Through Lend-Lease the USSR received 13,000 aircraft from the US. Mainly P-39, P-40, P-63, A-20, and B-25. Interned aircraft were also studied and the B-29 for instance was reverse engineered to come up with the Tu-4 Bull. However, the Red version was not a duplicate. It had different engines, weapons, payload, instruments, and parts. Different performance envelope too. But what is seldom discussed is the 196 P-47s given to the USSR out of an order of 203. Most came by ALSIB but others came through Iran. The Red pilots didn't like them comparing them to heavy targets against the Me Bf 109Gs and Fw-190As. So, they served in air defense regiments. None were used in combat. Only 12 combat pilots flew. In the summer of 1945 after VE-Day, they were flown over the Soviet Sector and were kept in service until 1947. Very odd. Of course the Luftwaffe refused to fly captured IL-2s as too dangerous.

http://img.photobucket.com/albums/v220/ColJDLanders/RuskieP47.jpg