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Thread: Had an interesting experience

  1. #61
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    Mar 2017
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    VI
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    Madracer if you will to share the setup, prop, motor size and kv, ESC, battery capacity and c rating I might be able to tell you the likely speed out come.

    Native Paul crazy thing is ampdraw is not the issue with us. We have much longer runtime based on my research but sadly less speed.

    Did you guys see my last video. My revolt was significantly faster on 5s than when it did 54mph just by using more powerful batteries.

    Them smc cell are really good.

    Reducing prop diameter will slow the boat down.

    I have used the grimracer 4255, octura x442, x642, m545, m645, graupner k42 and ABC 1814 17 45 2 blade.

    The graupner k42 have 150 percent more runtime than the grimracer 4255.

    And its a lot slower too.

    The stock spartan did 35mph on 6s with the stock spartan prop.

    The octura x442, x642 and grimracer 4255 give a big advance in speed over the k42.

    The m545 and m645 gives another 4 to 5mph faster than the 42mm props.

    The ABC prop let me down I took much longer to get on plane and the little sail I got before wringing was a lot slower the the octura.

    The m545 was .5 mph faster than the m645 at a lower cell count on GPS for me.

    The m545 give a bow lifting effect and the m645 ran more wet.
    So I think the loser running was the reason for the speed increase over the m645.

    I cannot run more than the m545 on 5s with my revolt because my 4092 size motors are putting out too much torque. The coupler cannot hold the upgraded shaft beyond that.

    I am getting my motors to put out far more power than my running mates. They buy better ESC and all kind of stuff but not getting the power that I get.

    It have a few of my running mates who get the motors to put out good power though.

    But mine run cooler.

    I have seen my run mates run bigger props than me without the problems that I describe but that is because they are not getting the power that I get.

    But back to you madracer if you share the setup I might be able to tell you the likely speed.

  2. #62
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    Mar 2017
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    VI
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    Madracer I ask you for the setup before watching the video.

    I glad I saw that video. If you get pass 15 to 18mph in our waters with that thing my jaw might fall off.

  3. #63
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    Mar 2017
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    VI
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    After doing the calculation the little boat should run between 23 to 26mph in BVI waters. So from 33mph to the above listed speeds.

  4. #64
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    Feb 2017
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    na
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    Quote Originally Posted by Speed3 View Post
    After doing the calculation the little boat should run between 23 to 26mph in BVI waters. So from 33mph to the above listed speeds.
    Awesome thanks!
    TFL Zonda (124mph), Miss Geico Zelos 36 (108mph), Veles 29 (91mph), Zelos Twin 36 (90mph), Miss Geico 29v3 (83.5mph), Sonicwake 36 V2 (83mph), Blackjack 42 (81mph), TFL Pursuit (79mph), UL-19 (75mph), Sonicwake 36 (73mph), Motley Crew (47.5mph), AquaCraft Rescue 17

  5. #65
    Join Date
    Feb 2008
    Location
    GB
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    Quote Originally Posted by Speed3 View Post
    The salt water requires 140% more amps for the same exact setup. I did the test to compare the two waters.
    Quote Originally Posted by Speed3 View Post
    Native Paul crazy thing is ampdraw is not the issue with us. We have much longer runtime based on my research but sadly less speed.
    That crazy contradiction is too crazy for me, I am out.
    Paul Upton-Taylor, Greased Weasel Racing.

  6. #66
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    Mar 2017
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    VI
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    My revolt when new with the stock prop and ESC I used to run with a GPS in the boat.

    I used to sail 6.5 minutes with some grimracer 4200 mah 4s.

    I would sail full throttle back and fort.

    When time to recharge the cells they took 2800 mah to charge back to the starting voltage.

    33amps average for the run.

    Full throttle back and fort slowing down only to turn.

    Top speed was 31.7mph.

    My research show that many others was pulling around 60amps and top speed of 35 to 38mph was seeming common for a stock revolt.

    As far as the 140% increase in amp draw goes.

    I did test at a know load to calculate the internal resistance of my battery.

    The aim was to predict voltage drop at a given load.

    And calculate ampdraw based on voltage drop.

    I tried varying load to make sure the method was something I could rely on.

    After learning the internal resistance. I did an experiment.
    I went to an area where I commonly sailed my boat. I place the boat on the stand put it in water deep enough to stimulate how much amp it would draw at full throttle. I had a multimeter connected to the battery wires. And I monitor the voltage underload. Recorded it.

    Then released the throttle and recorded the first voltage that I say after throttle release.

    Then I subtract the loaded voltage from the initial that came up after releasing the throttle.

    This gave me the voltage loss.

    I divided the voltage loss by battery internal resistance. Which intern give me the ampdraw.

    I did the same test in a bath tube with rain water or fresh water.

    The I divided the sea water ampdraw by rain water amp draw.

    The result was that salt water required 140% more amps than the rain water.

    I performed the test more than once and the result was the same.

    So it may seem like am giving contradictory data but I am going off of many hours of testing experimenting with recorded data and research.

    Based on my research, the claimed runtime that some report and the put back capacity reported. I have concluded the those guys boat pulls 172% more amps for a similar setup to us in BVI waters.

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