My father was a mechanical engineer, and I remember him hating the Wankel after they did some testing on them in his lab. They had nothing but problems with them once they got it under load and tried to make it do something besides just run.
I had a great ‘74 RX-4 wagon. Ran great until my sister drove it for a year without checking the radiator. I put a rotary short block in and drove it another 100K
http://alex62.typepad.com/imsablog/2006/02/mazda_rx7_winni.html
Mazda RX7 : winningest car ever