In mid-1930s Maurice and Jacques Roussel both designed a radial-engined fighter, Maurice with team at Bloch works and his brother privately. Latter worked on his own, but resulting Roussel 30 light fighter was built at Bloch works at Courbevoie, flying April 1939; destroyed Bordeaux 1940. In parallel Jacques produced attractive Roussel 10 high-wing cabin 2-seater (July 1939). He never had his own company.