[spanktheuser]

And it wasn’t even the most expensive. The Norden Bomb Sight cost slightly more than the Manhattan Project. B-29 development and production cost nearly 3x the cost of the fission bomb.

[dreamcompiler]

The Norden stands out because it couldn't see through clouds, and Europe has very few cloud-free days. So it turned out to be largely useless in practice. The US didn't get much value for its money with that project.

[speed_spread]

Well, if you include the cost of decontaminating the Hanford site, amongst others, the numbers grow rapidly. Once the B-29 was done, it was done.