5 decal variants:
1. C-11, LSK/LV, DDR 1956
2. C-11, Display team "Major Seppel", air-parade Cottbus, DDR, 1957
3. C-11, JG7, Luftdiesnt, Drewitz, DDR 1955
4. C-11, No. 227, Langenlebarn/Tulln, Austria, 1955-65
5. C-11, Romania A.F., 1956
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.