RE: tt pro
We are using a Stalker Pro Radar gun (roughly $1300). Pretty accurate (although not perfect). It is the radar gun that most of the pylon guys use for accuracy.
Heres another question. The 8.8" x 8.75 prop turns far more rpm (16-16.5) k, yet is barely 5mph faster. How can that be? You can question the accuracy of the radar, but it at least should give you numbers that correlate with one another.
Planes are your basic 3.5 lb quickee