Temperature control on brushes motors

Discussion in 'Research and Development' started by Skeeterbug, Nov 26, 2021.

  1. Skeeterbug

    Skeeterbug New Member

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    Greetings. I’m working on my first build, USS Texas, and have 2x 750 motors I’ll be using. In a previous RC, a tank, build I had some concerns over motors getting too hot, so for this build I’m looking at installing copper coils with a water pump. For those who have been around, do you find cooling the motors to be necessary?

    Next, I have also looked into temperature control switches to turn on and off as the motors heat and cool. Is this even necessary or am I over thinking this? Would just a continuous water flow be better?
    Thoughts, suggestions, tips?
    Thanks
     
  2. Kotori87

    Kotori87 Well-Known Member

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    Definitely over-thinking things. Unless you've totally buggered your prop-and-gears combo, two 750s should be in no danger of overheating. I've only seen motors overheat when they are severely overloaded (ie running a small 6v motor on 12v to reach speed) or stalled due to weeds/etc. Unlike with tanks, you'll have a regular fresh supply of cool water inside the boat to keep ambient temperatures down. If you're really worried, a properly rated fuse will provide adequate protection. It won't blow under normal combat loads, but will pop when you've sucked up a 4-pound blob of pond snot and your props are stuck fast.

    Now one thing that could potentially benefit from a water jacket would be the CO2 bottle. We lose a huge amount of gas efficiency when our bottles cool down, so using a fresh source of warm flowing water could significantly improve endurance. Provided, of course, that you can avoid freezing the water in the jacket. I run my CO2 bottle directly in my water channel, and I regularly pull huge chunks of ice out afterwards.
     
  3. Skeeterbug

    Skeeterbug New Member

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    Over thinking things is something I’m good at. I was going to install fuses just as a protective measure anyways. A water jacket around the bottle wasn’t something I had been considering. But now that you mention it, I can look at using this motor cooling pump for that purpose. Hmm…

    Cheers
     
  4. BigGunJeff

    BigGunJeff Well-Known Member

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    Yeah, I cut out a big section of hull and made an aluminum bottle cradle on one of my boats. It sucks heat out of the water and warms the bottle through the aluminum.

    Not sure how necessary it is though.
     
  5. Nomercy

    Nomercy Active Member

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    If you are pulling chunks of ice out, you sir have a leak in the system somewhere.
     
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  6. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

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    Fraid not. It is simple thermo... Liquid to gas phase change takes energy. And with fast gun rates of fire you can readily freeze water around the tank.
     
  7. Nomercy

    Nomercy Active Member

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    We can agree to disagree
     
  8. darkapollo

    darkapollo Well-Known Member

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    Hes right though. The bottle will get cold enough to frost. What is frost other than frozen moisture. If it is in the water channel it will form ice.
    It is the same reason a glass of ice water gets condensation on it.
     
  9. Commodore

    Commodore Well-Known Member

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    The only time I've frozen a tank is when I popped the blow-off patch.
     
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  10. Kotori87

    Kotori87 Well-Known Member

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    Bigger bottles are more resistant to frosting. I'm currently running a 4oz steel bottle. It's got enough gas to support 3 units worth of very high-flow cannons, but it gets frosty fast due to its low mass and small size. A bigger bottle can handle the same amount of gas flow much longer without freezing, both due to stored energy and better heat transfer due to greater surface area. I recently test-fitted a 5-oz aluminum bottle, and I'll be swapping out next refit. Not so much for the gas, but for the extra thermal mass and heat transfer capability.
     
  11. Kevin P.

    Kevin P. Well-Known Member

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    I recommend focusing on building the core systems well, any sort of active cooling system is unnecessary. You can have the slickest CO2 bottle temperature control system in the hobby, but if the boat can't drive, pump doesn't work, guns don't work, can't survive a sink, etc. then it will serve no useful purpose. As a few of the experienced guy have said, having a bottle or regulator freeze to the point of impacting operation not common, and can easily be mitigated by having the bottle in the waterchannel and ensuring the bottle isn't angled down. The only time I've seen it be a large issue is when we battled when it was ~35F outside. For the Texas, 750 motors are a bit overkill, and 540/550 would do just fine.
     
  12. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

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    This. A lot of us are geeks who will happily try new things out, but don't do it until you have a functioning boat that works well and you understand what your needs and issues are
     
  13. Skeeterbug

    Skeeterbug New Member

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    For the Texas, 750 motors are a bit overkill, and 540/550 would do just fine.[/QUOTE]

    overkill? Really. I figured it being 50+ inches long and with all the weight I could use big motors to push it around. I guess I’ll just get it on the water and add systems as needed. The co2 bottle jacket wouldn’t be a first priority.
     
  14. Kevin P.

    Kevin P. Well-Known Member

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    Yes, the swap over point between 540/750 motor size for a two drive shaft ship for traditional IRCWCC/ fast gun rule set is typically in the 60-65” and 35lbs range. It’s important that the bottle be easy to remove and install, typically it can be a pain just with gun hoses and deck crossmembers, I wouldn’t want to have to deal with getting it in and out of a coil or similar
     
  15. darkapollo

    darkapollo Well-Known Member

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    I just looked at the IRC ship list for the Texas. Dual 750’s are way too much motor. 28s and 24-28lbs is easy for dual 550’s. My Derf is 22lbs and 24s, and dual 550’s push it there with (too much) ease.

    I used a single 750 to push my Bismarck around. Thats a 40lb ship.
     
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  16. Skeeterbug

    Skeeterbug New Member

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    Thanks for the feedback. Scaling down to 550s is easy at this point. Well, was until I seized a mounting screw in the new motor and broke it off. Oops. I need to place an order with BC so I’ll pick up an extra 550.