Finally, something 'meaty' we can all sink our teeth into and yet has no real importance or meaning to get this thread back ONTOPIC (which of course means, having no topic).
So what was the most expensive single project of WWII? Most would certainly guess the Manhattan Project I am sure, as I would have before finding out the actual answer.....
Then answer is: the B-29 Superfortress. Easily the most expensive Allied project of WWII, and very probably the most expensive undertaking by any entity or group of entities during the war. At first it does not make much sense because something such as the Manhattan Project, the V2 project, or even something such as the U-Boat type XXI, the B-29 just does not seem to encompass any kind of new, 'cutting edge', never been done before technology. Nothing could be further from the truth.
The B-29 first and foremost needed a lot of power, more than was nominally available from piston engines. So new engine types, and new technologies were developed to force those horsepower from piston engines. And it was at a great cost, not so much perhaps in development but in practical usage; it was a long time before B-29's had <reasonably> reliable engines capable of powering the air-frame.
Another first was that the B-29 was a pressurized aircraft. That simple had not been done before, and there were a lot of 'hoops' to jump through to make it work..... mostly. Now the entire air-frame was not pressurized but the human containing compartments were, including a crawl-way from the cockpit to the tail gunner's position. That, in and of itself, may have been the greatest engineering feat of the entire aircraft. Not to mention the constant source of fear should the air-frame be damaged while someone was actually IN that pressurized crawl-way.
In the end, the air-frame was a success but only because it was not used as intended; instead of high altitude bombing with relatively large bombs, it was most effective against Japan at lower altitudes with smaller, incendiary bombs. Nevertheless, it inflicted tremendous damage to Japanese cities toward the end of the war, and of course due to its sheer size, was able to carry the less expensive but technologically newer atomic weapons to Japan.
As an aside, there are only two flying examples of B-29's (or the later mod., the B-50) in flyable condition: one is the Fifi, the other is Doc. For the sentimental among us, there is a fantastic instance where Gen. Paul Tibbits Jr. ( the man who flew the Enola Gay and piloted the first atomic weapon to be used to Hiroshima) flying 'Fifi', with the aircraft being co- piloted by the current commander of the 509th bomber group, Air Force Brig. Gen. Paul Tibbets IV (yep, his grandson).
http://www.kansascity.com/news/local/article30103137.htmlBrian