Considering the thermal efficiency of a modern jet engine, the usable energy compared to a lithium battery will be ~15 higher per kg, still bad, but not as bad.
Considering the thermal efficiency of a modern jet engine, the usable energy compared to a lithium battery will be ~15 higher per kg, still bad, but not as bad.
Also some napkin math using common examples gives a range of 0.2 - 1.2 horsepower / kg for gasonline motors, and 8 - 21 horsepower / kg for electric. So even though the batteries weigh more, the motors weigh less.
Doesn't it compound since it costs fuel to carry fuel in a flying machine?
I'm not sure about math but isn't it like 1/15th Isp, even with that maximally optimistic value?