Konstantin Alexievich Kalinin patented a wing of elliptical
form in 1923, and
K-5
in 1925 built the K-1 (RBZ-6), a small
high-wing monoplane. Most notable developments were
the K-4 (22 built) and the scaled-up K-5 (260 built, 1930-
1934). K-5, typically an eight-seater,
K-7
made a significant
contribution to Russian civil avip.ion. K-7 was an exceptionally
large experimental bomber of 1933, having two
faired underslung tandem-wheel landing-gear units and
six engines. K-12 and K-13 were also bombers. In all,
Kalinin designed 16 types before his bureau was disbanded
in 1938.
