I read an article about the drones used by the armed forces. Before deciding on the rotary as the power source they tried other engines, 2stroke and 4 stroke and the rotary came out on top in terms of all the tests. Wish I knew where I read it now.
Basically the rotary was better because of its weight, power output, useable with many different fuels etc, although the rotary engine used doesn\'t have Apex seals like ours but uses exotic materials that don\'t wear and the fuel lubricates the rotors. A shame they couldn\'t put these designs into the road goog rotors.