[chrisseaton]

These batteries don't get lighter as they fly though do they?

I heard that airliners can't land with a full load of fuel and they have to dump it to land in an emergency. I wonder if that means you can't even replace max fuel weight with the same battery weight because then it'd be permanently too heavy to land.

I wonder if airliners could drop exhausted battery packs by parachute over designated DZs as they fly across the continent or ocean?

[greedo]

Not all airliners can dump fuel. Some have to burn it off to get under maximum landing weight, or just risk land over the prescribed MLW.

[icebraining]

These batteries don't get lighter as they fly though do they?

Technically they do - the battery of a Chevy Volt loses half a microgram from full to empty :)

https://physics.stackexchange.com/a/34424/6210

[chrisseaton]

That’s obviously not going to be significant at all and clearly not what I meant.

[icebraining]

Hence the "technically" and the smiley :)

[ksrm]

hacker news dot com

[gjem97]

>I heard that airliners can't land with a full load of fuel and they have to dump it to land in an emergency

I think the main reason they do that is that way there's less stuff to burn if there's a fire or explosion.

[jingleheimer]

No the main reason is with equal weight it is way harder on the airframe to land than take off.

Electric airplanes are small so it's not as a big of a deal, but it will limit their ability to scale.

[dredmorbius]

Jettisonable batteries (or lift magazines of battery + motor) are one design that's been explored. Take-off and initial climb is a major fuel-demand flight phase.