Just ran up an ancient Enya 45 BBTV 6001 using an Enya muffler that has an extension on it, adding about 50% more volume, which should make it less restrictive...
MA 12x4 11,000 rpm
Zinger 13x5 8300 rpm (I think there was a little more to be had; I didn't want to lean it out to the max with such a large prop)
Old TF 14x4 8100 rpm
I want the large prop diameter for a VK Nieuport that weighs 5 lbs 6 oz. and has a huge cowl, plus I don't like the look of dinky props on WWI types. Note that the rpms for the 13x5 prop give 90 oz of thrust, which is plenty for my Nieuport. This is to substitute for a PAW 40 diesel that flew the plane well on similar props. The PAW actually did not turn as fast on such large props. A five inch pitch at 8300 gives plenty of speed potential for this plane.
The torque curves in an old review (on a website by Downunder) show that the engine has a lot of low end torque. So a good diesel substitute, I'm thinking.
I think I probably need a cooling hole in the firewall out the bottom of the fuse. I'm concerned about overheating. Any reason why I shouldn't do this?
Jim