- Where can I get a single rotor eccentric shaft?  I'm thinking that the only ones running now were cut down from 13B shafts, which I understand is a mighty tough job. 

 

- Folks have done plugs-up engines, but has anyone ever done a plugs-down engine?  Do you see any reason why it wouldn't work as well as plugs-up?  Having the intake and exhaust on top would be the best arrangement, but it won't be possible to do this unless I can get a planetary drive unit to keep the prop in the center of the engine.