Enlarged Piece Models

Combining seven solid hexagons you get a figur, which looks like a enlarged hexagon. Now you can stack three layers of this hexagon and a 3-dimensional model of a hexagon is constructed. This way stacked tetrahexes can be enlarged using 21 pieces for each model.
The bar and the cross-section of the enlarged bar look like this.

These are the completed models of the propeller and the arc pedestal.

All pieces can be replicated except for the column due to the conditions for constructions. Furthermore there are some problems with a physical realisation, if parts of the construction are hanging over. For the flat pieces and the three pedestals pictures of the layers are provided.

So far I haven't checked, if solutions are possible without using the replicated piece.