I have here the airship timetable for Germany - South America in 1939.
Depart Frankfurt Wednesday evening, arrive Recife, Brasil Saturday evening. On to Rio (possibly the same crew) to arrive Rio Sunday evening.
And if you thought that was long enough, the return took an EXTRA day.
It's 4153 nm Recife to Frankfurt so for the 4 days of the eastbound trip they averaged 43 knots.