By 1939 the biplane was supposed to be finished. Monoplane fighters — the Bf 109, the Spitfire, the Hurricane — were establishing what air combat in World War II would look like. And yet the Soviet Union was, that same year, accepting deliveries of a new biplane fighter: the Polikarpov I-153 Chaika. It had two wings, an 800-horsepower engine, and a startling concession to modernity — retractable landing gear that folded into the lower fuselage. It looked, to anyone outside the Soviet Union, like a contradiction.

And yet the I-153 served. It fought. It went on serving. It engaged Japanese aircraft at Khalkhin Gol, Finnish forces in the Winter War, German Bf 109s in 1941, and — astonishingly — was still in marginal operational use as a trainer when MiG-15s were entering Soviet service in 1949.

A Last-Generation Compromise

The I-153 was the final evolution of a design line that started with the I-15 in 1933. By the mid-1930s, Soviet doctrine called for a "high-low" mix: a fast monoplane fighter (the I-16) for speed and a maneuverable biplane (the I-15 family) for dogfighting. The I-153 represented the apex of the biplane half of that pairing — agile, well-armed, and crucially equipped with retractable gear that closed roughly 30 km/h of speed gap with monoplane fighters.

It was, by the standards of 1937 when it was designed, an entirely reasonable aircraft. By the standards of 1941, when it met the Luftwaffe, it was a generation out of date.

Surprise Performance

What the I-153 lacked in speed it kept in turn radius. It could out-turn almost anything in the sky. In Mongolian skies during the 1939 border war against Japan, I-153s tangled with Nakajima Ki-27s — nimble fixed-gear monoplanes — and came out reasonably well. Soviet pilots discovered they could lure Japanese pilots into protracted turning fights and shoot them off the tail of their own loops.

This success bred dangerous confidence. When Operation Barbarossa opened in June 1941, the I-153s caught on the ground at forward airfields were destroyed wholesale. Those that got airborne could turn inside a Bf 109, certainly — but the Bf 109 simply zoomed away, climbed, and dove again, refusing to dogfight on the I-153's terms. Soviet biplane losses in the first weeks of Barbarossa were catastrophic.

The Long Quiet Twilight

What the I-153 lost in air-to-air combat, it gained in unglamorous utility. Its short-field performance and low maintenance demands made it an excellent ground-attack platform. Equipped with RS-82 unguided rockets — making it one of the earliest production aircraft to carry rocket armament — it served the partisan war effort and forward Soviet air regiments throughout 1942 and into 1943.

By 1944, the I-153 had been retired from front-line service. But it remained in flight schools and second-line units for years afterwards. A handful of surviving airframes were still on Soviet rolls when the MiG-15 entered service in 1949 — meaning the same air force that operated the first practical swept-wing jet fighter was, that same week, still flying a 1939 biplane somewhere down the chain of command.

The Last Biplane Fighter to Matter

The I-153 has a strong claim to being the last biplane fighter that ever mattered operationally. The British Gloster Gladiator was already obsolete when war broke out. The Italian CR.42 had a longer combat career but was a pure rear-guard story. The Polikarpov, with its retractable gear, rocket armament, and surprising sortie count, took the biplane concept as far as it could possibly go.

Three thousand four hundred and thirty-seven were built. A handful, restored to airworthy condition in the 1990s, still fly today.

Why the Soviets built a brand-new biplane in 1938 — the Polikarpov I-153.

Sources: Polikarpov design bureau archives, “Soviet Combat Aircraft of WWII” (Gordon & Khazanov), VVS Operational Records.