In 1922 Oemichen was able to dispense with the gasbag of the first machine and fly free. Etienne Oelimichen's No. 2 machine was powered by a 120‑hp Gnome rotary engine. It had four large rotors and eight stabilizing and steering propellers about an open lattice‑work frame and it flew for the first time on 11 November 1922.
Etienne Oelimichen's first helicopter flew in 1922 for a distance of 60 m (197 ft). In 1923 he made the first hovering flight of more than five minutes.
The Oemichen No.2 was basically a steel-tube framework of cruciform layout, with 2-blade paddle-shaped rotors at the extremities of the four arms. The angle of these blades could be varied by warping. Five of the propellers, turning in a horizontal plane, served to stabilise the machine laterally; another propeller mounted at the nose was for steering the helicopter; and the remaining pair acted as pusher propellers for forward propulsion. The opposing pairs of rotors were of slightly different diameters. The Oemichen No.2 exhibited, for its time, a considerable degree of stability and controllability, and in all made more than a thousand test flights during the middle 1920s. By 1923 it was able to remain airborne for several minutes at a time, and on 14 April 1924 it established the first-ever FAI distance record for helicopters of 360m. Three days later it increased this to 525m. On 4 May 1924 this contraption made a closed circuit flight of 1 km (0.62 mile) at Arlonans to set a distance record for helicopters, It was airborne for 14 min with the kilometer taking 7 minutes and 40 seconds, to win a 90,000 franc prize.
A 180hp Gnome engine was substituted later.
Despite the fact that it was able to demonstrate sufficient controllability and power in ground effect for this historic flight, it was not a practical flying machine. In recognition of the impracticality of the machine, Oemichen began pursuing a series of aircraft with a single-main rotor and two anti-torque rotors, but had little success.
Engine: 1 x Gnome Rhone, 135kW
Rotor diameter: 2 x 7.60m + 2 x 6.40m
Empty weight: 800kg