In the summer of 1928 the French government contracted Nieuport-Astra and Société des Avions Bernard to produce racing seaplanes to compete in the 1929 Schneider Trophy.
[2] The wing, built around two duralumin spars and with a thin profile, was trapezoidal in plan out to rounded tips, with sweep only on the leading edges.
Much of the wing surface was formed by thin, smooth radiators for the liquid-cooled engine; the rest was wood-covered with spruce leading edges.
The fin had Nieuport's characteristic elliptical profile and the horizontal tail, set low on the fuselage, was a broad oval in plan.
[1] In August 1929, following a dispute with the Trophy organizers, France decided to pull out of the contest but the aircraft development programme continued; delayed by engine problems it was not until February 1930 that flight trials, piloted by Sadi Lecointe, began.
Modifications to it were based on the lessons of the earlier tests; externally, the principal alteration was a much larger aperture in the nose to assist engine cooling.