I think it's time for some science experiments. As described in detail by Robert W. Deters and Michael S. Selig in their 2008 conference paper on props (http://aerospace.illinois.edu/m-selig/pubs/DetersSelig-2008-AIAA-2008-6246-MicroProps.pdf), it's tough to come by good data in the RC world. The static thrust calculator I found seems legit, but... I need real world data that I can trust. Also, as mentioned in the comments for the previous project log, coaxial contra-rotating propellers are a pretty tough aerodynamic problem to solve on paper. 

Since the world loves pictures, here are a few from Forrest Frantz' great thread on copter design (http://diydrones.com/forum/topics/build-your-own-copter-part-ii):

I will not be testing anywhere near that many combinations unless the RC motor and propeller delivery truck happens to break down in my front yard. In any case, here are my objectives for this minor but somewhat interesting tangent:

• Set up a rig to quantify motor/propeller performance
  • Static thrust
  • Total power consumption
  • RPM
• Test a few single motor/propeller configurations to cross-check the calculations from the previously linked static thrust calculator, and develop RPM/thrust/power maps for these configurations
• Test a contra-rotating configuration using the above combinations, varying propeller spacing in addition to thrust
• Block part of the contra-rotating propeller assembly to simulate actual installation in the GimbalBot frame

Just a brief post for now. I'll throw together a basic sketch with requirements for the rig at some point and get into detail on its construction. Hint: it's going to be cheap.