A two-seat, parasol monoplane sports plane (with HP slats) of 1931. Series aircraft were built in 1934, powered by a 55 hp 3-cyl Walter Polaris radial engine.
An Š.139 development prototype (OK-ELA) of 1933 was powered by an 80 hp 7-cyl Pobjoy R radial.
Sixteen Š.239 developments were built, powered by an 85 hp 4-cyl Walter Minor 4. Ten went to flying clubs.