This is a Significant Technology milestone.
The tests by Bousman provided evidence that air responds to the motion of the rotor as a a whole, which is described well by simple dynamic inflow models for a rotor. This provided confidence in the use of dynamic inflow models for rotor response modelling.
(Note: Only the month and year for this milestone are valid)
Source: Johnson W., "Milestones in Rotorcraft Aeromechanics", NASA/TP-2011-25971, May 2011, Page TBA