It seems a bit odd. The main rotor imparts an opposite spin on the body. Tha tail rotor is there to counteract that spin by blowing sideways. A horizontal one would have to use just its spin, not getting the benefit of the air mass being pushed sideways.
It seems a bit odd. The main rotor imparts an opposite spin on the body. Tha tail rotor is there to counteract that spin by blowing sideways. A horizontal one would have to use just its spin, not getting the benefit of the air mass being pushed sideways.
That (chinook-style solution) only works if both rotors are the same size and speed.
Perhaps Sikorsky’s tethers to the ground worked around the problem for that photo anyway. Not sure.