I found 1 thing, it's not a flail, but another roller gizmo.
282/283 The Minenraumpanzer Raumer was a prototype mine-clearing vehicle. It was a giant articulated armored vehicle with heavy solid wheels, intended to detonate mines by its great weight. The front section was 2.6 metres wide, the rear section 3.27 metres wide, the height was 3.93 meters and overall length 15.63 metres. The wheels were 2.7 metres in diameter and the rims were 53 cm wide.
The vehicle was not put into production. I have 1 picture of a U.S. soldier standing next to it...he is a little over 1/2 the vehicles height.
Another in a long list of development wonders, without production.

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There's one way to find out if a man is honest-ask him. If he says "Yes", you know he's a crook. Groucho Marx