The five-blade rotor desciption doesn't fit, but the Russian 'bang out' helicopter is the Kamov Ka-50 (3-blade co-axial rotor). The following comes from Jane's:
"Specially designed Zvezda K-37-800 ejection system for safe ejection at any altitude; following explosive separation of rotor blades and cockpit roof, pilot is extracted from cockpit by large rocket; alternatively, he can jettison doors and stores before rolling out of cockpit sideways."
T/shaft