Talon Smithee
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From Jason Nicholas Moore's Soviet Fighters of the Second World War, p.243:
"Yakovlev was, of course, interested in keeping the Yak-9 competitive with the German fighters being introduced in the latter part of the war. To this end, he developed the Yak-9U VK-105PF-2, which was based upon the Yak-9T airframe and was powered by the VK-105PF-2. The VK-105PF-2 (designated M-105PF-2 until April 1944) was more powerful at low altitudes than the M-105PF engine that was then powering the Yak-9 production examples. In addition to the different engine, the Yak-9U VK-105PF-2 featured individual ejector-type exhaust stubs that generated a small amount of thrust. A plywood covering on the aft fuselage replaced the fabric covering of the Yak-9T to decrease drag; this plywood covering was also used on the Yak-9U VK-107A (the aircraft that made the Yak-9U VK-105PF-2 redundant). The aircraft was designed to carry a variety of guns in the nose, including the VYa-23 23-mm cannon along with two UBS machine guns with 170 rounds each, a B-20 20-mm cannon with two UBS, or a NS-37 37-mm cannon along with one UBS machine gun.
The single prototype of the Yak-9U VK-105PF-2 was built in November 1943 and underwent manufacturer's (factory or OKB) tests in December. NII VVS (state) testing was undertaken from 2 January to 11 March 1944. The tests revealed that the aircraft had good performance, with a top speed of 385 mph (620 kph) at 12,631 feet (3,850m). In a combat turn, it had similar performance to that of the Bf 109G-10, the fastest version of the Bf 109G, with a top speed of over 420 mph (676 kph).
Although it was recommended that the changes made to the Yak-9U VK-105PF-2 be introduced to the production Yak-9s, this did not occur. It was probably considered that the Yak-9U VK-105PF-2 was something of a stopgap until the Yak-9U could be fitted with the more powerful VK-107A engine, and only one example of the Yak-9U VK-105PF-2 was built."
"Yakovlev was, of course, interested in keeping the Yak-9 competitive with the German fighters being introduced in the latter part of the war. To this end, he developed the Yak-9U VK-105PF-2, which was based upon the Yak-9T airframe and was powered by the VK-105PF-2. The VK-105PF-2 (designated M-105PF-2 until April 1944) was more powerful at low altitudes than the M-105PF engine that was then powering the Yak-9 production examples. In addition to the different engine, the Yak-9U VK-105PF-2 featured individual ejector-type exhaust stubs that generated a small amount of thrust. A plywood covering on the aft fuselage replaced the fabric covering of the Yak-9T to decrease drag; this plywood covering was also used on the Yak-9U VK-107A (the aircraft that made the Yak-9U VK-105PF-2 redundant). The aircraft was designed to carry a variety of guns in the nose, including the VYa-23 23-mm cannon along with two UBS machine guns with 170 rounds each, a B-20 20-mm cannon with two UBS, or a NS-37 37-mm cannon along with one UBS machine gun.
The single prototype of the Yak-9U VK-105PF-2 was built in November 1943 and underwent manufacturer's (factory or OKB) tests in December. NII VVS (state) testing was undertaken from 2 January to 11 March 1944. The tests revealed that the aircraft had good performance, with a top speed of 385 mph (620 kph) at 12,631 feet (3,850m). In a combat turn, it had similar performance to that of the Bf 109G-10, the fastest version of the Bf 109G, with a top speed of over 420 mph (676 kph).
Although it was recommended that the changes made to the Yak-9U VK-105PF-2 be introduced to the production Yak-9s, this did not occur. It was probably considered that the Yak-9U VK-105PF-2 was something of a stopgap until the Yak-9U could be fitted with the more powerful VK-107A engine, and only one example of the Yak-9U VK-105PF-2 was built."
