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Thread: Best water pick-up ever!

  1. #151
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    Quote Originally Posted by Fluid View Post
    A propwash pickup has significant drag, more than a rudder pickup, etc. Try putting your hand in the spray coming off a full-sized boat and then tell me there is no force pushing your hand backwards! The propwash is even worse because the roostertail spray is traveling faster than the boat is moving forward, and when it hits the pickup tube it causes lots of drag. This doesn't mean that a propwash pickup shouldn't be used, but if you think it is better because there is no drag, think again.



    .
    2nd that yes what he said.

  2. #152
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    Quote Originally Posted by dogg View Post
    I'll probably cop some flak for this as I'm a newbie on this forum; but when it comes to heat transfer in cars, I would like to clarify something...
    It is a totally different scenario to the one you are relating it to.
    Firstly the overheating of the motors in cars (be them race or road) without use of the thermostat is NOT due to too much flow through the motor but due to the speed of flow through the radiator being TOO HIGH/FAST to effectively cool it before it re-enters the motor to begin the cooling cycle again.

    It is however true with an internal combustion motor that too much cooling can cause increased wear and less efficiency with fuel consumption and overall performance.

    With boats, be them model or full scale (bearing in mind the less efficient and higher wear of internal combustion engines that may result) the fact is that no matter how fast the flow of the water/coolant passing through the motor (water jacket in the case of an inrunner), the higher flow of water will always cool the motor faster and more efficiently.

    Try cooling your motor with 80 degree water when its running at 130 degrees and it will only ever cool to minimum of 80.
    Try cooling it with almost freezing point and the minimum possible it can get down to is the same as the almost freezing water.

    The higher the flow rate, the faster the cooler water reaches the motor replacing the preheated water from the motors water jacket, resulting in better cooling period.

    I hope I don't offend people with this frank description but I believe this to be true and am interested to know if anyone else finds fault with the logic. I've been in the automotive industry for almost 22 years and have had both road and race cars and this has been my experience and is the only logical explanation in my opinion.
    Correct!
    anyone can look at http://www.stewartcomponents.com/Stewart_faq.htm
    Mike

  3. #153
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    Hi guys Ive just fitted these..

    http://imageshack.us/a/img405/7946/2013011419001751.jpg
    http://imageshack.us/a/img18/8964/20130114185951445.jpg

    I was wandering the pro's and cons of using them, Ive been told to expect them to cause a 10kmh drop in speed form the drag they will cause, which Im not to worried about. Just want to be sure Im not going in circles creating more heat with the drag, than Im gaining in cooling ability with this type of pickup.

  4. #154
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    I would definitely file them down some, you don't need that much in the water to get good flow. Seems like a bad spot for them too. Have you ran the boat like that yet?

  5. #155
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    No not yet, will try this weekend. Why do you say bad spot?? Have you used this position on the genesis hull and had issues??

  6. #156
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    That's gonna create ALOT of drag

  7. #157
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    Quote Originally Posted by Mike Caruso View Post
    Correct!
    anyone can look at http://www.stewartcomponents.com/Stewart_faq.htm
    Mike
    I'm not sure if even alot of top car guys realize what the thermostat actually does, the system is really based on the radiator and not the thermostat. The thermostat and cap are in relation to the amount of heat dissipation the radiator can preform at a given airflow. Bigger radiator more cooling. No forward movement of auto= no cooling. This is why they install fans, to help with cooling. The thermostat is designed to restrict water flow at certain temps (allowing radiator to dissipate more heat through air thermodynamicly). So it's not really addressed in simple physics because the components in use are limited. X amount of coolant in closed system dependant on x amount of cfm (airflow) all in a relative ambient temperature. Anybody know why ski boats don't have radiators? The lake they run in is there radiator. So please for those that still believe to slow restricted water flow will cool better just believe in physics, it works on keeping you from putting 50 volts through that 3500kv motor with a 15 amp esc doesn't it?

  8. #158
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    Quote Originally Posted by TristanJones View Post
    No not yet, will try this weekend. Why do you say bad spot?? Have you used this position on the genesis hull and had issues??
    Oh for some reason I thought those were sponsons on a 3 point hydro. They should be fine there. Try them how they are and see what happens. I've only used that style on a super vee hull and ended up doing what stadium Yamaha described in your other post. Flush with hull at the front with just a lil nub at the rear. When they were longer I was getting weird handling characteristics

  9. #159
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    Thanks heaps mate. Wish I had a hydro!
    I just wanna run over 60mph even just 2 or 3 times then I'll run it on lower voltage if its unstable.

  10. #160
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    Quote Originally Posted by Cooper View Post
    I'm not sure if even alot of top car guys realize what the thermostat actually does, the system is really based on the radiator and not the thermostat. The thermostat and cap are in relation to the amount of heat dissipation the radiator can preform at a given airflow. Bigger radiator more cooling. No forward movement of auto= no cooling. This is why they install fans, to help with cooling. The thermostat is designed to restrict water flow at certain temps (allowing radiator to dissipate more heat through air thermodynamicly). So it's not really addressed in simple physics because the components in use are limited. X amount of coolant in closed system dependant on x amount of cfm (airflow) all in a relative ambient temperature. Anybody know why ski boats don't have radiators? The lake they run in is there radiator. So please for those that still believe to slow restricted water flow will cool better just believe in physics, it works on keeping you from putting 50 volts through that 3500kv motor with a 15 amp esc doesn't it?
    Yes,
    A lot of people still think water moving FAST through an ESC, motor or IC race engine does not have time to pick up the heat from the casting. They are wrong! I love the ski boat reference that should hit home. HA I still believe this nonsense came from the 60's when people Drag racing the 283 -327's would over-heat. Back then and for many years and yes even today still the fix was to slow the water pump down. It worked great but why? Water must be moving too fast right? WRONG The truth is the high RPM that the SBC could turn the stock water pump was too fast causing it to go into Cavitation. Now pumping the foaming water through the engine like A&W Root Beer Foam which did not cool the casting. Less water to contact the castings to remove the heat. This is what caused the over-heating.
    Mike
    Last edited by Mike Caruso; 01-17-2013 at 09:27 AM. Reason: text

  11. #161
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    Good day all... Since there is no rudder with 4 water pick ups, I made this. Prop wash water pickup.
    I bent the brass tube (ID 4mm, OD 5mm) using tube bender and the bracket were made using 3D printer.
    The water flow was fast. But, the drag, not sure.
    Only I'm not sure whether current inlet mouth is the at its best position or not.
    Feel free to comment and suggest.
    IMG_20140922_082158.jpgIMG_20140922_082356.jpgIMG_20140922_082449.jpgIMG_20140922_082507.jpg

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