Yakovlev Yak-9 versions
By Michal Sekula
Updated on April 20, 2020
Here is a brief description of the important variants of Yakovlev’s fighter during WWII. More about Yak-9 family in English at https://en.wikipedia.org/wiki/Yakovlev_Yak-9 and in Russian with line drawings, photos etc. at http://www.airfield.narod.ru/yak/yak-9/yak-9.html and https://coollib.com/b/261705/read.
Yak-9 was a development of the robust and successful late Yak-7B with the M-105PF engine and lowered rear fuselage decking and all-around vision canopy. It was armed with 1 × 20 mm ShVAK cannon firing through the propeller spinner and 1 × 12,7 mm UBS machine gun. Yak-9 had 2 fuel tanks with total capacity of 320 kg of fuel, two fuel hatches on the upper wing for filling the tanks. One tank and one filling hatch per one wing. Yak-9 arrived to Soviet fighter aviation regiments at the Stalingrad Front in December 1942. Yak-9 was produced from October 1942 to August 1943, totally 459 planes were made.
Yak-9D was long-range version of Yak-9, fuel capacity increased from 320 kg to 420 kg in 4 fuel tanks (2 per each wing) giving a maximum range of 1400 km (870 mi). Combat usefulness at full range was limited by lack of radio navigation equipment, and number of aircrafts were used as short-range fighters with fuel carried only in inner wing tanks while external fuel tanks (e.g. fuel tanks closer to the wing tips) usually were not used. Mechanics simply sealed their filler neck. It means that visible were always the fuel hatches of the inner tanks while the fuel hatches of the outer tanks were sometime visible, sometime sealed. Yak-9/-9D/-9B had 20mm motor cannon with internal cartridge shell accumulation and 12,7mm cowling machine gun with external shell ejection through the wing root. Yak-9D was produced from March 1943 to June 1946, totally 3058 planes were made.
Yak-9B fighter-bomber was a modification of the serial Yak-9D. Four bomb compartments were behind the cockpit, arranged in pairs one after another in the form of tubes for hanging four high explosive bombs FAB-100 or four cartridges with anti-tank PTAB bombs weighing 1.5 kg, 32 bombs in each cartridge. The conversion of the Yak-9D into a fighter-bomber was completed on March 20, 1944. State tests took place from March to August 1944. Totally 109 planes were produced.
Yak-9DD was a modification of Yak-9D or Yak-9T. It had installed 8 main
and one expendable fuel tank (total 630 kg of the fuel). The panel covers are
fitted under the fuel tanks, 6 additional hatches are cut in the upper wings.
Yak-9DD was produced from May 1944 to September 1944, totally 399 planes were
Yak-9T was a modification of the serial of Yak-9 armed with more powerfull 37 mm cannon with 30 rounds firing through the propeller spinner instead of the 20 mm ShVAK. Due to dimensions and weight of the gun the whole cockpit was moved 40 cm back to the tail to compensate the heavier nose. Both 37mm motor cannon and 12,7mm cowling machine gun had internal cartridge shell accumulation, e.g. no ejection hatch on the wing root as on the Yak-9/-9D. Initially poor quality led to multiple oil and coolant leaks from cannon recoil. 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 armor from 500 m), but it was also successful against aircraft with a single cannon hit usually sufficient to tear apart the target. Yak-9T was produced from March 1943 to June 1945, totally 2748 planes were made.
Yak-9M was a modification of the serial Yak-9D and had a fuselage made by the
type of Yak-9T. The modification was carried out in order to unify the design
of the fuselage and using them depending on the needs for the production of
either Yak-9T or Yak-9D. In addition, the changes were made on the wing, cockpit,
dust filter at the engine inlet was installed, the antenna was shortened, etc.
Yak-9M was produced from May 1944 to June 1945, totally 4239 planes were made.
Yak-9K was Yak-9T modified with a 45 mm cannon NS-45 with 29 rounds and
a distinctive muzzle brake to deal with the massive recoil. Both 45 mm motor
cannon and 12,7mm cowling machine gun had internal cartridge shell accumulation,
e.g. no ejection hatch on the wing root as on the Yak-9/-9D. 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.
Only 53 planes were produced.
Yak-9U equipped with Klimov VK-107A engine (1650 hp) was definitive Yak-9 variant. It was armed with the 20 mm ShVAK cannon firing through proppeller spinner and two 12,7 mm USB machine guns. The prototype's top speed of 700 km/h (435 mph) at 5,600 m (18,370 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 441 mph on military power. However, engine VK-107A was problematic, prone to overheating, oil leaks, loss of engine pressure during climbs etc., so the first production batches of Yak-9U starting in April 1944 were powered by the reliable M-105 PF-3 engine. The next drawback of the VK-107A engine was its small engine life - only 25 hours. In practice it was forbidden to use combat regime, since then the engines would have to be changed after two or three sorties. Only Yak-9U planes produced in the spring and summer of 1945 had flight characteristics that practically coincided with those obtained during the tests – the top speed 672 km/h at an altitude of 5000 m. This was the result of increased production quality and improved aerodynamics. Yak-9U serial version with the engine VK-107A was produced between April 1944 and August 1945, totally 3921 planes were made.