-2

In our society, the majority of the aircraft are powered by fuel. Recently, electric aircraft using electric batteries have begun to appear.

However, the range of these aircraft are limited by the amount of energy in its batteries.

So the question has to be asked; can't we just add larger batteries for extra energy? I understand that large batteries increases the weight of the aircraft, but certainly the energy provided can generate lift far greater than the weight added by the size enlargement, right?

Some articles regarding the battery issue:

https://theconversation.com/climate-explained-why-dont-we-have-electric-aircraft-123910 https://sbi.sydney.edu.au/why-dont-we-have-electric-aircraft/

Ralph J
  • 51,356
  • 17
  • 157
  • 249
Super
  • 1,283
  • 1
  • 13
  • 28
  • Both answers are good and very similar to the other "why don't we have electric commercial airliners yet" questions. This is definitely a dupe, just don't have time to find it right now. – FreeMan May 21 '20 at 17:31
  • "...but certainly the energy provided can generate lift far greater than the weight added by the size enlargement, right?" Wrong! – jamesqf May 21 '20 at 17:41
  • 5
    Gosh, just add bigger and more batteries. Why didn’t the engineers think of that?! – Michael Hall May 21 '20 at 18:17
  • I don't quite understand the downvotes... – Super May 21 '20 at 19:19
  • @jamesqf It's not wrong at all. It's only ignoring the more interesting question that is: "for how long?" – bogl May 21 '20 at 19:50
  • "Ok, so we dig an escape tunnel, but where are we going to hide the excavated earth?"...."Easy, we dig another tunnel and bury it". – Martin James May 24 '20 at 06:20
  • 3
    Please do not vandalize your question by deleting the text. Under certain conditions, you can delete your own question, but realize that those who responded put time into writing answers for you (and in this case, I don't think the question can be deleted now). Please be respectful of their work by not removing the question to which they responded. It's closed, but still visible, and can be found in searches to help point those with a similar question to the best answers. – Ralph J Sep 14 '20 at 02:04

1 Answers1

2

Jet fuel is around 43 MJ/kg while battery is 0.9MJ/kg

Fossil fuel airplanes is already taking off with 1/3 total weight being fuel 1/3 weight being payload (B737-300, 62t MTOW, 18t fuel, 16t payload). On long trips fuel weight goes up to about half MTOW, so you are facing some choices:

  1. Same MTOW and payload weight, electric have about 4% of the range of fossil fuel (electricity is 1/50 as energy-dense but 2x efficient).
  2. Same MTOW, no payload, electric have 8%-12% of the range.

And point 2 answers your question: no, power doesn't solve your weight issue. Even an airliner fully loaded with batteries to MTOW doesn't fly more than 500 miles. But in practice even loading a B737 with batteries is too expensive to even build a demo.

user3528438
  • 2,910
  • 1
  • 18
  • 16
  • But even with commercial planes, the weight of the fuel doesn't STAY at 1/3 to 1/2 the takeoff weight, but declines throughout the flight. Batteries always weigh the same. – jamesqf Sep 14 '20 at 18:16
  • Yes, @jamesqf. Until we find a way to jettison the electrons right off the plane after they have done their work having moved from one battery pole through the engine and then back to the other pole. I mean, such an electron is quite heavy, ain't it? And there's a whole flock of them. ;-) – PerlDuck Sep 15 '20 at 06:19