Radio control

[Colin BishopModerator @colinbishop34627]

Difficult to diagnose really. Have you tried plugging the rudder servo into a different channel?

Is the speed controller the same as the one in your other model? Are you using the BEC on the speed controller to supply the receiver with power or do you have a separate battery?

Colin

[BRYAN ASTONParticipant @bryanaston57723]

Hello Colin

I tried it on the Sea Commander which has the identical receiver and runs perfectly normally but when I swapped the receivers nothing happened. The power comes from the speed controller.

In the past when I installed the same radio equipment in the Huntsman , I had the cables reversed and the steering and the speed control were reversed but it still worked, I swapped them over, I tried to do the same this time but it did not work. I am at a loss.

regards

Bryan

[Colin BishopModerator @colinbishop34627]

I'm afraid I'm not a radio control expert Bryan. Like you, I buy the kit, follow the instructions and trust that it will work – as it usually does. Perhaps one of our more expert members will be able to help with your problem.

Colin

[Kimosubby ShipyardsParticipant @kimosubbyshipyards]

Hello Bryan,

sounds maybe that you've done what one of our new chaps did.. The BEC lead you say you are using [from the speed controller] needs to be plugged into the throttle channel on the receiver (1 usually) and not the one marked B or battery – leave that one blank. That's what the BEC stands for battery eliminator connector. If you are already connected this way then, sorry, without your kit to hand I've no other suggestions. I do know of one gentleman who actually had a duff speed controller [ESC] which is quite rare.

Do you get any response from any channel of the receiver?

Kimosubby

[Dave MilbournParticipant @davemilbourn48782]

Bryan
It's forensic, not electronic. Some also call it common sense or methodical.
You say the installation in the new model is identical to the one in the working one. OK – that's a good start.
Firstly charge up all of your batteries and check your wiring for correct polarity etc. 90% of problems start and end here.
First question – are you using a 'digital' rudder servo in the new boat? Yes? Then throw it away. There's your problem. (Ask me why later.)
Try your old working receiver in the new model. If things are OK then it's the new receiver which is suspect. Confirm this by trying the new receiver in the old boat and then in the new one again.
If both receivers are OK then try the same trick with the speed controllers.
Now try swapping the rudder servos around, followed by the motors and the batteries.
Don't forget to keep notes of what you've connected to what or you'll gradually go mad. Ask me how I know.
Sooner or later you will get to a point where a working circuit suddenly doesn't work when you connect a different item into it. That's your culprit.
Dave M

[BRYAN ASTONParticipant @bryanaston57723]

Thank you Kimo & Dave

My first boat The Sea Commander runs perfectly with the r/c fitted, however, when I could not get the second boat to run which had a new speed controller and a identical new receiver fitted , only the batteries and transmitter from the first boat were transferred, The new speed controller started flashing a red light and the receiver just showed a red light, after my asking for help on the forum I realised that I had not tuned , if that is the correct term, the new receiver to the transmitter that mistake was corrected, now we had a green light showing in the receiver, still no response from the motor. As a test I fitted the new receiver in the first boat, no response at all,I then fitted the original receiver back in the Sea Commander and it ran perfectly.

Conclusion , the new receiver is NBG and should be filed in the WPB. I am sure stamp collecting is less problematic.

If anyone has any more suggestions I would be most grateful.

Regards

Bryan

[BRYAN ASTONParticipant @bryanaston57723]

Greetings Kimo & Dave

This is a ps.

The batteries were fully charged, I have no idea what a digital rudder servo is, and when I used to transfer all the r/c equipment from the first boat the to the second boat it ran perfectly.when I say all the r/c equipment I only mean the receiver and the speed controller., the servo is identical to that fitted in the first boat.

In an effort to get more speed out of the 46 inch Huntsman, the second boat, I bought a Johnston 785 motor from ebay, on reading the technics of the motor ,it can use 56 amps so I bought a speed controller that can handle 56 amps, but at this present time I cannot try it out. Perhaps I should have stuck with the 600 Johnston, if its not broke don't fix it.

Happy days

Bryan

[Dave MilbournParticipant @davemilbourn48782]

Bryan

Yes – I think the symptoms definitely indicate a dud receiver. Did you buy it from a UK retailer? If so you should send it back and ask for a replacement. If you bought it from China then good luck with that; you'll be lucky to get a response of any kind.
The big Huntsman will take a 785 – but only a 3:1 geared one  – "Darke Horse" – which you then run on 20 cells. I have two of these and they are fearsome! At that voltage they draw surprisingly little current (<20A). The planetary gearboxes are industrial quality and are fitted to very close limits (using a lathe to set them up). Consequently they are very expensive. Johnson 600 motors are good only for ballast.
I would seriously suggest using a brushless motor in your Huntsman. There is nothing more sad than a Fairey power boat limping round the pond like a narrow boat.

Dave

Edited By Dave Milbourn on 04/07/2014 09:01:19

Edited By Dave Milbourn on 04/07/2014 09:02:07

[BRYAN ASTONParticipant @bryanaston57723]

Dave

As a matter of interest and my education why would a 785 Johnston motor need a gearbox, what would be likely to happen if it was run without a gearbox. I only ask as I am still learning this game.

Regarding brushless motors what power,if that is the correct term ,would I require? and I understand that I would also need a special speed controller and would it run on 7.2v .

Regarding the receiver I bought it on Ebay from a private individual as almost new ,working order and surplus to his needs. I will be in touch with him, could be interesting.

Bryan

[Dave MilbournParticipant @davemilbourn48782]

Bryan
To answer all of your questions fully would take a very long time. Briefly the 785 will spin a prop whose maximum size is insufficient to propel a big Huntsman by direct drive. If you try to spin it too fast then you will draw huge currents and quickly burn out the motor. The Australian guys – led by a genius called John Darke – worked out that if you geared one of these down to allow it to turn at its optimum speed, then you could greatly reduce the current and turn a big enough prop if you used sufficient volts. That's why they use a 785 and not, for example, a lower-wound motor i.e. because it can take the high voltages. One of these on 20 cells will produce a figure approaching 1BHP and, as I said, is a fearsome thing to hear! Steve Jones of the Barry club has a Huntsman with two of these fitted……….. The main drawback seems to be brush life which, despite water-cooling, isn't very long. You can imagine that the sight through the cooling slots in the motor case at full speed looks like a busy welding bay. As we say around here, you don't get owt fer nowt.

Brushless motors are a huge subject on their own. My article on this website will give you a very broad overview while there is another one by John Parker which goes into much greater depth. At the end of the day it's down to experiment or finding someone who's equipped the same model with a brushless motor and ESC and using what he's used. **LINK**

Dave M

[BRYAN ASTONParticipant @bryanaston57723]

Dave

Thank for the info on the 785 motor it seemed a good idea at the time ,,anyone want a 785 motor ?.

If anyone has fitted a brushless motor to 46 inch Huntsman or Sea Queen will they let me know the result .

In the mean time I will carry on building the SS Balboa, to make life easier I have stretched it to 33 inches from the 20 inches shown on the free plan.

Once again thank you for the info

Regards Bryan

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