Germany needed to develop a new and robust system of force projection to turn the tide of the war in their favor by the middle of 1943. One of the ideas that produced some results was the massive Junkers 322 and the Messerschmidt 321 troop carrier. Both of these planes were so big, and when fully laden with troops, would be so heavy that no existing plane could tow them into the air.
So the idea was to join two bombers together by their wingtips and create one massive plane with an extra engine in between them. The result was the Heinkel 111z. Twelve were built and pilots said they liked them. They worked just fine. Eight of the originals were destroyed by fighters and bombers.
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