Dornier P 406

The Dornier P 406 was a project design by Dornier for a crane helicopter able to carry external loads of up to 40 tonnes, to meet requirements the German defence ministry published in the early 1960s. It was cancelled when the ministry dropped the requirement, while under the same requirements the Vereinigte Flugtechnische Werke offered licence production of the Sikorsky S-64. The helicopter had the typical outline of the S-64 with a tall undercarriage faired with large stabilising surfaces for fast flight. Its rotor followed the tip drive proved on the Dornier Do 32, which needs no tail rotor because the reaction drive creates no counter torque, but with the hot gas drive tested on the Do 132 project: three turbines of 18,000 horsepower each would feed hot gas through the insulated hollow mast and blades to nozzles at the blade tips, with a small ducted fan for yaw control in the hover. The maximum take-off weight, including payload, would have exceeded 80 tonnes, and standard containers could be held inside the undercarriage.