Polikarpov I-16

In the early 1930s the fighter aircraft of every air force in the world were still, overwhelmingly, fabric-covered biplanes. Into that conservative landscape the Soviet designer Nikolai Polikarpov launched something genuinely revolutionary. First flown on the last day of 1933, his I-16 was the world's first cantilever low-wing monoplane fighter with a retractable undercarriage to enter mass production — a clean break with everything that had come before.

Short, stubby and barrel-shaped, the little fighter was built around a licence-produced American Wright Cyclone radial (the Shvetsov M-25) and clothed in a mix of wood, metal and fabric. It looked unlike any contemporary, and it flew unlike any contemporary too: blisteringly fast for its day, but also nervous, demanding and unforgiving — qualities that would define its whole career.

The I-16 was, in the truest sense, a pilot's challenge. Its extremely short fuselage gave it lively, almost vicious handling: it was unstable in all axes, snappy in the stall and quick to punish carelessness, yet in capable hands that same twitchiness translated into superb agility. The early aircraft had an enclosed canopy, but pilots distrusted the poor visibility and slow-sliding hood, and many later machines reverted to a simple open cockpit with a small windscreen.

Across its production life the design was steadily uprated. More powerful Shvetsov engines (the M-62 and M-63) pushed top speed upward, and armament grew from a pair of rifle-calibre ShKAS machine guns to four, with cannon-armed versions mounting two 20mm ShVAK. Ground-attack variants could carry bombs and the pioneering RS-82 unguided rockets — among the first air-launched rockets used operationally by any nation.

For all its modernity in 1934, the I-16's wood-and-fabric construction and inherent instability set hard limits on how far it could be pushed. By the end of the 1930s the aircraft that had once led the world was being overtaken by a new generation of faster, more stable, all-metal monoplanes — including the Bf 109 it would soon meet in combat.

The I-16 appeared in a long succession of “Types”. The early Type 5 established the breed; the Type 10 added a second pair of machine guns and refinements; and the Type 17, 24 and 27 introduced cannon armament, more power and underwing stores for the fighter-bomber and ground-attack roles.

A two-seat trainer, the UTI-4, was built in large numbers to convert pilots onto the tricky little fighter. In total something on the order of 10,000 I-16s of all types were produced, making it one of the most numerous fighters of the late 1930s and the most important Soviet fighter of the pre-war years.

The I-16 went to war long before 1939. In the Spanish Civil War it stunned the Nationalists and their German and Italian allies: faster and better-armed than the biplanes it faced, it dominated the skies until the arrival of the Bf 109. Spanish Nationalist pilots called it the “Rata” (rat), while the Republicans who flew it knew it as the “Mosca” (fly); to its Soviet crews it was the “Ishak”, the little donkey. It also fought the Japanese over Khalkhin Gol in 1939 and saw action in China.

For its day the little Polikarpov was a revelation — one of the first low-wing monoplane fighters in the world with a retractable undercarriage: stubby, fast and astonishingly agile. It was also a handful, unstable and unforgiving of a careless pilot; but in trained hands over Spain it had, for a time, no equal.

By the time of Operation Barbarossa in June 1941, however, the I-16 was thoroughly obsolete — yet it still equipped a large part of the Soviet fighter force and so bore the full fury of the German onslaught. Hundreds were destroyed in the opening days, many on the ground. But the type fought back with a ferocity that became legendary: its pilots pressed home attacks against overwhelming odds and, when their guns failed or their ammunition ran out, some resorted to the taran — deliberately ramming German aircraft. The little fighter soldiered on in front-line service into 1942–43 before finally being withdrawn.

That the obsolete little fighter fought on at all was a testament to its pilots more than its qualities. It could still turn with the Bf 109 at low speed, and in the desperate summer of 1941 that was sometimes enough to matter. By 1943 it had finally given way to the new Yaks and LaGGs — but the Ishak had helped hold the line at the moment the Soviet Union most needed it to.

The Polikarpov I-16 holds a permanent place in aviation history as the fighter that ushered in the modern era — the first mass-produced monoplane to combine a cantilever low wing with retractable gear, years ahead of its contemporaries. For a few years in the mid-1930s it was arguably the most advanced fighter in the world.

That very precocity meant it was also among the first to be rendered obsolete by the breakneck pace of late-1930s design. Demanding to fly and outclassed by 1941, the “Ishak” nonetheless fought on with extraordinary tenacity in the hands of Soviet pilots who refused to give ground, and it remains both a technological landmark and a symbol of the desperate, defiant air battles of the early Eastern Front.

• Yefim Gordon & Keith Dexter, Polikarpov’s I-16 Fighter (SAM Publications).
• Yefim Gordon, Soviet Air Power in World War 2 (Midland Publishing).