Built in vast numbers, Aleksandr Yakovlev’s fighters were among the most important Allied aircraft of World War II.
Yakovlev aircraft have become as closely associated with World War II Soviet air power as Messerschmitts are with the Luftwaffe, Spitfires with the Royal Air Force and Zeros with the Japanese. More Yak fighters were built than any other warplane in history, with the possible exceptions of Germany’s Messerschmitt Me-109 and another Soviet design, the Ilyushin Il-2 Shturmovik. That massive production was achieved despite the severe disruption of the Soviet Union’s industrial capacity brought about by the Germans’ 1941 invasion.
Like the Me-109 and Supermarine Spitfire, Yak fighters were produced in a host of different models that were tailored to specific missions. And like the Spitfire and North American P-51 Mustang, Yaks soldiered on after the war, appearing over Korea in 1950. Unlike the Me-109, Spitfire, P-51 and Mitsubishi A6M Zero, however, Yakovlev completed the transition into the jet age by adapting its airframes for jet propulsion.
During the war years, Yaks were often derided by foreign aviation experts as crude and lacking in high-altitude performance. But what those pundits failed to realize was that many of the characteristics they criticized were specifically designed into the aircraft and were largely responsible for its success. In fact, Yaks proved to be the optimum plane for the sort of fighting to which they were committed.
What Western critics saw as crudity was actually a simplicity of design that enabled semiskilled workers in hastily set up factories to produce Yaks by the tens of thousands. It would have been far more difficult, if not impossible, for the wartime Soviet industrial infrastructure to have produced a similar number of more sophisticated fighters such as Spitfires or Mustangs.
In addition, high-altitude performance was not a primary concern over the Russian Front. American fighters such as the Lockheed P-38 Lightning, Republic P-47 Thunderbolt and P-51D were called upon to escort strategic bombers flying at 30,000 feet. The air war over Russia, however, was primarily a tactical conflict, fought mainly at altitudes below 15,000 feet.
Aleksandr Yakovlev, the man behind the ubiquitous Yak, began his aviation career in 1923 at age 17, when he helped another designer build a biplane glider for a competition. Disappointed when his colleague’s glider didn’t win, Yakovlev designed and built his own monoplane glider, which won that competition the following year.
Sponsored by the Association of Societies for the Promotion of Defense and Aero-Chemical Development, Yakovlev built his first powered aircraft in 1927. The light two-seat sport biplane, called the AIR-1, justified his sponsors’ support by setting class records for speed and distance. It also gained Yakovlev admission to the Soviet air force academy, from which he graduated in 1931. By the late 1930s, he headed his own aircraft design bureau and was acknowledged as his country’s foremost producer of light aircraft and training planes.
During the 1930s, the Soviet Union boasted one of the most progressive aviation development programs in the world. Many Soviet planes set load-carrying and distance records. Some of its bombers were so large that they were actually capable of carrying fighters slung beneath their wings. The Soviet Union was also among the first countries in the world to deploy paratroops.
One of the most significant innovations to appear in the Soviet air forces, the Voyenno-Vozdushny Sili (V-VS), during that period was the introduction in 1934 of Nikolai Polikarpov’s I-16, the world’s first single-seat, single-engine, all-metal low-wing monoplane with retractable landing gear and an enclosed cockpit (though it later reverted to an open cockpit). Armed with four machine guns—enhanced in some versions to two machine guns and two cannons—the I-16 was the first production aircraft to combine all the important features that were to characterize the majority of WWII fighters.
Committed to combat during the Spanish Civil War, the I-16 proved superior to the conventional biplane fighters of its day. The tempo of aircraft and engine development during the late 1930s was extraordinarily rapid, however, and in 1938 the Luftwaffe introduced a far more advanced fighter over Spain, the Messerschmitt Bf-109B. It quickly became apparent to V-VS leaders that their once-unbeatable I-16 would soon have to be replaced by a more modern design—and that the I-16’s designer was not up to producing a suitable successor. Polikarpov’s successful fighter designs thereafter reverted to the old biplane formula, while his only new monoplane fighter design proved unsuccessful until it was taken over and modified by another team of designers, Artyom Mikoyan and Mikhail Gurevich. It eventually went into production as the MiG-3. In their search for a replacement for the I-16, the Soviets invited several other design bureaus to submit prototypes for evaluation. Among them was that of Aleksandr Yakovlev, who had never before designed a single-seat fighter.
The Soviet aviation industry did not have privately owned aircraft manufacturing companies like Western nations. Rather, the state sponsored a number of independent design bureaus with limited facilities for the production of prototype aircraft. If a prototype proved successful, the government would assign one or more state-run aircraft factories to build it in quantity. Yakovlev had presided over one such design bureau since 1934.
Initially known as the I-26 (the “I” stood for Istrebitel, or fighter), Yakovlev’s first fighter prototype undertook its maiden flight at Moscow on January 13, 1940. The bright red plane was of mixed construction, with its forward fuselage consisting of a tubular steel framework covered with duralumin, while the rear fuselage was made of fabric-covered wood. The wings and tail were also constructed of wood, and the control surfaces were duralumin. The intended armament was a 20mm cannon firing through the propeller hub and four 7.62mm machine guns, though two of the machine guns were eliminated from the production model to save weight. Later versions replaced the eliminated 7.62mms with a single 12.7mm weapon. Powered by the same 1,050-hp Klimov M-105 liquid-cooled V-12 engine fitted to the competing Lavochkin-Gordunov-Gudkov LaGG-3 fighter (which also entered production), the I-26 was 563 pounds lighter.
Yakovlev’s fighter demonstrated excellent flight characteristics from its earliest trials, proving that it was fast as well as maneuverable. It was easier to fly than the MiG-3 and LaGG-3, and performed better than the LaGG-3. Moreover, the I-26 also proved relatively easy to manufacture, demonstrating that Yakovlev understood not only aeronautical design but also the limitations of the Soviet aircraft industry. In recognition of Yakovlev’s efforts in developing the new fighter, Josef Stalin awarded him 100,000 rubles, along with the Lenin Prize, and also presented the designer with a new car. In addition, the production version was officially redesignated the Yak-1.
As with any new aircraft, the Yak-1 experienced its fair share of teething troubles. The engine’s lubrication system leaked, and the oil cooler proved inadequate. Both of those systems required modifications before the fighter was deemed acceptable. Another component that needed beefing up was the landing gear. A test pilot lost control of the prototype and died in a crash after one of the main landing gear legs opened during a low-level roll. Despite those early problems, however, the Yak-1 was judged a formidable combat plane, and the first production aircraft entered service with the V-VS toward the end of 1940.
The Yak-1 was 27 feet 9 inches long and had a wingspan of 32 feet 10 inches. Powered by the 1,050-hp M-105PA engine, it achieved a maximum speed of 360 mph. The fighter was initially built at a Moscow factory, but production was soon transferred to Saratov when the Moscow plant switched to building the Yak-7. A total of 8,721 Yak-1s were manufactured before they were replaced on the production line in 1944 by an improved version, the Yak-3.
One of the principal differences between the Yak-1 and its competitors was that Yakovlev had prepared plans for not just a single fighter plane but a whole family of aircraft tailored to specific missions. Whereas the basic Yak-1 was intended for operation over front lines at low to medium altitudes, a separate version, the Yak-5, was designed to serve as a high-altitude interceptor. In the end the project was canceled due to problems with its supercharged engine, and the Yak-5 never got beyond the prototype stage.
A far more successful variation of the Yak-1, the versatile Yak-7 stemmed from Yakovlev’s design for a two-seat trainer. The fact that Yakovlev had provided for such a conversion trainer was a major reason why Soviet pilots accustomed to biplane fighters or the I-16 monoplane could master the Yak-1 with a minimum of mishaps.
More than simply a Yak-1 with an additional cockpit, the Yak-7 featured a stronger airframe than the single-seater. The wing and radiator were moved aft to balance the second cockpit, and the landing gear had to be repositioned and strengthened. Though intended as an advanced trainer, the resulting aircraft performed almost as well as the production Yak-1 fighter. Its maximum speed was about 360 mph, roughly the same as the Yak-1’s. With a length of 27 feet 6 inches and a wingspan of 32 feet 6 inches, the Yak-7’s dimensions were also essentially the same as the Yak-1’s. In addition, the 5,465-pound trainer was only 154 pounds heavier than the single-seat fighter.
Early in the war Soviet authorities recognized that the Yak-7 trainer could be developed into a whole series of useful combat aircraft, including a high-speed two-seat liaison and reconnaissance plane, a courier aircraft and a single-seat fighter-bomber. Yakovlev was initially reluctant to proceed with the single-seat version, which was known as the Yak-7B, but it proved fully capable of taking on the best Luftwaffe fighters. When powered by the improved 1,180-hp M-105PF engine, it had a top speed of 381 mph. The Yak-7B represented one of the few instances of the successful adaptation of a trainer into a fighter plane.
A more potent version, known as the Yak-7-37, carried a 37mm cannon mounted to fire through the propeller hub. To accommodate the large cannon, the rear cockpit was eliminated and the pilot’s cockpit moved back 15.8 inches. The 37mm proved effective against aircraft, armored vehicles and small ships. As a bonus, repositioning the cockpit had actually improved the fighter’s handling characteristics.
Both the Yak-1 and the Yak-7 underwent a continual series of improvements during the course of production. Modifications to the engine produced greater power output as well as improved lubrication and cooling. The most noticeable alteration to both types was to the cockpit canopy. As with the Spitfire, Thunderbolt and Mustang, the Yaks’ original razorback fuselage was modified to accommodate a bubble canopy that greatly improved the pilot’s rear view.
In the spring of 1942, Yakovlev began working on an improved version of the Yak-7, known as the Yak-7DI (Dalny Istrebitel, or longrange fighter). Of mixed construction with duralumin spars and wooden ribs, its wings weighed considerably less than the original allwood wings, enabling the new version to carry appreciably more fuel than the production Yak-7B. The long-range fighter entered production in autumn 1942 as the Yak-9, and had its combat debut over Stalingrad in November of that year. After 6,399 Yak-7s had been built, the Yak-9 completely superseded it on the production lines. The Yak-9 went on to become the most prolific Soviet fighter of WWII. A total of 16,769 were built before production terminated in 1947, 14,579 of which were completed before the war ended.
Like the earlier Yak-7, the Yak-9 was developed into a wide variety of specialized variants. The Yak-9T (tank-buster) followed the pattern set by the earlier Yak-7-37, with its cockpit moved aft to accommodate a 37mm engine-mounted cannon and one synchronized 20mm cannon in the fuselage upper cowling. It first saw combat during the Battle of Kursk in August 1943. Despite the Yak-9T’s antitank designation, it was credited with nearly half the enemy aircraft destroyed during the course of the battle. That same type was further developed into the Yak-9K (Kanon), mounting 45mm and even 50mm weapons. The Yak-9K was not produced in large numbers—partly because the fighter’s structure could not take the strain of firing such powerful guns, and partly because the heavier automatic cannons were in relatively short supply.
As the Red Army began taking the offensive in 1943, a need arose for longer-range fighters to operate deeper behind enemy lines. The Yak-9D incorporated additional fuel tanks that increased its fuel capacity by 75 percent. It proved to be just as fast as the earlier Yak-9, but pilots considered it less nimble. Nevertheless, the Yak-9D went into large-scale production and proved very successful. An even longer-legged version, the Yak-9DD, increased fuel capacity to 186 gallons, 30 percent more than the Yak-9D and 92 percent more than the standard Yak-9. Performance suffered somewhat, but the Yak-9DD managed to achieve a range of 1,420 miles. Although the aircraft was primarily intended as an escort fighter, one fighter regiment of Yak-9DDs was deployed to Italy to provide air support for Marshal Tito’s Yugoslav partisans.
The Yak-9D’s wingspan was 31 feet 11 inches, and it was 26 feet 3 inches long. At a gross weight of 6,790 pounds, it weighed 110 pounds more than the Yak-7B. The fighter’s M-105PF engine gave it a maximum speed of 374 mph, slightly slower than the Yak-7B, but its 876- mile range was 71 percent greater.
The Yak-9B fighter-bomber, a less successful variant, was unusual in that it incorporated an internal bomb bay behind the cockpit that held four 220-pound bombs or four containers of 4.4-pound antitank bomblets. The additional weight slowed the Yak-9B down and adversely affected its stability and handling. In addition, no adequate method was provided for the pilot to accurately aim his bombload. Although used in action by at least two fighter regiments, only 109 Yak-9Bs were built before the type was discontinued.
The final Yak-9 production version, the Yak-9U (Uluchshenny, or improved) was designed around the 1,500-hp Klimov VK-107 engine, which produced 27 percent more power than the Klimov used in the Yak-9D. The cockpit was moved back 1 foot 4 inches, as it had been in the Yak-9T, a modification that improved maneuverability and also reduced the likelihood of nosing over on landing. The engine cowling and air intakes were also redesigned to reduce drag, with the oil cooler transferred to the port wing root and the carburetor air intake to the starboard wing root. Armament was increased to two 12.7mm machine guns and one 20mm cannon.
The most important improvements in the Yak-9U were to its structure. By the middle of 1943, the Soviets realized that the light alloys needed for aircraft production were not in such critically short supply as had been thought. Furthermore, the Yak-9U was expected to continue in postwar service, and since wooden planes tended to deteriorate fairly rapidly, they were not regarded as cost-effective for the peacetime air force. Yakovlev therefore took the opportunity to redesign the Yak-9U with an all-metal, stressed-skin airframe.
The result was indeed a greatly improved fighter, one that fully realized the excellence of Yakovlev’s original concept. Introduced to frontline squadrons in autumn 1944, just as the last of the Yak-1s and Yak-7s were being retired, the Yak-9U was 62 mph faster than its predecessors and reduced climbing time to 15,000 feet by more than a minute. Flying the Yak-9U, Soviet fighter pilots were confident they could take on any German piston engine fighter. The all-metal Yak-9 remained in production until 1947. Erroneously identified as “Yak-11s” by the Americans, they were encountered by U.S. Air Force pilots during the early stages of the Korean War.
While Aleksandr Yakovlev pursued one line of development that led to the Yak-9U, he did not neglect the development of the original Yak-1, completing the prototype for an improved variant, the Yak-1M (Modifikatsirovanny, or modified), in February 1943. On this version, the Yak-1’s wooden wing was replaced by one similar in construction to that of the Yak-9, but with the area reduced by 24.3 square feet. The oil cooler intake was shallower, with the rear fuselage cut down to accommodate a three-piece canopy offering better rear vision. An improved radio was installed, and plywood skin replaced fabric on the rear of the fuselage. Armament included two 12.7mm machine guns and one 20mm cannon. The Yak-1M was 540 pounds lighter than the production Yak-1, resulting in a much faster and more agile fighter.
One of Yakovlev’s design team members, K.V. Sinelshchikov, refined the lightened Yak further, reducing the wingspan and its aspect ratio. The nose incorporated the same aerodynamic improvements later featured in the Yak-9U, and the radiator installation was cleaned up to further reduce drag. The new lightweight fighter boasted a maximum speed of 433 mph, and its acceleration was so good that pilots had difficulty keeping it from exceeding the airframe’s limitations. For reasons that are unclear, this ultimate lightweight variant entered production with the designation of Yak-3, despite the fact that it appeared after the Yak-7 and Yak-9. Entering service with Soviet fighter units in the late spring of 1944, it be – came an instant favorite.
Yaks were so numerous in the V-VS and other Soviet air arms during WWII that for a while there were more of them in service than all other fighter types combined. Although the leading Soviet ace did not fly them (Ivan Kozhedub scored all of his 62 victories in Lavochkin La-5s and La-7s), it would be impossible to list even a fraction of the other high-scoring fighter pilots who flew Yaks. Notably, they included history’s only two female aces, Lydia Litvyak and Yekaterina Budanova. By the time Litvyak was killed in action on August 1, 1943, she had flown 168 missions and was credited with 12 enemy planes and one balloon, plus three shared victories. Budanova, who has received far less attention than Litvyak, flew 256 missions and downed 11 enemy planes (some sources cite as many as 20 or 22) before she was shot down and killed on July 19, 1943.
Many foreign pilots from Eastern European countries, such as Poland and Czechoslovakia, flew Yaks with the V-VS, as did Groupe de Chasse 3 “Normandie,” a fighter unit made up of Free French volunteers. Flying Yak-1s, -9s and -3s in Soviet markings, usually with cockades painted on their spinners and the Cross of Lorraine on their tail fins, the French commenced operations in the spring of 1943, expanding from squadron to regimental strength by the summer of 1944. The 95 Frenchmen who served with the outfit were credited with 273 victories, at a cost of 42 pilots. Among its many notable members were Marcel Albert, France’s leading ace with 23 victories (see story, May 2008 Aviation History); Roland de la Poype, who scored 16 and like Albert was awarded the Gold Star of a Hero of the Soviet Union; and Roger Sauvage, who remains the world’s leading black fighter ace, with 14 victories to his credit.
There was one further extraordinary chapter to the story of the wartime Yak fighters. By 1945, Stalin was well aware that the Soviet Union lagged behind the West in the development of jet fighters. Soviets designers had already made several attempts to incorporate their own jet engines into new mixed-power fighter designs, but with no success. In 1942 Yakovlev participated in early Soviet jet engine experiments by fitting a pair of Merkulov DM-4S ramjet engines under the wings of a Yak-7 trainer. Later, in March 1944, he mounted a pair of improved DM-4S engines beneath the wings of a Yak-7B fighter. The performance benefits of the installation were not deemed sufficient, however, and the project was discontinued.
In April 1945, the Soviets acquired access to German turbojet engine technology, and Stalin demanded that his aircraft designers use it to come up with a jet fighter as soon as possible. Yakovlev’s solution was simply to fit a Junkers Jumo 004B engine into the nose of an all-metal Yak-3U, with the jet exhausting beneath the fuselage. The prototype was constructed so hastily that it doesn’t seem to have occurred to anyone that the rubber tail wheel was directly in the path of the jet exhaust. The tail wheel burned away as soon as the engine started for the first time, along with part of the fuselage’s duralumin skin. A steel tail wheel and additional fuselage heat shielding were fitted before the first flight of the Yak-15, on April 24, 1946, the same day as that of its principal competitor, the more original MiG-9.
The use of the Yak-3U airframe meant that the Jumo-powered Yak could carry only a limited amount of fuel, and consequently had a relatively short range. On the other hand, it considerably reduced research and development time and enabled the new fighter to quickly enter service. Although the Yak-15 looked more like a flying tadpole than a jet fighter, it proved surprisingly pleasant to fly; 280 were built before production ceased in 1947. Late in the spring of 1947, tricycle landing gear was added to the Yak-15U, which was further refined into the Yak-17, with wingtip fuel tanks introduced to compensate for the loss of fuselage fuel capacity. Though those aircraft were never used operationally, a great many Soviet fighter pilots learned to fly jets in Yak-15s and Yak-17s.
The importance of the piston -engine Yak fighters to the war on the Eastern Front cannot be overemphasized. The Soviets did use many other types of fighters during the war, including the LaGG-3, La-5, La-7 and MiG-3, as well as various Lend-Lease American and British fighters. But more Yaks saw service with the Red air forces than all other fighter types combined. An astonishing total of 36,737 piston engine Yak fighters were produced, of which 34,547 were built before the end of the war. Though it was often criticized as crude, the Yakovlev fighter’s sound design and simplicity of production made it a winner. Like the Spitfire, Mustang and Zero, the Yak was the right plane at the right time.
For further reading, recently retired U.S. Merchant Marine officer and frequent Aviation History contributor Robert Guttman recommends: Yakovlev’s Piston-Engined Fighters, by Yefim Gordon and Dmitriy Khazanov; and Yakovlev Aces of World War II, by George Mellinger.
Originally published in the July 2008 issue of Aviation History. To subscribe, click here.