Hydrogen Zeppelin / balloon
Density:
0.08988 g/L H2
1.2250 g/L air
Lift: 1.13512 kg / m3
Volume to lift 250 kg -> 220.4 m3
220 m3:
6 m diameter tube -> 7.8 m long
4.5 m diameter tube -> 13.9 m long
6.1 m cube
7.6 m sphere
Volume to lift 150 kg -> 132 m3
Wing with 1 m2 cross-section x 132 m long
Wing with 2 m2 cross-section x 66 m long