sky" propaganda aircraft, fitted with a loud speaker. Po-2L : Limousine version with an enclosed passenger cabin. Po-2P : Postwar floatplane version; built in small numbers. Po-2S: Postwar air ambulance variant, with a closed rear cab. Po-2S-1: Postwar ambulance version, similar to the pre-war U-2S. Po-2S-2: Postwar ambulance version, powered by a M-11D radial piston engine. Po-2S-3: Postwar ambulance version, which had two underwing containers, each one was designed to transport one stretcher patient. Also known as the Po-2SKF. Po-2ShS: Staff communications aircraft, fitted with an enclosed cabin for the pilot and two or three passengers. Po-2SP: Postwar aerial photography, geographic survey aircraft. Po-2W: Yugoslav modification powered by license-built Walter Minor 6-III engine. 62 modified by Utva 1958–59. RV-23: This floatplane version of the U-2 was built in 1937. It was used in a number of seaplane altitude record attempts. The RV-23 was powered by a 529 kW (710 hp) Wright R-1820-F3 Cyclone radial piston engine. CSS-13: Polish licence version, built in Poland in WSK-Okęcie and WSK-Mielec after World War II (about 500 built in 1948–1956). CSS S-13: Polish ambulance version with a closed rear cab and cockpit and Townend ring (53 built in WSK-Okęcie in 1954–1955, 38 converted to S-13). E-23: Research version, built in the Soviet Union in 1934, for research into inverted flight. Operators Albanian Air Force received 78 aircraft between 1950-1966 and operated them until 1985. Bulgarian Air Force - 10 aircraft in 1949-1969 Civilian aviation People's Liberation Army Air Force Czechoslovakian Air Force designated as K-62 Slov-Air Finnish Air Force Free French Air Force operated Po-2s in the Normandie-Niemen unit. Luftwaffe operated Beuteflugzeug captured aircraft. Barracked People's Police East German Air Force Sport and Technology Association Hungarian Air Force The Hungarian Sport Bureau operated some aircraft before the 1956 Hungarian Revolution; Three confirmed were in Dunakeszi, one confirmed in Kisapostag. MIAT Mongolian Airlines Mongolian People's Army Air Force Korean People's Air Force Air Force of the Polish Army (after 1947 Polish Air Force) LOT Polish Airlines - Five Po-2 operated in 1945–1946, 20 CSS-13 for aerospraying in 1953–1956. Aeroklub Polski Polish Air Ambulance Service Polish Navy Romanian Air Force received 45 aircraft in 1949 Civilian aviation Soviet Air Force Aeroflot OSOAVIAKhIM DOSAAF Turkish Air League (Turk Hava Kurumu) received two U-2s which were given to Turkey as a gift from Russia in 1933 on the occasion of the 10th anniversary of the Turkish Republic. SFR