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Author Topic: pensioners special Mixer??  (Read 1452 times)

portside II

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pensioners special Mixer??
« on: July 19, 2008, 11:55:40 PM »

Right guys this was put to me by a fellow club member.
He like myself has a RTR southampton  and if you have ever sailed one of these you will know that the turning circle is not good,and he would like to improve it.
The first thing i did to mine was to enlarge the rudders which made a difference but what about a mixer in the running gear.
Now the chappy with the other southampton is a pensioner and cant realy afford a dedicated mixer and i cant remember if one would work with only one esc (FLJ will tell me {-) ).
I have an idea , after fitting a basic micro switch on a club 500 for power to the motor via a servo (one way) i thought what if i fitted a pair to the rudder servo on southampton ,so when the ridder is full port/stboard then that motor is cut off so the outside prop is only working  O0 . But then i thought (this is when FLJ and Wombat are needed) what if the micro switches reverse the polarity and put the static prop in reverse would this work or would it be like reversing the polarity on the ESC on the output side and would this harm the ESC (so many questions), if this is the case what about twin switches off set to 1 disconnect the power to that motor ,2 then to reconnect the power in reverse  :o .
In terory if it works then when full port/stboard is applied the in board prop will reverse making the boat turn on it's self  O0
Please tell me this may work cos my head hurts  :o .
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Robert Davies

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Re: pensioners special Mixer??
« Reply #1 on: July 20, 2008, 02:04:25 AM »


The Southampton sails along quite nicely with one prop U/S with very little deviation from the straight ahead, so I think you're correct in wanting the inboard motor reversed.

You'll need a tiny bit of rewiring before you start as the Southampton's motors as standard are wired in series - Wire goes from speed controller to the first motor then the second motor and then back to the speed controller. I think it would best to start from a point of having a separate out and back feed for each motor.

I'm having a think about the rest of it for now....

The rudder servo is tricky to get as far as mounting external switches.... I think I'd get a y lead and another servo and wire them into the same channel and use the separate servo for the switching.

It's late... or very early! but I'm guessing a pushbutton dpdt switch set in each motor feed and actuated by the separate servo should do what you want. If there is such a thing!

My head hurts too NOW!!  :P

-Rob
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FullLeatherJacket

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Re: pensioners special Mixer??
« Reply #2 on: July 20, 2008, 10:23:52 AM »

Daz

A mixer does what it says on the tin i.e. it mixes two input signals and puts the resulting train of pulses to two ESCs, so if you only have one ESC it's a bit like trying to clap with one hand. I don't know what set-up is in the standard model; I suspect it's just one speed controller operating both motors.

If your old chap doesn't want to strip out the standard gear and fit two ESCs then your idea of using microswitches is probably the cheapest way (much as it offends both my lofty esoteric principles and my base commercial instincts). As Rob says, you'd need to connect the motors in parallel - which might increase the speed to an unreasonable degree as it effectively doubles the voltage to each motor.

Without sitting down with a pencil in my hand and my brain in gear, I reckon you would need four such switches; two fitted "piggy-back" at each extreme and switched simultaneously to act as one DPDT switch. We stock some very small 10A ones for úNot-a-lot. Setting them up would be fun - sooner you than me, sunbeam! The only other problem I foresee is that it might be very fierce in operation - more like the old "bang-bang" sequential escapements than a proportional response. IMHO a mixer and two small ESCs is the best option by far - but I would  say that, wouldn't I?!

You pays your money and you takes your pick - suit yourself!

FLJ
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Wiggy

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Re: pensioners special Mixer??
« Reply #3 on: July 21, 2008, 03:09:21 PM »

Hi Daz,

Done it, been there and if you want, i'll show you one on sunday at your club open day. Had the unit in my 'Smit' and one in my 'Al Khubar', either that or give me a ring or mail me.
Have been using the devices for over five years now but some folk reckon that you should fit two ESC's and use your thumbs to mix things but 'Duh! that just makes my bwain hurt!' :-\

Cheers,

Paul.
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portside II

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Re: pensioners special Mixer??
« Reply #4 on: July 21, 2008, 03:50:46 PM »

cheers Paul will have a look at your setup . i have an idea as what to do as i made a simular thing for a bow thruster ising 2 switches and a servo to reverse the polarity .
Rob the idea of using a Y lead  O0 that i could make the unit seperatly and fit it where i want .
Dave Dave Dave always the buisness man in an ideal world i would get the pensioner to buy one of your twin esc's with mixing facilitys but i used the word pensioner and this means (at my age i cant afford to buy one as my pension wont sterach that far) tight (please dont be offended as i dont mean all of them only some).
I think there may be a hole around me ,stop digging .
Yes i will have to rewire the motors into the switches to make it work but my main worry is that just switching one motor in reverse may blow the ESC  thats why i was thinking of 4 switches , will have to do some expreimenting .
daz
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