Re:The Tupolev Tu-4, the reversed copy of the B-29 Superfortress .
Comparing fully armed bomber production versions with B-29, B-29A (in WWII configuration) vs the Tu-4:
major design differences Wright R-3350 engines replaced by ASH-73TK 2,300 hp engine designed by A.D. Shvetsov, crew communication tunnel was omitted; aluminum skin thicknesses changed – overall weight increased; 23mm cannons replaced the M2 0.50” mgs in all gun positions, changes to computers to develop new firing solutions for 23mm cannons; control cabling and piping differences; different instruments, IFF and radios; and?
The Tu-4 entered Soviet service in 1949, ahead of the RAF B-29s in 1950.
Other copy jobs:
US JB-2 Loon was a development of the German V-1 Buzz Bomb from captured missiles from which drawings were made. The JB-2 was a larger vehicle with an improved guidance system. Some 1,200? were built; Republic built the airframe and Ford Motor Co the engine; production delivery began in Jan 1945, and was cancelled on VJ Day; the first JB-2 was test flown at Eglin Field, FL in Oct 1944. Just before the end of the war, JB-2s were aboard an aircraft carrier enroute to the Pacific for possible use in the proposed invasion of the Japanese home islands.
France, Sweden and the USSR also built versions of the V-1.
The Germans developed anti-tank weapons based on the US Bazookas they captured in N Africa.
There are probably many other reverse engineered examples.
Neat idea: obtain a Tu-4 from Com China to be referbed in the Seattle Museum of Flight to be displayed along side their B-29. There are probably many still living air and crew in Russia – they could be contacted to give a narrative of their experience with the Tu-4 and possibly help with the referb. A deal could also be made to obtain a Tu-16 from China to display along side the museum’s B-47.