I've been researching about helicopter flight without a tail rotor and the closest I've found is intermeshing rotors or this: https://www.quora.com/Why-dont-helicopters-have-rotor-blades-at-the-bottom
Looking at this new method:
Seen in this frame, the rotors are single winged and I'm guessing they rotate at opposite phases. What is this called and where can I find more information about it?
You are right, the two rotors move in opposite direction. This is called a co-axial rotor and is used by the Russian helicopter design bureau Kamov. A co-axial rotor can also be found on many model helicopters for indoor flying. They are a subspecies of helicopters with contra-rotating rotors.
Helicopters with contra-rotating rotors do not need a tail rotor and are much easier to fly than Sikorsky-type helicopters, because they suffer much less from instability. This group also comprises intermeshing rotors like those used on Flettner or Kaman K-Max helicopters.
Kamov Ka-32 with co-axial rotors operated by HeliSwiss (picture source)
Kaman K-Max with intermeshing rotors modified as an unmanned vehicle (picture source)
For more info, just follow the links.
