Evolved in parallel with the D 9 as a contender in the 1923 C1 programme, the larger, sin-gle-seat parasol D 12 fighter was powered by a 450hp Lorraine- Dietrich 12EW 12-cylinder W-type water-cooled engine and armed with two 7.7mm Vickers guns.
With a basically similar fuselage to that of the D 1, the D 12 first flown in June 1924.
In September 1924, the D 12 was fitted with a higher compression 450-hp Lor-raine 12 Eb and a pair of 7.5mm Darne model 19 guns on the wing centre section.
The paired Lamblin radiators on the undercarriage legs was replaced by a frontal radiator and a wing similar to that finally adopted on the D 9 was fitted. On 5 February 1926, the D 12 was written off in an accident at Cazaux. A second prototype had meanwhile entered flight test, having flown at the end of 1925, this having a W-type Hispano-Suiza 12Gb engine, but further development was discontinued.
It was eventually to take third place in the 1923 C1 programme after the Nieuport-Delage 42 and the Gourdou- Leseurre 32.
Max take-off weight: 1636 kg / 3607 lb
Empty weight: 1070 kg / 2359 lb
Wingspan: 12.80 m / 41 ft 12 in
Length: 7.60 m / 24 ft 11 in
Height: 3.00 m / 9 ft 10 in
Wing area: 25.00 sq.m / 269.10 sq ft
Max. speed: 239 km/h / 149 mph