Norden Bombsight

Norden Bombsight in the nose of a B-25 bomber

Posthip Scott sent me an Ebay listing for a Norden Bombsight. I'd heard of them and I knew they were sort of a big deal, but I had never come across any good information about them, like how the machinery inside actually worked. I realize now that they are horribly complex mechanical computers that performed some operation that any $2 digital calculator could do now. The 20th century military-industrial complex was full of this stuff. In short, they were complicated, expensive pieces of precision machinery and if you were so inclined you could spend years sorting out all the ins and outs of their design, construction and operation. It might be fun, but at this point it's more like archaeology.
     Looking around I uncovered a couple of interesting bits. I found this one on Wikipedia.

At the beginning of WW2, after Britain was engaged but before the USA got into it, the Brits were keen on obtaining the Norden bombsight, so they sent some guys to the USA to talk about it. During one visit there was a demonstration.

The RAF's desires were only further goaded on 13 April 1939, when Pirie was invited to watch an air demonstration at Fort Benning where the painted outline of a battleship was the target. "At 1:27 while everyone was still searching [the sky for the B-17s] six 300-pound  bombs suddenly burst at split second intervals on the deck of the battleship, and it was at least 30 seconds later before someone spotted the B-17 at 12,000 feet". The three following B-17s also hit the target, and then a flight of a dozen Douglas B-18 Bolos placed most of their bombs in a separate 600 yd × 600 yd square outlined on the ground. - Top Secret Exchange: The Tizard Mission and the Scientific War by David Zimmerman

Malcolm Gladwell gave a TED Talk about the Norden bombsight back in 2011, wherein I found this bit:

And the U.S. military spends 1.5 billion dollars -- billion dollars in 1940 dollars -- developing the Norden bombsight. And to put that in perspective, the total cost of the Manhattan project was three billion dollars. Half as much money was spent on this Norden bombsight as was spent on the most famous military-industrial project of the modern era. 

That's in 1940 dollars which were worth about 20 times what they are now.