10/31/2009. The Gemeaux was developed by Estalissements Fouga et Cie. at Aire-sur-1'Adour for use as a flying test bed for the Turboméca range of light turbojets. It comprised two C.M.8.R-9.8 Cyclope fuselages, and two Cyclope outer-wing panels and tail units, the fuselages being joined by a parallel-chord center wing and a horizontal strut aft below the tail surfaces.

Two Gemeaux airframes were built, F-WEPJ and F-WFKN, each being flown with several types of turbojet. Most of the flying was done by Fouga test pilot Léon Bourrieau.

The Gemeaux I was first flown on March 6, 1951, with two 220 lb (100 kg) st Piméné turbojets, one mounted on each fuselage.

The Gemeaux II flew on June 16, 1951, powered by a 606 lb (275 kg) st Marboré I mounted on the center wing midway between the fuselages.

Redesignated Gemeaux III, the prototype Marboré II (initially developing 772 lb, 350 kg st) was installed, and flown on August 24, 1951, and with 882 lb (400 kg) st production Marboré II on January 2, 1952.

As the Gemeaux IV, the airframe was used as a test bed for the Turboméca Aspin I ducted-fan turbojet of 441 lb (200 kg) st, with which it flew on January 2, 1952.

The Gemeaux V was fitted with the 794 lb (360 kg) st Aspin II and flew for the first time on June 21, 1952.

The Gemeaux had a wing span of 35 ft 4 in (10.77 m), a length of 21 ft 10 in (6.65), and a height of 6 ft 4 in (1.93). Weights and performances varied with the type of turbojet installed, loaded weight ranging from the 2,412 lb (1,094 kg) of the Gemeaux I to the 2,718 lb (1,233 kg) of the Gemeaux V, and maximum speed at sea level ranging from 155 mph (250 kmh) for the Gemeaux IV to the 249 mph (400 kmh) of the Gemeaux III. The Gemeaux carried five fuel tanks with a total capacity of 58,1 (220 l) gal.