in 1938 gaucher joined newly founded secat ("société d'etudes et de construction d'avions de tourisme") in boulogne and designed a series of light aircraft very similar to the week-end apart from their engines. the secat vi la mouette, powered by a train 6t inverted six cylinder in-line engine, flew before world war ii and was produced in a series of five, one of which survived the war as the secat s.4 la mouette. the secat s.5 and secat rg.75 were post-war developments, powered by régnier 4d2 four cylinder, inverted in-line engines.