They had to be partially disassembled anyway to be moved by rail , and it was noticed that areas were looked into that had nothing to do with transport . The Russians also found parts missing , that were later returned . This was the early 1950’s , and China was behind Russia in aircraft development . China wasn’t in on the German brain drain or capture of German special equipment conducted by the allies and Soviet Union during and after WW2 . Both sides got their share of German technology , scientists , and technicians . Of course , the ones the Russians had were there by force .