Some engineer over at Bell had the brilliant idea to essentially place a quad-copter on the tail of a Bell 429 helicopter. The four electrically-driven fans replace the single mechanically linked tail rotor of the traditional helicopter. Power for the fans is generated by the turbine engines that drive the main rotor, and the blades of the fans are fixed. To go in different directions, the fans just reverse their spin, and it’s all controlled by the flight computer. Bell says that the helo can operate safely with just a single fan. Pretty cool.
The Warzone has a big writeup about it.