Originally Posted by
Herod
Maybe von Zeppelin got it right. RIGID airships, not blimps. Solar panels across the top, power only required for propulsion. (standing by for flak)
Not wishing to attack, just exploring the limits of physical possibility.
Hindenburg: Wikipedia figures are 245m length, 41.2m diameter. The square box that encloses those dimensions has an area of 10,290 sq. m. Taking the NASA figure for insolation, far higher than airships flew, as 1,360 W gives a maximum available power of 13,994 kW.
Hindenburg had installed power rated at 4 x 890 kW: take a cruise power output of 2,500 kW. Taking into account all the gross rounding errors in that approximation, and a 25% efficiency of the solar panels, and ignoring the extra weight of the panels, it is just about within the limits of physical possibility in the brightest daylight. Which is a hell of a lot better than comparable calculations for aerodynes, but still adds a further dimension of marginality to a highly marginal mode of transport. Alas. I could really get behind the idea of travelling at a stately 150-200 kph in a solar powered airship, but I don't think it's going to happen.