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Thread: Best water pick-up ever!

  1. #31
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    Wow, didnt mean to stir this up LOL. Was just stating what I had heard a few years ago from some smart people on this forum and other places. Oh well whatever works for ya. Have a good day. Will
    Many issues!!!

  2. #32
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    there is no question about it, don is right. if water flows through the system to fast it can not absorb the heat. everything is designed with a optimal opperating tempature, determined by tolerances. just because the water coming out and the outside can of a FE motor is cooler does not mean the internals are colder. it is possable to cool the outside can so fast that the rotor and stator do not have a chance to transfer maximum heat to that can. when you check the tempature of the motor it may be cooler in places (outer can) but the internals can verry well be hoter.
    also, yes you can blow lines even at slower speeds. i know this from experience and none of my boats are faster than 62-63mph and i dont restrict the flow other than by the size of the lines and water outlets.

  3. #33
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    Hello!

    An water pickup that drives alot of water trough the cooling tubes is awesome, altough, mine opinion is that you have to get the correct placement for it!
    I putted mine near the keel of mine DF35 and tried everything to trim the boat up...weeks after weeks....It was chine waliking a lot and dindn´t have a sable behaviour..after 2 months i thought...What a a hel...let me try taking off the water pick up......I couldn´t don anything more to trim the boat...i tried everything....
    The boat behaviour was from water to wine... :D
    The issue is...look where you put it...

    regards

  4. #34
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    When things slow down for me I'm going to build a suitable water cooled heat exchanger, fire up a 30,000 BTU torch and a video camera, and put this to bed.LOL
    Do you want to make coffee, or do you want to cool your componets?? Think about it.

    The absolute bottom line is this. If you can't get adequate cooling by means of what we consider standard water cooling, your boat has the wrong set up, it is poorly set up, or you are running the wrong prop.
    Just my .02 till I have more time.
    Hang tough fellas!!
    Doug
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  5. #35
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    Doug has it right. Maximum Flow = Maximum Cooling!
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  6. #36
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    Heat from components needs time to dissipate into the water (thermal exchange) inorder to properly cool the component. This is done by utilizing a bigger bore tubing, slows water rate down when entering the component then back to a smaller diameter bore tubing to quickly evacuate the thermally heated water.
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  7. #37
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    Quote Originally Posted by egneg View Post
    Doug has it right. Maximum Flow = Maximum Cooling!
    Bingo!
    I run the stock cooling on my SV's with a bigger hole in the rudder pickup and I get much more flow out of the system, and get this I can run any prop I want and my temps never get above 125* no matter what and usually hand at 110* and lower

    I think some are over thinking this
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  8. #38
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    Quote Originally Posted by Brushless55 View Post

    I think some are over thinking this
    Most people don't run 100mph, or have big block chevys in their rc boats. I'm talkin your basic 40mph sport boat. Can't have too much water @ that speed.

  9. #39
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    Quote Originally Posted by forescott View Post
    Most people don't run 100mph, or have big block chevys in their rc boats. I'm talkin your basic 40mph sport boat. Can't have too much water @ that speed.
    Yes!
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  10. #40

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    Quote Originally Posted by Steven Vaccaro View Post
    I didnt know that, do you happen to have the part number?
    Hi, Steven...
    Call Trudy and tell her you want part "(SMWP) Stern Mount Water Pick Up"
    They are Shweet!

  11. #41
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    Default water-pikup

    nothing
    Last edited by FRED; 02-07-2011 at 08:35 AM.

  12. #42
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    Westbeach has hit the nail on the head.
    Heat from components needs time to dissipate into the water (thermal exchange) inorder to properly cool the component. This is done by utilizing a bigger bore tubing, slows water rate down when entering the component then back to a smaller diameter bore tubing to quickly evacuate the thermally heated water.
    That's the theory I used when I up graded my home made ESC cooling plates from having only one pathway cross drilled through the plate (in the usual 'U' shape), to having 3 pathways. This effectively increases the volume of water in the plate at all times & it slows down as it is divided evenly over 3 tubes & then speeds up again on exit as it recombines at the outlet tube. The ESC with this plate definitely runs cooler than it did before in the same boat & setup. Might try 4 cross holes next time.
    The photo shows the three cross holes in the plate about to be re attached to the ESC
    Cheers.
    Paul.
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  13. #43
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    Default pickups

    nothing
    Last edited by FRED; 02-07-2011 at 08:35 AM.

  14. #44
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    Hello Guys,

    just want to join the discussion. First a few words about myself. I've been studying mechanical engineering for 5 years now and topically making my masters degree. Within these 5 years I also learned a lot concerning this topic due to lectures in thermo and fluid dynamics as well as heat exchange.

    Therefore I can say, the more water flow, the better it is. The idea of slow water because it needs time to heat up is just a so-called hoax. So I think limitation should only be a choice when the pressure gets too high that the flexible hoses get off even if they are already secured.

    And as I also run several FE quite fast FE boats for several years now I can say, the experience approved the theory. So my statement: The more - the better.

    If interested I might try to explain the theory behind it with an easy explanation.

    Best regards,
    Manuel

  15. #45
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    I'am with Manuel:

    I am a degreed engineer (for 35 years now) at an industrial plant.
    One of my projects was to design a $1,000,000 cooling system for our process.
    It involved many large heat exchangers.
    This project gave me an oppertunity to study heat transfer.
    All the principals involved are exactly the same as cooling an RC motor.

    I am absolutely sure that more water cools better.
    I am absolutely sure: the faster the water flows the better.
    Slowing down the water flow will result in a hotter motor.

    Mark
    Last edited by mm123521; 02-06-2011 at 08:35 PM.
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  16. #46
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    Default water pickup

    nothing
    Last edited by FRED; 02-07-2011 at 08:36 AM.

  17. #47
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    Fred:

    I started running water cooled RC boats 15 years ago.
    I am 60 years old, so I guess I been around the block also.
    I have studied all the science behind water cooling and have done it on an industrial scale.
    If I could have restricted the water flow on that $1,000,000 project AND improved the cooling, I could have saved $200,000 in pumps and pipes. But it just doesnt work that way.

    I have adjusted flow rates on that industrial cooling system and observed temperatures, so I also have first hand, practical, experiance that validates: More water flow= better cooling.

    We would get zebra mussels (little clams) that clogged up the pipes and restricted the cooling water flow and the temperatures always went up as the water flow choked down. When we cleaned the Zebra mussels from the pipes (increased the water flow), the temperatures always went down.

    I am 100% sure of what I say, as I have book learning AND practical experiance.

    Its exactly the same principals: RC boat or industrial water cooling.

    Mark
    Last edited by mm123521; 02-06-2011 at 11:52 PM.
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  18. #48
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    Funny how this thread had gone
    how about we use what works for us?

    bottom line.............................................. .....................
    if a motor is getting very hot then the setup is not 100%
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  19. #49
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    just get a heat gun and pick a target temp you want.(heat you want for your application)simple!

  20. #50
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    @ Fred:
    Well, so you want to talk about my experience with FE boats? Well I might have studied and I'm quite young as well (23 to be honest), but I think I have already more experience and knowledge than most others.

    And comparing apples and oranges: You compare the experience of a guy with 1:1 cars racing to the cooling system in our boats?
    To explain it as simple as possible: They "reduce" flow to increase pressure and therefore avoid that the water in their closed-loop cooling system boils, which would be absolute horror. Normally water boils at 100°C, but like in a pressure cooker under pressure it will boil much later. And thats why they make it. Otherwise the water will boil in certain hot parts and cooling power will there decrease dramatically, resulting in blown engines due to overheating.

    We wether have a closed-loop cooling system nor problems with boiling water (if so, get a bigger engine and ESC or rethink your setup ;-D ), therefore its just a completely different story.

    I just want to help with my knowledge and experience, that's why I absolutely recommend to increase flow as much as possible. And only because something was done so for ages, it doesn't need to be the best solution.

    Best regards,
    Manuel

  21. #51

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    ever see someone drill a hole in steel?
    remember the little spout running coolant on the bit?
    that cools as fast as it touches the bit, and falls away instantly.
    the contact time with the bit is less than a second...

  22. #52
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    Heat transfer is due to temperature differential. The higher the differential, the more heat transfer. In general, higher delta T's occur when the flow is the HIGHEST!

    What complicates matters is the geometry of the contact area and flow dynamics. Hot spots can be created due to flow separation at certain velocities, etc... so there is a limit to the statement above. However, it is still the "meat and potatoes" of the answer.

  23. #53
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    Quote Originally Posted by Shooter View Post
    Heat transfer is due to temperature differential. The higher the differential, the more heat transfer. In general, higher delta T's occur when the flow is the HIGHEST!

    Quote Originally Posted by egneg View Post
    Doug has it right. Maximum Flow = Maximum Cooling!
    I agree, but keep the pressure and flow rate reasonable. The right setup is the best solution to over heating.
    Last edited by ReddyWatts; 02-08-2011 at 02:03 PM.
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  24. #54
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    I used one of those water pick ups on the UL-1 I used to have.It worked great.I can say,Ill probably use another one somewhere in the future.

  25. #55
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    My 2 cents related to a car heater,, the slower the fan the hotter the air is the faster you run the fan the cooler the air gets that to me means that the higher air flow is removing more heat !!!

  26. #56
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    Quote Originally Posted by ManuelW View Post
    Hello Guys,

    just want to join the discussion. First a few words about myself. I've been studying mechanical engineering for 5 years now and topically making my masters degree. Within these 5 years I also learned a lot concerning this topic due to lectures in thermo and fluid dynamics as well as heat exchange.

    Therefore I can say, the more water flow, the better it is. The idea of slow water because it needs time to heat up is just a so-called hoax. So I think limitation should only be a choice when the pressure gets too high that the flexible hoses get off even if they are already secured.

    And as I also run several FE quite fast FE boats for several years now I can say, the experience approved the theory. So my statement: The more - the better.

    If interested I might try to explain the theory behind it with an easy explanation.

    Best regards,
    Manuel
    I cant beleive this arguement is still going on. I have bit my tongue with every post in this thread since my last one because it seems to be one of those things that people just choose to beleive. I am amazed at how many people buy into such a silly theory. I dont understand how one can logically come to the idea that water becomes insulative at higher flow rates, or that the water "goes away" to fast even though there is constant contact between the heat source and water. I didnt mean to create such an arguement with my initial post, but I have witnessed the same myth in auto racing and felt the need to kill it before it spread.
    My wife once stuck a hot french fry out the window of our car moving down the freeway at 70 mph to cool it off before feeding it to our baby. If I told you that it never cooled down because the air was simply moving to fast to remove the heat, would that make sense?
    I too work in a field that allows me to test these things, but Im honestly baffled that this is any more than common sense to people.

  27. #57
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    I understand your frustration, Keith. Not sure how that myth was started in the first place, but I would bet that people are thinking opposite......i.e. if we were trying to HEAT a fixed amount of water, then YES, the flow can be too fast! I think Doug alluded to that when he said "making coffee". Too funny!!

  28. #58
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    Quote Originally Posted by keithbradley View Post
    My wife once stuck a hot french fry out the window of our car moving down the freeway at 70 mph to cool it off before feeding it to our baby. If I told you that it never cooled down because the air was simply moving to fast to remove the heat, would that make sense?
    My wife did the same thing except the french fry was frozen with dry ice, when it was held out the window it instantly burst into flames because the air was simply moving to fast to remove heat.

    Seems logical enough to me...

    Harry

  29. #59
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    Maybe I should just seal a chocolate shake inside the hull instead?

  30. #60
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    Quote Originally Posted by forescott View Post
    Maybe I should just seal a chocolate shake inside the hull instead?
    and then get some marshmallows for the hot chocolate when your done!
    Jesus is King .......NAMBA20...Caterpillar UL-1, P-Spec OM29, P-Mono DF33, P-Spec JAE, Aussie 33" Hydro-LSH, Sprintcat CC2028 on 8s, PT SS45 Q Hydro, PS295 UL-1 power, OSE Brothers Outlaw QMono 4-sale, Rio 51z CC2028 on 8s

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