Advice for a novice

[Tom IsaacParticipant @tomisaac25702]

Hi Guys,

Although I have built a few boat kits over the years, these have always been for static display. I have now decided to make my next project a motorised one. I have aquired the plans to scratch build a 1/24 Narrowboat.

I am reasonably happy about the radio set I’m going to use but, despite reading everything I can find about the choice of motor, propeller & shaft, speed controller, power pack etc – I am none the wiser, in fact I’m more confused than I was before I started researching.

Can anyone suggest what would be a sensible installation. As you would expect with a working narrowboat, space is going to be tight.

Many thanks

Tom

[Penny LeeParticipant @pennylee76979]

Hi Tom,

I made a 4" wide 3 foot scratch destroyer and a 385 motor did the trick.You can replace the standard servo with a mini servo if neccessary.

A 385 or cassette tape motor and the smallest separate prop (15-20mm 3 blade shallow pitch) should do. Don’t go for a 380 or a geared 380 combo as that is too much. Don’t use a medim to large prop as a 385 has a low torque.

Hold the speed control until you decide on your drive voltage and if you want to use a receiver/rudder battery or a speed control with a 5 volt BEC output (a minimum input voltage is required).

If four to six AA NiMh pencells in a battery clip gives sufficient propulsion then a very inexpensive small speed control will handle a stalled 385 or cassette motor.

If you use a 385 or cassette motor you can reliably use a speed control with 5volt BEC (battery elimination)with a drive battery as low as 6-cell (7.2 nominal) and dispense with a receiver battery.BEC operation requires a minimum input voltage.

If space permits use a separate receiver battery (You can get 1/3 AA or AAA metal hydride batteries at 500mAh) That gives better radio reception and you don’t need to have a 6+ cell drive battery.

Regards,

Lee Penny

[ashley needhamParticipant @ashleyneedham69188]

Yup, I would go for an MFA 385 motor. Great little motor and of low current consumption.  I use a pair to drive my fat heavy 1880 battleship with 40mm props on 6v and they cope manfully, and it fairly zooms along on 12v – in a most un-scale but satisfactorally yobbish manner . It may be argued that 40mm props are overloading it a touch, but I have never had a prolem, the motors stay cool and I still get over an hours running on a 6v 4.5 Ahr battery. I think this motor could cope with a 30mm brass prop on your canal boat no probs on 6v, I alway go brass, as plastic ones are rubbish in reverse (compared to a brass prop) , an important factor on the pond. Given the relate low cost of these items, personally I would leave room for, say, up to a 40mm prop size and you can fiddle around with different props later on. Use a standard 4mm size prop tube/shaft and the world is your oyster as to trying out props. I would NOT recomend a 2mm shaft, usually advertised as suitable for lightweight boats, as there is a very small chioce of propellor in this shaft size. I would also use a proper solid coupling and not a bit of plastic tube. I have recently tried  the plastic onesa from SHG marine and they seem to be ok, cheap and short, considering the wide range of alignment that they give.    Ashley

[Tom IsaacParticipant @tomisaac25702]

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