During WW2 the Luftwaffe used mainly medium bombers like the He-111, Do-17, and Ju-88 (plus all variants) to drop loads of between 4-5 tons compared to up to 20 tons carried by Allied aircraft like the Lancaster, B-17, and B-24. Even a Mossie could carry a 4000 lb "cookie"!!! And for special targets the Lanc was the only bomber that could carry the 22,000 lb Grand Slam bombs for the German U-boat pens! But the Germans just HAD to try to make a bigger bomb which was 39,690 lbs! No German bomber including the He-177 could carry it so to test it a modified Me-323 Gigant (Giant) transport was used. It didn't have a weapons bay but instead used an internal rail system and clamps to hold and then release the bomb when the aircraft nosed down. The huge bomb would slide down the rails, the clamps released, and it exited through the modified nose. The problem was that the aircraft had been strafed days earlier and either no one noticed or they flew anyway. It took several RATO units plus a special He-111Z (Zwilling, or Twinned 5 engine aircraft) to get it into the air. Once the bomb was rolling for release, the stress broke the spine and tail causing the aircraft to take an uncontrollable dive into the ground with the bomb! It worked but no German bomber could carry it for special missions. A total waste of time and effort. No pics of the modified craft anyway, but the Gigant was the largest transport of WW2. Pics below...

http://www.fiddlersgreen.net/aircraft/Messerschmitt-Me321/IMAGES/Me323-IMAGES/Me-323-flyby.jpg http://www.fiddlersgreen.net/aircraft/Messerschmitt-Me321/IMAGES/Me323-IMAGES/Me-323-doors.jpg http://www.fiddlersgreen.net/aircraft/Messerschmitt-Me321/IMAGES/Me323-IMAGES/Me323-loading-engine.jpg http://www.century-of-flight.net/Aviation%20history/photo_albums/images13/79.jpg