1. 
   Wirbelwind
   The Flakpanzer IV "Wirbelwind" (Whirlwind in German) was a self-propelled anti-aircraft gun based on the Panzer IV tank. It was developed in 1944 as a successor to the earlier self-propelled anti-aircraft gun Möbelwagen. In the first years of the war, the Wehrmacht had less interest in developing ...
   Found op http://en.wikipedia.org/wiki/Wirbelwind
   
   
2. 
   Wirbelwind
   The Flakpanzer IV/2 cm Vierling or Wirbelwind was a German self-propelled anti-aircraft defence of the Second World War produced between 1944 and 1945. The Wirbelwind consisted of a Panzer 4 chassis upon which was mounted a polygonal, open-topped turret mounted with four 20 mm automatic guns (a Flak...
   Found op http://www.probertencyclopaedia.com/browse/FAFVW.HTM
   
   

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