Hello found this site about rotary valve from the early beginnig to present day.
http://www.way2speed.com/2012/01/rotary-valve-internal-combustion.html?m=1
Take a look at this. http://www.mecoa.com/hp/vt/21.htm
I own one http://www.rcgroups.com/forums/attachment.php?attachmentid=4302759
and one http://antiquemodelenginesrunning.blogspot.com/2012/05/rcv-58-cd-rotary-valve-glow-engine.html?m=1