BROC
crab
fully agree, the reference is taken at the bottom of the power curve.
If that bottom is at 50 or 53 Kts looks a little academic to me, since I believe it will depend on the context (cleaness of rotor, TOW) etc.
If find some time I will check my simulator to predict some BROC speeds on a R44-I in different weight conditions. Of course on a calm day, with some patience one can experiment this for real: try to fly level with the least collective and see what speed you get. The problem doing this is the unstable character of the bottom point: slowing down makes you hit the unstable part of the curve (more power needed when slowing down), so that can be a bit tricky.
d3