The "clear" call is for piston engines. They start suddenly, instead of having to spool-up like a turbine. Much easier to dodge a slow starting jet engine than and instant-on piston engine.
Props probably are more dangerous. They cover a much bigger area, are hard to see, and they a more prop planes that jets.
Thanks. I've seen a lot of props in pictures where the tips are painted yellow, presumably to form a big yellow danger circle when spinning.
There was a guy who bought an abandoned airfield to live on and who made a living off his new design for propellers. Anyone know what was involved in his "new" design?
Always wondered about that. Only things I could think of would be a change in the airfoil as you went to the prop tip to better account for different rotational speeds, or "winglets" on the prop tips to avoid tip turbulence, like the winglets on a plane's wingtips.
I wouldn't even know what to use for a search term for that, but I'm still in Kindergarten on search engine technique.