Sud Ouest Aviation/Sud Est-SNIAS SO-1221-Djinn
The multipurpose helicopter SO-1221 "Djinn" was the first series helicopter in the world powered by blades.
The first prototype took off on December 16, 1953. The first Djinn from the series production lifted off the ground on January 5, 1956. Until the end of 1965, a total of 178 Djinn were constructed that were utilized by the military as well as in agriculture, ambulance and rescue missions in the Alps.
The French Armed Forces procured over 100 copies of the small and light helicopters. They were utilized as contact, observation and training helicopters. They were also used for rescuing the wounded with one pilot and two external carriers. The German Armed Forces recieved five copies and Switzerland received four. The US Army tried and tested three Djinn under the name YHO-1DJ. The remaining copies were used in the civil sector both domestically and abroad.
The experiences that Sud Ouest had with this experimental helicopter "Ariel" that had a reactionary engine, helped convince the designers that it would be possible to power a helicopter rotor just with compressed air. This would save additional weight of a fuel system that was necessary for the jet engines of the Ariel helicopter. This consideration lead to the construction of a one-seater SO-1220 prototype with a simple steel framework and a dual-bladed rotor. The pilot's seat remained opened. This model was powered by a Palouste Turbocompressor from Turboméca. The produced air was blown directly on the blades. The pilot Jean Dabos had its initial flight with this aircraft on January 2, 1953. The tests soon showed that this simple "cold" power from the blade led to better than the complex blades of the jet engine of the Ariel.
There were five two-seater prototypes of the S.O.1221 which were constructed with a vitrified cabin and an uncovered, grind-like steel framework with three fins. The first of these prototypes lifted off the ground on December 16, 1953. Soon afterwards it was proven how efficient this simple method worked. Already 13 days after the first initial flight, the pilot Dabos set a new high world underclass record with an initial take-off weight of 500 kg and traveled for 4,789 kg with a "Djinn". On March 22, 1957, Dabos increased this to 8,492 m which was an international high record for all weight classes of helicopters.
The constructed pre-series helicopters were overwhelmingly used and tested by French troops. Series production began in 1955.
The simple designed "Djinn" consisted of a fuselage with a cabin. The central portion of the fuselage held the undercarriage, the fuel tank, the engine and the rotor machinery which held two metal rotor blades which were securely fastened together. The rotor of the Djinn helicopter was powered through condensed air which was expelled from the turbine and without fuel injection. The "cold" combustion of the jets was compressed. The pressure from the compressor condensed the air to 2.7 kg/qm.
The Turbo-Compressor Turboméca Palouste IV with 240 PS (179 kW) was used. The high and side empennage was completed in normal construction. The rudders were made of steel so that they would prove to be very effective. The undercarriage had two wheels for land movement.
The military version of the "Djinn" was equipped with panzer defense rockets. The civil version was primarily used in the agricultural sector. The chemical holders could contain up to 200 liters. The chemicals could be sprayed on fields and vineyards through the design of the fuselage. The "Djinn" had a reach of 60 m, by spraying it was 18 m, by dusting 13 m.
The "Djinn" was known for its steering and maneuver capabilities. It was soon displaced by the machines of the series "Alouette II" und "Alouette II" in flight performance and carrying capability.
The "cold" combustion was not enforced due to its low efficiency rate.
The second prototype, which broke the world record in the 500 kg category, achieved an altitude of 4,789 m, is on exhibit in the Musée de l'Air in Le Bourget in Paris.
Technical data
S.O. 1221 Djinn
| Type | two-seater, light multipurpose | |
| Manufacturer | SNCASO (Société Nationale de Constructions de Sud Ouest) | |
| Power plant | Turboméca Palouste IV with 240 WPS (176.5 WkW) | |
| Year of construction |
1953 beginning of series production 1956 |
Performance
| Top speed | 130 km/h |
| Travel speed | 100 km/h |
| Hovering altitude | 1,800 m off the ground |
| Service altitude | 4,500 m |
| Operational range | 200 km |
| Flight duration | two hours and 15 minutes with standard fuel volume |
Weight
| Framework weight | 360 kg |
| Initial take-off weight | 800 kg |
Dimensions
| Rotor diameter | 10.97 m |
| Fuselage length | 5.30 m |
| Height | 2.60 m |
| Crew | 2 persons | |
| Production quantity | 178 copies |
