Mitchell Castle battery/radio control

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JackBlack
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Mitchell Castle battery/radio control

Postby JackBlack » Sat Dec 14, 2019 10:39 pm

I'm going to build 4094 Dynevor Castle from a Mitchell kit that I bought from eBay about 18 months ago. The box included a 4000 gallon tender. I've never actually built a tender locomotive, although I have a couple half-built. So this is going to be a voyage of discovery...

It will carry the battery in the tender, which will also have a switch somewhere, and the charging socket. The loco will contain a DT RX63 receiver, and the chunkiest 4v motor that I can get in there.

Starting with the tender, the chassis comes with two sets of frames, so I set up a simple csb using the spare frames to make the inside chassis, using High Level hornblocks and carriers.

IMG_20191208_134315076.jpg


I then put the internal box of the tender body together so I could see what size battery I could fit in there. The biggest battery we currently have is the 18650 (18mm by 65mm), it fits perfectly!

IMG_20191208_134245809_HDR.jpg


The 18650 outputs 3.7v and is rated at 3800mAh, so should keep a loco running continuously for probably a weekend. We shall have to see. The battery has been fitted with a charging protection strip and charges exactly the same way as the other lipo batteries we use. Here it is pictured next to the largest 4v motor we've been looking at.

IMG_20191208_134228048.jpg


I'm not certain I can actually get this motor into the Castle without some fairly invasive surgery, so I may go with the Mabuchi FF50. In the meantime, basic tender looks like it'll work. The rest is cosmetic and will keep me occupied this week...

IMG_20191208_134542069.jpg


Cheers, Nick

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JackBlack
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Re: Mitchell Castle battery/radio control

Postby JackBlack » Wed Dec 18, 2019 9:32 am

A little bit of progress.

The main Castle chassis has gone together with no drama. CSB as usual with High Level horn blocks and carriers. Some minor modifications needed to the spacers but nothing too drastic. As I'm driving the centre axle I needed to move the centre spacer forward a bit. I will solder that in place once I have the motion bracket and cylinder assembly built. I've then put together most of the body...

IMG_20191216_092116224.jpg


IMG_20191216_190800360.jpg


After attaching the splasher tops (my most hated job), it became apparent that I can make the changes required to fit the larger motor. This involved opening a hole in the bottom of the back of the boiler and removing the bottom of the front of the firebox. It's been a bit nerve-wracking especially as this is an irreplaceable kit. But hopefully it will all work. The modifications will be hidden by the splashers...

IMG_20191218_090214851.jpg


IMG_20191218_090225568.jpg


IMG_20191218_090324022.jpg


I've had to make a new fixing plate for the motor, which has 12mm spacing holes - I modified the gearbox to accommodate this, and I've had to file a small dip in the tops of the chassis sides to allow for the shoulder of the motor. Once I put the brake wires in place the one under the motor will keep it at the correct angle.

I can now continue and finish the body and the tender over the next few days. I intended to get the coupling rods put together and the driving wheels mounted, but then I realised I left the crank pins in London... :cry:

Onwards and upwards...

Cheers, Nick
Last edited by JackBlack on Wed Dec 18, 2019 5:42 pm, edited 1 time in total.

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JackBlack
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Re: Mitchell Castle battery/radio control

Postby JackBlack » Wed Dec 18, 2019 12:00 pm

Someone has asked, so just adding the link to the motor I'm using here:

GEE FF180

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JackBlack
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Re: Mitchell Castle battery/radio control

Postby JackBlack » Mon Dec 30, 2019 1:14 pm

Hi folks,

A quick update, as things are progressing slowly but steadily on my Castle project. As I mentioned on one of the other R/C threads, I wanted to tidy up how the various components connect together. So far I have been using small stripboard pieces with components either soldered to them, or connected via 14BA nuts and bolts. It's a bit fiddly and doesn't look too tidy.

On this new project I'm using 1.7mm micro plugs and sockets, two pin and four pin. I've ordered them from eBay Here and Here, around £3 for a bag of 50. As well as the heat-shrink (0.6mm, 1mm and 4mm) from Here.

We use fine silicon sleeved wire to connect everything, again from eBay Here - £1.79 for 5m. It's really nice to work with.

The various components all plug together so can be changed out really easily, and all come together into a 4-pin plug and socket - a hub that connects everything correctly. I've used different coloured paint blobs to indicate to myself what goes where, but in future we can use different coloured heat shrink to indicate what connects to what.

IMG_20191228_145442919.jpg


IMG_20191228_145710722.jpg


Here it is with everything connected, receiver switched on and bound to the transmitter:

IMG_20191228_145747311.jpg


If there was interest we could maybe make something like this available as an r/c starter kit. Plug and play...

Cheers, Nick

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JackBlack
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Re: Mitchell Castle battery/radio control

Postby JackBlack » Wed Jan 01, 2020 4:22 pm

David Catton very kindly took my badly hand-drawn sketch and turned it into a nice circuit diagram showing the components and connectors, that anyone can understand (hopefully).

So the above RC connections I've put together for the Castle are like this:

Wiring-Diagram.jpg
Wiring-Diagram.jpg (37.25 KiB) Viewed 1140 times


And were you using a 12v motor and needed a booster, this would be the diagram:

Wiring-Diagram-Booster.jpg
Wiring-Diagram-Booster.jpg (44.6 KiB) Viewed 1140 times


And here's both in one PDF:

Schematic Wiring Diagram for RC.pdf
(33.07 KiB) Downloaded 15 times


Cheers! Nick

David Catton
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Joined: Fri Mar 13, 2009 7:23 pm

Re: Mitchell Castle battery/radio control

Postby David Catton » Wed Jan 01, 2020 6:29 pm

Unfortunately, I allowed a little glitch in the second (with booster) one to escape my attention. The positive (red) lead from the charging socket should be a tad over to the right so that it connects to the wire from the connecting plug and socket, as the black (negative) one just below it does. I've attached the corrected version.

HTH avoid any problems.

Happy New Year!

David C
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Schematic Wiring Diagram for RC.pdf
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nigelcliffe
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Re: Mitchell Castle battery/radio control

Postby nigelcliffe » Wed Jan 01, 2020 6:32 pm

I'd have used a slightly different switch arrangement - a SPDT (aka "changeover! switch), so that in one position it would connect the charging +ve to the battery, and in the other position connect the battery to the receiver(and rest of loco). Thus the loco must be turned off in order for the charging to be connected.

May be a bit of "belt+braces", but relatively simple to do, and thus certain what's connected and what is not connected.


- Nigel

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JackBlack
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Re: Mitchell Castle battery/radio control

Postby JackBlack » Thu Jan 02, 2020 11:12 am

nigelcliffe wrote:I'd have used a slightly different switch arrangement - a SPDT (aka "changeover! switch), so that in one position it would connect the charging +ve to the battery, and in the other position connect the battery to the receiver(and rest of loco). Thus the loco must be turned off in order for the charging to be connected.


The switches that we use are SPDT so could certainly be set up for this. Personally for me it's not been an issue because I only switch a loco on when I'm running it, so when charging it's switched off. It would need a three pin connector for the switch, not sure how much that would complicate the circuit.

Also, I'm not sure how that would affect folks wanting to charge from the track. I'd need to defer to my colleagues, but I think you can charge the battery while running (I could be wrong on this though...).

We're also looking at making polarised connectors, so that it's not possible to inadvertently connect the battery the wrong way around and fry the RX, which is possible with the current set-up. They can be made up using two sockets and the pins from one plug:

Polarised-Connectors.jpg
Polarised-Connectors.jpg (60.06 KiB) Viewed 1039 times


Thanks, Nick

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JackBlack
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Re: Mitchell Castle battery/radio control

Postby JackBlack » Fri Jan 10, 2020 9:36 am

I'm slowly plodding away with this, work gets in the way unfortunately...

The last few days I've undercoated and painted the tender. For the first time I've used acrylic paints on a locomotive. I did a bit of trawling around online to see if anyone had matched Vallejo acrylics to Great Western colours and found an old post on RMWeb. It seems that 71.022 is a match for loco green, this is RLM82 Hellgrun. I put a blob onto a piece of card and compared it to a blob of Precision GWR Loco green and it looked good, if a little light. When I came to apply the green I darkened it 1 drop of black to 5 drops of green - the little Vallejo bottles make it easy to fairly accurately mix colours...

Undercoated with Halfords grey primer and then black areas done, plus some pre-shading of rivet lines...

IMG_20200109_141429_107.jpg


IMG_20200109_141429_073.jpg


Then the green...

IMG_20200109_141429_071.jpg


IMG_20200109_140242604.jpg


And finally applying the decals...

IMG_20200109_221505_633.jpg


IMG_20200109_221505_635.jpg


It's difficult to see the colour in these photos, but it looks good compared with my locos sprayed with the enamels. Airbrushing with acrylics is so much easier, especially now that I've started using the Vallejo Airbrush Flow Improver as a thinner, it has a retarder that means the paint doesn't dry so fast, which has always been my bugbear with acrylics - I like to take my time when airbrushing and enamels allow you to do that, acrylics dry fast and clog the needle. I've used Golden Airbrush Medium before, which was okay, but not as good as this Vallejo stuff.

Next I'm going to add the coal load and then do my weathering with oils...

Cheers, Nick

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Le Corbusier
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Re: Mitchell Castle battery/radio control

Postby Le Corbusier » Fri Jan 10, 2020 12:52 pm

Lovely work Nick ... the tender will have to have a very full load of coal given the battery size :thumb
Tim Lee

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JackBlack
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Re: Mitchell Castle battery/radio control

Postby JackBlack » Fri Jan 10, 2020 1:14 pm

Le Corbusier wrote:the tender will have to have a very full load of coal given the battery size :thumb


Yes indeed. I was a bit worried about how I was going to make that work. I want the big battery, but I also don't want to compromise on how the model looks. But I think it works:

IMG_20200110_130939648.jpg


While I wait for that to dry I'm going to amuse myself painting some lovely crew figures from Modelu. I'm so impressed with the quality these guys are producing!

Cheers, Nick

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Le Corbusier
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Re: Mitchell Castle battery/radio control

Postby Le Corbusier » Fri Jan 10, 2020 1:59 pm

That looks very convincing ... and not overly full. Look forward to seeing the Crew :thumb
Tim Lee

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JackBlack
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Re: Mitchell Castle battery/radio control

Postby JackBlack » Thu Feb 13, 2020 12:30 pm

Hi folks,

I had an extended stay in Portugal mainly for domestic reasons, so a bit of delay in updates.

I'm parking the Castle for now while a couple of my more learned colleagues look at a way of springing the bogie (and other 2-4-0 loco bogies).

IMG_20200213_120458314.jpg


I have moved onto a new project and I'll start another post about that later on...

Cheers, Nick


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