It was built in the Szybowcowy Zakład Doświadczalny (SZD, Glider Experimental Works) in Bielsko-Biała and first flew on 17 May 1951.

It appeared quite successful, and was cheaper in production and service, than the CSS-13 (licensed Polikarpov Po-2), but was not produced, because the Aviation Institute (Instytut Lotnictwa, IL) found some lacks in calculations and too weak landing gear.

In 1956, the design was taken over by WSK-Mielec factory (partly due to an interest of the press, combined with shortages of aircraft in aero clubs).

The S-4 was a high-wing monoplane (parasol wing) of wooden construction, conventional in layout, with a semi-monocoque fuselage and fixed tail-wheel landing gear.

The first S-4 Kania-2 prototype (registration SP-PAA) was shown on World Gliding Championship at Leszno in 1958, towing several gliders.