The first flights shown at the video link above had a slight tailwind and appeared to go much higher and landed much farther away than the second set of flights which had a slight headwind (the launch rod was angled away from the launch area). However, in the second set of flights the 4-blade version actually auto-rotated upon descent, unlike in the first set of tests.

Anyway, I'm going to try some additional 13mm powered spinners, all single motor powered, to see how they perform. Single engines reduce potential ignition issues and extend the number of flights using a single 4-motor 13mm motor pack to four.

One is a smaller diameter bladed version and two with Kline-Fogleman airfoils, one a KFm-2 with one 50% chord step, the other a KFm-3 with two steps, one at 50%, the next at 75%.

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__________________
The other day I sat next to a woman who has a profound fear of flying. I wanted to comfort her, so I said, "Don't worry, we're not gonna' crash. Statistically, we got a better chance of being bitten by a shark." Then I showed her the scar on my elbow from a shark attack. I said, "I got this when my plane went down off of Florida." - Dennis Regan