Yakovlev Yak-7

In 1939 Alexander Yakovlev drew a tandem two-seat advanced trainer, designated I-27 and then UTI-26 — uchebno-trenirovochny istrebitel, training fighter — intended to give pupils time on a high-performance machine before they were let loose on a real one. It was, structurally, a Yak-1 with a second cockpit.

The German invasion of June 1941 ended that plan. The Soviet Union needed fighters immediately and in any condition, and anything that could carry a gun was ordered armed and sent forward. The trainer was redesignated Yak-7, given a cannon and machine guns, and pushed into production as a combat aircraft — the reverse of the path aircraft normally travel, and one of the clearest illustrations of how bad the summer of 1941 was.

The conversion turned out to be an improvement, for a reason nobody had planned. Removing the instructor left a substantial volume behind the pilot that the single-seat Yak-1 did not have, and that space could be filled with whatever the situation demanded: extra fuel, heavier radio equipment, oxygen, or — in the field — cargo, a mechanic, or a rescued pilot.

The first two-seat fighters, the Yak-7A, reached front-line units in late 1941 armed with a 20 mm ShVAK cannon firing through the propeller hub and two 12.7 mm Berezin UB machine guns. The definitive Yak-7B refined the airframe and the armament, and by 1942 the type was one of the standard Soviet fighters — a trainer that had become the front line.

That internal volume also made the Yak-7 the natural test bed for weapons too large for a small fighter. The most striking was the 37 mm cannon installation firing through the propeller hub, an anti-armour and anti-bomber weapon of a calibre normally found on the ground — the same idea that would later reach production on the Yak-9T.

Other versions explored the opposite direction: the Yak-7V reverted to the trainer role the airframe had been designed for, with fixed undercarriage and no armament, and served throughout the war teaching the pilots who would fly the fighters it had spawned. Few airframes did the round trip from trainer to fighter and back again.

The Yak-7B carried much of the Soviet fighter effort through the hardest year. By mid-1942 it was one of the most numerous fighters in VVS service, flying over Stalingrad and along the whole southern front at the moment when the Soviet air force was still losing badly but had stopped collapsing — escorting Il-2s, covering river crossings, and contesting airspace it could not yet control.

Against a Bf 109F or G it was outclassed above 4,000 m and roughly competitive below, which describes most Soviet fighters of the period and matters less than it sounds: the fighting happened low, over the battlefield, and the Yak-7 was there in numbers. Guards regiments such as the 12th GIAP flew it through 1942, and the two-seat versions did work no single-seater could — ferrying mechanics to forward strips, carrying a spare pilot, and flying reconnaissance with an observer in the back.

The Yak-7’s most important descendant came from that same empty space. Fitted with metal wing spars and the volume behind the cockpit turned over to fuel, an experimental version designated Yak-7DI — dalny istrebitel, long-range fighter — flew in 1942 and went into production under a new name: the Yak-9.

That aircraft became the most-produced Soviet fighter of the war, with 16,769 built. The line therefore runs from a 1939 trainer, through an emergency conversion, to the fighter that equipped the Soviet air force for the second half of the war — and every step of it was driven by what could be done with the room where the instructor used to sit.

About 6,399 Yak-7s of all versions were built between 1941 and 1944, which alone would make it a significant fighter; set beside the Yak-1, Yak-9 and Yak-3 it is the least remembered member of a family that dominated Soviet fighter production. It was not the best of them at anything in particular: the Yak-3 turned better, the Yak-9 carried more.

Its importance is as the hinge. The Yak-7 is where Yakovlev’s line stopped being a single lightweight fighter and became an adaptable family — and it got there by accident, because an invasion forced a training aircraft into combat and the aircraft turned out to be better at the job than anyone had intended.

• Yefim Gordon, Yakovlev’s Piston-Engined Fighters (Midland, Red Star).
• George Mellinger, Yakovlev Aces of World War 2 (Osprey, Aircraft of the Aces 64).
• Yefim Gordon & Dmitri Khazanov, Soviet Combat Aircraft of the Second World War (Midland Publishing).