"Kelly was now so desperate to save weight that he upped the ante to one hundred and fifty bucks to anyone who could save him a measly ten pounds. I suggested we inflate the Blackbird's tires with helium and give each pilot a preflight enema. Kelly tried the helium idea, but helium bled right through the tires. The enema idea he left to me to try to promote among the pilots."

   -- "Skunk Works" by Ben Rich

30 minute flight time, not 15. Should have approximately 86 mile range with this one.

There's plenty of room for passengers in this concept. Where are you getting this false information?

See: https://www.skiesmag.com/news/harbour-air-makes-history-with...

From the article:

> What certainly hasn’t been done before is to fill a Beaver’s cabin with lithium-ion batteries, taking the plane to its gross weight. As a technology demonstrator, this eBeaver isn’t carrying passengers — there isn’t room — and will only have a 15-minute endurance with a 25-minute reserve.

Sorry, you seem to be quoting a bit selectively. From the same article:

> These are batteries that NASA is using, but they’re not batteries that we’d use if we were going to try and make it economical to fly today, because they’re very low in watt-hours per kilogram

On the other hand, it's not like NASA was trying to get the lowest energy density possible. They were trying to get a li-ion battery pack with acceptable safety margin. And for this I understand one of the biggest factors is to have sufficient space between cells that a thermal runaway in one cell cannot spread.

Imagine the headaches when the airport tells these guys to hover for a while wile delays clear out. This is a niche product, albeit a cool one.

It's a seaplane, it lands on the water, not an airport. Additionally, the total flight time including reserve is 40 minutes in this prototype and will be at least 60 minutes on the operational one (with Tesla-like-energy-density batteries).

It seems to me that they have two somewhat separate engineering challenges. The electric motor and throttle control system, all the drive train stuff forward of the instrument panel in a Beaver. Plus however they retrofitted the cockpit engine control. Which might be quite a bit lighter than a pt6 turbine retrofit to turn an old Beaver into a turbo Beaver.

And then the other much harder problem which is achieving sufficient Wh per kg energy density in batteries, and Wh per litre of volume. For which they are dependent on global factors for r&d of batteries and improvement in density.

Do you have a source? (Not trying to be snarky but seriously interested. Haven't seen any technical details anywhere...)