1979 C&C 30 Mk I - 2QM15
Join Date: Mar 2009
Location: Annapolis, Maryland
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No need to get defensive... I just pointed out the very obvious fact that the original test you cited drags a fixed prop through the water in no particular orientation vs. a free wheeling prop while completely leaving out the specific test condition that was in my original post of "vertically aligning" a "2-Bladed" prop with a leading keel and the overall effect on parasitic drag.
The second study you cited (even with the collective brainpower of MIT), also doesn't vertically align a 2-blade fixed prop with the keel. It just tests them in no particularly cited orientation in fixed vs. free wheeling mode.
And the last study you cited only graphed out the drag of 3-blade props that could in no way be aligned with the turbulence pattern of a straight vertical keel.
It's all good info, but it's just not relevant to what I stated in my original post, which was the common routine of racers with fixed 2-blade props to set them so that they're aligned with the keel. If you've got a study that cites that particular condition and shows a negligible, or negative affect on drag, I'd be more than happy to read it. Because I didn't devise or propose the theory, I just know that many racers follow it...
Last edited by backcreeksailor; 05-03-2009 at 07:08 PM.