4 decal variants:
1. C-11, No. 171707, 47. průz. let. pluk, 2. let., Mladá, 1956
2. C-11, Hungarian Air Force
3. C-11, Gdynia - Oksywie, Babie Doly, Poland, 1960
4. C-11, Mali Air-force, 1961
The first prototype of the new trainer, designated Yak-UTI or Yak-3UTI flew in late 1945. It was based on the radial-powered Yak-3U, but with the new Shvetsov ASh-21 seven-cylinder radial replacing the ASh-82 of the Yak-3U. It used the same all-metal wings as the Yak-3U, with a fuselage of mixed metal and wood construction. Pilot and observer sat in tandem under a long canopy with separate sliding hoods. A single synchronised UBS 12.7 mm machine gun and wing racks for two 100 kg (220 lb) bombs comprised the aircraft's armament.