This isn't a "think piece" - this is a several year old application, with LOTS of very happy electric Ringmasters out there - because this set-up WORKS.
There is no substitute for using the correct equipment; in this case the 4 cell pack with the 1100 kv motor and the 9x4.5 prop generating usable RPM (i.e., at 70%-85% throttle) in the range of 11,396 RPM to 13,838 RPM. The 9x4.5 prop likes to run around 11.400 RPM and at that speed will pull the Ringer at around 5.0 seconds per lap. At that throttle there is plenty of "headroom" for governing.
Put another way, the reason 3 cells CANNOT WORK in this application is that it will not generate nearly enough RPM. With 3 cells the usable RPM range falls to 8,547 - 10,379 RPM. That top RPM is about 1000 RPM short for using the 9x4.5 prop - might work with a 9x6, but at the cost of almost the entire govening range. If you wanted to reclaim the lost headroom with 3 cells then you better find an 8"-9" pitch prop! Better still, with 3 cells and the 9x4.5 prop, find a motor rated at 1500 kv; I know that will work because I have flown those too on the Brodak Super Clown.
About 5 years ago I published a piece in Stunt News on matching props, cell count and KV. I do not remember which issue it was but I attached a PDF of the article below - might help detail some things - or cure your inomnia...