Letov Š-228 in Estonian Service
Letov sent the Š-128 registered OK-VOT on a demonstration tour of the Baltic states in September 1931. Estonia expressed interest but required several modifications.
To meet the Estonia requirements, the Š-128 received a new landing gear with hydropneumatic shock absorbers and an increased vertical and horizontal tail area. The modified aircraft was redesignated the Š-228. Four Š-228E aircraft were then produced for the Estonian Air Force in 1932. The original prototype aircraft was left in the possession of Letov and in February 1932 now registered OK-VOU it was sent on another demonstration trip to the Baltics, focusing mainly on Finland. It crashed there a month later, but the interest it aroused in Finland gave rise to another version marked Š-328.
The Estonian Š-228s took no part in the Soviet invasion of Estonia in 1940.