Sikorsky first tried the camera on the rotorhead. The camera was mounted on an S-51 rotorhead, which was attached to a whirl stand. The pictures showed the sinusoidal traveling wave on the blade but it also provided some unexpected data. When they introduced cyclic control they discovered that the advancing blade led and the retreating blade lagged. Up until that time it was assumed the opposite was true.
It is my understanding that when some helicopter pilots saw the film they refused to fly helicopters.
