WHats the best prop for a OS.40MAXFP Engine?
11-25-2008, 01:24 PM
#2
Join Date: Sep 2007
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RE: WHats the best prop for a OS.40MAXFP Engine?
Hi blhollo2 ,
As a plain bearing engine, the 40FP is not the greatest powerhouse but is a great, lightweight, sport engine. I have used it in a control-line racing class and on low nitro fuel (5%) and 20% oil, it liked a 9x6.5 APC or a 9.5x6 Bolly. A 9x7 may work fine too. As a matter of interest I now have a Davis Diesel head on it (but unrun due to lack of ether where I live/work), that according to adverts, jacks up the torque well and could probably run 9x7 or 9x8.
Good luck!
P
As a plain bearing engine, the 40FP is not the greatest powerhouse but is a great, lightweight, sport engine. I have used it in a control-line racing class and on low nitro fuel (5%) and 20% oil, it liked a 9x6.5 APC or a 9.5x6 Bolly. A 9x7 may work fine too. As a matter of interest I now have a Davis Diesel head on it (but unrun due to lack of ether where I live/work), that according to adverts, jacks up the torque well and could probably run 9x7 or 9x8.
Good luck!
P
11-25-2008, 02:30 PM
#3
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RE: WHats the best prop for a OS.40MAXFP Engine?
Hi partner. The FP is a great sport engine, but not a very fast motor (also is a plain bearing one). To obtain the maximum power from it try a scimitar prop design like APC or similar props ballanced carefully. Try one that give you some 13.000/13.500 rpm in the air because this engine dont have the power curve in the high rpm. For speed purpose i would try from 9X6 to 9X8, testing each in the model. For normal sport i would try a 10X6 or 11X5 for trainer duties, the same for scale models. This engine haves great torque at lower rpm and will serve you better as a sport engine. You could also try hotter fuels with more nitro in search for more speed, and in general OS engines run fine with nitrated fuels up to 20%, as we see in our flying field.. (reduce compression ratio if you note detonation or plug blowing, also reduce the prop load in this case)
enclosed a pic from my 40 FP
have a nice day
enclosed a pic from my 40 FP
have a nice day
11-25-2008, 05:44 PM
#4
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RE: WHats the best prop for a OS.40MAXFP Engine?
ORIGINAL: stg61abc
For speed purpose i would try from 9X6 to 9X8, testing each in the model. For normal sport i would try a 10X6 or 11X5 for trainer duties, the same for scale models.
For speed purpose i would try from 9X6 to 9X8, testing each in the model. For normal sport i would try a 10X6 or 11X5 for trainer duties, the same for scale models.
MJD
