The first original fighter design to be produced by the Vojenská továrna na letadla (State Aircraft Works) “Letov”. The Š 3 was created by Ing Alois Smolik who had formerly worked for the Austro-Hungarian government Initially designated as S B.1, the original prototype was destroyed in a fire at the Prague-Letnany factory on 5 November 1921, but a second prototype entered flight test early in 1922.
A single-seat parasol monoplane powered by a 185 hp BMW l1la six-cylinder in-line engine and carrying an armament of two 7,7-mm Vickers machine guns, the Š 3 was of mixed construction with a wooden wing and metal fuselage and tail. The Š 3 participated in the International Meeting in Zurich in 1922, taking third place in the precision take-off and landing contest and seventh place in the aerobatic contest. Further development was discontinued in favour of the S 4.
Š.3 Crew: 1 Engine: 1 x 185hp BMW IIIa Max take-off weight: 928 kg / 2046 lb Empty weight: 662 kg / 1459 lb Wingspan: 10.13 m / 33 ft 3 in Length: 7.08 m / 23 ft 3 in Height: 3.04 m / 10 ft 12 in Wing area: 17.60 sq.m / 189.44 sq ft Max. speed: 225 km/h / 140 mph Cruise speed: 195 km/h / 121 mph Rate of climb: 508 m/min / 1650 ft/min Time to 9,840 ft (3000 m): 5.9 min Range: 472 km / 293 miles Armament: 2 x 7.7mm