"Ed Huntress" wrote in message
...
On Mon, 15 Apr 2013 17:36:34 -0700 (PDT), BottleBob
wrote:

Very nice! Axial-shaft rotary valves. They've been around for at
least
60 or 70 years. g I think they were tried in aircraft engines even
earlier than that.

Since 1849.
http://en.wikipedia.org/wiki/Corliss_steam_engine