Read on a forum somewhere that someone did. One cylinder flew off due to the high rotational speed and that led to serious vibration.
Problem is the difference in rotation speeds. A rotary engine operated at around 1,200 rpm and for a scale speed the outrunner would need either to be slowed way down for a direct mount or have some sort of reduction system fitted for the rotary part. There might be an outrunner out there that could provide usable thrust at 1,200 rpm but I'm not aware of it.
You'd also have to deal with the increases in weight, drag, and torque. I seem to recall that the WW1 planes fitted with rotories would turn readily with the torque but would struggle to turn the other way. The opposition pilots knew this and used this limitation against them.
If you try it, keep us posted.
Science has proven that six out of seven dwarves are not Happy.
Its doing about 7000 rpm. There is a big difference in the centripetal force between a full size engine and a model.
The cylinders are paper tubes with cotton wound round for the fins and are glued directly onto the out runner bell. The whole 'engine' only adds about 2.5 g
Yes, it absorbs a bit of power but well worth it for the scale effect.
The rotary in the finished 24" span Sopwith Pup.
That's so cool! I'm building a 1:6.5 Fokker D8, and started thinking about how to represent the rotary. It is a lot bigger than the Pup, and forces would be higher. Balancing would be critical of course. Since i first posted the query, I thought about having the cylinders rotating on a separate bearing and using a turbine (hidden behind the motor) to spin them from the airflow, obviating problems with high revs, and strength. We'll see....