> Because even those, substantially heavier than a balloon, would go off in random directions due to their susceptibility to wind from the low weight.
Just be sure to keep in mind that while zepperlins, dirigibles and aerostats are subjected to non-negligible amounts of buoyant force due to low density, that does not make them light, nor easy to push around.
If you carry 20kt of cargo, plus the weight of the vehicle (including the weight of the lifting gas), I don't think a wind gust would blow you away, regardless of how strong it is.
Try to push around a big buoy, that gives an idea of the challenge.
Moreover, spheres are one of the aerodynamically poorest shapes (if not the most), actually worse than a flat sail. That's probably the biggest reason for Zeppelin's shape (or the rugby ball, for that matter).
Just be sure to keep in mind that while zepperlins, dirigibles and aerostats are subjected to non-negligible amounts of buoyant force due to low density, that does not make them light, nor easy to push around.
If you carry 20kt of cargo, plus the weight of the vehicle (including the weight of the lifting gas), I don't think a wind gust would blow you away, regardless of how strong it is.
Try to push around a big buoy, that gives an idea of the challenge.
Moreover, spheres are one of the aerodynamically poorest shapes (if not the most), actually worse than a flat sail. That's probably the biggest reason for Zeppelin's shape (or the rugby ball, for that matter).