[DrSAR]

Yes. 12kWh/kg chemical energy for kerosene, a little more for avgas. But with a 25% efficiency you are only getting 3kWh out of a kg of fuel. Electric motors tend to have higher efficiency -- maybe up to 75% so you might nearly get 500Wh from a kg of battery.

[oblio]

Electric motors are over 85%, some reaching 95%, from what I remember.