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 (pretty apparent from the "design").
Having recently watched several engineering videos on the limitations for electric flight I was surprised to see this article. As your comment points out, it certainly appears too good to be true.
Yeah, I see this kind of thing repeated any time Eviation comes up.
I don't believe them. The design is sound, if radical in the decision to be mostly-battery. And I think that's partly why people are so skeptical: it definitely goes counter to the industry grain. But it IS the right way to build a serious electric aircraft for regional/commuter passenger travel. Pressurized, extremely high lift-to-drag ratio, very high battery mass fraction, focus on high propulsive efficiency by ingesting boundary layer with the pusher propeller and countering wing-tip vortices with wing-tip propeller. The passenger count is also right, at the limit of FAR-23, allowing you to use a single pilot.
The only thing I would do differently is probably have a higher cruise altitude and higher aspect ratio wings (and probably counter-rotating dual-motor pusher propellers) instead of using wing-tip propellers and gettin, but theirs is a valid design choice as well.
So much group-think especially with the larger aerospace companies. They insist on hybrids for flight (notice how whenever Airbus or Boeing buy one of these exciting electric flight startups, they all of a sudden switch to hybrid?), which ends up compromising the design and adding a whole new propulsion system to validate and certify. Others have a valid approach of retrofitting electric onto older airframes, but that is not going to get anywhere near the operational efficiencies of a clean-sheet design. And still others insist on VTOL, but I have my doubts as to whether the focus on VTOL by so many of these electric flight startups is going to really be worth it in the end except for niche cases.
The design is "sound" ? It is ridiculous! Those engines are at each end of a wing. That is a 100% no no. They are feet from the ground, and would make one engine out operation impossible. Even someone with a cursory understanding of aerodynamic could see this is a ridiculous design.
The key is that the Alice aircraft is capable of take-off with just the rear propeller. That's possible because electric motors (unlike jet engines) can operate at much higher power for short periods of time. It was addressed recently at the Paris airshow Q&A for Eviation. If a wingtip motor (not engine) fails, the other side is designed to immediately stop (electric motors such as these respond immediately to input) and flight continues with the remaining tail motor.
Additionally, electric motors are fundamentally more reliable than jet engines.
Compare the number of propellers on NASA’s version. They have serious backup in the event any single engine fails.
Being able to take off with one engine that’s rapidly overheating, does not mean is safe to continue a flight with a single engine. Electric aircraft don’t get lighter in flight because they don’t burn fuel.
It’s possible that that could be the case, but it’s a poor assumption that it will be the case. Especially as it’s such a useful feature they likely would have mentioned it.
1. Rear prop strikes.
2. Wing tip prop strikes.
3. Wing tip inertia
4. Prop wash over a wing is a good thing
If (big if) this thing ever flies, it won't be in this form
Prop wash over a wing is good if you're lift-starved at take-off (which you aren't with this design). But otherwise it actually increases drag. Pusher configuration is superior in that you can ingest boundary layer air which has been slowed down by the fuselage and get an increase in efficiency. That efficiency gain is partially why pushers are often used in long-duration drones.
I had the impression that pushers were typically less efficient than pullers.
A puller takes advantage of the volume behind the prop taken up by the body of the aircraft to offset the loss of air volume caused by accelerating the air (Bernoulli's theorem). A pusher can't do that.
The opposite is true. The accelerated airflow over the body of the aircraft actually increases the drag whereas a pusher ingests the boundary layer from the fuselage and the suction also helps keep flow attached. The problem, however, is that turbine engines need a smooth airflow in order to operate efficiently, therefore they aren't suited for pushers as the wings (etc) produce an uneven airflow into the turbine core.
>Those engines are at each end of a wing. That is a 100% no no.
I assume they are at the end of the wings on purpose to deliberately interact with the wingtip vortices. The back prop is power, those wingtips are for drag reduction.
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 (pretty apparent from the "design").