Good stuff. This reminds me of the "added mass swimmer" -- theoretical propulsion purely by the added mass effect, avoiding the shedding of vortices (with the

Good stuff. This reminds me of the "added mass swimmer" -- theoretical propulsion purely by the added mass effect, avoiding the shedding of vortices (with the propulsion device working in water, or any suitably heavy fluid). The navy has been funding studies into it for a while. Not going to work for an owl though. Air is not heavy enough.