strey,
Don't confuse a 205 with a UH-1 and vice versa.
205A LHS of which they only made about 39. L-11 engine.
205A-1 RHS which makes up probably all of the fleet as they will have been all converted. ~ about 360 aircraft in total. 212 T/R. L-13 engine.
The conjecture on here regarding the whys and wherefores of why it works better is interesting! If air would only move in straight lines like in the classroom and not get tied up in knots as it really does!
Hell even Ray Prouty is not too sure why -
Rotor and Wing Article