davparlr
Senior Master Sergeant
A supply container may be much bulkier for it's weight than bombs. While there maybe room in the fuselage (or not, depending on fuel tanks):
http://img35.imageshack.us/img35/2922/heinkelhe177a5greifarti.jpg
Getting any real amount of supplies though the existing hatches and passageways may have been a real problem.
Good transports have large volume in addition to good weight capacity. High performance bombers have small fuselages (small volume).
And that is exactly why they stretched the C-141. It typically was full of cargo well before any weight limit was met. They increase the cargo volume capacity 30%, but interesting enough, increased max weight from 325k lbs to 342k lbs without changing the wings or the engines. It was obviously overpowered when I flew it, which is not bad at all, you never have too much thrust. It was originally designed to carry one minute man ICBM.