size of this prop ok to use
08-02-2007, 09:52 AM
#1
size of this prop ok to use
on my os 91 BB engine, the nearest prop I have is an 11x7.5 with a wide blades ,the recomend a 12x6, but being that the prop has such wide blades and is almost x8 in pitch will this be OK on this engine until I get a 12x6
08-02-2007, 10:17 AM
#2
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RE: size of this prop ok to use
according to ThrustHP the 12x6 has about 10% more load then the 11x7.5 before considering the wide blade. I doubt it would hurt anything. People experiment with all types of props without problems if you stay in the recommended manufactures rpm range.
08-02-2007, 01:01 PM
#3
RE: size of this prop ok to use
ORIGINAL: Mike Connor
according to ThrustHP the 12x6 has about 10% more load then the 11x7.5 before considering the wide blade. I doubt it would hurt anything. People experiment with all types of props without problems if you stay in the recommended manufactures rpm range.
according to ThrustHP the 12x6 has about 10% more load then the 11x7.5 before considering the wide blade. I doubt it would hurt anything. People experiment with all types of props without problems if you stay in the recommended manufactures rpm range.
08-02-2007, 02:42 PM
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RE: size of this prop ok to use
Its a little light for a .91 and will probably turn up some pretty good R's, but I wouldn't hesitate to run it. Just keep it a little rich and it should be fine.
08-03-2007, 07:05 AM
#8
RE: size of this prop ok to use
ORIGINAL: i live for 3D
also what do you guys think about an 11x8 on a 91size engine?
also what do you guys think about an 11x8 on a 91size engine?
08-03-2007, 10:06 AM
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RE: size of this prop ok to use
prop size depends a bit on the aircraft it will be used on, as well as the engine....
What airplane ?
Stock muffler or something other ?
Typically a stock OS 91 likes to run around 12,000 rpm....
So in general, if you select a prop that hits that peak ground rpm, you are in the right ball park.
An 11x8 is ok, a 12x6 will run about the same.
No, you will not hurt the engine with the smaller prop. It is not going to turn up 'that' high in rpm.
Bob
What airplane ?
Stock muffler or something other ?
Typically a stock OS 91 likes to run around 12,000 rpm....
So in general, if you select a prop that hits that peak ground rpm, you are in the right ball park.
An 11x8 is ok, a 12x6 will run about the same.
No, you will not hurt the engine with the smaller prop. It is not going to turn up 'that' high in rpm.
Bob
