The fuselage is narrow with a short, wide, and rounded tail fin. The bottom wing is rectangular with rounded tips. The top wing is slightly swept with rounded tips and constant chord.
Control surfaces are present on both wings.
The wings are connected by a single I-strut on either side. Tailplane is rounded. Landing gear with tail wheel is not retractable. Main wheels are enclosed in aerodynamic fairings. The development of S-1 began in 1943.