RCU Forums - View Single Post - Is it a phenomenon of these little 2-strokes that until well broken in, they will not turn a larger
Old 09-28-2009, 01:23 PM
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NM2K
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Default RE: Is it a phenomenon of these little 2-strokes that until well broken in, they will not turn a larger


ORIGINAL: MJD

I would never bolt a 10-4 to a .15 no matter how broken in it was! 8-4 is as big a load as I'd ever subject one to. What rpm are you expecting it to turn this prop, is there some data to reference? .15's aren't traditionally ported and timed to behave at those rpm.

MJD

Today's folks have had their minds warped by OS with their ridiculous prop recommendations.

I fly lots of .15 size engines, and, like you, never run more than an 8x4 on them. In fact, my favorite size prop for .15 sized engines is a 7x4 to 7x6. More than that and you are loading the little rascal down too much for decent performance. Yes, there was a time when some control line .15 size engines (Fox mostly) used an 8x6 prop. The 9x4 and above sizes were for engines in the .19 to .23 sizes.

As mentioned where the engine (rpm) is tuned to run makes as much difference as the displacement of the engine. Sport engines were/are all tuned around a common point that favors the 7x4 to 8x4 prop sizes.


Ed Cregger