Three pole is the slang for the typical NMPRA.ORG style racing. Depending on the class the planes are a bit over 100 MPH to 200+. I also fly the Club 40 two pole racing, planes fly about 90 MPH.
In three pole the pilot and caller stand in the center of the course and fly around yourself. The two poles pilots stand on the side and the course and all the racing happens in front of you.
The two pole is easier to do at any model field, three pole is more difficult with safety set backs from the pit area. We usually have our two pole up 4-6 months of the year at our field since it really isn't in the way for general sport flying.
And allows for practice any time,That's why I'm the two time National Club 40 champion 2015 and 2016.
Sparky