Model Boat Mayhem
Technical, Techniques, Hints, and Tips => BRUSHLESS Motors and Speed Controllers => Topic started by: BruceD on July 21, 2025, 04:40:44 am
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When using counter rotating props. What's the best set up 3 props? Counter rotating on left and center, clockwise on the right? Thank you
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Good question ....!
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Depends on the type of model and its handling characteristics, position and number of rudders and whether you tend to drive round the lake clockwise or anticlockwise!
Also props are less likely to be lost if the propulsive force when going ahead tends to screw the prop on tighter rather then the opposite.
Colin
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hi
here are a few photographs which you can decide upon yourselves to which way the props rotate.
One is of a destroyer stern from the very early 1900s.
The other is a Vosper MTB.
There are ones of an air sea rescue launch and also a Vosper Perkasa or a Brave Borderer.
John
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Clarification: I'm using 3 props and trying to figure out the correct (best) set up for them. I building a Dumas 1:20 scale Hull for the PT596. I'm told that the boat has a tendency to pull to the right on acceleration, so was thing of getting 2 counter-clockwise props on the left and center props, and a clockwise one on the right prop would this be correct?[/size]I'm using a 3 bladed 1 7/8" propsThank you
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Whatever you do you will get a bias to one side or the other although this might be corrected by a small rudder trim. So it seems to be a question of whether the two outboard props rotate inwards or outwards. You have the option of swapping them over to make comparisons as long as you change the motor connections to match. If the hull itself is symmetrical then if you omit the centre prop then it should steer straight but may respond differently to the rudder(s) depending on whether the outboard props rotate inwards or outwards.
Introducing the third prop basically just adds a bit more thrust and a slight bias to one side that can be trimmed out.
Colin