Guys,
I found my Ringmaster needing a bit more power to get through the OTS vertical 8's in the wind. The ship has a OS Max 25, with a 0.25" venturi and ST NVA. Had been running a 9x6 APC and 7% nitro, 26% oil fuel. If we go a bit lean (from a very rich 2 cycle to a kinda rich 2 cycle) the ship picks up a just a bit of speed and will do OK. Looking at the set-ups for the FP20/25 they have venturi's of around 0.265", for the old MAX this is a bit outside the range of rpm needed for good pumping but maybe a 0.257" would work and still have a good neeedle. Seems the 0.25" might be a bit small with the ST NVA, but I get very consistent needle settings. I would like to see if I can get to a 9 3/4 -10" diameter 5"ish pitch prop (narrow blade) to get a little more pull through the top without stressing the engine to much.
Question is can going up to say 10 -15% nitro with the current set-up give the power boost that you would get if I went to a larger venturi say 0.257"?
Best, DennisT