New RC modeller

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New RC modeller

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18 December 2020 at 20:43 #92764
Stephen Garrad
Participant
@stephengarrad28964
Good evening, my first post on this forum.

I have very nearly finished building a narrowboat model, Amelia Rose (I saw a post recently from someone who has just finished the same model) which I think is about 1 12th scale. I haven't had any problem with the woodwork & modelling part but the radio control part of it is completely new to me.

My local model shop were very helpful & have supplied me with a Reflex Stick PRO 3.1 2.4 ghz controller & a Viper Marine 20amp ESC & a Voltz Ni-Mh battery pack which they described as an entry level set up.

I've got everything in & appears to be running OK, we haven't been in the water yet as I've still got the ballast to sort.

My question is that when I operate the propeller motor the ESC makes a whistling? noise. Nothing when the steering servo is operated. Should it do that? I cant find any reference to the noise in the instruction leaflets. Can anyone shed any light on it for me please?

Thanks

Stephen
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18 December 2020 at 20:43 #2968
Stephen Garrad
Participant
@stephengarrad28964
ESC noise
19 December 2020 at 11:15 #92771
Colin Bishop
Moderator
@colinbishop34627
Yes, the noise is quite common and varies according to the ESC and motor combination. It's to do with the way that the ESC feeds power to the motor and usually there is not much you can do about it. We have some experts on here who can explain it better than I can.

Colin
19 December 2020 at 13:33 #92772
Charles Oates
Participant
@charlesoates31738
Yes, perfectly normal. The noise is coming from the motor, it's working a bit like a loudspeaker. The electrical pulses that change the motor speed are what you are hearing from the motor. Don't worry about it, the Viper is an excellent piece of kit.

One extra item of advice, many of us fit a fuse between the motor and the esc to protect it if the motor stalls, perhaps from weeding up. Whether you need to depends on your motor and it's stall current.

If any of that doesn't make sense, just ask.

Charles.
19 December 2020 at 21:56 #92778
Stephen Garrad
Participant
@stephengarrad28964
Thanks very much for the replies, it had me a bit worried but I shan't panic now.

The motor is an MFA/como drills 719RE540/1 but I don't think I know the stall current, what rating fuse should I use? Weeding up seems likely looking at the canal out the back!!

Sorted the ballast this morning, in the bath, it only just went in!!!

Thanks for your help.

Stephen
19 December 2020 at 23:07 #92779
Dave Milbourn
Participant
@davemilbourn48782
MFA show a speed of over 14000 RPM at 12v, which is way too fast for a narrowboat. It doesn't show a stall current for that voltage but it does for 6v (8.4A). I'd suggest using a 540LN instead. MFA's website is here MFA Como Drills

The tab you need is Miniature DC Motors.

Dave M
19 December 2020 at 23:40 #92781
Charles Oates
Participant
@charlesoates31738
Hi Stephen,, not all that long ago that motor was a popular choice in a fast electric model. Even if you used the throttle gently your narrow boat would be horrible to sail. Follow Dave's advice and you'll be fine, the motor is very inexpensive. Narrow boats need very little power to sail well. Re the fuse, I would still fit one, but It's not essential with the LN motor. A car type blade fuse is the simplest to use, they can be connected with slip on connector's. 10 amp would be my first choice, but I'm guessing about the voltage you're using, 7.2 volts? you could change to a 15 amp one needed.

There was a picture posted recently of a very neat installation with a similar fuse used, one of Colin's I think, I'll have a look for you.

Charles.
20 December 2020 at 09:32 #92783
Colin Bishop
Moderator
@colinbishop34627
You can see it below. Two standard spade connectors attached to an automotive fuse. (towards the top right of the image) Click on the image for a larger view.

Colin

Edited By Colin Bishop on 20/12/2020 09:34:19
20 December 2020 at 09:40 #92784
Charles Oates
Participant
@charlesoates31738
That's saved me a search. I forgot to say, the L N motor is the same physical size as the motor you have, so no problems with installing it.

Charles
20 December 2020 at 17:44 #92792
Stephen Garrad
Participant
@stephengarrad28964
Thanks very much Dave, Colin & Charles for your help & guidance with this. The motor I have came with the model kit & so is what I have fitted but based on your suggestions I have ordered a 540LN, as you say they are not expensive. It will be interesting for me to see the difference in performance of the boat. Grandson & I were planning a maiden voyage on Boxing day but sadly that has now gone by the board.

That's a very neat installation in the picture, much tidier than mine, I can see the fuse, I can do the same. I have all I'll need & a proper crimper on our real narrow boat.

I have been thinking about the next model:**LINK**

a 37ft Oakley Lifeboat which I used to be involved with in Ilfracombe a long time ago. I haven't been in touch with the website yet, do you have any experience of those models, are they static or RC?

Thanks again for your help.

Stephen
30 December 2020 at 22:18 #92932
Stephen Garrad
Participant
@stephengarrad28964
We had the maiden voyage Christmas day afternoon when grandson visited, was a complete success till son in law fell in the canal at the back of our house. Grandson (9yrs) had a good laugh and carried on.

The new 540LN motor that Dave suggested would be more suitable came Christmas eve & was fitted & was fine. Minor panic when I found the drive shaft was about 5mm shorter than the old motor so needed a bit of tweaking. The old motor was fitted with what I now know is an RF suppressor, the new one isn't, is that a problem, what effect will that have on anything?

Did anyone have any thoughts about the Tony Green lifeboat model as the next project?

Just out of interest, in Colin's picture, what is the bit which appears to be suspended on elastic string but connected to nothing?

Thanks for all your help

Stephen
30 December 2020 at 22:34 #92933
Colin Bishop
Moderator
@colinbishop34627
That's the receiver. The connections come out of the back close to the bulkhead. One goes to the rudder servo in the stern (you can just see it just to the right of the battery), the other (black/red/white) comes down to the speed control which is mounted under the side deck and also supplies the receiver with power.

Colin
31 December 2020 at 11:04 #92935
Malcolm Frary
Participant
@malcolmfrary95515
Modern 2G4 radios are allegedly immune to radio interference, and will remain so until some creative soul manages to do it. But that only covers interfering signals entering the system via the radio. A big enough signal can be picked up by wire going to any electronic devices. ESCs can give stuttering or uncontrolled motors, servos can twitch.

Suppressors can keep the interfering signals that the motor generates within the motor, where they are harmless. If checking the new motor shows that the terminals have a thin wire vanishing into the insides of the motor, they may be already fitted.

While your boats radio might be unaffected, there is a chance that somebody else with an older radio sailing near to your boat could be affected.
31 December 2020 at 17:41 #92947
Dave Cooper 6
Participant
@davecooper6
Just to add a little to the radio interference bit : my vintage RAF launch has a 380/385 motor and operates with a 'Bob's Board' (old-fashioned ESC substitute !) and 27MHz radio.

I was concerned about keeping the RF side clean so, fitted a RF choke to each motor terminal and put a capacitor across the terminals as well. I also ran a short lead from the motor canister to the prop. shaft outer. This may be overkill but it certainly works…

Values for the chokes (miniature coils) and capacitor network are not too critical but will be in the "micro-henry" and "micro-farad" range. A quick Google search of someone like RS Components should provide something suitable.

I think you'd have to be unlucky to be troubled with 2.4GHz kit, but, we have had the odd bit of interference with our electric gliders in the recent past.

Dave C
2 January 2021 at 21:56 #92994
Stephen Garrad
Participant
@stephengarrad28964
Thanks again for all of you for your help. I've had a look at the new motor, there doesn't appear to be any thin wires from the terminals disappearing into the motor. I didn't notice any stuttering from the ESC or twitching servo on the maiden voyage Christmas Day but I'll keep an eye out for it. If there is a problem I'll need to come back for some more specific advice about what I need to get & what to do with it.

Thanks again.

Stephen
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