Citroen RE-2 (1975): the story of the failed helicopter rotary engine of Citroën

did you Know that Citroën was on the verge of commercializing a helicopter in the 70’s? it All started with Comotor, a joint-venture between NSU and Citroën for the development and marketing of rotary motors. The small Citroën M35 preceded the Citroën GS Birotor, which, despite of their good performance and exclusive image, always suffered from high fuel consumption and low reliability. The last attempt to save Comotor was the helicopter staff RE-2, a last attempt that was, unfortunately, a failure.

The Citroen RE-2 could be considered the flight forward of the program of rotary motors, doomed to failure.

The damage to Comotor was already done. Sales of the Citroën GS Birotor were disastrous, and the Board of Directors of the brand I wanted to put point and end to the project. Clutching at straws, Citroën looked at the sky: “we will produce a helicopter, and we’ll use our thrusters rotating to make it fly”. An idea that could have only been approved in a company like Citroën. Said and done, the gauls were recruited to Charles Marchetti, the aeronautical engineer who had designed the successful helicopter Alouette.

citroen-re-2-5Initially, the project was to build a autogyro staff, we would end up drifting in a helicopter more conventional. After months of rushed development, the first prototype would rise from the ground, the christmas eve of the year 1975. The Citroen RE-2 had a length of 7,18 meters 2,59 meters high and a weight of 700 kilograms. It was a helicopter designed for two occupants, for recreational use. Citroën wanted to have his helicopter ready as soon as possible, and with the rush even had difficulties to find a test pilot.

The lack of funds and technical problems delayed the certification of the aircraft, that it would never be completed.

In its first flight even had to remove the doors to the helicopter, if there was some technical problem and the pilot had to jump. The grace of the helicopter – of refined design and modern – it was, of course, its engine. A Comotor 624 of two rotors, a propeller of 1,990 cc and 101 HP that would be adapted to a life in the air: you replaced your power supply by carburetor Solex by a system of mechanical injection of fuel, developed by Citroën. The fuel feed and cooling were modified.

citroen-re-2-3This engine was capable of to propel the aircraft to a cruise speed of 173 km/h and on the paper, could climb to a ceiling of 3,500 meters altitude. Citroën had been flown successfully with its RE-2, but did not yet have the government certification to sell it to the public. During the rigorous processes of approval, it was discovered that the engine sobrecalentaba after a time running at high-rate. The French government approved its sale and the helicopter had to go back to the drawing-board.

The only unit produced, is currently in the museum of the French brand, where it will not come out.

While the ingenieros solved the engine problems, Citroen changed hands and became the property of Peugeot, in the recently formed PSA Group. Although the RE-2 solved their problems and got a permit of flight six months in 1977 for the final adjustments, in Peugeot were fed up. The project was a bottomless pit of money, and may 5, 1979, ordered to Citroën the immediate cancellation of the project. “Yes, bwana,” was the response of the Vehicle, which would keep for ever their unique RE-2 after only 38 hours of flight.

Comotor also died after this decision, as well as a CX equipped with a rotary engine and improved manual gearbox that Citroën was developing at that time.

Source: RWP