Third Bratukhin helicopter, based on G-2 but planned from outset for operational use by VVS as AK (Artilleriiskii Korrektirovshchik - artillery correction). No significant differences apart from more powerful engine. Two prototypes ordered 1944, flown 1945. On completion of State trials in 1945 batch of ten AK ordered. Soviet histories mention only original two prototypes as having flown. A single AK delivered to VVS with dual control for training helicopter pilots.
Bill Gunston "The Osprey's Encyclopedia of Russian Aircraft", 2000
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It was the first helicopter in the USSR with defined military function - artillery spotter. Small series was started before two first machines completed the test program.
At least one G-3 was transferred to military unit for training purposes.