Sud-Ouest SO-1221 Djinn

Sud‑Ouest, SNCASO

First Flight December 16, 1953

Two seats

Acquisition Source: American Eurocopter Loan

The Djinn was designed by Sud‑Ouest as a two‑seat utility helicopter using a unique 'cold jet' propulsion system.In this system a 240‑hp Turbomeca turbogenerator mounted aft of the cabin supplied compressed air through ducted channels inside the rotor shaft and twin rotor blades to rotor‑tip ejectors, creating nearly a ramjet effect without the bulky combustion chambers necessitated by the latter system at the rotor tips. The compressed air from the gas turbine engine expelled through nozzles at the rotor tips is warm enough to eliminate the need for other means of de‑icing the blades. No tail rotor is needed. A cantilever monoplane-type tail unit provided directional stability with two fins mounted at the ends of the horizontal stabilizer and a large central rudder positioned in the engine exhaust.

The fuselage was a welded steel‑tube structure surrounding an extensively glazed cabin with accommoda­tions for a pilot and one passenger. A skid‑type landing gear was fitted; instru­mentation was minimal. The Djinn was highly maneuverable and 'lenient where flying faults are concerned'. The Djinn can take off and land quite easily on the back of an ordinary truck.

Twenty‑two pre‑series S.O. 1221s were then built, pri­marily for evaluation for the French Army, and the first of these was flown on 23 September 1954. The French Army, the main customer for the Djinn, acquired one hundred of the one hundred and fifty that were produced. Djinns completed up to 1961, and still had about half of these in service in mid‑1967. Three Djinns were evaluated by the U.S. Army, under the designation YHO‑1DJ.

Civilian Djinns were employed in ten countries, mostly in an agricultural role, for which Sud­Aviation offered renewed conversion facilities in 1965. The so‑called ‘agricopter' version of the Djinn can carry up to 200 l. (44 Imp. gal.) of liquid chemical in twin tanks, and is fitted with lateral spray bars for the spraying, dusting or 'fogging' of crops with fertilizers or pesticides.

Aircraft Specifications

Rotor Diameter: 
32 ft. 10 in.
Fuselage Length: 
17 ft. 5 in
Maximum Speed: 
80 mph
Cruise Speed: 
65 mph
7 ft. 9 in
Empty Weight: 
694 lbs.
Gross Weight: 
1,389 lbs.
250 shp Turbomeca Palouste IV