by Mario Bazzani

The Djinn1 is a French two seat turbine powered helicopter which made its first free flight on December 14th, 1953 with pilot Jean Dabos at the controls. In this helicopter the main rotor is driven by compressed air supplied by a turbine located behind the cabin. The compressed air is transmitted directly to the rotor blades and is expelled from a nozzle placed on each blade tip. The elimination of the usual mechanical transmission also eliminates the need of an antitorque tail rotor. The Djinn in fact dispose of a simple rudder placed in the continuos flow of the engine exhaust gas which is controlled by foot pedals like in the others helicopters of conventional design and offer an “efficient” control on the vertical axis. The great inertia of the Djinn’s rotor is one of its most appreciated characteristics.
Up today this French model is the only one with this configuration produced in series for military and civil uses, and is even the first turbine powered helicopter mass produced.

The prototype, registered as F-WGVH, was the result of the experiences made before with the predecessors built by the French company Sud Ouest, like the Ariel series or the SO.1220, the single place version of the SO.1221. The Djinn was an excellent climber, and set many altitude records. On March 22, 1957 it set a new unofficial world record when it climbed to 8482 meters, a record that later was broken by an Alouette II.

On February 1955 the pilot Dabos and a small technical staff arrived here in Switzerland with the F-WGVY (the first pre-serie model of the Djinn) to demonstrate its flight characteristics. Between February 7th and March 3th 1955 the helicopter made several flights in the Jungfrau region and proved to be a good mountaineer. It took-off and landed without problems from the Jungfraujoch at 3520 m with a passenger. In this occasion the small helicopter captured the interest of Air Import SA (the Swiss first civil helicopter’s company) and the Swiss Army.

Air Import SA was so impressed by the performances of the Djinn that decided to acquire one of them in November of the same year. Unfortunately the helicopter, registered as HB-XAN (an SO.1221 PS), was lost on May 4th 1956 in an accident in the Innerthal/Trepsenalp during a slung load transport. A second one registered as HB-XAS (an SO.1221 S) joined the fleet by the end of the year and remained in service until October 16th, 1958. In January 1957, after Air Import was absorbed by Heliswiss AG, it was used for school and much later it was sold in France. Heliswiss had decided to use only Bell 47 models, because these offered more space in cabin (two passengers instead of one), a greater payload and superior performances.

The Swiss Army put in service a total of four SO.1221 S. The first 3 were registered as V-21, V-22 and V-23 and entered in service in February 1958. On September 2nd, 1958 the V-21 was destroyed in an accident occurred in Andermatt (cable collision). On July of the following year a fourth Djinn was acquired and registered as V-24. These 3 helicopter remained in service with the Army until 1966. The V-23 is now exposed in the “Fliegermuseum” in Dübendorf.

The Djinn was a versatile helicopter, designed especially for light transports, school, aerial observation and photography, air ambulance and liaison duties, aerial sprayer, etc. It could be equipped with 2 external litters, an agricultural kit, an hook for slung loads, and was experimentally used for trials with guided missiles. In the Unites States the Djinn was tested by the U.S. Army as YHO-1DJ. On August 6th, 1958 it received the CAA type certification. 

The appearance of the new turbine powered SE. 3130 Alouette II signed the end of the Djinn’s military career. The limited forward speed and short range, as the limited payload and high fuel consumption were its main limitations. However this helicopter continued to be used for many years in civil roles as a school helicopter or in agriculture as aerial sprayer. Today, after 50 years from its first flight, many Djinn still survives, but the major part of them is exposed in museums. Very few are still in flying condition - among them the F-AZAC
 
 

HB-XAN - The first of two civil Swiss Djinn's
 

HB-XAS - Owned by Air Import and later Heliswiss
 

A Djinn engine during rebuild
 

F-AZAC - After rebuild by Jet Systems in 2002
 

F-AZAC - in June 1995 at Monaco