Go Back  PPRuNe Forums > Flight Deck Forums > Accidents and Close Calls
Reload this Page >

Electric plane prototype caught fire

Accidents and Close Calls Discussion on accidents, close calls, and other unplanned aviation events, so we can learn from them, and be better pilots ourselves.

Electric plane prototype caught fire

Old 28th Jan 2020, 10:17
  #21 (permalink)  
Moderator
 
Join Date: Feb 2000
Location: UK
Posts: 14,202
Received 46 Likes on 24 Posts
I suspect that anybody who genuinely knows detail about the cause of the accident isn't putting that knowledge in the public domain this quickly.

But, generically the major issue with Lithium battery fire risk is thermal runaway, cause by some problem of battery thermal management. That can be poor storage, physical damage, incorrect charging cycles - there are plenty of opportunities. The phone industry are reasonably mature in their understanding of that, but with the best will in the world, you can't instantly map knowledge applicable to a $10 phone battery to a $200k aeroplane battery array. There will be more accidents like this, hopefully with similar limitations to only property damage and not loss of life, as our communities develop this knowledge.

Onboard lithium fires in carry on devices, incidentally, are recommended (on the back of quite a lot of research by FAA in particular) to be handled with lots of water - so the use of large quantities of water and foam in this case, would seem entirely consistent. Other firefighting compounds are less likely to cool effectively, and the combustion process does not require external oxygen, so simply excluding air doesn't get you very far.

Most expert commentators have considered the various media releases by Eviation about progress on the Alice to be basically exaggeration and hyperbole. It will be interesting to see how those modify in the light of this.
Genghis the Engineer is offline  
Old 28th Jan 2020, 11:05
  #22 (permalink)  
 
Join Date: Jan 2008
Location: Reading, UK
Posts: 15,789
Received 196 Likes on 90 Posts
Was the fire in a hangar?
DaveReidUK is offline  
Old 28th Jan 2020, 15:55
  #23 (permalink)  
 
Join Date: Jul 2008
Location: Only occasionally above FL50
Age: 71
Posts: 209
Likes: 0
Received 5 Likes on 4 Posts
I reckon the 16l of petrol carried in my self sustaining (turbo) glider would give me a total of about 20,000 feet of climb. From what I hear, electric self launchers would do about 4000’ at best. In practice they usually use another form of launching to preserve their battery for getting home when the lift runs out. At low power they will fly a fair distance - certainly enough to get to a landable field, and usually enough to get home. Electric passenger transport is a very different matter!
Andrewgr2 is online now  
Old 28th Jan 2020, 22:36
  #24 (permalink)  
Moderator
 
Join Date: Feb 2000
Location: UK
Posts: 14,202
Received 46 Likes on 24 Posts
There are photographs and video online which appear to show the fire to be consuming the aeroplane, which is in the middle of an open hard area.
Genghis the Engineer is offline  
Old 30th Jan 2020, 18:53
  #25 (permalink)  
 
Join Date: Jan 2017
Location: Warwick
Posts: 197
Likes: 0
Received 0 Likes on 0 Posts
The 25% efficiency of a 2 stroke self launcher or sustainer is very optimistic, the current crop of jet sustainers are outrageously thirsty.
Agree about electric aviation in general, maybe small recreational or training types, not passenger carrying.
Deltasierra010 is offline  
Old 8th Mar 2021, 23:34
  #26 (permalink)  
 
Join Date: Apr 2010
Location: Montréal
Posts: 72
Received 5 Likes on 5 Posts
Originally Posted by unmanned_droid
Nope, not really. That's the entire electric propulsion problem in a nutshell.
Battery vs petrol tank is at 1 to 10 disavantadge, but given that the electric motor is so much lighter than the gas engine, this brings the disavantadge of the current electric propulsion down to around 1 to 5. That's why an electrified aircraft has usually 1/5 the range (or climbing potential) of the petrol-powered version. Still useful in some applications like training or very short-haul transportation.
OTOH, the King-Air-like Eviation specs sound very optimistic at best. These 260 Wh/kg batteries still are in the "experimental" class of performance, and they need to stuff them in a 1600 kg airframe, motors and 11 seats included.
Petit-Lion is offline  
Old 9th Mar 2021, 13:28
  #27 (permalink)  
 
Join Date: Dec 2017
Location: Yakima
Posts: 573
Received 159 Likes on 66 Posts
And there's not just that to consider; the plane weights the same coming down as it did going up......
Winemaker is offline  
Old 26th Mar 2021, 00:55
  #28 (permalink)  
 
Join Date: Mar 2021
Location: Florida
Posts: 28
Likes: 0
Received 0 Likes on 0 Posts
Maybe Tesla has some ideas for resolving this problem. Oh, never mind...


Batteries running a little warm today


Last edited by jeepjeep; 4th Apr 2021 at 04:54.
jeepjeep is offline  
Old 26th Mar 2021, 17:18
  #29 (permalink)  
 
Join Date: Nov 2005
Location: UK
Age: 77
Posts: 249
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by Winemaker
MCR01

I'm curious. 22 liters of petrol is about 16.5 kg providing about 45 MJ/kg, so about 740 MJ total energy. Assuming 25% efficiency of a piston engine, that's about 185 MJ of available energy. Lithium batteries (middle range) energy density is 0.6 MJ/kg. So, assuming 100% efficiency of the electric side, that means that to equal the energy of the petrol, one would need a battery pack weighting 185 kg. How could this possibly work? Have I made a maths error?
Very true but you have to consider the complete package of IC engine and fuel source so even if the battery is heavy the motor is lighter, example 300hp motor 15kg but it does rotate at 20,000 rpm so needs a gear box. But you are correct at the moment batteries are to low in power density, the break point seems to be 500W/h/Kg still heavy but feasible, once they hit 2.5Kwh/Kg then IC engines are totally finished this will happen.
horizon flyer is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.