Tupolev I-8

The Tupolev I‑8 was an experimental Soviet fighter developed in the early 1930s under the direction of the Central Aerohydrodynamic Institute (TsAGI). Conceived as a successor to the earlier I‑5 and I‑6 designs, the I‑8 incorporated several aerodynamic innovations that reflected the institute’s research into high‑speed flight. The aircraft featured a low‑wing cantilever monoplane layout, an enclosed cockpit, and a retractable, split‑type landing gear—a rarity for Soviet aircraft at that time. Power was provided by a 530 kW (710 hp) Hispano‑Suiza 12Ybrs V‑12 engine, driving a two‑bladed propeller and delivering a top speed of roughly 470 km/h. Structural testing at TsAGI emphasized the use of duralumin stressed‑skin construction, which reduced weight while maintaining rigidity. Although only two prototypes were built and the type never entered mass production, the I‑8’s flight trials supplied valuable data on wing loading, control surface balancing, and high‑altitude performance. These findings directly influenced later Tupolev fighters such as the SB bomber and the I‑16 monoplane. In retrospect, the I‑8 stands as a key stepping stone that helped transition Soviet aviation from biplane tradition to modern monoplane design during a critical period of technological advancement.

Central Aerohydrodynamic Institute

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