Controlling twin motors

[Philip MitchellParticipant @philipmitchell70963]

Hi,

I know that this subject has been mentioned in the past but I am having trouble getting my head round some of the prospective problems.

If you only use one ESC to control the two motors how can you make sure that the motor outputs will be matched and the boat won't just go round in circles.

Using two speed controllers would seem to be the answer but if one is on the left hand stick and one on the right is that not a bit of a handful to control and two ensure that outputs are matched.

Phil

[Philip MitchellParticipant @philipmitchell70963]

Best way of controlling two motors in model boat

[BanjomanParticipant @banjoman]

Hi Phil,

Dave Milbourn has written a most lucid and interesting artcile on the subject that can be found on the Action Electronics website, here: **LINK**

For obvious reasons. the solutions discussed are based around Action Electronics products, but this, in my view, does not at all detract from the general interest or the basic principles also discussed therein.

For that matter, I would also say that the Action products mentioned are very interesting, too, and, again in my view, well worth considering; I have so far never heard anything against them but many things in their favour.

/Mattias

Edited By Banjoman on 30/03/2016 19:23:09

[mark69Participant @mark69]

Hi Phillip I've not read all of Dave Milbourns article but I cannot see how you could control two motors using both sticks independently ,maybe I'm wrong just that I've not seen this setup in all the years I've been "into RC" ….mark .

[Colin BishopModerator @colinbishop34627]

Basically you have a separate speed controller for each stick. This is referred to as 'tank steering'. One of the sticks, usually the right hand one, also controls the rudder in the horizontal plane.

However tank steering isn't the best way to control a twin screw model, a mixer is preferable but you still need two speed controllers. Finish reading Dave's article which I think explains most things. If you are still not clear then we will be happy to answer your questions.

Colin

[Graeme LinskeyParticipant @graemelinskey75588]

Hi,

If your tx has mixers then that's the way I do it' plugging a y lead into your rx that should in theory work

[Malcolm FraryParticipant @malcolmfrary95515]

If you only use one ESC to control the two motors how can you make sure that the motor outputs will be matched and the boat won't just go round in circles.

You live in hope that the motors and their drive trains are matched and that any mismatch can be trimmed out by the rudder.

Using two speed controllers would seem to be the answer but if one is on the left hand stick and one on the right is that not a bit of a handful to control and two ensure that outputs are matched.

Yes, use either a hardware mixer in the boat to combine the throttle and rudder or a software mixer (if available) in the transmitter. Doing it with two throttles is quite achievable using optical feedback (when it runs in a straight line, a match has been achieved).

[ashley needhamParticipant @ashleyneedham69188]

Philip. There is no easy answer to this. There are so many variables in two separate drive trains that it is unlikely that both sides will match exactly. I would not worry about it, the difference will be very small if indeed it is even noticeable if using just one ESC, and the very slightest amount of trim set on the rudder will sort this out unless there is something seriously wrong with the boat.

I hazard a guess that almost no boat steers a dead straight line if left to its own devices (obviously the ones produced by forum members do, naturally) and if there is the smallest breeze blowing this will put the boat over in any case.

Ashley .   Usual disclaimer.

Edited By ashley needham on 31/03/2016 10:28:22

[Dodgy Geezer 1Participant @dodgygeezer1]

…and the beam of the boat will have an impact. If your props are only a short distance apart, slight differences aren't going to be as important …

[BRYAN ASTONParticipant @bryanaston57723]

Philip

My Calypso ship has twin motors and only one ESC and I have had no problems at all ,perhaps you are anticipating problems that do not exist, just switch it on put it in the water and away you go. Keep life simple.

Bryan

[Ian GardnerParticipant @iangardner62867]

Hello Philip,

I went throught the process you are going through and Dave Milbourn's article is very helpful. In the end I opted to use a speed controller on each motor and Y lead to one channel on the rx. I use a separate radio battery but there is the issue of disconnecting one red lead on a controllerif you use BEC. I found it the system works well.

I tried a clubmates boat that had tank steering and was all over the place- couldn't cope at all,so personally I'd avoid that!

Ian

[Graeme LinskeyParticipant @graemelinskey75588]

Hi

I totally agree with Ian post above I also posted a question about the same issue I am now useing 2 rx plugged into the throttle channel side by side and it works a treat but no reason why a y lead would not work..and yes you need to snip the red wire if useing BEC one one of the ESC

Regards

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