I guess these RC wankel engines need mucth more research, since the big ones, designed for real cars, are considered the most efective, specially when talking about fuel consuption.
The truth is that this engine doesn't have three combustion chambers. It does have instead one rotating "triangle" that creates three diferent function areas, fuel intake, combustion and exaust areas.
The advantages of the wankel engine (not the RC one) would be:

In addition to its performance dynamics, the rotary engine offers many other benefits. Because the rotors move in a constant circular motion, instead of back-and-forth like pistons and valves, there is very little engine vibration, eliminating the need for counter-weights, balance shafts and other response-slowing compensating systems common to conventional engines. And because it never has to change directions, the rotor’s momentum is never lost, providing a smooth, even distribution of power from start to redline.
Mazda has one comercial model that uses the wankel engine and won the 2003 International Engine of the Year, beating BMW, Mercedez,all of then.

Wankel explanation including motion view can be seen at:
http://www.keveney.com/Wankel.html

or at Mazda page below:
http://www.mazdausa.com/MusaWeb/disp...de=RX8#renesis

Nilo