The original iteration of the Yak-9 was not produced in large numbers. Subsequent models defined the variant. The Yak-9D, long range fighter, quickly replaced the basic aircraft. The long range of the Yak-9D was the result of putting two additional fuel tanks in the wings. These additional fuel tanks were not well protected, so the aircraft were frequently assigned to junior pilots. Due to its greater all-up weight, the long range version possessed poorer maneuverability than previous Yak models. Even so, the D model had the advantage in horizontal maneuverability against enemy fighters up to 3,500 meters. It also proved more durable than earlier Yakovlev fighters being able to absorb heavy damage from enemy anti-aircraft fire while providing top cover for Il-2 strike aircraft flying at 200 to 400 meters altitude.
Used primarily for long range escort of bombers, it also provided cover for armor and infantry penetrating deep behind German lines. In case of bad weather this aircraft had the range to divert to more distant airfields, though its poor instrumentation did not allow poor-weather navigation. An additional drawback was the radio’s 60 km range.
Pilots complained about the slow speed of the Yak-9D. During the winter of 1944, improvement of the sealing of fuselage and engine cowling joints increased the fighter’s speed by 60 km/hour at 3,650 meters altitude. The modification did not improve climb rate or maneuverability.
Units frequently used a variety of Yak models. Additional range was not needed for many missions, so the outer wing tanks were not always filled.
Combat evaluation of the Yak-9T anti-tank aircraft, equipped with the NS-37 cannon, took place during the Battle of Kursk. Of 110 enemy aircraft destroyed by Yaks almost half were shot down by Yak-9Ts. The NS-37 cannon was effective against twin engine aircraft at 500 to 600 meters range, and against single engine machines at 400 meters. Accuracy deteriorated during long bursts so pilots used their machine guns for sighting before using the cannon in one to three round bursts. The Yak-9T was assigned to the flight leaders while regular Yaks were used by wingmen providing protection for the leaders.
Some of the most famous Soviet pilots flew Yak-9s, including Alexandr Pokryshin, three times Hero of the Soviet Union with 59 kills. Major Luganski, double Hero of the Soviet Union, achieved 34 kills. Also famous were the Glinka brothers. Boris, two times Hero of the Soviet Union, downed ten enemy aircraft in 1943 alone, while Dmitri, also a double winner of the Hero of the Soviet Union, achieved 50 victories during his career. Grigori Rechkalov achieved 56 victories in addition to many shared kills, in 122 sorties.
Sources: Yakovlev Fighters of World War Two, Yefim Gordon, Sergey Komissarov, Dmitriy Komissarov, Hikoki Publications, Manchester, England, 2015
Yakovlev Aces of World War 2, George Mellinger, Ospreay Aircraft of the Aces #64, Osprey Publishing, Oxford, UK, 2005
The Yak-9 Series, Witold Liss, Profile Publications Number 185, Profile Publications ltd., Surry England, 1967