comparing water pickups

[kingwrench]

The solution is what ever works for your application, There are so many variables. I was a NHRA Pro Mod Crew Chief, Engine tuner/Builder, You could take the same chassis set up, same car, samer motor fuel system set up, clutch/ trans blower, ETC take all your data for that day, track, elevation, water vapor, corrected alt,and try it on the the other clone car, and It will do you no good. My point is we all have our tune up, and idea's of what works, can it be improved maybe, maybe-not. Find out what works for you and run with it.

[Heaving Earth]

Yeah but there are no variables in water cooling other than,more or less. Period.
Sure there are plenty when considering hull type, motor, batteries etc.... But what variable is there to water flow?

[Heaving Earth]

I always just look for a nice steady stream of water coming out and I'm happy anyways

[lenny]

Hear is a test to try,
In car not moving but running turn on the heater or the ac depending on the state you are in and weather and climate.
Now with the car running a normal temps turn on the blower to high and temp to max heat or cold.
And give it a few minutes to work, Now feel the air coming out the vent and check the temp there to,
Now turn the blower to low and feel the air again and check the temp.
There will be a temp difference with flow of air rate, Just like the water.

If the water is heated some when it exit,
Then the motor has loss some heat in the thermal conduction and heat transfer through the water.
It is basics of HVAC/R that I studied,
Hears a good read on it. http://search.yahoo.com/r/_ylt=A0oGd...alP/u18l1e.cfm

[Heaving Earth]

Air and water are completely different thermodynamically

[ReddyWatts]

Sundog is correct. He gets a gold star!

[sundog]

Aw, shucks, I'm blushing....

If the water is heated some when it exit,
Then the motor has loss some heat in the thermal conduction and heat transfer through the water.

Yes, but one might assume if the water is cold coming out, it must not have removed any heat. But in the situation of high velocity or cold (or both) water, it can remove all the heat and feel cold coming out. But that doesn't mean it hasn't removed any heat. You can recover it from the 'cold' water with a heat pump. Just because it feels cold, doesn't mean it isn't removing any heat, lol!

What was alluded to earlier was that water needed preheating to remove heat efficiently. At what temp is it most effective at removing other heat? ans: as cold/fast moving as you can get it.

Lenny, you are a trouble starter! LOL

[mtbenjamin77]

I think you guys are splitting hairs. If theres water flowing your fine, slow or fast it doesn't matter. If your system is pushed to the point where how fast your water cooling flows makes a difference then you have other things to worry about and your steup needs to be revised. Run your cooling to the ESC first then the motor. When you check temps the motor will retain heat longer than the ESC becuase it has more mass than the ESC so you'll get a temperature reading closer to the actual operating temp. I have never seen an esc that comes in hotter than the motor. Also, having multiple water pick ups is a waste and causes more drag than help. The more pickups you have the more chances you have of picking up trash and clogging a line. One pickup running to the ESC first then the motor in the shortest possible length. For twins, one pickup split with a Y then to both esc's then to both motors and out. keep the line short and as straight as possible

[Heaving Earth]

For twins, one pickup split with a Y then to both esc's then to both motors and out. keep the line short and as straight as possible

I respectfully and strongly disagree. Y connectors don't split water flow evenly. Even if one side has a slight more resistance than the other which side gets more flow?
We aren't splitting hairs, just discussing what we feel is an obvious truth. Sure water cooling isn't used to band aid an inferior system and never should, but the fact remains that more water equals more cooling.

[TheShaughnessy]

Here we go again. Might as well bring up smooth hull bottoms vs scuffed. While I don't agree with jays slower is better approach I do have to respect his FE pedigree and his contributions to model boating. All this talk and I have yet to see anyone do a controlled test. Lots of speculation, but that's it.

[Heaving Earth]

I feel like I made some legitimate points based on water cooling of other things. Stands to reason that more is better.

[mtbenjamin77]

I feel like I made some legitimate points based on water cooling of other things. Stands to reason that more is better.

I agree more is better. as for equalizing the flow using a Y, a simple test procedure is all that's needed. A water bottle with a fitting installed on the cap.. fill with water and hook to the hose at the rudder let gravity pull the water throught hte system and which ever side has a weaker stream flowing out of the outlet just shorten the line. but again your splitting hairs. if the left side outlet has a 3" stream of water flowing out and the right side has a 2" stream that's not enough variance to make any difference in temps. The only thing I'd worry about is if one side had nothing coming out. Also when installing the Y it needs to be placed as close the the water source as possible kinda like this..............

DSC03303.jpg

[Heaving Earth]

Yeah I mean I guess it wouldn't make a huge difference. Honestly I have no twins so I've never had a use for a y.
I run single or dual pickups and they work good for me. On the transom pickup I don't bury the thing like I've seen on other boats, I just set it so the tip is just touching the table then move down 1/16 at most. Thing still puts out ALOT of water

[tlandauer]

this is turning out to be a great discussion! Here is my observation on some of my boats:
I have noticed that looking at the water outlet is only useful to see if one's system is functioning or not, from all the rudder pick ups that I have, some will seemimgly shoot out a steady stream while others I can barely see. In the end, I rely on my temp gun, if it is within the threshold, then I have to assume that it is working despite the fact that I would love to see a big stream shooting out.
The long hole on some rudders are narrow, ( as with the Speed Master21 ) and they are somewhat affected by the attitude /speed of the running hull. Recently I maidened my MeanMachine and I wasn't sure if any decent volume of water was coming out and I slowed down every time when the boat was in front of me, there was very little water! But my temp gun tells me it is working.
The ramped pressure builds up as the boat picks up speed. , if it is slowed down, any changes in the ramped pressure will create inconsistent volume. That is until a new consistent speed is obtained again. The reason I couldn't see is the boat is relatively fast and during the moment of slowing down there is big changes in the ramped pressure.

[sundog]

I just read "Watercooling an RC Boat" by Paul Pachmayer here on OSE http://www.offshoreelectrics.com/inf...tercooling.php and he ends his article with this statement "The last thing I do is make a "thermostat" for the cooling system. Just like in a car you don't want the water going through the system so fast that it doesn't have a chance to remove heat." Then he goes on to say he makes an orifice to slow the flow down.

Paul was no doubt just repeating something he heard, perhaps from the gas boaters (inadvertently perpetuating the myth). In a car, the thermostat allows the engine to warm up to optimum operating temperature, before allowing the coolant to flow again. The cap keeps the system pressurized, allowing it to reach a higher temp without boiling. Otherwise, if the water continually flowed, it would stay so cool, it would never reach that optimum temperature, and efficiency would suffer.

In a FE boat motor (as with lipo batteries), that optimum temp is much lower - closer to room temperature. Unless you're running in ice water, you want to remove as much of the heat as possible. The faster you can move water past an object the more heat it can remove. You can call it the Sundog Factor.