Dornier Do 132

The Dornier Do 132 was a utility helicopter under development in Germany in the late 1960s. While the design was a conventional pod-and-boom layout, the propulsion system was unusual in that it used a turbine engine not to drive the rotor directly, but to provide a source of hot gas that was fed through the rotor shaft, along the blades, and out through tip jets. The intention was to do away with the weight and mechanical complexity of a gearbox and an anti-torque system for the tail.

This engine system underwent extensive static tests while a full-size mockup was built to prove the aerodynamics in a wind tunnel. Ultimately, however, the programme was cancelled in 1969 before a prototype was actually constructed.