On the German IFMA show of 1951 the Velmo-Motoren GMbH from Hamburg showed their hub engine,

it was a complete engine, including fuel tank integrated in the front wheel hub. 

According to Manfred Nabinger, writer of a book on German cycle engines, it is assumed that the series production of this engine started one year later by the Nordap Kraftfahrzeuge GmbH in Ladeburg am Neckar. Difference to the model showed on the IFMA were another name, "Nordap", and the fact that the fuel tank was now mounted outside the wheel hub. First as cylinder shaped tank in front of the steering head, later as a kind of saddle over the front wheel. 

The only difference between the Nordap and the Velmo showed on this web site is the name on the wheel cover. In Germany they were sold as Nordap, abroad as Velmo. 

Thanks  for info - picture Mr. Joost H.

VELMO heter en ny tysk cykel motor som till våren introduceras i Sverige. 

Hela motoraggregatet är inbyggt i framhjulet. 

Motorn är tvåväxlad har hårdförkromat cylinderlopp och ger vid 4000 v/min 0,8 hästkrafter.