Yves Gardan designed a two-seat monoplane for the
Société Industrielle pour l'Aeronautique (SIPA)
based at the suburb Suresnes, west of the center of Paris, France.
Under the designation S.90, the aircraft was intended to fulfil the
post-war need for a small sport and training aircraft. Powered by a
75 hp Mathis G4F engine the prototype F-WDVA made its first flight on
June 15, 1947.
The aircraft construction was of a wooden frame and fabric coverings,
it was fitted with a sliding canopy and a fixed tailwheel
undercarriage; three more were built. In 1947 the French government
announced a contest for a light training aircraft to be built for use
by the flying schools of the SALS. SIPA reacted to this
opportunity by developing a S.90 with a more powerful engine and
other refinements under the designation S.901.
The first S.901 F-WDLV flew for the first time on June 25, 1948 but it
was not tested enough in time for the SALS fly-off in July 1948, so
SIPA entered the contest with a S.90 and emerged as winner, gaining
an order for 100 aircraft. Subsequently these 100 aircraft were built
in four versions: the S.901 through S.904, basically the same
aircraft but with other engines (see Models below).
When the S.901-S.904 production came to an end SIPA changed the
construction method and the new series S.91 to S.94 had the fabric
coverings replaced by plywood. This alteration did not bring further
orders and the production of the S.90 series ended in 1951.