Hi, Nico:

The prop in the photo is a 13x8 Zinger Pro (wood) that I modified to make it useable.

The basic prop is poorly made, with squared edges and a very inefficient airfoil shape. However, I sanded the leading edges of the blades until they were smooth and a better aerodynamic shape (at least to my eye), and I sanded a lot off the top/rear edge of the blades which were waaaayyy too thick and had squared-off edges. Much thinner and sharper on the back edge. Then painted and balanced.

I flew the Zinger before and after the modification, and I can tell you it is noticeably quieter and has better pull after all the re-working.

If you want to save a lot of work, just get an APC 13x8 sport prop, which pulls the plane well and doesn't require all the effort to modify the Zinger! APC is also much better than MA because it is stiffer - you can hear the change in pitch with MA.

Vertical is very good - not spectacular - using either of these props and 15% nitro fuel.