ZASPL, the Aviation Association of students of the Lwów Technical University, was the oldest aviation organization in Poland. Revived after World War I, by 1926 it had workshops in Lwów which began building the glider designs of ZASPL member Wacław Czerwiński. The 1931 CW 5 was his response to a call from the government for a high performance glider. His earliest draft, the CW 5, specified the Gôttingen Gô 652 airfoil that Alexander Lippisch had used on the RRG Fafnir, despite the lack of full information on its characteristics at the time, and wind tunnel tests proved very disappointing. The CW 5.bis design that followed used a thinner and lower camber airfoil from the Warsaw Aerodynamic Institute. Wind tunnel results for it were much closer to expectations and the CW 5.bis was completed in the ZASPL workshops in 1932.
