Cooling pick-up

[clarkm]

Has anyone found it necessary to add a manufactured cooling pick-up behind the prop and would it add drag?

[dana]

Prop wash pickup

[dana]

And no it does not, it doesn't drag in the water

[Fluid]

You'd better believe that it adds drag. Actually the prop wash pickup can be the draggiest of all pickups. The water coming off the prop hits it at a much higher velocity than if it were actually in the water. It also does not pick up a solid stream of water. The has lots of air in it so your cooling system ends up with bubbles in it; bubbles don't conduct heat very well. Not that a prop wash pickup doesn't work, it does - but a rudder pickup has less drag and sucks solid water.


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[dana]

Yes, but how does this cause drag? I'm a but confused. I understand it is impairing the thrust cone? But is this really considered drag? Thanks -)

[dana]

I have a prop wash pickup, but now I'm thinking just going with the rudder pickup alone.

[Fluid]

Dana, yes it does. Stick your hand in the prop wash of a full scale boat sometime, it pushes against your hand like a fire hose! The whole prop wash pickup tube - the bent part anyway - is hit by the wash, causing a "lot" of drag. The real question is, how much drag does it really cause? Even if it is three times what a rudder pickup causes, I don't know how much it actually slows the boat. I doubt it is very much....but I do not know.


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[clarkm]

Thinks for the input no one talks about prop wash pick up so I assumed it was rarely used. My friends in hot Florida us it because the pond temp can reach 90 degrees (they tell me)so they feel they are getting better cooling from it. I guess the real question is is rudder pick up sufficient for cooling and what can I do to improve rudder pick up.

[stadiumyamaha]

I tried a prop wash pickup on a genesis once the was mounted on the left side of the rudder where a second servo arm could be mounted.
The force of the wash great enough to cause the boat to turn right do to the wash pushing on the pickup.
I would imagine it was slowing the boat down as well and would no matter what location it was mounted.

[dana]

Well... I guess I've been schooled here lol! I never have really grasped the full concept of how a prop works. I think it has both to do with thrust cone, and the blade area in the water? If the water throne from the prop is partially or fully responsible for the work then yes, the prop wash pickup would affect it. I'm certainly gonna try removing it from the equation to see what differences I notice. Firstly, if the boat goes straight after removing it. Logically, the trim should be off a little? Good info guys -)

[JoeOvercoat]

UL-1 Test Runs With & Without Prop Wash Pickup?

...gonna try removing it from the equation to see what differences I notice....

Did removing/adding the prop wash cooling pickup make any noticeable difference in trim, top speed, or acceleration?