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Comment by FabHK | Hacker News Reader

They claim 4 hours endurance, which would give it nearly 400 NM range. Not bad, if it works. The 4 seater can carry 800 lbs. Wonder how long charging takes.

https://en.wikipedia.org/wiki/Bye_Aerospace_Sun_Flyer_4

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For carrying scheduled air passengers, you need to fly IFR. You need to have fuel to fly to destination airport, then to reserve airport, and then 45 minutes. No sane pilot flies with that little reserve. Most airlines have enough for destination, reserve, and 90-120 minutes. With that safety margin, this thing has a "useful" range of maybe 150 nautical miles

For floatplanes, you can nix some of those requirements.

However it's a four-seater that has substantially more landing options than a 747.

This is not scheduled, but Air Taxi, which I believe is a different part of the FAR. And, yes, for small planes, there are plenty of alternate airports. I'd say 200 NM or more are realistic.

Looks good. They seem to be pretty cheap, and with a low operating cost, would be quite appealing even for private fliers. A rental service for these would be amazing. Plenty of people would rent it out for fun, unique day trips that would hopefully only be a couple times more expensive than a car, albeit with stricter licensing requirements.

FWIW, you can rent a Cessna 172 for less than $200 per hour, and take it in a trip where you agree to fly at least say one or two hours per day, depending on location and season etc.

So, that’s only a few times more expensive than a car, and quite a bit more fun.

In practice, 4 hours of endurance give you around 2.5 to 3 hours of actual flight. You must plan for an alternate and with Reserve fuel. And you might not get all the clearances you expect.

Charging will take in any case much longer than refueling.

Long charging times are only an issue if the batteries aren't removable. An electric plane with two sets of batteries on each end of its route can pretty much fly non-stop.

This removing batteries thing comes up a lot on HN. People seem obsessed with it and are coming up with all sorts of theories as to how this is absolutely essential. It's not a thing for cars. It's not going to be a thing for planes.

With rapid charging infrastructure, you can top batteries up in 30-45 minutes to about 80%. That's for a high end car. Probably it could be done faster with specialized equipment. Typically, you don't drain the battery to 0% and you don't charge to more than 80% unless you are planning to fly to the maximum range. Finally, charging times are non linear and it slows down the further you charge a battery.

Also, people forget that airlines are on the ground quite long in between flights. Offloading and on-boarding passengers takes quite a bit of time. Programming the flight computers is quite fiddly. Running down checklists with dozens of items takes a lot of time. Waiting for engines to spin up and get to the right temperature, etc. 30-40 minutes is quite common.

Plenty of time to top up some batteries. And waiting a bit longer for some cheap electricity is probably well worth the tonnes (literally) of fuel you are not going to be burning.

That's right - the "non-stop" part is usually an hour at the terminal at least between landing and next takeoff. It's still a non-trivial amount of energy (the total expenditure of the flight) to be loaded into the battery. For the kind of range we are talking these days, that's more or less the same average rate the battery gets discharged during flight.

Swapping batteries would make more sense if we get to the point a full charge could allow a passenger plane to fly for many hours and charge speed would be limited by the total amount of power a terminal full of recharging planes would be requiring.

It depends. A lot of flights are around or below an hour and these include some of the busiest routes in the world. E.g. London - Dublin, all domestic flights in the UK, Germany, France, Spain, and other European countries and quite a few flights between those countries. Same for states in the US.

The Eviation Alice has a maximum range of around 600 miles. That's only a nine seater but it is going to be very disruptive in servicing anything between 100-400 miles. This kind of range you could take off with 80% charge and land with enough left for legal requirements and then top up back to 80% in about 45 minutes and maybe charge it to 100% overnight. That sounds like the sweetspot for this type of plane. It would likely be cheap enough to compete with e.g. cars on that distance and be way faster and possibly even be price competitive or close enough to make it interesting as an alternative to driving (at least from a cost perspective).

The Bye planes make more sense for smaller distances; perhaps as an air taxi in metropolitan areas. I don't think they are designed for longer distance commercial usage. Though obviously this is fine for GA type recreational flying. If you are flying those kind of routes commercially, you'd want to be able to do several flights between charging.

Over time, battery capacity, charging times, and ranges will improve. Also electricity cost is likely to benefit from on/near airport solar/wind as more planes are going to be flying electrical.

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