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Eviation’s Alice is an all-electric, nine-person aircraft (robbreport.com)
70 points by EastLondonCoder 9 days ago | hide | past | web | favorite | 85 comments





I'm afraid this is a nonsense.

https://twitter.com/BenBrelje_says/status/106484220091004108...

https://twitter.com/BenBrelje_says/status/106485722028904038...

https://twitter.com/BenBrelje_says/status/106491195862390374...

To recap, based on financial statements the company:

used to be a "waste management" company that failed and was sold as a "public shell" to enable the formerly private company to go public and sell shares (the waste management business it was engaged in was an effort to commercialize a process to treat low-level nuclear waste developed by Russian scientists)

has $64 mil in debt apparently unrelated to aviation

has spent $3.8 mil on R&D for this project

has 8 R&D employees

only 2 of those 8 have any evident experience related to designing aircraft


650 mile range may not be as much as it sounds like. I'm not a pilot but I know there are regulations for reserve fuel.

So you need enough fuel (kWH in this case) for taxi, take off, the trip itself, divert to alternate airport, plus reserve for 30-45 minutes of holding, at least one missed approach/go-around, plus maybe more emergency reserve beyond that. It might add up to only 300-400 of practical travel range.


I have no idea if this actually covers it or not, but the website[1] claims "Range + IFR reserve: 650 miles".

[1]: https://www.eviation.co/alice/


Turboprops are usually sub 2-hour flights; 400 miles would be 80 minutes, which covers most of the passenger flights a turboprop might do.

Another question might be whether or not the range can be extended when there are no passengers; a turboprop can be loaded with extra fuel when only the plane needs to be moved; the beechcraft super king (10 pax turboprop) has nearly a 2000 mile range with no passengers.

It was also slightly shady to specify the range in miles, when nautical miles are more typically used.


650 miles is a wishing number with a full passenger load based on current battery technology. When the unexpected weight increases that impact every new aircraft design inevitably hit, that theoretical range will drop significantly.

Interesting concept.

I’m curious what voltage the pack runs at and how long it would take to charge. Many of these types of aircraft operate in FAR Part 135 on-demand operations. Aircraft and crew utilization are crucial for the business model.

Expensive airplanes and pilots don’t make money sitting on the ground. Of course, if operating costs (fuel) are a fraction of a traditional aircraft then margins get better but do they get good enough to offset 2-3x more aircraft and pilots to operate those aircraft to be able to fulfill demand?

I hate to sound like the people who constantly naysay electric cars because of charging times but in this industry turn around time is crucial.


>I’m curious what voltage the pack runs at and how long it would take to charge. Many of these types of aircraft operate in FAR Part 135 on-demand operations. Aircraft and crew utilization are crucial for the business model.

This is the number one question I had as well, for the same reasons. Porsche has a 1000V system in their new Taycan EV, so I'd assume they're at least at that level. At 900kWh, a system like that could charge from 10% (assumed minimum reserve) to 95% (Batteries are never really charged to 100%) in under 2 hours @ 400KW, which is about the power level of the beefiest EV chargers being developed right now.

More likely they will have swappable batteries, which makes a lot more sense from a thermal management point of view as well. You can either load up the pack with all kinds of cooling and deal with the added weight, or just make it passive air-cooled and swap it out between flights before it gets too hot.


In my humble opinion swappable batteries on an airplane would run afoul of the maintenance regulations that require an A & P to perform and sign off on changes to the aircraft.

>In my humble opinion swappable batteries on an airplane would run afoul of the maintenance regulations that require an A & P to perform and sign off on changes to the aircraft.

Pipistrel Alpha, the only real production electric plane shipping, is using swappable batteries. There's really no other viable way with current technology to have reasonable recharge times.


Correct.

> At 900kWh, a system like that could charge from 10% (assumed minimum reserve) to 95% (Batteries are never really charged to 100%) in under 2 hours @ 400KW, which is about the power level of the beefiest EV chargers being developed right now.

There's no particular reason charging a big, multicell battery needs to bottleneck on a single charger. (is there?) It's done with cars for what I always assumed were cost and convenience reasons.



Will not be swappable as that would add too much weight.

Current electric aircraft like the Pipistrel Alpha Electro (https://www.pipistrel.si/plane/alpha-electro/overview) have swappable battery packs. I can't see why this wouldn't be an option here.

Weight.

> I’m curious what voltage the pack runs at and how long it would take to charge

It's surely not a new battery chemistry. Lithium cells have a voltage in the 3-3.5V range. If you want more, you put them in series. And fed with an appropriately regulated supply, all common cell types will charge to full capacity from empty in 4 hours or so, reaching 50% sometime inside of 1 hour (that is, most of the time spent is in "topping off" the thing, broadly you can get energy into a battery at least as fast as you can get it out). It's literally no different than your phone battery.


They are claiming a price of $3 million plus. While that sounds like a lot, from what I can tell it is cheap for aircraft of that size. (it is very hard to track down prices for new aircraft so feel free to correct me). It may well be feasible to buy 3 of these to replace 1 of something else, and have 2 charging all the time.

Alice really compares more to large turboprops rather than small jets like the HondaJet. When comparing to the used turboprops on the market the Alice isn’t really that competitive. A used Cessna Conquest with more range could be had for around $1-1.5 million depending on condition. Of course operating expenses are significantly more so someone still needs to figure out the math there.

If you’re buying a fleet of new aircraft I suppose it’s competitive but for similar price a Pilatus PC-12 gets you significantly more utility. Land just about anywhere and easily find fuel.

Another factor is these MSRP estimates are really hard to pin down before the aircraft is fully developed. In the early 2000s there was a flood of companies claiming $1 million jets. Eclipse Jet being the most notable. Most of those programs either didn’t survive or ended up charging more like $5-10 million. Getting an aircraft certified isn’t cheap and it’s really hard to get economies of scale on something so expensive.

I don’t want to completely discount the program but I keep going back to the charging when I try to flesh this idea out. The only possible way I see this succeeding is if the company also facilitates building a charging network. When I was in high school I worked at a small Midwest airport and the idea that the city, who owned the airport, would build charging infrastructure for a niche aircraft is laughable. They almost shutdown their Jet A fueling infrastructure (that they charged money for) because they claimed it was too expensive to maintain.

Overall point is that it’s doable but there are hurdles and a half baked idea and marketing fluff is going to result in yet another failed aviation venture.


They don't have electricity at the airport? The Tesla superchargers use regular commercial hv lines, nothing special. The additional expense for an airport that will be a new transformer. This is why Tesla is able to put chargers in so many locations, cause it doesn't cost 3 million dollars each time they do it. Dig a whole, run the power, add a transformer, pain, fill in the hole. They built one in a week nearby.

> I keep going back to the charging when I try to flesh this idea out.

Could they burn jet fuel in an electric generator? Maybe not economically, but the infrastructure is there.


Jet fuel is basically diesel fuel without lubrication. Diesel engines will run on it. If you don't mind replacing your injectors more often than you change the oil you could go so far as say they run just fine.

I understand there are diesel aircraft engines that run on it - presumably this means that the injectors are different from all the engines I'm familiar with. You could install this engine connected to a generator and get a hybrid, though I don't know if it is a good idea. One the plus side you can put the engine where you want it for weight distribution reasons, because it is a hybrid you can always run at optimal rpm, diesel fuel has a better energy/mass ratio, and when/if it fails you have plenty battery backup so your wouldn't need as much maintenance as most aircraft engines get. On the negative side, you are paying to haul this engine around even on short flights.


It's a pretty low price. The HondaJet is close at approx. $5MM, though it has more than double the claimed range of the Alice.

Is? No it's not. It could be.

> aims to have one flying early next year.

Using the present tense is not justified.



also Bloomberg[1] mentions this:

> The company plans to fly a prototype of the “Alice” design at the Paris Air Show in June ...

So yea, seems premature, since they're getting close to a prototype.

[1]: https://www.bloomberg.com/news/articles/2018-11-12/pioneerin...


They're building it now, so it exists in some form already if not complete.

Sure. Flying cars just around the corner, for a century now. Not holding my breath.

Bilbo Baggings is a Hobbit.

Words are used in a context which shapes their meaning. “Is” there implies to most that the aircraft already exists.

“It depends on what the meaning of the word ‘is’ is.”

Well, he was right about that, although there is little doubt his intent was to deceive.

Bilbo Baggins currently exists, as a fantasy character.

The character in my new novel Tina Taggins will be a gnome though. I haven't written in that character yet.

"is" vs "will" is a tense thing. This isn't yet a plane like Tina Taggins isn't yet a character in my novel so "will" is a appropriate.


There is no third “g” in Bilbo’s last name.

Thanks, fixed.

Are you saying that the headline obviously belongs to the fantasy domain?

These cost reductions are a big deal and they are largely based on energy cost reductions. It offsets some of the inconveniences of not so long range, lack of infrastructure for charging, and having to wait for recharging.

For reference, typical business jets or twin props burn hundreds of gallons of fuel on a single trip costing hundreds of dollars. They also need frequent maintenance as there are a lot of things that need to be checked and fixed with such planes. So, the proposition of charging with cheap electricity and getting rid of most of the stuff that needs fixing and maintaining on a regular basis is highly attractive. If it works as advertised, this plane will sell like crazy. Electrical engines basically last a very long time and are easy to check and service. Charging batteries is comparatively cheap to burning fuel and likely to get cheaper in the future.

Practically speaking, if you have a home base with charging infrastructure but most other airports do not (yet), effectively you are looking at a 300M range for a return trip unless you are flying to a place with infrastructure to charge. That's still fairly nice.

For commercial operations, there are plenty of use-cases that would be well served by a plane like this. A plane like this gets passenger cost down to something that is quite competitive with a train ticket.


Jet engines are conceptually simple and very low maintenance but still very expensive. Difficult materials and high precision. And use a massive amount of fuel.

It is fascinating to compare with an electric aircraft. It's not so clear to me what the economics would be like as a whole.

It's not just fuel but investment and maintenance cost.

To me it might make sense in a short high frequency operation. Like to some island. Not as a business jet that mostly just sits around.


In the light turboprop market, jet engines are surprisingly primitive. The most common engine family (PT6A) was created in the 1970s. Today, the engines cost half a million dollars new because the production volumes are tiny and the liability costs are huge. I don't see a reason why electric airplanes will avoid either cost issue.

It's pretty clear what the economics are. Electrical engines are relatively uncomplicated, small, light, and extremely reliable. Also, they tend to last quite long. E.g. in many electrical cars, engine failures or battery replacements tend to be relatively rare and are typically not needed until after hundreds of thousands of miles on the road and usually not because they failed but simply because of degraded performance.

With electrical planes you'd expect similar benefits. Maybe a regular quick inspection of the few moving parts for wear and tear, make sure battery performance is fine and that any sensor read outs don't hint at any problems with cooling, performance, etc. Of course you still need to inspect the rest of the plane as usual. However, the engine tends to be one of the more expensive parts normally.

Jets are indeed reliable but they do need to be inspected regularly to ensure they stay that way. If e.g. there's some hairline cracks or corrosion, the engine might still work but be about to fail in some spectacular way. Inspections for that are expensive and a regular thing. Same with piston engines. Typically engines are certified for a fixed number of hours before they need their overhaul. I expect similar inspections and overhauls to be needed for electrical engines for the same reasons. But they should be much cheaper to do and the engines could likely be certified for much longer because there is less that can go wrong with them. So, less frequent inspections and overhauls, and cheaper inspections are a good thing. Also replacing parts / engines is likely to be a lot simpler if there are any problems.

Other factors are that unused engines tend to need more attention when you take them back into use. E.g. oil can solidify, fuel lines can clog up, etc. Most planes need to be flow regularly in order to avoid extra maintenance cost. To make sure things are functioning, you also have elaborate warmup and runup procedures before take off. A jet or piston engine is not usable until a few minutes after startup when everything is nicely warmed up and properly lubricated. Then you need to typically still go through elaborate runup procedures. Electrical engines are a lot less needy. Also they don't need to warm up, you just flip a switch and they are ready to go.

And that's aside from the fuel cost of course, which is a big deal as well.


But if you look at the whole plane, the electric one will be about double the weight.

What about the landing gear? Brakes? Control surfaces? All double size.

The battery will likely be a somewhat complex system with active cooling and monitoring and will need maintenance. They are aiming for higher than car level energy to weight ratios.

If they use a battery with air as a component, that's also again somewhat more complicated.

There's probably a trade off point in flight hours per year, above which the electric plane is more affordable. Depends on finances, too since likely it's more expensive to acquire.


Audi also introduced a concept eVTOL with detachable "pod". It's an interesting design choice. Creating modular components that could be shipped across air, sea, and land boundaries.

https://www.autoblog.com/2018/11/28/audi-demonstrates-pop-up...


For reference: Model 3 apparently has 75 to 100 kWh. This plane seems to spec out - Li-lon - 900 kWh. For a layman, it sounds like 9 times the battery weight of a Model S flying in the sky...

Wonder how they made it light enough to be able to fly...

https://www.eviation.co/alice/


>Wonder how they made it light enough to be able to fly...

You get a massive weight savings in the engines and all related components. DC motors are multiple times smaller and lighter than the equivalent powered turbine engine when you consider the entire system. On top of that you totally eliminate the need for variable pitch props and the related transmission parts since electric motors can adjust power instantly. You also negate a lot of hydraulic systems (and their redundant backups) without the need for things like fuel pumps, thrust reversers, etc.

It also seems they are not using anything like standard li-po tech. From their site:

>Utilizing industry-leading lithium-ion batteries and a proprietary Aluminum-Air system for range, we’ve surpassed the 400Wh/kg mark.

For reference this is nearly double Tesla's energy density. Of course the cells will be much more expensive, but that matters a lot less for a low volume, high usage application that can be amortized.


Slight quibble: you'd probably still want variable pitch props. Variable pitch props give you a lot of options for noise, speed, efficiency, etc that I wouldn't want to give up just because I have a different power plant. They're also extremely useful for engine-outs (you can feather them which reduces drag significantly) and for landing (you can reverse them which helps which reduces load on your brakes and lets you do questionable things if you need to get into a small strip.)

> DC motors are multiple times smaller and lighter than the equivalent powered turbine engine when you consider the entire system.

Airplanes this size can use cruise missile engines, which are very light. See the F-5 for more info (7:1 thrust to weight ratio.)

> On top of that you totally eliminate the need for variable pitch props

Why is that? Variable pitch props have nothing to do with engine type. They're variable to be more efficient depending on RPM and speed.

> You also negate a lot of hydraulic systems (and their redundant backups) without the need for things like fuel pumps, thrust reversers,

Not really. A lot of flight controls are boosted with hydraulics, and thrust reversers are for increasing drag (descending faster or slowing down.) None of these depend on engine type.

The real issue with electric planes is that they're a fire hazard. Already people have been killed when their electric plane's battery caught fire mid-air:

https://www.flyingmag.com/two-people-killed-in-first-crash-e...

The JAL 787 battery fire was a near-tragedy and resulted in interruption of service to SJC for 2 months:

https://en.wikipedia.org/wiki/Boeing_787_Dreamliner_battery_...

I find the most erroneous posts on HN to be about airplanes and databases.


>Why is that? Variable pitch props have nothing to do with engine type. They're variable to be more efficient depending on RPM and speed.

Variable pitch props have everything to do with engine type. They exist because turbine and piston engines have a very specific power/torque curve which requires them to operate at certain RPMs for certain conditions to achieve peak efficiency. With electric motors you have no need for this because you get a constant increase of efficiency across the entire power curve.

>Not really. A lot of flight controls are boosted with hydraulics, and thrust reversers are for increasing drag (descending faster or slowing down.) None of these depend on engine type.

Thrust reversers have nothing to do with descending faster or slowing down in flight, they are used solely for landing retardation. But an electric aircraft wouldn't even need thrust reversers. You literally just reverse the propeller immediately at full power when touching down. You can even save on less flaps required because the motors will be able to "windmill" on the descent and slow the aircraft as well as regen power.


Variable pitch props are useful for other design conditions. The prop RPM is typically limited to a speed that prevents the prop tip from reaching supersonic speeds, for noise certification. On fixed-pitch props at this fixed RPM, there's a tradeoff between climb and cruise performance, because these operate at two very different advance ratios. Constant-speed props allow the blade to adjust some of this difference.

There's also the engine-out design case, it's much easier to add prop feathering than add more power to the operating engines.

This design doesn't make a lot of sense, the props are located at literally the maximum arm from centerline, which requires bigger control surfaces for engine-out design (heavier and more drag) and gives very little ground clearance in crosswind landings. On the economics side, fuel costs are a small part of operating light turboprops/jets. The biggest costs are airplane depreciation/capital and crew. The real breakthrough would be an autonomous turbine plane that could eliminate crew cost and achieve 2000 hours/year utilization (versus ~200 for some privately-owned jets).


Your post exaggerates the danger from batteries. Tesla's billions of miles with fewer car fires than gas cars per mile driven is at the very least evidence that they are no more dangerous than conventional gas cars. The infamous boeing battery fire came about from poor design, and the battery wasn't used to run the engines. Tesla heats and cools their batteries and also tolerates batteries failing; boeing's design was a single large cell and did not tolerate failure, ie it was poorly designed.

Tesla has shown battery tech is a safe and reliable energy source. However, this doesn't mean there can be no problem - of course there can! Airplanes also have had many problems with catching on fire, crashing, burning in the air.


900KWH / (400WH/kg ) =2250kg > 2 ton for battery ?

That seem to be non trivial amount of weight.

I am curious how that compare to weight of typical fuel + engine for a small plane.


A pt6a runs 190-225kg dry. But I have no idea how much the combined weight of all engine systems, fuel, etc weigh together.

Also the fuel required to carry the remaining fuel goes down over the course of a gas powered flight, but obviously will not over the course of an electric flight. This would serve to further reduce the range. Curious too!

> 400Wh/kg [..] this is nearly double Tesla's energy density

Slight quibble: that's specific energy (ie, per mass). Density is per volume. (For airplanes, specific energy is the hugely important metric)


The airframe of airplanes is surprisingly lightweight. Engine(s) can easily be around 25% of the (empty) weight, and on anything with decent range, the fuel dominates. Both necessitates a lot of supporting infrastructure.

The airplane can probably pack battery cells much denser than Tesla. Tesla uses active, liquid-based cooling; an airplane could employ the airstream for that. Plus I expect a lot less of battery heating; while the capacity is 9x of Model 3, the engine power (thus electrical drain) is around just 3x of Model 3. [1] Also the metal shield under the battery can probably be done away with.

As others pointed out, electric engines are much different beast than any hydrocarbon burning ones. You need less support structure (for starters, less vibrations) and also much less auxiliary gear; think of all the cooling systems (either liquid cooling or flaps & openings & shrouds to direct air around); fuel tankage, pipes, valves, pumps & booster pumps; electric generator & possibly hydraulic pumps, and lots and lots of wires to both send electricity and control signals. As electric engines are essentially low-maintenance, you'd save a bunch of weight on monitoring instrumentation & servicing access panels. Maybe i'm reading too much into the renders, but the engine- and prop cowls seem to be very tight fit; both lessening drag and also simply being smaller, lighter parts.

Lastly, electric engines can typically be over-loaded way over their continuous power for well understood short stretches of time, facilitating extra power for prompt & safe take-off. Not so with piston or jet engines; the take-off power is typically maybe a dozen percent more than the rated continuous power, and that's about it. You end up carrying through the whole flight engines over-sized (and thus over-weight) just for the sake of take-off power.

Small weights savings all over the airframe add up.

--

[1] https://en.wikipedia.org/wiki/Tesla_Model_3#Specifications - 258 kW for Model 3 AWD, vs 3x260kW for the airplane.


That's an interesting statistic. According to Wikipedia, the Tesla's battery is around 500kg, so the aircraft is carrying around 4500kg in batteries. For comparison, the 10-seat Cessna 404 Titan weighs just 2200kg when empty and has a max take-off weight of 3800kg. So the battery alone weighs more than a similar Cessna, full of pax, luggage and fuel. Hm.

They list a MTOW of 6350 kg. Less 800kg for 10 fully clothed adults and the weight of the battery, there's only 1000kg left for the plane. Maybe that's possible?


About 3.8 tons they say for the battery. They're relying on removing some excess structure from the battery.

The thing is about 60% battery by take-off weight. That's not as crazy as it sounds. A 777 is about half fuel at max fuel load.


It burns that fuel as it flies though, reducing weight which is important for landing safely. The EV aircraft will weigh the same landing as taking off, which presents some complications.

...but those complications can be overcome. Partially because the airframe is so efficient that the landing speed should be tolerable even with a high landing mass.

Materials have improved significantly in the last few decades. There's a lot more possible now than in the past.


Good question. The Model 3 battery[1] weighs 478 kg so 9x = ~4,300kg. 11 people on board is another 1,000kg (not including the golf clubs). MTOW[2] is 6,350kg so the airframe needs to weigh in at ~1,000kg.

I'm sure they can make a battery lighter than a Model 3 battery (optimized for weight rather than cost), but how much lighter???

Unlike liquid fueled aircraft, you won't be able to trade off fuel weight for passenger weight to stay under MTOW.

[1] https://evannex.com/blogs/news/tesla-s-battery-pack-is-both-...

[2] https://en.wikipedia.org/wiki/Maximum_takeoff_weight


Excellent point. Often times only enough fuel for the route is taken so more payload can be taken. In a battery setup your max payload is always the same. No trade offs for range.

I would imagine that planes could have much higher battery cell per battery pack utilization, because the protective shell for the battery packs is less necessary.

Some back of the envelope math for the Model 3 battery: it has 4416 2170 cells, 66g each, is 291.5 kg, and the total battery pack weight is 478 kg. So only 60% of the battery pack weight is the actual battery cells.


The article makes it sound like it is made from commoditised components of today.

Given how similar it sounds to that of a Tesla Model S + SpaceX - Battery, Electric motor, propeller and such, Why wouldn't Tesla attempt such a thing based on components they already build for Tesla or SpaceX?


While on Joe Rogan's podcast Elon Musk did say he had the design for a VTOL electric plane that regained the energy used for lift on descent. I was a little bit more than intrigued by that.

Airplanes always get most of the energy from ascent back in descent.

VTOL will get less back because it's grossly inefficient.

Note that drag needs to be deducted from the potential energy. There's parasitic and induced drag.


> Airplanes always get most of the energy from ascent back in descent.

Given that the aeroplane ends up stopped on the tarmac at (approximately) sea level with (approximately) empty tanks, how so? A bit of heat I suppose but that's not usable. I'd say current aeroplanes generally deliberately dump energy to the environment (via deliberately increased drag, spoilers etc.) during descent, no?


They're not recharging batteries but they are extending range. The whole time they're descending, they're moving forward and overcoming air resistance, without needing as much fuel as if they were flying level the same distance and altitudes.

I think that compared to energy expenditure X in level flight at cruising altitude, the aircraft would expend X+Y in the climb and a little less than X-Y in the descent, assuming all horizontal distances are the same.

To the extent that they deliberately increase drag, that wouldn't hold true, but I'm guessing that's mostly on final approach.


His context was that the energy was returned to the battery, not in the laws-of-thermodynamics sense.

What, so he was serious in Iron Man 2?

Why doesn’t Tesla make flashlights too?

Tesla should focus on building cars first. They have enough supply chain issues that getting into the general aviation market would be spreading far too thin.

> But this isn’t another claim by another overoptimistic purveyor of electric dreams.

Really? So, it's built and demonstrated?

> the first planes are being built right now.

Oh, so when you say “Eviation’s Alice is an all-electric, nine-person aircraft” you mean “Eviation claims Alice will be an all-electric, nine-person aircraft” and when you say “this isn’t another claim by another overoptimistic purveyor of electric dreams” you mean “this probably is another claim by another overoptimistic purveyor of electric dreams.”


TFA claims electric planes are quieter, but I thought the majority of the noise from a turboprop was caused by the propeller. Does anyone have actual knowledge of the noise difference?

> and they receive power from a 900 kWh lithium ion battery pack.

Wow! One of the amazing things about EVs is how easy it makes it to reason about the energy usage. That’s about $250 in energy here in CA. I might produce a mW of energy with my solar panels on a good month here.

If it actually has a range of 650 miles then that comes out to be about 50c a mile, which would be quite amazing.


Zunum Aero is also working in this space.[1] Learned about them through a recent Breakthrough Institute talk.

[1] https://zunum.aero/ [2] https://www.youtube.com/watch?v=A1ioXfa_jpY


With the engines placed at the tip of the wings it must be next to impossible to operate with a single engine.

It has 3 engines, one is at the tail. While I agree in principle, I think having just one engine at the tip of the wing left running is going to be a rare event.

Aviation is all about remaining operational during rare events, though.

Single engine failure is a rare event that you have to be operational for. Certification generally requires you to be able to take off fully loaded with any one engine off (except single engine planes). If two engines fail you are allowed to turn the rest off and ditch wherever you are.

Remember airplanes have a fair amount of glide ability even with no engines. The airplane is coming down, but the pilot has a significant choice as to where and plenty of time to choose between alternatives and get there.


So, Al-air battery. While it may be not practical for a car (even just once in 2000 miles as those prototypes), refueling the plane by reloading with fresh aluminum would be just ok. My bet was on Li- or K-air, yet I'd take the Al one for starters.

Exciting - remember that battery tech is still in the early days, it will only get cheaper, more energy dense, and more reliable. If this company doesn't succeed, it will get better soon.

I do like the v-tail look. Not sure on the pros and cons of the approach, but it's my favorite tail style of aircraft (if one keeps track of such things)

Probably because it has a third propeller in the tail - not easy to spot in the article's photo, but you can see it better on their site[1].

[1] https://www.eviation.co/alice/


That rear propeller will be screwed by anything kicked up by the main gear. And good luck with rotation on take off, and landing flare.

Also, the adverse yaw if you lose one of the wingtip motors or propellers will be severe.


I agree with you about rotation. The main gear is so far forward of that prop that I'm actually wondering if this thing doesn't rotate, like the B-52. As for landing flare, those wings aren't holding any fuel so they are razor thin. I'm having a hard time deciding about when they stall.

But I don't see asymmetrical thrust as being a real problem on this plane. It has far fewer moving parts than the single- or dual- motor props that it aims to replace. This is not an ETOPS aircraft, and even if an outboard motor fails you still have that central pusher to help. Back to those razor-sharp wings: they are quite long and it looks like this plane would have a mighty fine glide ratio.


Photo? You mean CGI ...

Another aviation rendering... Not going to take it seriously until there's a flying prototype video.



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