Having flown a hot formation with a JU 52 I can confirm with a conversation with the pilot that it was a heavy old bird to push around.
Chugalug mentioned the JU53/3M. The 3M was not the bodge tape it was held together with but the designation for three motors as the first ones were built with just one engine. The Fokker DVII/3M that Kingsford Smith flew across the Pacific was of a similar description, the aircraft being available with two (DVII/2M) or three engines.