The large-span, five-engine He 111 Zwilling was specifically designed as a heavy transport powerful enough to tow the large Messerschmitt Me 321 gliders.
The He 111 Z (or "Zwilling" - twin) was an interesting, albeit bizarre, joining of two He 111 medium bombers. In an attempt to bring together existing designs to produce a large enough transport capable of towing the Me 321 glider, the He 111 Z was conceived of as such a solution with the intent that a large wing area and five powerplants would be sufficient. Externally, the creation appeared as nothing more than two He 111 airframes joined at a wing with an extra (fifth) engine fitted to the joining structure.
