B2431 wrote:

From: Chad Irby

snip

The big problem for the German program was Heisenberg. Before the war,
he'd calculated some fission cross-sections incorractly, and apparently
never recalculated them. He thought the mass for a chain reaction was
something on the order of forty *tons*.

snip



OK, we know the bombs didn't need 40 tons of either uranium or plutonium.

Given the size and weight of Fatman or Littleboy type bombs just what would the
Germans, let alone the Japanese, have used to deliver them? Other than by
submarine or surface vessel I can't imagine how they would have been able to.

Fat Man (for certain) and Little Boy (I think) were much heavier than they had to
be, because their casings were constructed out of thick armor steel to prevent them
from being damaged by flak etc. IIRR, without the thick steel armor the bombs
would have weighed somewhere in the 3-5,000 lb. range. IIRC, the thick steel also
improved the yield slightly by increasing the containment for some fraction of a
second longer, but probably not enough to matter. If the Germans had been willing
to do without that protection (as we were with later weapons), then they almost
certainly could have delivered Little Boy; Fat Man would have presented space
problems, but they might have been able to modify an He-177 or similar. I don't
know how big the bomb bay of the He-177 was, or its arrangement.

Guy