Bill and group,Sorry, I don't have any magic for you on single rotors Wankels. They would be pretty heavy for the power produced. Several reasons:
Really big counterweights are necessary;
Firing order vibration would be huge, requiring one or both of, torsional pendulums and very long stroke "soft" isolation system.
With only one rotor, the entire eccentric mass of the shaft and rotor has to be balanced with counter weights. With two or more rotors, the primary (up and down) imbalance is taken care of by having the eccentrics evenly distributed, and the counterweights only have to balance the pitching moments. The more rotors, the smaller this whole effect is and less counterweight size needed.
The firing frequency on a single rotor is one per rev and really strong. Torsional pendulums would be useful, but they would have to be really big to tame that low a firing order. A soft system would require pretty low spring rates, which means a lot of travel and volume occupied by the spring system. You might need both...
In the end, Wankel single rotor engines will be heavier and more complex than two rotor engines of the same power.
All our work has been with 2 or more rotors. To make a LSA single rotor I beleve it could be done with a light weight rotor. Either machined steel or cast titainum. That would allow counterweights of about 1/3 the mass. The torque pulses would still present some problems but no worse than a big single piston. Smoother actually since it isn't reciprocating. Just a thought. The pendrlum style dampers could be built into the counterweight and flywheel, (which is also a counterweight), to make a compact package.
The other Bill