The Yakovlev Yak-9 is a single-engine, single-seat multipurpose fighter aircraft that was utilized by the Soviet Union and its allies during World War II and the early Cold War.
It was developed from the successful Yak-7B fighter, which was based on the tandem-seat advanced trainer, Yak-7UTI.
The Yak-9 was introduced to Soviet fighter regiments in late 1942 and played a significant role in regaining air superiority from the Luftwaffe’s new Focke-Wulf Fw 190 and Messerschmitt Bf 109G fighters during the grand Battle of Kursk in the summer of 1943.
The Yak-9 featured a cut-down rear fuselage with an unobstructed canopy.
Its lighter metal structure allowed for an increased fuel load and armament over previous models built from wood.
The Yak-9 was highly maneuverable at high speeds when flying at low and medium altitudes and was also easy to control, making it one of the most produced Soviet fighters of World War II.
It was produced in various variants, including the Yak-9T with a 37 mm (1.5 in) cannon, the “large-caliber” Yak-9K with a 45 mm (1.77 in) cannon firing through the propeller hub, which was used for antitank duty and as a potent aircraft destroyer, the fighter-bomber Yak-9B with an internal bomb bay behind the cockpit for up to 400 kg (880 lb) worth of bombs, the long-range Yak-9D and the Yak-9DD with additional wing fuel tanks to escort bombers over Eastern Europe, and the Yak-9U with a more powerful engine and improved aerodynamics.
The Yak-9 remained in production from 1942 to 1948, with 16,769 built (14,579 during the war).
Following World War II, the Yak-9 was also utilized by the North Korean Air Force during the Korean War.
The Yak-9 fighter aircraft was developed as a successor to the Yakovlev Yak-7, which had proven to be a successful combat aircraft.
The Yak-9 was a production version of the Yak-7DI, which was constructed using duralumin, a lightweight metal that allowed for modifications to the basic design.
The Yak-9 was produced in various variants, which featured different wings, engines, fuel tank configurations, and armament setups.
One of the variants of the Yak-9 was the Yak-9U, which was introduced in December 1943.
The Yak-9U featured a new airframe and was equipped with the more powerful M-107A engine, which replaced the previous VK-105PF engine.
The engine installation was redesigned, and the aircraft featured individual faired exhaust pipes, an enlarged radiator bath, and a centred supercharger intake.
The rear antenna cable was moved inside a lengthened rear canopy, which provided the pilot with a better view to the rear.
The wings and fuselage structure were made of metal and skinned with Bakelite.
The Yak-9U was typically armed with a 20 mm ShVAK cannon and two 12.7 mm Berenzin UB machine guns.
State trials conducted from January to April 1944 revealed that the Yak-9U had a better top speed compared to other fighters in service on the Eastern front at 6,000 m.
Unlike the I-185, the Yak-9U was stable and easy to fly.
However, the M-107A engine inherited the problems of the VK-105PF and was prone to overheating, oil leaks, loss of engine pressure during climbs, spark plugs constantly burning out, and intense vibrations that would fatigue assembly bolts leading to a short engine life.
These defects forced the first production batches, starting in April 1944, to be powered by the more reliable M-105 PF-3 engine.
Further modifications were made, including increasing the fuel capacity and re-balancing the aircraft by moving the wings forward and replacing the propeller.
A total of 1,134 Yak-9U aircraft were produced by December 1944.
Military History
The Yak-9, a Soviet fighter aircraft, was introduced into service in October 1942 and saw combat in the same year.
It was equipped with a diverse range of armament suitable for anti-tank, light bomber, and long-range escort roles.
The aircraft’s maneuverability at low altitudes, where it predominantly operated, surpassed that of the Bf 109.
Despite a series of performance and armament improvements, the Yak-9’s handling characteristics remained uncompromised.
Soviet pilots regarded the Yak-9’s performance as comparable to that of the Bf 109G and Fw 190A-3/A-4.
However, during the initial stages of the German invasion of the Soviet Union, the Yak-9 performed poorly against the Luftwaffe due to a lack of training.
Nevertheless, by the Battle of Stalingrad, the aircraft began to perform better.
After the Battle of Smolensk in the second half of 1943, the renowned Free French Normandie-Niémen unit became a Groupe and was equipped with the Yak-9.
The Yak-9U, the first unit to use this variant, was deployed between 25 October and 25 December 1944 by 163.IAP.
Pilots were instructed not to use the engine at combat speed as it reduced its lifespan to only two or three flights.
Despite this, the unit claimed 27 Focke-Wulf Fw 190As and one Bf 109G-2 in the course of 398 sorties, with only two Yaks lost in dogfights, one to flak, and four in accidents.
The Yak-9U played a significant role in the Soviet Union’s attainment of air superiority, and the Germans learned to avoid the Yaks “without antenna mast.”
A large formation of the Yak-9DD version was transferred to Bari, Italy, to assist Yugoslav partisans in the Balkans.
First Lieutenant A.I. Vybornov was one of the top-scoring Yak-9 pilots, achieving 19 air victories, nine shared, and receiving the Gold Star Medal of the Hero of the Soviet Union in June 1945 while flying a type-T equipped with a 37mm NS-37 cannon in the nose.
Lieutenant L.I. Sivko from 812th IAP achieved an air victory against a Messerschmitt Me 262 jet fighter on 22 March 1945, but he was killed soon afterward by another Me 262, probably piloted by Franz Schall, a top-scoring Me 262 pilot.
Fighter units operating the Yak-9 suffered lower losses than average, with only 383 of the 2,550 Yak-9s manufactured up to the end of 1943 lost in combat.
During the Cold War, Yak-9 fighters were used to buzz American, British, and French flights in the air corridors to West Berlin.
During the Berlin Blockade, Yak-9 fighters interfered with the U.S. Air Force-Royal Air Force airlift.
In 1949, the Soviet Union provided surplus Yak-9P (VK-107) aircraft to some satellite states in the Soviet bloc to help them rebuild their air forces following the West Berlin blockade.
However, a section of the aircraft’s operating manual was accidentally omitted from the translation from Russian into some languages, resulting in frequent engine seizures during the take-off roll and initial climb, causing several fatalities during 1950.
Variants
Yakovlev OKB created 22 modifications of the Yak-9, of which 15 saw mass production. The most notable of these include:
Yak-9
First production version, Klimov M-105PF engine with 880 kW (1,180 hp), 1 × 20 mm (0.79 in) ShVAK cannon with 120 rounds and 1 × 12.7 mm (0.50 in) UBS machine gun with 200 rounds.
Yak-9 (M-106)
Prototype with Klimov M-106-1SK engine with 1,007 kW (1,350 hp), did not advance to production because of problems with the engine.
Yak-9T
Yak-9 armed with a 37 mm (1.5 in) Nudelman-Suranov NS-37 cannon with 30 rounds instead of the 20 mm (0.79 in) ShVAK, cockpit moved 0.4 m (16 in) back to compensate for the heavier nose.
Initially poor quality control led to multiple oil and coolant leaks from cannon recoil.
It was a problem only during the prototype tests, Recoil and limited supply of ammunition required accurate aiming and two-three round bursts.
Yak-9T was widely used against enemy shipping on the Black Sea and against tanks the cannon could penetrate up to 30 mm (1.2 in) armour from 500 m (1,600 ft), but was also successful against aircraft with a single cannon hit usually sufficient to tear apart the target.
Virage (constant altitude and velocity turn) time: 18–19 seconds. 2748 were produced.
Yak-9K
Yak-9T modified with a 45 mm NS-45 cannon with 29 rounds and a distinctive muzzle brake to deal with the massive recoil.
Firing the cannon at speeds below 350 km/h (220 mph) caused dramatic loss of control and tossed the pilot back and forth in the cockpit; however, accurate shooting was possible at higher speeds and in 2–3 round bursts.
The recoil also caused numerous oil and coolant leaks.
The heavy cannon installation degraded performance, even more so at high altitudes, sufficiently to relegating the Yak-9K to be used as a heavy fighter and resulting in the need for a fighter escort of Yak-3s.
The Yak-9K saw only limited use due to unreliability of the NS-45, airframe performance issues caused by both the NS-45 and larger fuel tanks used on the Yak-9K, as well as a reduction of bombers used by the Germans.
Yak-9D
Long-range version of Yak-9, fuel capacity increased from 440 to 650 L (120 to 170 US gal) to giving a maximum range of 1,400 km (870 mi).
Combat usefulness at full range was limited by lack of radio navigation equipment, and a number of aircraft were used as short-range fighters with fuel carried only in inner wing tanks.
Circle time: 19–20 sec, Weight of fire: 2 kg/s (4.4 lb/s).
Yak-9TD
Yak-9D with NS-37 cannon and provision for 4 × 50 kg (110 lb) FAB-50 bombs under the wings.
Yak-9B
Fighter-bomber version of Yak-9D (factory designation Yak-9L) with four vertical tube bomb bays aft of the cockpit with capacity for up to 4 × 100 kg (220 lb) FAB-100 bombs or 4 PTAB cassettes with 32 × 1.5 kg (3.3 lb) bomblets each, although normally only 200 kg (440 lb) of weapons were carried in the front bomb bays.
Poor handling with a full bomb and fuel load and lack of special aiming equipment limited combat usefulness.
Yak-9DD
Yak-9D and Yak-9T modified to further increase the range, fuel capacity increased to 845 L (223 US gal) giving a maximum range of 2,285 km (1,420 mi), radio navigation equipment for night and poor weather flying.
Yak-9DD were used primarily to escort Petlyakov Pe-2 and Tupolev Tu-2 bombers although they proved less than ideal for this role due to insufficient speed advantage over the bombers.
In 1944, several Yak-9DD were used to escort B-17 Flying Fortress and B-24 Liberator bombers attacking targets in Romania using the Ukraine-Romania-Italy routes.
Yak-9M
Yak-9D with the cockpit moved 0.4 m (1 ft 4 in) to the rear like on Yak-9T, numerous fixes and improvements based on experience with previous versions.
Yak-9M PVO
Yak-9M with slightly reduced fuel capacity, Klimov VK-105PF2 engine with 925 kW (1,240 hp), and radio and navigational equipment for night and adverse weather flying for PVO Strany.
Yak-9 MPVO
Single-seat night fighter aircraft, equipped with a searchlight and an RPK-10 radio compass.
Yak-9S
Yak-9M with Klimov VK-105PF engine, new propeller, and armament consisting of 1 × 23 mm (0.91 in) Nudelman-Suranov NS-23 cannon with 60 rounds, and 2 × 20 mm (0.79 in) Berezin B-20 cannons with 120 rounds.
Did not enter production due to poor performance compared to Yak-3 and Yak-9U.
Yak-9R
Single-seat tactical reconnaissance aircraft.
Yak-9P
This aircraft was the last and the most advanced version of the Yak-9 fighter, which became the pinnacle of development among A. S. Yakovlev’s piston-engine fighters.
The Yak-9P (Product P) that appeared in 1946 was a modification of the Yak-9U fighter of composite construction. Unlike its predecessor, it had all-metal wings with elliptical tips.
By this time, the manufacture of high-strength aluminium alloys was established in the Soviet Union, simplifying aircraft operation and increasing aircraft service life.
Yak-9PD
High-altitude interceptor (unrelated to the two other Yak-9P above) with Klimov M-105PD engine designed specifically to intercept Luftwaffe Junkers Ju 86P high-altitude reconnaissance aircraft overflying Moscow in 1942–1943.
Initially poor performance due to unreliable engine dramatically improved with adoption of Klimov M-106PV with water injection, with the aircraft reaching 13,500 m (44,300 ft) during testing.
Armament reduced to the ShVAK cannon only to save weight.
Yak-9T with Klimov VK-105PF2 engine and numerous aerodynamic and structural improvements introduced on Yak-3.
Main visual difference from Yak-9T was in the oil coolers in the wing roots like on Yak-3 and in plywood covering of the fuselage instead of fabric.
Visually differed from Yak-3 only by main landing gear covers.
Armament increased to 1 × 23 mm (0.91 in) VYa with 60 rounds and 2 × 12.7 mm (0.50 in) UBSs with 170 rpg.
The VYa cannon could be replaced by a ShVAK, B-20, or NS-37, the latter requiring removal of the starboard UBS machine gun.
Did not enter production because the VYa cannon was considered unsatisfactory and because the one cannon, one machine gun armament seen on previous models offered a significant increase in range.
Yak-9U
(VK-107)
The definitive Yak-9 variant, Yak-9U (VK-105) equipped with the new Klimov VK-107A engine with 1,230 kW (1,650 hp), and the 20 mm (0.79 in) ShVAK with 120 rounds replacing the VYa. Weight of fire: 2.72 kg/s (6.0 lb/s).
Early test flights in 1943 indicated that the only comparable Soviet fighter was Polikarpov I-185 prototype which was more difficult to fly and less agile due to higher weight.
The prototype’s top speed of 700 km/h (430 mph) at 5,600 m (18,400 ft) was faster than any other production fighter aircraft in the world at the time, other than the P-51B that could reach up to 710 km/h (441 mph) on military power.
Early problems with overheating were fixed by enlarging the radiators and production aircraft had further improved aerodynamics.
Turning ability to complete a circle: 23 sec, best Soviet fighter at altitude.
Yak-9UV
Two-seat trainer version of Yak-9U (VK-107), armament reduced to a single Berezin B-20 cannon with 100 rounds.
Did not enter production due to introduction of jet aircraft.
Yak-9UT
Yak-9U (VK-107) armed with 1 × 37 mm (1.5 in) Nudelman N-37 cannon with 30 rounds and 2 x 20 mm (0.79 in) Berezin B-20 cannons with 120 rpg, giving a total one-second burst mass of 6 kg (13 lb).
Similarly to the Yak-9TK, it could be converted to replace the N-37 with a 20 mm (0.79 in) B-20, 23 mm (0.91 in) NS-23, or 45 mm (1.8 in) N-45.
Production aircraft carried NS-23 instead of the N-37 cannon as the default armament.
Yak-9-57
The Yak-9-57 was a one-off conversion of a Yak-9UT armed with a 57 mm cannon.
The large calibre cannon did not protrude out from the spinner cone like the Yak-9-37/45 models.
Yak-9V
Two-seat trainer version of Yak-9M and Yak-9T, Klimov VK-105PF2 engine, armament reduced to 1 × 20 mm (0.79 in) ShVAK with 90 rounds.
Modern replicas
In the early 1990s, Yakovlev started limited production for the warbird market of Yak-9 and Yak-3 replica aircraft using original World War II equipment and Allison V-1710 engines.
These modern-built replicas using the Allison engines, have counter clockwise-rotation props, unlike the originals which strictly used clockwise-rotation Soviet V12 powerplants.
Sources Yakovlev Aircraft Since 1924 – Bill Gunston & Yefim Gordon. OKB Yakovlev, A History Of The Design Bureau And Its Aircraft-Yefim Gordon, Dmitriy Komissarov & Sergey Komissarov. Soviet Aircrafts Illustrated-A.S.Yakovlev. Soviet Combat Aircraft of the Second World War, Vol 1, Single Engined Fighters-Yefim Gordon and Dmitri Khazanov. Soviet AF Fighter Colours 1941-45-Erik Pilaeskii. Red Stars 1939-1945, Soviet Air Force in World War Two-Carl Fredrik Geust, Kalevi Keskinen & Kari Stenman.
