The history of the rotating wing aircraft began with Sud-Est which supported the famous German helicopter designer Prof. Heinrich focker and a few of his closest employees to create. The first helicopter by Sud Est was the SE 3000 with two rotor blades and an improved replica was the German Focke-Achelis Fa 223 "Drachen". By 1946, the group of French and German engineers along with Prof. Focke had developed the successor project to design and construct a one-seater experimental helicopter SE 3101 that first lifted off the ground on June 15, 1948 and was piloted by Jean Boulet.
The SE 3101 was a one-seater with a 110 PS strong Mathes engine. It possessed a triple-bladed main rotor with a diameter of 7.5 m and two rear rotors in a V-shape which served to facilitate the rotation motion. The direction of rotation of the main rotor was in the clockwise motion which was a unique characteristic of the French helicopter. The very simple machine had a steel gas cell. In order to protect the pilot there was a window for wind protection. Reduction of weight was a characteristic of the helicopter and in order to fly this model, the motor system had to be tested.
The SE 3101 was a step in the right direction for later helicopter generations and is regarded as the predecessor of the very successful "Alouette" helicopter family.
As an enlarged version of this experimental model, the SE 3110 was designed in 1949 with the SE 3101 in mind, however, it was a two-seater helicopter with a closed cabin and was powered by a similar rotor system with a main and two rear rotors. The diameter of the rotor was 12 m and the engine was a 200-PS. However, it remained as an experimental model.
Sud Est - SE 3101
| Type | Light experimental helicopter | |
| Manufacturer | Sud-Est | |
| Power plant | A four cylinder Boxer engine Mathis 4 GB 20 with 110 PS (82 kW) | |
| Year of construction | 1946/47 |
Performance
| Top speed | 120 km/h |
| Service altitude | 3,000 m |
| Operational range | 100 km |
Weight
| Framework weight | 400 kg |
| Initial weight | 520 kg |
Dimensions
| Rotor diameter | 7.50 m |
| Length | 6.90 m |
| Crew | 1 person | |
| Production quantity | 1 prototype |
