed, top and bottom and something is in the way to maintain a pressure differential;- low airspeed and near no aspect ratio = insignificant lift.

It all changes when things get faster as the velocity term is squared, even for the A&B team’s aerial buses.

The guy behind the claim of revolutionary Alice’s fuselage lift is also the same guy behind its original unworldly range (recently corrected when he resigned) … bit of a clue as to it’s validity me thinks

 

[Nicknick]

The VW Beetle really didn't have more aspect ratio, but it produced more than enough lift to become unstable at "higher" (LOL) speeds.

Lift on the front end might be more valuable than lift in general, because it acts a bit like a canard without it's disadvantages. The Tail must produce less downforce in this case, so that it add double the value.

For shure, this doesn't fundamentally change the equations and we are talking about having 400 nm or 150 nm as range...

 

[Nicknick]

Edit: this was the answer to a now deleted posting before

I added a quotation for the lift of the fuselage, so in case that I'm wong, I'm not the one to blame (Do you have any evidance, for the opposite?). Also the fact that cars tend to produce lift (if no additional efforts are done like adding spoilsers, diffusors etc.) is a widly knowen fact (see my last link). Lift is produced, when rotaion in the flow is occuring, that what I learned in flow dynamics, curvature is producing exactly that. Rotation doesn't mean, the flow on the bottom is flowing backwards, but the integral oft the flow shows a superposition of a parallel flow and a swirl. I learned that at the University (managed to get trough flow dynamic I and II), so I know what I'm talking about...

For all classic layouts, the tail is in fact producing downforce, this is basic knowledge you can find in all good books about aerrodynamics. Take a look:

Longitudinal Stability

How to balance the cargo on a plane with the wings further aft?

For example on an MD-88, is the center of gravity on the back of the plane because the empennage, wings and engines are located there? So they would have to put most of the cargo on the back of the...

aviation.stackexchange.com

Aircraft Design Characteristics

Technical knowledge for Aviators on aircraft systems and components maintenance; theory; methods; procedures; troubleshoot; repair; testing; diagrams;

www.aircraftsystemstech.com

https://www.sciencedirect.com/topics/engineering/aerodynamic-lift

 

[TomcatViP]

Please guys let's not start here another conversation where each one of us lecture the others on such matters.
@Nicknick : the term you are looking to dig out from your memory is circulation

 

[alberchico]

Eviation readies for Alice maiden sortie as ground tests wrap up

Eviation is gearing up for the first flight of its all-electric Alice prototype in the coming months having completed ground testing earlier in May.

www.flightglobal.com

Ground tests have finally wrapped up. Hopefully we'll see the maiden flight soon.

"Davis declines to provide details but says the results of ground tests convinced it to slow the push towards first flight."

"When we completed the ground-test programme we found some things that we needed to tweak and that’s what we are working on as we prepare the aircraft for first flight,” he says."

So it looks like there was some sort of technical issue that needed to be resolved, my guess is that it was related to either the engines or the complex battery system.

Edit: This article has a lot of information so I will provide a quick summary for those who can't get past the paywall.

"Davis says flights of the first of three certification aircraft will begin in 2024. This should lead to type approval for the unpressurised version from the US Federal Aviation Administration under Part 23 regulations in 2025"

* The production conforming prototype will not take flight until 2024. So the aircraft that they currently have is only a demonstrator to see if the basic design works. Any test flights it performs will not count towards certification. If the certification process doesn't formally begin until 2024, I don't know why they think they can get this thing in service by 2025. It seems that they are being overly optimistic to keep investors and customers happy.

* High speed taxi tests still have not been conducted, that will only come once the aircraft receives its experimental permit to fly from the FAA. I assumed they already had that.

* The cargo version for DHL will enter service first in 2025 and it will be unpressurized. It also reduces weight and complexity. The version for Cape Air will be pressurized and will enter service around 2026.

* They still have not decided which company will be contracted to supply the composite fuselage as well as the tail. The French company that built this prototype will not be used to manufacture production aircraft as they cannot build in the large volumes that will be required. The wings will be built by GKN Aerospace.

* They still have not decided which company will provide the avionics for the flight deck, although they are leaning towards Honeywell's Anthem cockpit design. This is why the current prototype's cockpit looks so spartan, it's nothing more than an interim configuration. Honeywell will be providing the fly by wire system, which is optimized for light electric aircraft.

* They are actively looking for a launch customer for the executive version. They are claiming operating costs up to 66% lower than a conventional aircraft. Eviation also believes most operators will fly it on routes ranging from 150 to 300nm. I wonder if this aircraft can really fly a 300nm segment with a full payload on a miserable winter day while battling headwinds and having the anti-icing and cabin heat switched on plus full IFR reserves.

There was one last thing that stood out:

"However, he cautions that the Eviation is being selective about which customers will receive their aircraft first, seeking those that are experts in onboarding new aircraft” and which can assist with driving maturity into the platform"

That seems to explain why they want DHL to be the first customer to put this thing into service. They know this aircraft will likely be very temperamental and they need an experienced operator that can put up with a lot of teething troubles. DHL has more resources to deal with these issues than a small operator like Cape Air, who is very unhappy with all the teething problems their new fleet of Tecnam P2012's are giving them.

 

[Zoo Tycoon]

Alice in wonderland?
An interesting independent assessment of Alice’s expected performance based on the recently disclosed data;-

Oh dear, 10kft cruise range of 45 nm with almost zero time at cruise altitude, I guess there’s no point in having a cabin pressurisation system.

 

[alberchico]

Wow that is bad. If those figures are true then this project is toast. The Tecnam P-Volt would be a far more practical and affordable aircraft. I wonder if that is why 2 top executives associated with this program abruptly left a few months ago. Leeham called this a few months ago, claiming that the figures that Eviation were presenting just did not add up.

Bjorn’s Corner: Sustainable Air Transport. Part 6. Energy consumption. - Leeham News and Analysis

February 11, 2022, ©. Leeham News: In a sister article, Part 6P. Energy consumption, the deeper discussion we use Leeham’s Aircraft Performance Model from our consulting practice to generate the aeronautical energy consumption for aircraft like Eviation’s Alice... Read More

leehamnews.com

Here are the relevant quotes:

"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."

With a useful range of less than a 100nm when you factor in the IFR reserves required for commercial ops, this aircraft is just not suited for neither airline, cargo or business flights. So who the heck will buy it ? That's assuming of course they make it all the way to certification and production with those atrocious range figures.

 

[Zoo Tycoon]

Yet more problems for Alice;- The report also picks up on the pitching authority problem (Ref my post no 131). It even goes so far as to suggest their home airfield (5330 feet runway) isn’t big enough for the test flying;- Probably explains why the first flight date slipped as they couldn’t lift the nose with sufficient runway left to stop. Yes this can be fixed with a high lift system to improve the Clmax and a redistribution of the volume coefficients but it all adds to the airframe mass which draws down the payload. Sadly there goes the dream of lots of short hops.

It would be great to get a “fly on the wall” view of just how both Alice 1&2 got funded. A friend of mine has been unsuccessfully looking for funding for a really sound, well engineered and innovative project. He said there’s so much science fiction being put to investors described as feasible, that the real stuff just looks boring.

In the Hydrogen and Electric aeroplane feasibility thread there’s a self proclaimed Technology Strategist claiming a 14seater EV aircraft with a range of 500km is doable with today’s batteries. How does such a clueless opinion get so much publicity?

 

[alberchico]

Yet more problems for Alice;- The report also picks up on the pitching authority problem (Ref my post no 131). It even goes so far as to suggest their home airfield (5330 feet runway) isn’t big enough for the test flying;- Probably explains why the first flight date slipped as they couldn’t lift the nose with sufficient runway left to stop. Yes this can be fixed with a high lift system to improve the Clmax and a redistribution of the volume coefficients but it all adds to the airframe mass which draws down the payload. Sadly there goes the dream of lots of short hops.

An article just came out saying that the prototype had to be taken apart and relocated to a different airfield with a much longer runway. The company remains tight lipped on exactly why their current location wasn't suitable for test flights, but I guess we now have a reason why.

Eviation relocates Alice to Moses Lake for maiden flight - The Air Current

Alice heads east as Eviation rebuilds the battery after completing ground trials.

theaircurrent.com

I wonder if this project would have been more viable had they gone for a more simpler configuration, such as a high wing to improve short field performance, no fly by wire, no retractable landing gear, no pressurization, and an all metal fuselage to make it more maintenance friendly. Sort of like the type of aircraft that their rivals are designing.

 

[Nicknick]

Well, as said, if DHL is investing in something about electric parcel transport, it will certainly fail...

StreetScooter - Wikipedia

en.wikipedia.org

Aus für den Paketkopter: DHL stoppt Zustellung per Drohne

Die Deutsche Post DHL Group stellt die Entwicklung des Paketkopters ein. Alle Projekte im In- und Ausland wurden beendet.

www.eurotransport.de

 

[alberchico]

View: https://m.youtube.com/watch?v=xCJlp4KiPRo

 

[Nicknick]

Unlike in conventional airplanes, the passenger compartment is fully in front of the wings, thus the variable mass (passenger) is placed far away in front of CG of the empty plane. The first test flight would shurly have been done with an empty plane. If they couldn’t lift the nose fast enough without load (CG in aft position), it must have been totally far off any practicallity with a fully loaded plane (CG moved to the front)!

Hard to believe for the leader in electric aviation...Maybe they were so desperated that they added some more batteries in the front to increase the range for some show flight? Hard to explain otherwise...

 

[AeroFranz]

Could also be too small of a horizontal tail (not enough down force to raise the nose). But yeah, too far forward CG would explain a lot.

 

[alberchico]

Unlike in conventional airplanes, the passenger compartment is fully in front of the wings, thus the variable mass (passenger) is placed far away in front of CG of the empty plane. The first test flight would shurly have been done with an empty plane. If they couldn’t lift the nose fast enough without load (CG in aft position), it must have been totally far off any practicallity with a fully loaded plane (CG moved to the front)!

Hard to believe for the leader in electric aviation...Maybe they were so desperated that they added some more batteries in the front to increase the range for some show flight? Hard to explain otherwise...

Wouldn't this design have been extensively tested and fine tuned in wind tunnels and on CAD software before any metal was cut ? I would imagine any potential CG issues would have been ironed out long ago. I found this interesting link that showcases the company that provided the design software.

Eviation Aircraft

Eviation Aircraft wanted to design and build an all electric airplane for mid-range distances that is cost-effective and environmentally friendly on an aggressive time schedule by using the 3DEXPERIENCE platform on the cloud.

www.3ds.com

View: https://www.youtube.com/watch?v=pmJ5UNlKics&ab_channel=SystematicsIsrael


A thought just occurred to me. An aircraft like this with a very long wingspan is going to need a comprehensive anti-ice system as well as cabin heat to cope with winter weather . How much energy will those systems consume when switched on ? Is that going to cut deeply into range ?

 

[Sundog]

It isn't a cg problem. If there was a cg problem, the engineers would have caught it a long time ago. I think it's just a flight test issue. In the sense that that long of a runway lets the pilots take off, fly in ground effect, then land within the length of the runway. It gives them a chance to get a feel for the flight characteristics without having to commit to a complete up and way flight.

 

[Nicknick]

There is a indication, that it might be a CG proplem, please read #221. It is obvios, that there is a problem with something, because, they delayed the first flight and had to switch to longer runway.

My personal theorie is, that they added battery mass after the design freeze (because they had to) and might have moved the CG in an unfavourable position.

Anyway, positoning the variable mass far away from the CG of the plane is never a good idea. On the other hand, the usefull load is very low compared to the empty weight.

 

[Zoo Tycoon]

It’s not a simple CoG problem;- that could be easily corrected with ballast mass. It’s a pitch controlability issue coming from the aero of the horizontal tail (particularly its minimal size), the overall aircraft ground effect and the positioning of the neutral pitch axis.

See https://second.wiki/wiki/vmu-test

As to why it’s in this mess, maybe as per Alice 1, engineers have been overruled by the graphic artists again.

Life gets tough when you’re got to do things for real.

 

[TomcatViP]

Latest interview :

Seattle-based aerospace company makes Moses Lake a proving ground for new electric airplane projects

AeroTEC is working on four electric airplane projects out of Moses Lake. CEO Lee Human talked to potential customers at the Farnborough Airshow.

www.seattletimes.com

 

[alberchico]

Parker Aerospace and Eviation Team Up on Development of Alice; the First All-electric Commuter Aircraft

Parker Aerospace, a business segment of Parker Hannifin Corporation, the global leader in motion and control technologies, today announced a partnersh

www.businesswire.com

So only now are they going to start development of some of the key systems the production conforming version of this aircraft will incorporate ? This will likely delay certification even further. It looks like they're aware of the range shortfall issue as there seems to be a concerted effort to reduce weight wherever possible.

 

[Hydroman]

So it looks like no full-authority EM FBW primary flight control actuation system for Alice, only EM flaps, a mechanical primary system and integrated power-pack hydraulic gear and brakes. I mentioned this in a previous Alice comment, there is still work to be done in the area of commercial EM primary FBW and the FAA for a manned commercial aircraft. Even an unmanned, commercial demonstrator with the proper EM architecture could perform the required risk-reduction testing. As a note, the Bell 525 (and Bell 429 as an option) is using a completely EM landing gear actuation system, but a hydraulic FBW primary FCAS.

 

[yasotay]

Perhaps the FAA challenges the Bell is having with 525 are part of the decision process for them?

 

[TomcatViP]

But why would they want some costly FBW from day one? They already have a test pilot to safeguard the test airplane. They are a long road to sale airplane before any rookie PiC endangers one airframe and a lot to demo before that day.

FBW are not a priority.

 

[Hydroman]

But why would they want some costly FBW from day one? They already have a test pilot to safeguard the test airplane. They are a long road to sale airplane before any rookie PiC endangers one airframe and a lot to demo before that day.

FBW are not a priority.

EM FBW was one of their initial requirements, you are correct, does not make sense currently.

 

[robby.main]

But why would they want some costly FBW from day one? They already have a test pilot to safeguard the test airplane. They are a long road to sale airplane before any rookie PiC endangers one airframe

I don't follow this point. What does FBW has to do with safeguarding the test airplane? Unless you are you referring to Envelope Protection which is not inferred by FBW...

 

[robby.main]

I know there are a lot of unanswered questions over this project especially in regard to the very major late configuration change and departure of CEO etc. but the assessment posted by ZooTycoon makes for sobering reading indeed!

 

[TomcatViP]

But why would they want some costly FBW from day one? They already have a test pilot to safeguard the test airplane. They are a long road to sale airplane before any rookie PiC endangers one airframe

I don't follow this point. What does FBW has to do with safeguarding the test airplane? Unless you are you referring to Envelope Protection which is not inferred by FBW...

They want something that can be flown with minimally experienced pilots. FBW in civilian airplane does have everything to do with flying the plane more economically and safely.

 

[robby.main]

But why would they want some costly FBW from day one? They already have a test pilot to safeguard the test airplane. They are a long road to sale airplane before any rookie PiC endangers one airframe

I don't follow this point. What does FBW has to do with safeguarding the test airplane? Unless you are you referring to Envelope Protection which is not inferred by FBW...

They want something that can be flown with minimally experienced pilots.

Fascinating. Where have Eviation stated this?

 

[TomcatViP]

Oh, what did they say, then?

 

[alberchico]

https://twitter.com/x/status/1558241665717981184

View: https://mobile.twitter.com/EviationAero/status/1558241665717981184


Finally we get an update. The aircraft is fully assembled at Moses Lake and appears to be ready for its maiden flight. We also get a peek at the aircraft being recharged.

 

[alberchico]

New Signs First Flight of Eviation’s All-Electric Alice May Be Near

A test article for the nine-passenger aircraft has been undergoing ground tests at Moses Lake, Washington.

www.flyingmag.com

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.

 

[robby.main]

New Signs First Flight of Eviation’s All-Electric Alice May Be Near

A test article for the nine-passenger aircraft has been undergoing ground tests at Moses Lake, Washington.

www.flyingmag.com

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?