Aviation of Word War II
Another direction in the development of the Yak-9, which for some time was given increased attention by the Yakovlev Design Bureau, were attempts to improve the altitude of the fighter. The actual ceiling of the Bf 109 was much higher than that of Yakovlev's machines, amounting to 11500 m for the Bf 109G-2, and 12100 m for the G-6. At altitudes above 5000 m, they significantly surpassed all Yaks. Stalin was greatly annoyed by the flights over Moscow in 1942-1943 by German reconnaissance aircraft Ju-86R-1. None of the Soviet and Lend-Lease aircraft were able to "get" them.
The first Yak-9PD fighter with an M-105PD engine, equipped with a Dolezhal E-100V two-stage supercharger, was created by order of the State Defense Committee on November 12, 1942; five aircraft were built. They were transferred for military tests to the 12th Guards IAP under the command of K. Marenkov, which is part of the 6th IAK Air Defense. The armament consisted of a ShVAK motor-gun with 120 rounds. The plane could not stand the military tests, tk. was not capable of continuous climb. The water temperature reached 120 ° С, oil - 100 ° С. The maximum height reached was about 11,650 m. The set was made intermittently to "cool down" ... After unsuccessful attempts to intercept German scouts on June 2 and July 22, 1943, by a GKO decree, A. Yakovlev was given the task to bring the Yak-9PD altitude to 13,000 m.The modified Yak-9 with the M-105PD was tested at the Flight Test Institute (LII) from 3 August to October 18, 1943. The maximum altitude reached was 12,500 m, the climb time was 33.2 minutes, the climb was carried out at a reduced engine operating mode due to overheating of the air in the supercharger. At high altitudes, the pressure drop in the main line led to interruptions in the operation of the engine, i.e. "Circumcision". The plane did not have a sealed cockpit.
In view of the unsatisfactory performance of the M-105PD during testing at the LII, it was replaced by the M-106PV (high altitude). This engine with the same E-100 allowed in one of four flights on September 15-18, 1943, to reach the aircraft's practical ceiling (the rate of climb at this altitude reached 0.5-0.75 m / s). But this engine was also very hot and did not allow to gain altitude continuously. The M-105 as an engine for a high-altitude interceptor was more than dubious. Finally, in 1944, the Yak-9U, serial number 106, was created, which was able to reach a ceiling of 12,800 m and even 13,500 m. This machine, which only KB engineers could consider a combat aircraft, had the same M-106PV with a gear ratio from the crankshaft to the supercharger equal to 9.72. And to reduce the temperature behind the supercharger, the engine was equipped with an injection system of a water-alcohol mixture (like the Messerschmitt one), a new ignition system, a new air cooler and a lightweight VISH-105TL propeller with reinforced blades, 2.8 m in diameter. To reduce weight, the landing flaps were removed from the aircraft with a mechanism for their release and cleaning, weights for mass balancing of the rudders and even shoulder straps with a device for pulling them up. The fuel stock was cut in half, and the oil stock was cut by more than a third. Thus, the weight of the aircraft was reduced by almost a quarter ton. The only weapon was the ShA-20M ultralight cannon with 60 rounds of ammunition. Naturally, there was no question of any pressurized cabin (especially about armor). But the result has been achieved. In this case, one can clearly see the desire of the KB and A. Yakovlev personally to create a false, exaggerated opinion about his successes among the leader, and among other people. The maximum speed of this ultralight fighter at an altitude of 10,500 m reached 620 km / h, and it climbed to an altitude of 11,000 m in 25 minutes. But the value of this machine in air defense looks almost ridiculous. What could such a device do against a formation of heavy bombers, each of which carried 12-15 heavy machine guns? The Germans did not have such aircraft, but the Americans already had them, and Stalin considered the possibility of a war with the United States, his then ally, quite practically. Fortunately, by the time the "air defense superaircraft" was created, Junkers were no longer flying over Moscow, Germany in 1944 had other interests.
And this "cardboard lion" calmly served until the very end of the war, never having tested his "only tooth" in the battle.