First flown in 1924, the Dewoitine D 9 was essentially a scaled- down development of the earlier D 1 single -seat parasol monoplane fighter, from which it differed mainly in being powered by a 420-hp Gnome-Rhone 9 Ac radial engine, a licence-built version of the 9-cylinder Bristol Jupiter.
Developed for participation in the 1923 C1 programme, two prototypes were completed. The Aviation Militaire purchased one for evaluation, but despite the extra available power the performance was not significantly improved, the D 9 took only 9 seconds less than the D 1 to reach 5000 m (16404 ft), and no French production contracts resulted.
Early in the flight test programme, the standard D 1 wing was replaced with a new wing of 2.5 sq.m greater area. A six-month delay in the commencement of evaluation of the contenders in the C1 programme provided Dewoitine with the opportunity to increase wing area by yet a further 2.5sq.m.
Armament consisted of two fuselage-mounted 7.7mm Vickers guns and two Darne model 19 guns of 7.5mm calibre mounted on the wing centre section outside the area of the propeller disc.
The D 9, placed sixth among the contenders, was destroyed on 15 October 1925.
Apart from the prototypes, only 13 were manufactured by Dewoitine, two for Belgium in 1925, Switzerland acquired the sec-ond prototype and assembled three others in 1928 from French-built components, and Yugoslavia (eight). The components of three were delivered in 1927 to the EKW (Eidg. Konstruktions-Werkstatte) in Switzerland for assembly, with delivery to the Fliegertruppe in 1928.
The largest production was undertaken by Ansaldo in Italy, which built 147 for the Regia Aeronautica with the designation AC 3.
Max take-off weight: 1333 kg / 2939 lb
Empty weight: 945 kg / 2083 lb
Wingspan: 12.80 m / 41 ft 12 in
Length: 7.30 m / 23 ft 11 in
Height: 2.93 m / 9 ft 7 in
Wing area: 25.00 sq.m / 269.10 sq ft
Max. speed: 244 km/h / 152 mph
Range: 400 km / 249 miles