Biological Blimps: Propulsion

A while back, I asked this question about the plausibility of giant floating whales and received an excellent and high-scoring answer from Dubukay demonstrating that, given the assumptions that Dubakay made, the idea was unfeasible. However, more recently I discovered some flawed assumption in the answer and wrote my own answer, demonstrating that, if we assumed a more reasonable gasbag skin thickness than Dubukay had, the idea became much more plausible. In my answer, I calculated that a creature with a mass of 500 kg (not counting the mass of the hydrogen) needed just over 400 kg for its gasbag. This leaves us with 100 kg for everything else.

Now, this flying gasbag will have to do more than just float around to survive. To find food, it will probably have to have some way to move around in the air. Blimps typically use propellers to do this, but propellers are unlikely to be viable for a biological creature for a variety of reasons. Aquatic creatures typically use some kind of flipper to move through the water, but because of the low density of air, the flippers would probably have to be impractically large. So the question is, what would be the best propulsion system for this type of flying creature?

posted about 5 years ago

Gryphon‭

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