Abstract: A two-stage turbine includes a first stage comprising a first stator having blades configured for accelerating the drive fluid to supersonic velocities and directing the fluid to the impulse blades of the first rotor. The turbine's second stage includes a second stator having blades configured for directing the fluid from the first stage to the reaction blades of a second rotor at a sonic velocity. Efficient operation of the turbine over a broad range of drive fluid velocities is achieved by providing the stators and rotors with elliptical leading edges to form high angles of attack and providing extended stator tail sections to control fluid flow to the rotors.