A Soviet experimental heavy bomber aircraft, designed by Konstantin Kalinin and constructed 1931-33 in Kharkov, Ukrainian SSR (modern Kharkiv, Ukraine).  Only one prototype was ever built; it crashed in November 1933, just three months after its first flight.  The project was canceled in 1935, and Kalinin himself followed (a victim of Stalin's purges) three years later.

"Wikipedia entry on the K-7":[https://en.wikipedia.org/wiki/Kalinin_K-7]
kalinin k-7