Ah... so a normal fin might add stability in yaw vector, but acts as a barrier to sucking air through the tail rotor, decreasing tail rotor power.
Sorry for the thread drift... have watched their video, but can't quite understand how it works.
With the Coanda effect - essentially the downdraft from the main rotor sticking to, and curving around the boom performs an anti-torque function - is that right?
How does a strake make that happen?
I understand the MD-500N blowing air out a slot to make it work - but a horizontal strake just disrupts laminar airflow?
Confused...