June 2020

SNCASE S.E. 3101 Helicopter


The Sud-Est S.E. 3101 experimental helicopter program was commissioned by the French government in December 1946. It was designed by a team composed of French and German engineers of Henrich Focke’s group, René Mouille and Prof. Henrich Focke, under the direction of Pierre Renoux, who was the Société Nationale des Construction Aéronautique du Sud-Est (SNCASE) chief engineer.

The S.E. 3101 helicopter concept was inspired by Prof. Focke’s Focke-Achgelis Fa 336 helicopter model, which was presented in Berlin on Oct. 1, 1943 to the Deutsche Akademie der Luftfahrtforschung.

The S.E. 3101 helicopter was built using basic components cannibalized from WWII German Focke-Wulf Fw 61 helicopter, for example the fully articulated main rotor and trapezoidal shaped blades. It used two 45° canted “butterfly” tailrotors to provide torque counteraction and yaw control by differential variation in pitch.

The fuselage of the SE-3101 was an uncovered, rectangular cross-section, steel tube welded structure to minimize aircraft weight. A 99 hp Mathis 4G engine was mounted within the fuselage, immediately below the main rotor and behind the pilot, who was provided with some instrumentation cannibalized from Piper L-4 aircraft and was sheltered by a flat windscreen. The aircraft had a fixed, wheeled tricycle undercarriage, assisted by a small tail skid. The pilot seat was borrowed from a military Jeep. The flight test of the vehicle at Villacoublay airfield was initially assigned to the chief pilot, Henri Stakenburg, who was unsuccessfully in lifting the helicopter off the ground due to the power limitations of the Mathis engine. SNCASE chief pilot Jacques Lecarme then asked a newly graduated test pilot, Jean Boulet, who was 33 lb (15 kg) lighter than Henri Stakenburg to fly the helicopter. Jean Boulet eventually took the aircraft off the ground about a foot (30 c m) for 15 minutes. Thus, S.E. 3101 was first flown on June 16, 1948. Within 18 months, the helicopter performed a total of 20 flight test hours and a 100 hour of endurance test. Although the French government terminated the vehicle’s development program in 1949, it led to successful development of French production helicopter “Alouette II” or S.E. 3130. The sole S.E.3101 is currently preserved at the Musée de l'Air et de l'Espace, Le Bourget, Paris, France.


  • Cruise Speed: 50 knots (93 km/h)
  • Max Speed: 65 knots (120 km/h)
  • Range: 54 nautical miles (100 km)
  • Service Ceiling: 9842 ft (3000 m)
  • Gross Weight: 1129 lb (512 kg)
  • Payload: 218 lb (99 kg)
  • Length: 22.74 ft (6.93 m)
  • Width (Fuselage): 2.30 ft (0.70 m)
  • Height: 7.38 ft (2.25 m)
  • Engine: Mathis 4G
  • Power: 99 hp at 3300 RPM, 64 hp at 3100 RPM


  • Daniel Liron, Les hélicoptères français de la SNCASE à Eurocopter, www.aerostories.org
  • Ernst Heinrich Hirschel, Horst Prem, Gero Madelung, Aeronautical Research in Germany From Lilienthal Until Today, Spring-Verlag Berlin Heidelberg, 2004
  • Steve Coates, Helicopters of the Third Reich, Classic Publications, 2003
  • Secret Projects Forum, www.secretprojects.co.uk
  • Arnaud, Sud-Est SE.3101: “A l'origine des Alouettes,” www.avionslegendaires.net
  • www.helico-fascination.com

Text by Jacques Virasak

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