The Tupolev I-4 was a Soviet sesquiplane single-seat fighter. It was conceived in 1927 by Pavel Sukhoi as his first aircraft design for the Tupolev design bureau, and was the first Soviet all-metal fighter. Design and development After the first prototype (under the development name Andrei Nikolayevich Tupolev fighter 5 | ANT-5), the I-4 was redesigned with a new engine cowling to decrease drag, with added rocket launchers on the upper wing and a larger tailfin. The lower wing was predominantly an attachment for the wing struts; it was almost removed in the second series, the I-4Z (where the lower wings were greatly shortened), and totally removed from the I-4bis, thus transforming the aircraft from a sesquiplane into a parasol-wing monoplane. Operational history The I-4 was used as a parasite fighter in experiments with the Tupolev TB-1 bomber. The aircraft was in Soviet service from 1928–1933. A total of 369 were built. Variants ANT-5 : Prototype. I-4 : Single-seat fighter aircraft. I-4Z : Single-seat fighter with span of lower wings greatly reduced. I-4bis : Monoplane version (lower wings totally removed). I-4P : Floatplane version. Operators Soviet Air Force Specifications (I-4) See also References Bibliography External links I-04 Biplanes Sesquiplanes 1920s Soviet and Russian aircraft Single-engined tractor aircraft Aircraft first flown in 1927