Electric Aircraft - The Thread

[riggerrob 139]

Good point dear sundevil,

Locking into any single technology too early limits investment into other forms of energy.

As an aside, I was reading up on nuclear power when I came across a graph that showed that countries that invested heavily in atomic power generating plants tended to invest less in other forms: solar, wind, tide, hydro-electric, fuel cells, bio-diesel, etc.

It is too early to say which is the "best" new energy source and it may end up that "A" is "best" for equatorial deserts, but totally useless in the Arctic. "B" might be "best" in mountains, but totally useless on plains, etc. In the long run, we will end up with 3 or 4 "best" systems, depending upon local circumstances.

I still believe that battery-powered airplanes will dominate short-haul routes: commuter, crop-dusting, banner-towing, initial flight training, glider-towing and skydiving.

[Divalent 5]

So I ran across this interesting article about the electric aviation industry. More of a survey of the companies and products that are underdevelopment, but not a lot about the technical details. Still ...

https://qz.com/1943592/electric-airplanes-are-getting-close-to-a-commercial-breakthrough

 

[BMAC615 3]

This is an interesting topic that I’ve been following for a long time - in 1987, at age 12, I converted my liquid fuel R/C airplane to electric and around that same time, I converted my gasoline lawn mower engine powered go cart to electric. I’m also an early adopter of the Tesla Model S and am on my 2nd one, so, I have some experience with electric vehicles. I’m very excited about the potential of Magnix’s electric 208B conversion revolutionizing the skydiving industry.

With that in mind, I haven’t read this entire thread, but, I do know there are a few things to know about BE aircraft: Charging from 0-50% happens very quickly compared to 50-90% and the last 10% takes forever. There are ways to charge a very large amount of battery storage very, very quickly compared to the way EV cars are currently charge with one cable - by compartmentalizing the pack and charging with 2, 4 or 6 cables/power sources for example. So, you could charge to full over night, fly until the battery is down to 10%, shut down to charge to 50% and just fly between 10 and 50%. How long that would take will be difficult to determine. I also know fast charging the packs puts a lot of stress on them and accelerates degradation. You’ll typically lose about 3-5% capacity soon after delivery and will eventually get to 10-15% capacity loss. As battery technology advances, expect these numbers to improve, but, not by much.

The main hurdle I see is that high power demand during climb to altitude is exponentially more kWh consuming than level flight. So, whatever numbers they are putting out for testing, they will be far, far worse. Right now, the eCaravan configuration is just putting batteries in the passenger area and that allows it to fly for 30 minutes of level flight - No where near required capacity for skydiving operations. Also, as the transition to BEV for terrestrial transportation unfolds, the demand for battery materials will be limited as the control of resources for battery production is already being locked up.

I’m much more keen on the idea of hydrogen powered fuel cells for aviation and the obvious advantages behind it. ZeroAvia recently demonstrated full flight in a Piper M-Class and Airbus is working on several fuel cell designs. Magnix is also working with Universal Hydrogen on a Dash-8 conversion in a very exciting way!

Hydrogen fuel cell conversions could be much more cost effective than conventional power plant replacement/overhaul. I could see a 208B using a compartmentalized liquid hydrogen storage tank in a belly storage configuration where the fuel would be loaded as cartridges with a forklift.

https://www.ainonline.com/aviation-news/air-transport/2020-09-18/conversion-plan-set-promote-early-switch-hydrogen-fuel

Now, all the cost advantages of switching is dependent upon conventional aviation fuel costs remaining high. I believe as the transition to BEV for terrestrial transportation and a general transition away from petroleum based plastics to plant based plastics occurs, the cost of aviation fuel will drop as demand for petroleum based products drop. Aviation will be the last to transition to alternative fuels and the remaining supply of refined oil will become incredibly cheap as the long tail of supply plays out.

Skydiving operations’ short flight requirements may turn out to be a perfect test bed for development of BEA (battery electric aviation) and FCA (fuel cell aviation) applications.

Edited December 26, 2020 by BMAC615

[Divalent 5]

Another article that gives more specific details on the Ampaire hybrid version of the Cessna Skymaster (named the Electric EEL), which has two engines in a front-and-back orientation (push-pull). The front engine has been replaced with an electric, so it is configured with a 300 hp piston in the back, and a ~200 hp electric in front.

Mokulele Airlines is current doing a month long series of trial flights on a 20 min route between two airports on Maui. Apparently it does the whole round trip (40 min) set on just one electric charge. Should provide good data on reliability and performance under simulated real route use.

https://www.flyingmag.com/story/aircraft/ampaire-hybrid-electric-trials-begin/

Here's the Wikipedia page for the Electric EEL:
https://en.wikipedia.org/wiki/Ampaire_Electric_EEL
 

Edited December 26, 2020 by Divalent