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Old 01-26-2013, 05:44 PM   #72
bfloyd4445
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City: coos bay
Country: usa
Join Date: Oct 2012
Posts: 1,237
Quote:
Originally Posted by Art View Post
"What I’m not clear on is the rudder’s water course actions in reverse due to boxed-in flat rear-end on rudder that no longer “cuts sharply” to enable direction-assistance water pressure juxtapositions while backing-up with no water flow from prop thrust."

About the only thing that matters in reverse is size and that dosn't matter much either. Even w a big rudder like mine one must go pretty fast in reverse to get much steerage. Then on Willy I've got to be careful, holding on to the helm to keep the rudder from being pinned hard over and if that happens suddenly damage could likely result. So I don't think it basically matters in reverse Art.
Eric

The matter of bigger rudder size is important due to the larger sq inch available the more availability to experience high and low water pressures on rudder sides depending in the rudder angle position.

Keeping rudder straight pretty much equalizes water pressure on both sides, in either forward or reverse. Turning rudder on an angle changes the high/low water pressure against it, depending on amount of rudder angle in accordance with direction of turn and if moving forward with prop thrust or reverse without prop thrust. So... it seems to me that the flat rear edge on rudder pictured would interfere with water pressures on rudder sides while in reverse. Flat rear edge moving into water increases water turbulence on rudder sides, sharp rear edge minimizes it... therefore increasing the % difference and usable sq inch of water pressure as compared to each side. I’ve never seen a successful airplane wing designed with a boxed flat edge on its forward edge or rear edge.

After all a rudder is basically a verticle wing acting as its own complete foil while boat moves forward or reverse. [/QUOTE]


whoa....Its Saturday and me mind is not able to understand. I'm cooking and when i do high gravity brew flows and my concentration is on FOOD. So your saying that in reverse with a single you have less control?.....I think someone else mentioned that with twins the effects of rudder are less in reverse.
Ok, so I'm slow today. What your saying is always go forward and never look back, just hit the throttle and......

Kidding aside you are right, I think. The trick is to use the absolute minimum power you can to maintain steerage under current wind seas conditions and big small rudder makes little difference compared other drag factors in reverse?

Is that correct?
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