Long Range Fighter
The Yak-9D with the M-105PF engine was a version of the usual serial "nine" with an increased fuel supply. All Yakovlev Design Bureau fighters had less time in the air after full refueling than the Messerschmitts, despite the fact that they were lighter than their opponents. And since in 1943 the Soviet troops went on the offensive, the task of covering operational breakthroughs from the air urgently required a greater range of fighters. The Yak-9D had two root gas tanks of 208 liters and two console tanks of 117 liters each. Thus, the capacity of the gas tanks was increased to 650 liters (480 kg) versus 440 liters (320 kg) for the Yak-9 with the M-105PF engine. The capacity of the oil tank was also increased to 48 kg, instead of 25 kg for its predecessor. Recall that on the Bf-109G, namely these fighters were the most massive in the Luftwaffe, the problem of increasing the range was solved differently. Each German fighter could carry one standard external tank with a capacity of 300 liters. With this tank, the range reached 620 miles (i.e. about 1200 km). And when entering into battle, the tank was simply dropped and the fighter became as maneuverable and fast as usual. The tank was suspended under the center section near the center of mass and had a streamlined teardrop shape. On Yak-9 aircraft of the military series, fuel was supplied to the engine from a supply tank with a capacity of 6 liters, and all gas tanks were connected to it independently. But a greater number of tanks and individual fuel lines increased the fire hazard. Check valves were installed in the fuel overflow lines from one tank to another. Trying to at least compensate for the shortcomings of these innovations, the design bureau specialists increased armor protection by 16 kg, the flight weight of the aircraft increased to 3117 kg, for comparison, the BM09G-2 of 1942 had a flight weight of 3050 kg **.
However, it was with him that the workers of the Yakovlevsky Design Bureau liked to compare their products of 1943, lighter, but made mostly of wood. A BM09G-6 produced in 1943-1944, however, had a slightly larger flight weight of 3150 kg, but at the same time not only an all-metal structure and armor, and therefore greater survivability, but also much stronger weapons. Since 1943, the installation of two MG-131 heavy machine guns with 600 rounds of ammunition (300 per barrel) has become standard on German fighters, and the gun could be either a 20-mm MG-151 with 150 rounds, or a 30-mm Mk-103 with 60 rounds. shells. However, it only makes sense to compare the later version of the G-6 with the Mk-103 with the Yak-9T or K. Unlike the NS-37 and NS-45, the German cannon allowed firing continuously until the ammunition was completely used up. Well, the Yak-9D in the series had the same 20-mm ShVAK with 120 rounds of ammunition and one (left) synchronous UBS with 200 rounds. The maximum flight range of the fighter was significantly increased. The plane could fly in a straight line up to 1360 km. However, on fighters of the early series, long-range flights, especially in bad weather conditions, became simply dangerous. Aeronautical equipment was very modest, radio compasses on the Yak-9 began to be installed much later, long-range flights were not included in the training of fighter pilots of the Red Army Air Force. In addition, after flying 69 km, the fighter stopped “hearing the ground”, and therefore receiving information. Therefore, with sufficiently long flights (even 300-400 km), the leadership of groups by bombers, attack aircraft or transport vehicles was often used. Let's not forget that pilots in 1943 were still trained according to the super-accelerated program. According to combat units, the maximum range of the Yak-9D was 211 km, the maximum flight duration was 1 hour. 20 minutes, and the average reached only 54 minutes. at an average flow rate of 270 l/h. Therefore, there was no point in fully refueling, because. usually only about 40% of the fuel was consumed.
In the Normandy Air Regiment, one of the most productive regiments in the Soviet Air Force, console gas tanks were drowned out on their own initiative, and all flights were carried out with refueling only root tanks, which significantly improved the aircraft's centering and increased safety. This experience of the French was also adopted in other Soviet flying units.
In air combat, the Yak-9D had a slight advantage over the Bf-109G-2 and FW-190A-8 in turns up to altitudes of 3500 m, and when half the fuel was used up, it was possible to fight in a vertical maneuver.
The experience of combat use of the Yak-9D together with the conventional Yak-9 and Yak-9T was not in favor of the former.
Therefore, it was considered expedient to use the Yak-9D to perform special tasks that could not be solved by conventional Soviet fighters due to the small amount of fuel: escorting bombers deep behind enemy lines, ensuring a breakthrough for tank groups, for example, protecting them from destruction by specialized tank destroyers Ju -87G and Hs-129. It was also recommended to use the Yak-9D for "deep raids" and reconnaissance.
The Yak-9D was one of the main series, although it was not always used with a full refueling. These aircraft were built from March 1943 to June 1946 3058 units. (according to English data - more than 3800 units), although by 1945 it was inferior in its main characteristics (especially in armament) to most enemy fighters and similar allied aircraft.
It should be noted that the serial production of wartime Soviet aircraft factories, for obvious reasons (low-skilled labor, etc.), differed significantly in quality from the standards. The performance characteristics of production aircraft were worse, and the resource was shorter. The attention of the leadership of the Yakovlevsky aircraft factories, including the Yakovlevsky Design Bureau, was repeatedly drawn to this. The German devices, right up to the very end of the war, corresponded much more precisely to the accepted standards, and their characteristics, especially of new machines, were very close to the standard.
In 1943, in addition to the development of aircraft produced in large series, the Yakovlev Design Bureau made a number of attempts to improve the aircraft, which nevertheless did not receive further development. It should also be mentioned here that A. Yakovlev, being more than all aircraft designers close to the person of the leader, had the opportunity to respond in a timely manner to the desires of the latter. And although Stalin largely lost faith in the power of his fighter aircraft, he nevertheless kept the development of new aircraft under control, within his personal, and now also Yakovlev's competence.