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Thread: Miss Geico 36 motors left right with control via steering

  1. #1
    Join Date
    Sep 2007
    Location
    NS
    Posts
    3

    Default Miss Geico 36 motors left right with control via steering

    Hi, yes sounds strange but this is something I wanted to try.
    I'm new back and this is my first dual prop cat, I have a small place to turn in on my pond if you could call it that and turning this cat seemed strange, like it wanted to roll over, I know i should probably go faster and like "drift" it around the turn but the edges of my pond are concrete walls.
    Anyway I am trying out an idea, when I turn the rudder more than about half to the right the the right motor pauses and when I turn the rudder more than about half to the left the the left motor pauses.
    I still have full speed control over the operational motor, when the steering returns to close to centre the paused motor is unpaused.
    I have only had 1 run and not enough practice to tell, short run as had a flip, but 1 advantage is when flipped I can use the system to help blow the boat back to shore.
    What do you guys think, dumb idea or something to work on?
    Regards,
    Rob
    Sydney Au
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  2. #2
    Join Date
    Mar 2020
    Location
    NH
    Posts
    38

    Default

    hi bandit if slow or stop a motor it will end in the concrete wall this boat needs the 2 motors if set the stingers exact 2.5 mm it will turn short but you need speed to do so

  3. #3
    Join Date
    May 2009
    Location
    UK
    Posts
    608

    Default

    your principle is sound, "splitting the sticks" as it's called does work, im a navigation officer with a large cruise line, it's how we manoeuvre the older smaller boats. - now I have 3 azipods to spin about

    If you could reverse one of the props, this would help a lot for example if turning to the right, reverse the right / Stbd prop, ahead with the left / port prop, rudder won't have that much effect on a cat but it will swing very nice. - also inward / outward props have a big effect on transverse thrust outward being preferable.
    2x Graupner Azimut atlantic challanger, HPR 115, H&M NoStep4, Etti mono 1.

  4. #4
    Join Date
    Dec 2010
    Location
    NY
    Posts
    2,616

    Default

    I'm pretty sure you can do that with a decent radio

  5. #5
    Join Date
    Jul 2016
    Location
    IL
    Posts
    3,165

    Default

    Cool project and I'm interested to see how you make out with it.

    I would suggest against the idea of reversing a prop. Yes, on large scale vessels it makes perfect sense and is effective, but the catastrophic downsides in a FE model boat are not worth even considering it.

    I would also advise against "blowing" the boat back to shore after a flip. That's a lot of RPM with no cooling to the motor.
    Vac-U-Tug Jr (13mph)

  6. #6
    Join Date
    Sep 2007
    Location
    NS
    Posts
    3

    Default

    Thanks for the replies guys.
    Trust me the last thing I want to do is hit a wall, where i test is too narrow to attempt a high speed turn that is why i decided to cut the inward motor to help induce the turn then max power to the outward motor, just need water time to prove or disprove this idea, but it is useful at slow speeds.
    I can reverse prop or props as I have not disabled reverse yet.
    I only "blew" the boat a short distance and at very low rpm but remember there is virtually no load so bugger all amps.

    I also think it's a cool project, just used a slave steering servo and glues 2 micro switches to the sides allowing the signal wire to each ESC to be disabled when the rudder is turned the set amount.
    If it's worth keeping I will make the set points easier to adjust and maybe use a channel to enable/disable the system.

    I tried to do this via the radio but you will need to use a stick radio that has mixing circuits such as a Spektrum DX6, unfortunately wheel radios don't offer the appropriate mixing, I tried using a Spektrum DX5C Smart Surface Transmitter but it's mixers are truck related.

    Upgrade parts just arrived from china so maybe upgrade time this weekend - 2 x Rocket 4074 2250KV and 2 x Mystery 200A ESC, plan to use stock props, already have cooling upgrade so hoping temps will be acceptable. Think it will be capable of going stupid fast.
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  7. #7
    Join Date
    Dec 2010
    Location
    NY
    Posts
    2,616

    Default

    a good cat boat could do 35' radius turns at 40-50 mph

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