Below; Zwilling coded 'DG+?' somewhere in the east during 1943
The Zwilling was constructed in small numbers- two prototypes (Z V1 and Z V2) and ten series Z-1 machines- by the expedient of joining up two He 111 H-6 bombers at the outer wing section and adding a fifth Jumo 211 F engine at the resulting wing join section. It was initially planned to deploy the type on Unternehmen Herkules but following testing in Rechlin during May 1942 only the two prototypes were available for the operation not the two Staffeln originally planned. Elsewhere the encirclement of the besieged 6.Armee in Stalingrad came to a conclusion just days prior to a planned deployment of He 111 Z machines and Me 321 gliders although as Horst Lommel reports in 'Jet & Prop' 1/03 a single He 111 Z-1 did fly resupply sorties over the Kessel. The first re-supply sorties in Staffel strength were flown into the Kuban bridgehead during 1943 and in Lommel's view made a major contribution to the success of the resupply operation in the Crimea. The He 111 Z Zwillinge of LLG 2 returned to Dijon while the gliders were based at Istres in southern France, prior to supporting the German response to the Anglo-American invasion of Sicily on 10 July 1943. Conceived for towing the Me 321 and Gotha 242 gliders, development of the machine was not pursued when the Me 321 was motorised. The He 111 Z were were assigned to I./LLG 2 and first deployed in early 1943 to Crimea on glider towing duties. Zwillings arrived in France (Nancy) in April 1943 and from July to September operated out of Istres (south of France) flying troop transporter missions for the Italian front...
See Dan Gilberti's page on I./ LLG 2 in Dijon