Dornier Do 132

The Dornier Do 132 was a utility helicopter under development in Germany in the late 1960s. Its pod-and-boom layout was conventional, but its propulsion was not: a turbine engine acted as a gas generator, supplying hot gas through the rotor shaft and along the blades to tip jets instead of driving the rotor through a gearbox, which was intended to remove the weight and mechanical complexity of a gearbox and an anti-torque tail system. The design called for one pilot and four passengers, a Pratt and Whitney Canada PT6-A20 gas generator of 540 kilowatts, a main rotor 10.70 metres across and a maximum speed of 229 kilometres per hour. The engine system underwent extensive static tests and a full-size mockup was wind-tunnel tested to prove the aerodynamics, but the programme was cancelled in 1971 before a prototype was constructed.