In 1940 the first machine from the new company appeared as the NR 55, which had a single-blade rotor. This rotor blade was counterbalanced by a 40hp engine which applied to it a torqueless drive by means of two small airscrews which pulled it round at about 135rpm. Because of gyroscopic forces at the engine location, the carburetor was mounted on the centerline of the rotor hub and fuel-air mixture was piped out to the engine cylinders. The rotor diameter was 10.5m, and the machine weighed about 338kg loaded, but, although a cruising speed of 97km/h was thought feasible, only hovering and lift test were undertaken because the machine was built purely for testing the rotor system.
Type Single seat experimental helicopter
Engine 1 40 hp
Dimensions Length  , height  ,  span  , wing area   ,rotordia. 10,5 m
Weights Empty , loaded 338 kg , max. take off weight  
Performance Max.. speed  , cruising speed (estmated) 97 km/h , range , endurance  , service ceiling   , climb