Reply To: General thought on old coal mines.

[Breakable]

zapkitty wrote: Walking before running…. let’s start with known electrically-powered aircraft and see what they can do with the limited resources available pre-fusion…

http://en.wikipedia.org/wiki/Electric_aircraft

… yes, the FF is much heavier than any other power source currently flying… but the power level is amazing for an electric aircraft and the range, of course, is unlimited…

… then begin looking not at “jet engine substitutes” but at industrial air-moving products that operate in the multi-megawatt range we need for FF-powered flight. These industrial units won’t be designed flightweight but that’s just engineering 🙂 and the figures you get will make sense…

The important part is not weight, but weight divided by power output.
The solar aircraft (Centurion) weight is 862 kg,
power output 31 kw.
If FF output is 5 MW
then the weight of aircraft it should carry with similar limitations is about 139 tons.
Comparably 747 is 442 tons
Where Cesna is 0.658 ton
so basically something in between should work on the lighter side if we want more speed.