This is a "torpedo director" used on the WW II Douglas A-20 bomber.
According to the Douglas A-20 Havoc Pilot's Operating Instructions (which we have), a torpedo director "is an instrument operated by the pilot
to help him approach a moving target in such a manner that the torpedo will intercept the target on its course."
The computation mechanism of the B-2 is simple, but it does compute in a way.
On the right is the first page from the 1945 patent for the B-2, which describes the operation of the B-2.
