Sud-Ouest SO.1120 Ariel III
The 1948 experimental Ariel helicopters used tip jets at the blade tips.
The SO.1221 was powered by a cold-jet propulsion system developed by Sud-Ouest for its earlier two prototypes Ariel II and III helicopters. Residual thrust from the engine is ducted to the end of the fuselage and used for directional control.
Engine: 275 h.p. Turbomeca Arrius gas-turbine
Rotor diameter: 35 ft 5 in
Rotors: 3-blade tip-powered main rotor.
Fuselage length: 27 ft 2 in
Loaded weight: 2,750 lb
Ceiling: 15,000 ft
Typical range: 155 miles at 85 mph with 1,000 lb load