RE: Rossi 1.05 DF tractor engine with propeller..?
I would not try to limit the output by any venturi size restrictions. We are happy about every rpm we can squeeze out of our engines for speed application. The 18 cc Rossi will not turn faster than the OS .91. It features improved torque good for heavier ducted fan jets. You will be happy to get an 10*10 prop near to 20K static. I would suggest to use the MACS pipe # 1190 starting with 14" between glow plug and middle of the fat pipe part.
As for wood, yes wooden props are light and also have good tensional strength. But wood is not comparable to the material properties of carbon fiber. Why not choose the safest way right from the beginning? Another drawback is the lack of suitable wooden speed props for your purpose to attain as much speed as possible.
Improve throttling for a speed plane? - Just fix that 'unimportant' throttle arm of the R/C carb at WOT and let it go [sm=tongue.gif] - or make a 13 mm ring venturi carb for ultimate performance [>:]