In another thread someone brought up how the P-51 Mustang was almost entirely redesigned even though it only served for the last 2 years of the war. That got me thinking, and I cant think of any aircraft except the F4U Corsair which was both successful and did not need to be redesigned. Most aircraft which were not redesigned were failures which were not redesigned because they were simply abandoned. But there were not many successful aircraft which did not need major redesign in order to become successful. I think maybe the P-38 might be second best of its day, as it only needed redesign of the controls to add boosters. Otherwise remained nearly unchanged, and very successful as well. What other aircraft from ANY time period do you guys think were designed near perfect from the outset?