How did you figure out your static thrust measurements? Just curious. I hooked a digi fish scale up to the firewall and ran it WOT a little rich with a 15x6 Pro Zinger and was getting readings in the mid 10lb range. It was also on grass so there is alot more drag. For me this is a real world #. Not like using a thrust program. I picked up an APC 15x6 and have a 15x4W on order that I want to try out. Seems to me that the Pro Z spools up pretty quick. Ooh, I am also using a Slimline Pitts muffler. I haven't tried with the stock muff. Sounds to me that I should try the 14x6 too!!!