HMS Norfolk Electrics Page 2


I had a SENIOR MOMENT when installing a Robbe switch module as I had presumed that the input voltage was the same as the one pictured on the left. This was a high powered unit 4.8 to 24 volts. BUT IT WAS NOT. It was only 4.8 to 6 volts and my being a SILLY OLD SOD I put 12 volts through it and that cost me £109.00. OH WHAT A PRATT you would say. But it happens when your mind is trying to do too many things.

Lower supply wiring and 12 volt BECs

The wiring looks in a muddle but it is not.
I used 2 x 6 way high quality stainless steel leaf strip connectors as these would not cut or shred the wires. There are about a hundred metres of wire aboard the model. I have used a spiral wire tidy as this makes it less messy. Forward of the connector strips is an extra plinth holding a 4-way strip connector supplying 12 volt power through a ribbon cable, then onward to the twin heat sinks, each containing two BECs. Also I installed a 4-way strip connector for the 5-volt supply to the forward RX and the aft RX including other modules. The reason I have put in two extra BECs is in case one goes down when attempting a record and I would be extremely MIFFED indeed if that happened! The searchlights that will be installed on the bridge wings and halfway back on the lower wings of the smokestack will be using the normal 12-volt supply. Instead of using grain of wheat bulbs I will be using ultra bright white LEDs and I will be inserting 470-ohm resistors for the LEDs.


Battery Compartment and Wiring


 These then feed the FR15HX-AN Electronize Speed Controllers. These use Power MOSFET`s that are more efficent type of transistors. You can use a supply of 6 to 24 volts and as you know when using 24 volt batteries that are fully charged will give up to 26 volts. These speed controllers survived 24 hours in apalling weather conditions on the River Waveny on 20th & 21st June 2013 enabling us to complete 101 miles.


We originally used two heavy duty German electric motors but we found that they could only rev to 1800 rpm so we bought High Quality British made. These were 24volt DC electric motors and would rev to 4000 rpm and these were made by Parvalux.

Build 22

I made an aluminium plate for each of the motors and attached them to a strong aluminium bar with medium size rubber mountings.
We used large industrial plastic couplings with 5/16" x 1/4" reducer bushes to connect onto the 1/4" stainless steel propeller shafts. I made up a partition plate as this would protect our little pinkies. This I attached with a magnetic catch.
 I also made a roof plate with a 12 volt 92mm fan inserted. This may have to be larger but we will see. The fan was sucking out but the motors became too hot as there was no circulation of air and I have reversed the fan to blow down onto the motors.
I have now bought two heat sensors to make sure that I have better cooling. Peter has now cut an extra long vent in the rear of the hanger top;also an extra partition to stop the warm air getting back down to the motors. I am in the process of making more vents in the said hanger.
I will also have to insert a partition between the warm air outlet to prevent the speed controllers overheating.


At the moment I am making two water jackets from 3/16" x 20 gauge copper tubing. I bent the copper on my small vice which had a bending former attached to it. Also the middle was made out of 7/32" brass tubing which I silver soldered together. It was a little difficult to make. I then used plumbing solder to attach the pipes to thin brass sheet which I bent around the electric motor as a former and to protect the tubing I am soldering a thin strip of brass to the top of the pipes, so when holding them down to the motor with a stainless steel jubilee clip it will not crush them.

The above was a prototype as it turned out they were to heavy. So I cut out all pipes and bends again and this time I used 25mm x 0.5mm thin brass strip for the top and bottom. Plus I silver solder every joint, this also looked much better and much lighter. To silver solder it all was quite difficult to do so a little thought is needed before you start.

I inserted two pick ups in front of the 75mm props to pick up the water for my rads that were on the the 24 volt motors.