A slight design change 6

[Sparweb]

Meet Alice. She's had a facelift and a new wardrobe. I guess she needed to look pretty for her date with DHL.

2018:

2021:

 

[RoarkS]

Software is going to monitor current input and output from charge storage systems largely based on service history. The software itself will be certified... the actual hardware is disposable. It will determine range, while monitoring available alternates realtime. Basically the aircraft ETOPS self certifies continuously. EOPS.

 

[rb1957]

"certifies" ? surely the range calculation (s/ware) is certified. Possibly the s/ware continuously updates ? I'd still be worried by the amount of charge I can extract from the battery ... even if they run 100s of scenarios.

another day in paradise, or is paradise one day closer ?

 

[WKTaylor]

'Alice' Update...

Eviation readies for Alice maiden sortie as ground tests wrap up

Eviation is gearing up for the first flight of its all-electric Alice prototype in the coming months having completed ground testing earlier in May.
However, the clean-sheet aircraft developer is staying tight-lipped on precisely when the proof-of-concept Alice prototype will take to the skies, simply saying the milestone will occur “this summer”.
... ...

https://www.flightglobal.com/ebace-...sortie-as-ground-tests-wrap-up/148798.article

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[WKTaylor]

Eviation’s Alice completes high-speed taxi test, ‘final’ step before flight

https://www.flightglobal.com/airfra...-test-final-step-before-flight/150248.article

Is the new ALICE FINALLY ready for flight???


Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[Sparweb]

Yes, they did it:

Eviation’s all-electric Alice aircraft makes maiden flight

https://www.youtube.com/watch?v=qjPO4_oe5h8

 

[btrueblood]

Long article in yesterday's Seattle Times. They apparently have no intention of getting FAA cert. for this aircraft. The (new) CEO says they need better batteries, which apparently are several years away, to make a viable passenger carrying version...

https://www.seattletimes.com/busine...electric-airplane-takes-flight-at-moses-lake/

 

[3DDave]

Better batteries? They need better batteries? This is my shocked face.

 

[WKTaylor]

Noble mission statement.
New/unique configuration airframe.
Composite materials.
All digital flight controls/systems.
Electrical propulsion by 100% battery power.
Extended [possibly indefinite] experimental-development/test/design/build time.

I can't shake off the feeling this looks-like 'death by a thousand cuts'.




Regards, Wil Taylor
o Trust - But Verify!
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation, Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", HBA forum]
o Only fools and charlatans know everything and understand everything." -Anton Chekhov

 

[rb1957]

so whilst Eviation says "just kidding about certifying these things", then there's this in Flight ...

"French start-up Aura Aero has disclosed 130 tentative agreements for its hybrid 19-seat Electric Regional Aircraft (ERA)."

I think Business aviation is where this market should start. Current batteries can give you reasonable range, just low payload and low cycle count (if you have to recharge batteries in situ).

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[3DDave]

Elsewhere it is mentioned there is a Seattle electric float plane that has been flying for some time.

https://harbourair.com/harbour-air-...t-certified-all-electric-commercial-airplane/

 

[rb1957]

yes, a beaver (DHC2) ... maybe restricted or experimental category ?

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[rb1957]

in Dec '19 ...
"magniX and Harbour Air will now begin the certification and approval process for the propulsion system and the retrofitting of aircraft. Once the certification is complete, the rest of the fleet can be magnified with magniX’s all-electric propulsion technology."

since then, cricket noises ?
correction, in August '22 ...
"The Harbour Air ePlane team is excited to announce that the first direct all-electric point to point test flight has been completed. The historic De Havilland Beaver has been completely retrofitted in 2019 to operate using 100% electricity flew 45 miles in 24 minutes. The aircraft left their terminal on the Fraser River adjacent to YVR and landed in Pat Bay adjacent to YYJ. This is a major milestone in the advancement of all-electric commercial flights."

so not certified yet ? I wonder what the TC STC database has to say ?
still 45 miles is pretty good ... covering a narrow water channel.

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[Sparweb]

Elsewhere it is mentioned there is a Seattle electric float plane that has been flying for some time.

Harbour Air is based in Victoria, BC. The article meant that it can travel from Victoria to Seattle, not that HA is based there.

since then, cricket noises ?

Gee RB, have you not been involved in a STC project that went on for more than 4 years before?

This also shouldn't come as a surprise, but the FAA and Transport Canada still have their knickers all in knots about lithium batteries. They have had various groups inside and outside their ranks arguing for a decade on how to deal with this technology. There is still no consensus and no sign of a resolution either.

 

[3DDave]

I don't see a great solution for batteries - they are basically mixing fuel and oxidizer in one container. If there's a glitch there is only thermal inertia and speed of reaction that slows it from exploding, though when confined they can rupture explosively. The ideal battery should have the same performance as a bomb - able to release all the energy instantly.

They need to build a more ideal battery which becomes closer to being a bomb.

 

[Sparweb]

No no, scientists are working toward a battery that can be charged faster and to release its charge at a higher rate.
Oh, wait... hmmm...

 

[rb1957]

"though when confined they can rupture explosively." ... last time I checked gas tanks could do the same thing.

yes, we're developing a new technology which will be painful.

A fundamental decision is where to put the batteries. Yes, I know a million decisions to trade-off; but this is IMO a primary reason why retrofitting is "doomed" ... without batteries in the wings you're limited to MZFW as MTOW (unless you're smart enough to use a DHC6 ... fuel in the fuselage). Batteries in the wing will be an utter pain to design, batteries in the fuselage are much easier, and allow for "quick change" paks (rather than charging in situ) to improve turn-around.

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[Lou Scannon]

"though when confined they can rupture explosively." ... last time I checked gas tanks could do the same thing.

I wouldn't say "the same thing". Excepting things like solid fuel rockets, typical fuel tanks for combustion engines do not have the oxidizer inside (as was well pointed out by 3DDave). So, Hollywood special effects aside, fuel (without oxidizer) tanks do not explode like a bomb. In fact, the tank designers typically take care to have a fuel tank that is subjected to crash and fire situations, vent or rupture in a controlled manner so as to limit the rate of chemical energy release to the outside environment.

"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz

 

[Macm_020171]

These electric aircraft programs are facing lots of engineering challenges. Especially with the battery integration. I wish all the success to the companies that are pushing the envelope so we can have cleaner skies. Batteries can experience thermal runaway, releasing hot gasses and fire, releasing high temperatures inside and outside the airframe, so especial consideration needs to be considered, due to thermal expansion for dissimilar materials (thermal stresses), material strength at high temperatures. Specific provisions are required to release the heat and fire in a safe fashion. I witnessed a thermal runaway test at an EVTOL manufacturer facility, it was a scary thing to watch.

I wonder where the batteries are installed in the Alice aircraft. Wings look very thin profile, and the cabin is extended, probably in the AFT fuselage. wonder how many batteries is Alice carrying to complete its mission.

 

[Sparweb]

Macm,
Answer to your question was in the Seattle Times article, linked by Btrueblood on 30 Sept, above.

 

[rb1957]

from Seattle Times article (yeah, I know you need the Coles notes ... TLDR ...

"It’s powered by just over 21,500 small Tesla-style battery cells that, at just over 4 tons, make up fully half the weight of the carbon composite airframe.
...
“Are the batteries on the prototype aircraft capable of propelling the certification aircraft, capable of providing sufficient energy? The answer is no, absolutely not,” Davis said.

but tellingly ...
"In an interview in February, Davis had spoken of pushing hard to certify a production model of the airplane for passenger service in 2024." But 6 months later ..."On Monday, he said that goal is probably five years away."

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.