S4-9?

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zebedeesknees
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S4-9?

Postby zebedeesknees » Sun Sep 13, 2020 4:12 pm

I found MRJ 279 most inspiring, particularly the 2mm and 3mm scale articles. It was an amazing 14 years ago when learning about belt drives from Nigel Lawton that he supplied and I built a 9mm gauge 40hp Simplex.

model Simplex 006.JPG


When David Knight asked me about r/c for 'Christine', I was reluctant to open her up, but looked at the Simplex.

Since then, Micron has withdrawn the Rx6x series of receivers due to impending component updates, so I looked at the Rx45:-

Rx45detail.jpg


That's one, on the nail of my little finger. That, and the 8 x 16mm batteries sourced by David Catton inspired me to fit r/c to the Simplex. The other thought festering has been the ready availability of 5 volt DC supplies for USB charging of mobile phones and tablets. These use a variety of the single cell Li-Po batteries that have previously been mentioned..

The small batteries with the clear wrap over the control circuit are generally 1C, meaning that they both charge and discharge at their stated capacity, so the 8 X 16 at 60mAh will supply 60mA for an hour, and take an hour to charge on a 60mA supply. It fits comfortably on the chassis under one bonnet end. When discharged down to approximately 3.2volts, the internal circuit switches the output off, protecting the cell.

The Simplex chassis was built with pickups of guitar string spring wire, and the axle holes enlarged downwards a little, to provide a small degree of suspension, within the limits of the gear mesh. The wires are mounted on Bill Bedford bearing carrier units, glued to a piece of 'U' section poly.

Not wishing to have to worry about track polarity, a small pcb carrying a Schottky bridge rectifier and the battery was introduced into the original pickup supply, and a Micron Rx45 wired between that and the motor.

model Simplex 002.JPG


That's all that is needed. Rectifier, battery and radio receiver. (And transmitter of course) No switches, sockets or programming tracks. The loco runs most of the time picking up from the track, with the battery providing a 'stay alive', charging at the same time. Fully charged, it will run for up to an hour depending on the current drawn by the motor and Rx, without track power. The battery can be safely left to discharge after use, and will 'wake up' quickly when power is restored to the pickups.

If it were to be used on 12vDC tracks, or on DCC 16vAC ones, there is room to fit an AMS1117-5 or equivalent voltage regulator next to, and electrically after the bridge.

Ted.

David Knight
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Re: S4-9?

Postby David Knight » Sun Sep 13, 2020 5:14 pm

Well, I’m impressed. That certainly qualifies as “small” Ted and with all the bits fitting inside to boot. Thank you.

Cheers,

David

PS Those “chopper” style couplings look the part for narrow gauge. Whose are they?

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zebedeesknees
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Re: S4-9?

Postby zebedeesknees » Mon Sep 14, 2020 11:00 am

David Knight wrote:Well, I’m impressed. That certainly qualifies as “small” Ted and with all the bits fitting inside to boot. Thank you.

PS Those “chopper” style couplings look the part for narrow gauge. Whose are they?


Thank you, David.

I am a complete innocent* when it comes to narrow gauge, both prototype and model, so have to confess that I am at the horizontal bottom level of that learning curve. I can only suggest that the couplings came with the Simplex kit. That is from Meridian Models of Benfleet, Essex No. MM15, but they don't appear to be trading now, some of the products are available from Narrow Planet and/or Dundas Models.

The instructions I have with the kit do not mention these couplings, nor are they shown on the etch pictures of the chassis kit MPD 18 from the same place. Nigel's site mentions a Mk2 chassis which uses ball races on the layshaft, but I haven't seen one of those. I have a second Mk1 chassis with a Billard T75 body, and have fitted 3mm od races with a 1mm layshaft on that one. No pickups fitted or battery for it yet.

I need to learn a lot more about modelling narrow gauge! My research so far has found the Corris was 2' 3" gauge, and the Society code 55 fb rail should suit, soldered direct onto copper clad. (?) No decision about stock or couplings yet, nor wheel standards. The N gauge wheels with the kit are under 2mm thick, but look 'orrible..

Membership of the 2mm Scale Association initiated.

Cheers!

Ted.
*Other descriptions are available...

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Tim V
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Re: S4-9?

Postby Tim V » Mon Sep 14, 2020 1:19 pm

The 2mm Association rail is too thin (across the head) for narrow gauge.

You could look for PECO code 40 rail which gives a much better section for narrow gauge rail.
Tim V
Scalefour News Editor

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zebedeesknees
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Re: S4-9?

Postby zebedeesknees » Mon Sep 14, 2020 4:51 pm

Tim V wrote:The 2mm Association rail is too thin (across the head) for narrow gauge.

You could look for PECO code 40 rail which gives a much better section for narrow gauge rail.


Thanks Tim, I wasn't intending to buy rail from the 2mm SA, but there are other bits that would be useful. I was hoping to use the Society's code 55 flat bottom from our stores as I mentioned earlier (below). Is there a reason for not using that?

Ted.

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Tim V
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Re: S4-9?

Postby Tim V » Mon Sep 14, 2020 6:20 pm

Code 55 is massively heavy for NG work. Referring to D A Boreham's work 'Narrow gauge railway modelling' he quotes the Southwold Railway rail section. 3" high, 3" across the lower foot, the running head of 1⅝" wide with a weight of 30lb per yard.

Unless you're building current Welsh Highland?
Tim V
Scalefour News Editor

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Horsetan
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Re: S4-9?

Postby Horsetan » Mon Sep 14, 2020 10:12 pm

David Knight wrote:....Those “chopper” style couplings look the part for narrow gauge. Whose are they?


A fret of chopper couplings can be obtained from Branchlines nowadays. Either five or five pairs per pack.
That would be an ecumenical matter.

David Knight
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Re: S4-9?

Postby David Knight » Tue Sep 15, 2020 1:08 am

Horsetan wrote:
David Knight wrote:....Those “chopper” style couplings look the part for narrow gauge. Whose are they?


A fret of chopper couplings can be obtained from Branchlines nowadays. Either five or five pairs per pack.


Thanks Ivan. They look the part, I just wonder how practical they would be for operating.

Cheers,

David

dal-t
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Re: S4-9?

Postby dal-t » Tue Sep 15, 2020 7:18 pm

Not very. For me, the prime requirements of a coupling are (a) couple up readily, (b) stay coupled when you want them to, and (c) uncouple reliably when you want them to. The Meridian choppers meet (a) and (c) fine (using a simple 00-9 push-up uncoupling ramp for (c), that also operates Bemo hook-and-loops), but unfortunately they fail (b). I was surprised, and disappointed, when my first pair (or should that be first and second - I fitted them to about six wagons before finding the problem) pulled apart without obvious provocation, and quite disappointed, because they certainly do look the part, and there's a definite attraction in the little hooks popping up and dropping down in operation (except half-way along the back end of the layout just before the real gradient starts). Of course, this could have been due to my incompetence in fitting them, or the appalling quality of my tracklaying, or just ham-fisted operation, but it didn't seem so at the time. Also, they may have been through improvements over the years - as I recall (but don't immediately have the time to rootle through boxes of old NG components to check) there were two versions, and i only had one of them. Maybe the other one always was better ...
David L-T

Terry Bendall
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Re: S4-9?

Postby Terry Bendall » Thu Sep 17, 2020 8:57 am

Tim V wrote:Code 55 is massively heavy for NG work


The weight of rail used on NG railways will vary, just as it dies on the main line. The Leighton Buzzard Railway now uses either 35 lb rail or 40 lb rail although much lighter rail was used when it was first laid in 1919. Flat bottom rail is used throughout. None of the lighter stuff - probably 25 lb, left now except in the museum collection. A piece of 30 lb rail I have just measured is 3 inches wide at the bottom web, 3 inches high and 1 1/2 inched on the head.

Terry Bendall


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