The Tairov OKO-4 (Opytno KonstrooktOrskoye - experimental design section) was an attack aircraft produced in the Ukrainian SSR in the USSR in 1939.
This small sesquiplane attack fighter was completed in 1939, but was unsuccessful.
The prototype was never flown and further work was cancelled.
"Encyclopaedia of Russian Aircraft 1875-1995".
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