I remember seeing somewhere in some rag (SA, AOPA pilot maybe
Kitplanes) a new variable pitch propellor system that used ram air
pushing against the tip of the spinner to govern the blade pitch. It
had not propellor control, no hollow crank, no rpm governer, no
connections at all. Just when you go faster, the blades bite more
air.

I've done an extensive web search and all I can find is the Aeromatic,
which is a 30yo propellor nolonger in active production.

Does anyone know what I'm talking about?

Bruce Meacham